Zoonotic Diseases


The table in this chapter lists zoonotic bacterial, viral, fungal, and parasitic diseases, grouped by category. Many proven zoonoses, including some diseases that are rare in humans, organisms that are maintained primarily in humans, some primate diseases, and diseases caused by fish and reptile toxins have been omitted. The table is intended to give a general clinical picture of each disease; current medical texts or review articles should be consulted for a more complete description. Clinical signs are listed; asymptomatic infections can also be assumed to occur in most cases. An indication of the mortality rate among healthy individuals has been provided for many infections. However, there is almost always a chance of death whenever lesions can become generalized, vital organs may be affected, secondary infections occur, and/or the patient is immunosuppressed. The mortality rate is often influenced by the availability of medical care, and it is generally lower where advanced medical support is available. The risk of death from some Bacterial Diseases with high mortality rates can be nearly eliminated with prompt antibiotic treatment.

If a disease is known to have unusual manifestations or to be particularly common and/or severe in immunocompromised persons, this has been noted. In addition to these diseases, many pathogens can cause more severe disease and/or unusual signs in immunocompromised patients. Information on the geographic range of an organism should be taken as a rough guide. The precise ranges of many pathogens have not been completely determined. Organisms may also expand their range or be eradicated from areas where they were once abundant.


Table 1


Global Zoonoses a


Causative Organism

Principal Animals Involved

Known Distribution

Probable Means of Spread to Humans

Clinical Manifestations in Humans


Bacterial Diseases

Actinomycosis (see Actinomycosis)

Actinomyces bovis and other species are zoonotic; most human infections are caused by commensals of humans, especially, Actinomyces israelii


Worldwide; very rare in humans

Probably contact; actinomycosis usually disseminates from endogenous flora

Granulomas, abscesses, skin lesions; chronic bronchopneuomonia; abdominal mass that may mimic a tumor; endocarditis; sepsis

Anthrax (see Anthrax)

Bacillus anthracis

Mainly in cattle, sheep, goats, horses, wild herbivorous animals; virtually all mammals and some birds are susceptible to high dose

Worldwide but distribution is focal; common in Africa, Asia, South America, Middle East, parts of Europe

Occupational contact exposure (abraded skin, mechanical transmission by biting flies, other routes); ingestion/foodborne, rarely airborne; early signs vary with route of inoculation

Ulcerative skin lesions; mild to severe gastroenteritis ± hematemesis, bloody diarrhea, ascites (abdominal GI form); sore throat, dysphagia, fever, neck swelling, mouth lesions (oropharyngeal GI form); pneumonia; all may progress to sepsis, meningitis; untreated cases fatal in 5–20% (cutaneous) to 100% (inhalation)

Arcobacter infections

Arcobacter butzleri, A cryaerophilus, A skirrowii, possibly others

Poultry, cattle, pigs, sheep, horses


Ingestion of contaminated water, undercooked meat (especially poultry) has been suggested

Gastroenteritis; bacteremia, mainly in patients with chronic illnesses; fatal acute respiratory distress, DIC, renal failure in a healthy child (1 case). Emerging, incompletely understood

Bordetellosis (see Respiratory Diseases of Pigs, see Respiratory Diseases of Small Animals: Infectious Tracheobronchitis of Dogs)

Bordetella bronchiseptica

Dogs, rabbits, pigs, guinea pigs, other mammals

Worldwide; rare in humans

Exposure to saliva or sputum, aerosols

Sinusitis, bronchitis, pertussis-like illness; pneumonia and disseminated disease, usually in immunocompromised

Borreliosis (see Lyme Borreliosis)


—Lyme disease

Borrelia burgdorferi sensu lato complex (B burgdorferi sensu stricto, B garinii, B afzelii, B japonica)

Wild rodents, insectivores, hedgehogs, hares, deer, other mammals, birds

Worldwide where Ixodes ticks are found

Ixodes spp bites

Fever, headache, malaise and other nonspecific signs early; target skin lesions in many; may progress to arthritis, neurologic and/or cardiac signs

—Tickborne relapsing fever

B recurrentis, B crocidurae, B turicatae, B hermsii, B persica, B hispanica, others; some species such as B duttoni are human pathogens and not zoonotic

Wild rodents, insectivores, possibly birds

Africa, Asia, Europe, Americas; species varies with region

Tick bites (mainly Ornithodoros spp)

High fever, malaise, headache, myalgia, chills; neurologic signs or abortion possible; recurring episodes, often milder, after a symptom-free period; death in 2–5%

—Southern tick-associated rash illness

B lonestari implicated

Deer, birds implicated

USA; most cases in southeast

Tick (Amblyomma americanum) bite

Resembles Lyme disease

Brucellosis (see Brucellosis in Large Animals, see Brucellosis in Dogs)

Brucella abortus

Cattle, bison, water buffalo, African buffalo, elk, camels; other mammalian spillover hosts

Once worldwide, now eradicated from some countries or regions; reservoirs in wildlife in some disease-free areas

Ingestion (especially unpasteurized dairy products), contact with mucous membranes and broken skin; strain 19 vaccine

Extremely variable, subacute and undulant to sepsis; often nonspecific febrile illness with drenching sweats early; arthritis, spondylitis, epididymoorchitis, endocarditis, neurologic, other syndromes if chronic; case fatality 5% in untreated


B melitensis

Goats, sheep; other mammalian spillover hosts

Asia, Africa, Middle East, Mexico, Central and South America, some parts of Europe

Ingestion (including unpasteurized dairy products), contact with mucous membranes and broken skin; rev-1 vaccine

As above; this species is highly pathogenic for humans


B suis biovars 1–4; biovar 5 has not been reported in humans

Swine and wild pigs (biovars 1, 2, 3); European hares (biovar 2), reindeer and caribou (biovar 4)

Biovars 1 and 3 worldwide in swine-raising regions except eradicated from domestic pigs in North America, other countries; Biovar 2 in wild boar in Europe; Biovar 4 in Arctic

Ingestion, direct contact with mucous membranes and broken skin

As above


B canis

Dogs; evidence of infection in wild canids including coyotes

Worldwide; rare in humans

Probably via ingestion or contact with mucous membranes, broken skin; transmission occurs during close contact

As above


B maris; or B pinnipediae and B cetaceae (proposed names; classification uncertain)

Marine mammals

Atlantic, Arctic, and Pacific Oceans; Mediterranean sea

Laboratory exposure; sources of other infections unknown; rare or underdiagnosed in humans

Headache, fatigue, severe sinusitis; neurobrucellosis with headache and chronic neurologic signs; spinal osteomyelitis

Campylobacter enteritis (see Enteric Campylobacteriosis)

Campylobacter jejuni, C coli, occasionally other species

Cattle, swine, poultry, dogs, cats, other mammals, wild birds


Foodborne (especially unpasteurized dairy products); waterborne; contact with animals including dogs, cats with diarrhea

Gastroenteritis, often with malaise, headache, myalgia, arthralgia; typically self-limiting; other syndromes including sepsis are uncommon

Campylobacter fetus infection

Campylobacter fetus

Cattle, sheep, goats


Probably direct contact or ingestion; often unknown; some may be endogenous

Opportunist; sepsis, meningitis, endocarditis, abscesses, other systemic infections in elderly, or immunocompromised, and infants; abortions, preterm births in pregnant women; rarely gastroenteritis, sometimes with bacteremia

Capnocytophaga infection

Capnocytophaga canimorsus, C cynodegmi

Dogs, cats

Probably worldwide

Bites or scratches

Fever, localized infections to sepsis; often in immunocompromised or elderly

Cat scratch disease

Bartonella henselae;Bartonella quintana; B clarridgeiae, other species also implicated rarely

Cats and other felids; other Bartonella spp in canids, rodents, other animals


Scratches, bites, “licks;” exposure to penetrating fomites (barbed wire, crab claws)

Lymphadenopathy, fever, malaise, rash in immunocompetent, usually self-limiting with complications (endocarditis, uveitis, neurologic disease) uncommon; bacteremia, disseminated disease, bacillary angiomatosis in immunosuppressed

Chlamydiosis (see also Psittacosis below)

Chlamydophila abortus, C felis

C abortus sheep, goats, other mammals, green sea turtles, snakes; C felis in cats

C felis worldwide; C abortus in most sheep-raising areas but not Australia or New Zealand

Contact with animals; C abortus probably contact with pregnant or aborting ruminants

Abortions, septicemia (C abortus); keratoconjunctivitis, endocarditis, glomerulonephritis (C felis)

Clostridial diseases (see Clostridial Diseases; see also tetanus, below)

Clostridium difficile; some ribotypes found in animals have been implicated as zoonoses

Ribotypes from some calves, dogs are identical to ribotypes found in humans


Possible zoonosis; from contact or ingestion in contaminated meat



Clostridium perfringens, type A (most common), C, or D

Domestic and wild animals, humans


Foodborne (usually type A); nonfood-associated intestinal infection; wound contaminant, usually environmental; may be endogenous in debilitated from GI or urogenital tract

Foodborne gastroenteritis, usually brief, self-limited except in debilitated; nonfood-related intestinal infection with prolonged diarrhea, sometimes bloody, mainly in elderly after antibiotics; life-threatening necrotic enteritis, often in debilitated; gas gangrene, sepsis; necrotic enteritis, gas gangrene, sepsis are fatal if not treated


C septicumC novyi

Domestic and wild animals, humans


Wound infection, usually from environment; endogenous cases in debilitated via GI or urogenital tract

Gas gangrene; fever, life-threatening necrotic enteritis, often in debilitated; sepsis; gas gangrene, necrotic enteritis, sepsis fatal if not treated

Dermatophilosis (see Dermatophilosis)

Dermatophilus congolensis

Cattle, horses, deer, sheep, goats, other mammals


Usually direct contact with lesions; mechanical transmission on arthropod vectors, fomites possible

Pustular desquamative dermatitis

Enterohemorrhagic Escherichia coli infectionsb

E coli O157:H7; also implicated are types O157:H-, and members of serogroups O26, O103, O111, O145, and others

Especially cattle, sheep; also goats, bison, deer, pigs, other species of mammals, birds


Ingestion of undercooked meat (especially ground beef), vegetables or water contaminated with feces; direct contact with feces or contaminated soil

Diarrhea or hemorrhagic colitis; up to 15% of patients with hemorrhagic colitis progress to hemolytic uremic syndrome (HUS); case fatality rate for HUS is 5–10% in children, up to 50% in elderly

Erysipeloid (see Erysipelothrix rhusiopathiae Infection)

Erysipelothrix rhusiopathiae

Swine, sheep, cattle, rodents, turkeys, pigeons, marine mammals; other domestic and wild mammals, birds, reptiles, fish, mollusks, crustaceans


Contact with animal products; via skin, usually after scratch or puncture wound; contaminated soil (survives for months)

Cellulitis, usually self-limiting, often on hands; arthritis in finger joints common; endocarditis; generalization with sepsis, other syndromes uncommon and often in immunocompromised

Glanders (see Glanders)

Burkholderia mallei

Equids, felids; many other domesticated and wild mammals also susceptible

Middle East, Asia, Africa and South America

Contact with infected animals, tissues through broken skin, mucous membrane; ingestion; inhalation

Mucous membrane or skin lesions; pneumonia and pulmonary abscess; sepsis; chronic abscesses, nodules, ulcers in many organs, weight loss, lymphadenopathy; case fatality rate 20% (localized disease, treated) to > 95% (untreated septicemia)

Helicobacter pullorum infection

Helicobacter pullorum



Ingestion of undercooked poultry suspected

Gastroenteritis or diarrhea, liver disease

Leprosy (see Tuberculosis and other Mycobacterial Infections: Mycobacterial Infections Other than Tuberculosis)

Mycobacterium leprae

Armadillos; nonhuman primates (rare)

Armadillos in parts of southern USA, Mexico; nonhuman primates in Africa, possibly other locations; only human reservoirs in other areas

Transmission of animal leprosy to humans suspected—never confirmed

Various skin lesions, sensory nerve lesions and deficits, nasal mucosal lesions; mild, self-limiting to progressive destruction

Leptospirosis (see Leptospirosis)

Leptospira spp

Domestic and wild animals; reservoir hosts include rodents, dogs, cattle, sheep, pigs, others


Occupational and recreational exposure; especially skin, mucous membrane contact with contaminated urine, infected fetuses or reproductive fluids; water- and foodborne

Asymptomatic to severe, sometimes biphasic; nonspecific febrile illness, rash in first stage; second stage with aseptic meningitis (anicteric form, which is rarely fatal) or pulmonary and cardiac signs, hemorrhages, jaundice/liver disease, renal failure (icteric form, with case fatality rate 5–15%)

Listeriosis (see Listeriosis)

Listeria monocytogenes (types most often associated with disease are ½a, ½b, 4b), Listeria ivanovii (rare)

Numerous mammals, birds, fish, crustaceans


Foodborne, especially unpasteurized dairy products, raw meat and fish, vegetables, processed foods contaminated after processing; ingestion of contaminated water, soil; direct contact with infected animals; nosocomial in hospitals, institution; vertical transmission in newborns

Acute, self-limited febrile gastroenteritis or mild, flu-like illness; ocular disease, conjunctivitis; abortion, premature or septicemic newborn if infected during pregnancy; meningitis, meningoencephalitis, septicemia in elderly, immunosuppressed, and infants; papular or pustular rash +/– fever, chills in healthy adults after handling infected fetuses

Melioidosis (Pseudoglanders, see Melioidosis)

Burkholderia pseudomallei; (other species of soil-associated Burkholderia, such as B oklahomensis sp nov in North America, rarely linked to human infections)

Sheep, goats, swine; occasional cases in many other terrestrial and aquatic mammals; also reptiles, some birds including parrots, tropical fish

Asia, Africa, Australia, South America, Middle East, Caribbean

Wound infection, inhalation, and ingestion; organisms live in soil and surface water; most cases are acquired from the environment, but direct transmission from animals is possible

Mimics many other diseases; acute localized infections including skin lesions, cellulitis, abscesses, corneal ulcers; pulmonary disease, septicemia, internal organ abscesses; often occurs in immunocompromised; case fatality rate varies with form, >90% in untreated septicemia

Methicillin-resistant Staphylococcus aureus (MRSA) infections

Staphylococcus aureus

Horses, dogs, cats, other mammals

Worldwide; rare reverse zoonosis or zoonosis

Usually by direct contact; other routes also described

Opportunist; localized skin and soft tissue infections, invasive disease including septicemia, toxic shock syndrome; mortality varies with syndrome and success in finding antibiotic

Mycobacteriosis (see Tuberculosis and other Mycobacterial Infections)

Mycobacterium avium- intracellulare complex

Many species of mammals, some birds


Environmental, from water and/or soil

Soft tissue and bone infections; lymphadenitis; pulmonary disease, often in immunocompromised or those with pre-existing lung conditions; disseminated in immunocompromised, especially AIDS patients


M avium paratuberculosis

Cattle, sheep, goats, camelids, deer, other ruminants; rabbits and other nonruminants; corvids


Ingestion; accidental injection of vaccine

Postulated involvement in Crohn's disease after ingestion; severe local reaction if vaccine accidentally injected


Mycobacteria other than tuberculosis (includes M simiae, M kansasii, M xenopi, M scrofulaceum, M szulgai, M fortuitum, M chelonae, M marinum, M ulcerans, others)

Cattle, other ruminants; swine, cats, dogs, koalas, other mammals, amphibians, reptiles, fish

Worldwide; distribution varies with the organism

Environmental, from water and/or soil

Same syndromes as M avium -intracellulare complex

Mycoplasma infections

Mycoplasma spp

Livestock, nonhuman primates, marine mammals, cats, dogs, rodents, other mammals

Worldwide; zoonotic infections rare

Direct contact; bites; wound contamination including accidental inoculation

Asymptomatic carriage; cellulitis; other syndromes including respiratory disease, septic arthritis, septicemia have been reported, especially in immunocompromised

Nocardiosis (see Nocardiosis)

Nocardia asteroides, N brasiliensis, N caviae, N otitidiscaviarum, N farcinica, N nova, and others

Cattle, dogs, cats, marine mammals, other domestic and wild mammals; fish

Worldwide; distribution of each species varies

Environmental exposure (inhalation or wound contamination); possibility of transmission in bites, scratches

Pneumonia; skin lesions, cellulitis, abscess, mycetoma; disseminated disease, including cerebral abscesses; many cases occur in immunocompromised

Pasteurellosis (see Pasteurellosis of Sheep and Goats, see Rabbits: Pasteurellosis)

Pasteurella multocida and other species

Many species of animals, especially dogs, cats, and rabbits


Wounds, scratches, bites

Wound infections, cellulitis, osteomyelitis, septic arthritis, sepsis, meningitis

Plague (see Plague)

Yersinia pestis

Rodents including squirrels, prairie dogs, rats are main reservoir; cats, rabbits; > 200 species of mammals susceptible

Foci in North and South America, Asia, Middle East, and Africa

Flea bites, aerosols, handling infected animals (contact with broken skin or mucous membranes), bites or scratches

Febrile flu-like syndrome with swollen, very painful draining lymph node(s) (buboes); pneumonia; sepsis can occur in either bubonic or pneumonic form; case fatality rate in untreated 50–60% (bubonic) to 100% (pneumonic); < 5% mortality if treated early

Psittacosis and ornithosis (see Avian Chlamydiosis)

Chlamydophila psittaci

Psittacine birds (especially parakeets, cockatiels), pigeons, turkeys, ducks, geese, and other domestic or wild birds


Inhalation of respiratory secretions or dried feces

Influenza-like febrile illness with nonproductive cough that may progress to pneumonia, endocarditis, myocarditis, sepsis; case fatality rate 15–20% in untreated, <1% with treatment

Rat bite fever

Streptobacillus moniliformis

Rodents; also transmitted by dogs, cats, ferrets, which are probably infected from rodents


Bites and scratches; handling or kissing a rodent, exposure to rodent urine; can be waterborne or foodborne; aerosol transmission possible

Fever, severe myalgia and joint pain, headache, rash, sometimes GI signs; complications including polyarthritis, hepatitis, endocarditis, focal abscesses, sepsis possible if untreated; overall case fatality rate 10–13% if untreated


Spirillum minus

Rodents; also transmitted by dogs, cats, ferrets, which are probably infected from rodents

Worldwide, but organism is common only in Asia

Mainly bites and scratches

As above, but indurated, often ulcerated lesion at inoculation site; can relapse; some have distinctive rash (large violaceous or reddish macules); polyarthritis is rare; overall case fatality rate 7–10% if untreated

Salmonellosis (see Salmonellosis)

Salmonella enterica and S bongori, (> 2,500 serovars)

Poultry, swine, cattle, horses, dogs, cats, wild mammals and birds, reptiles, amphibians, crustaceans


Foodborne infection or fecal-oral; some cases of occupational and recreational exposure

Gastroenteritis to sepsis; focal infections possible; especially severe in the elderly, young children, or immunocompromised

Streptococcal infections

Streptococcus spp, including S suis, S equi zooepidemicus, S canis, and S iniae

S suis in swine; S equi zooepidemicus in horses; S canis in dogs and other species; S iniae in fish; occasionally in other animals


Ingestion especially of unpasteurized dairy products, pork; direct contact often through broken skin; the human pathogen S pyogenes can also colonize bovine udder and be transmitted in milk

Pharyngitis, cellulitis, pneumonia, meningitis, arthritis, endocarditis, streptococcal toxic shock syndrome, sepsis

Tetanus (see Clostridial Diseases: Tetanus)

Clostridium tetani

Principally herbivores, but all animals may be intestinal carriers


Wound infection and injections; most cases from soil but feces can also contain organism

Muscle spasms and contractions (especially facial), seizures, high mortality; can be localized before generalization; case fatality rate was 90% in USA in 1947, but effective treatment can greatly reduce mortality

Tuberculosis (see alsomycobacteriosis, above, see Tuberculosis and other Mycobacterial Infections, see Tuberculosis.)

Mycobacterium bovis

Cattle, bison, African buffalo, deer, opossums, badgers, kudu can be reservoirs; swine and many other mammals can be spillover hosts

Was once worldwide but eradicated or rare in some countries

Ingestion (unpasteurized dairy products, undercooked meat including bushmeat), inhalation, contamination of breaks in the skin

Skin lesions, cervical lymphadenitis (scrofula), pulmonary disease; genitourinary disease; can affect bones and joints, meninges; gastroenteritis

Tularemia (see Tularemia)

Francisella tularensis Type A (F tularensis tularensis) virulent, type B (F tularensis holarctica) less virulent

Rabbits, rodents, cats, sheep, other mammals, birds, reptiles, fish; often in wild animals

Type A in North America; Type B in North America, Europe, Asia

Contact with mucous membranes, broken skin; insect bites; fomites; ingestion in food or water; inhalation

Fever, headache, malaise; ulcerative skin lesions, pharyngitis, adenitis, conjunctivitis, gastroenteritis, pneumonia, sepsis; case fatality rate 5% (localized disease, untreated) to 35% (untreated typhoidal form)


Vibrio parahaemolyticus

Marine and estuarine shellfish, fish


Ingestion; wound infections

Gastroenteritis; dysentery (especially in some geographic regions); wound infections, especially serious in diabetics; septicemia, usually in immunocompromised or those with liver disease (case fatality rate for sepsis 29%)


V vulnificus

Marine shellfish, shrimp, prawns, fish


Ingestion (often raw oysters); wound infection from water or handling hosts

Wound infections from mild, self-limited lesions, bullae to cellulitis, myositis; necrotizing fasciitis; gastroenteritis; sepsis, usually in immunocrompromised or those with liver disease, other debilitating illnesses (case fatality rate for sepsis >50%)

Vibriosis (continued)

V cholerae O1/O139 (epidemic strains)

Oysters, crabs, shrimp, mussels; most cases acquired from humans

Worldwide; rare/absent to epidemic (in some developing countries); one focus along US Gulf Coast in shellfish


Mild to severe, voluminous diarrhea, vomiting, dehydration; severe cases are deadly if untreated, but low mortality if treated


V cholerae Non-O1/O139 (non-epidemic strains)

Oysters, other seafood


Ingestion; wound infection

Gastroenteritis, usually mild and self-limited; wound infections; septicemia, usually in immunosuppressed or those with liver disease (case fatality rate for sepsis 47–60% or higher


Yersinia pseudotuberculosis

Many species of mammals including swine, dogs, cats, rodents, wild mammals, birds, reptiles

Agent probably worldwide; most human cases in Europe, temperate parts of Asia

Ingestion of water, food (including meat especially pork, vegetables); fecal-oral; dog bite (rare)

Mesenteric adenitis, mimicking appendicitis, gastroenteritis, fever, rash, pharyngitis, “strawberry tongue;” fever, scarlatiniform rash and acute polyarthritis; septicemia (rare), often in elderly or immunocompromised


Y enterocolitica; not all serotypes are pathogenic

Many domestic and wild mammals; some birds, reptiles, amphibians; zoonotic serotypes most common in pigs, dogs, cats



Gastroenteritis with watery diarrhea in young children, bloody stools uncommon; pseudoappendicitis in older children, adolescents; erythema nodosum in adults may follow gastroenteritis; arthritis, sepsis


Rickettsial Diseases

Granulocytic ehrlichiosis

Ehrlichia ewingii

Dogs, possibly deer

Southeastern and south central USA

Ticks including Amblyomma americanum

Few cases described; fever, headache, malaise, myalgia, nausea, vomiting; many patients were immunosuppressed

Human monocytic ehrlichiosis (see Rickettsial Diseases: Ehrlichiosis and Related Infections)

Ehrlichia chaffeensis

Deer, dogs and other canids, goats, lemurs, other mammals may also be reservoirs


Ticks including Amblyomma americanum

Asymptomatic to nonspecific febrile illness, rash; may progress to prolonged fever, renal failure, respiratory distress, hemorrhages, cardiomyopathy, neurologic signs, multiorgan failure; estimated case fatality rate 3% (often in immunosuppressed)

Human granulocytic anaplasmosis (formerly human granulocytic ehrlichiosis)

Anaplasma phagocytophilum (formerly Ehrlichia phagocytophilum and E equi)

Deer, equids, dogs, cats, llamas, cattle, sheep, goats, non-human primates, rodents, rabbits, other mammals; birds


Tick (Ixodes spp) bites

Resembles human monocytic ehrlichiosis; often asymptomatic to mild in immunocompetent; rash uncommon; estimated case fatality rate <1%

Q fever (Query fever, see Q Fever)

Coxiella burnetii

Sheep, cattle, goats, cats, dogs, rodents, other mammals, birds, ticks


Mainly airborne; exposure to placenta, birth tissues, animal excreta; occasionally ingestion (including unpasteurized milk); tick-borne infections probably rare or nonexistent in humans

Febrile influenza-like illness; atypical pneumonia, hepatitis, endocarditis in some; possible pregnancy complications; overall case fatality rate 1–2% if untreated

Sennetsu fever

Neorickettsia sennetsu


Japan, Malaysia, possibly other Asian Countries


Relatively mild, resembles infectious mononucleosis; fever, lymphadenopathy, hepatosplenomegaly malaise, anorexia, sometimes chills, fatigue, myalgia

Spotted fever group of Rickettsia


—African tick bite fever

Rickettsia africae

Cattle, goats

Sub-Saharan Africa, West Indies

Bite of infected tick (mainly Amblyomma hebraeum, A variegatum, also A lepidum, possibly Rhipicephalus decoloratus)

Painful regional lymphadenopathy in many; eschars often multiple; fever common; nuchal myalgia; sometimes sparse and/or vesicular rash; deaths do not seem to occur

—Boutonneuse fever; Tick bite fever; Mediterranean spotted fever

R conorii, related Rickettsia spp

Dogs, rodents, other animals

Europe, Asia, Africa, Middle East

Bite of infected ticks (often Rhipicephalus or Haemaphysalis spp), crushing tick

Eschar may or may not be present; localized lymphadenitis; rash often maculopapular; life-threatening disseminated disease or neurologic signs uncommon; case fatality rate 1–2.5% if untreated

—Fleaborne spotted fever; Cat flea typhus

R felis (synonym ELB agent)

Unknown; emerging disease

North and South America, Europe, Asia, Africa, probably worldwide

Flea bites; has been associated with Ctenocephalides felis (cat flea), C canis (dog flea), Pulex irritans

Few clinical cases have been described but resembles other spotted fevers; eschar, febrile illness, rash; CNS involvement in some

—Queensland tick typhus

R australis

Bandicoots, rodents, possibly dogs


Bite of infected Ixodes tick

Similar to Boutonneuse fever (see above); mild in most, but serious disseminated disease with renal and pulmonary complications, death possible

—Rickettsial pox

R akari

Mice, rats

USA, Africa, Asia, Ukraine, Croatia, Turkey; possibly southern Europe, Central America; rare

Bite of infected rodent mites, Liponyssoides spp

Eschar, febrile illness; vesicular rash, resembles chickenpox; self-limiting

—Rocky Mountain spotted fever (see Rickettsial Diseases: Rocky Mountain Spotted Fever)

R rickettsii

Rabbits, field mice, rats, opossums, squirrels, chipmunks, other small mammals, dogs

Western hemisphere

Bite of infected ticks, especially Dermacentor variabilis, D andersoni in USA; Rhipicephalus spp and Amblyomma spp implicated in Mexico and South America; also from crushing tick

Febrile illness; macular to generalized petechial rash; neurologic, pulmonary, and kidney signs in some; sepsis; gangrene; case fatality rate 15–30% or higher if untreated

—Tickborne lymphadenopathy; Dermacentor-necrosis-erythema-lymphadenopathy

R slovaca

Uncertain; wild boar may be involved

Europe to Central Asia

Bites of infected ticks; especially Dermacentor marginatus, D reticulatus

Eschar, local lymphadenopathy; localized alopecia at bite site; fever and rash uncommon

—Other tickborne species in spotted fever group

R parkeri, R sibirica, R japonica, R honei, R heilongjiangensis, R aeschlimannii, others

Various vertebrates

Worldwide; distribution varies by species

Bites of ixodid (hard) ticks; specific vector varies by species

Inoculation site eschar (most); febrile illness with headache, myalgia, sometimes other signs; rash; local lymphadenopathy (some species); major signs, risk of complications, severity vary with species of Rickettsia

Typhus group of Rickettsia


—Murine typhus; Flea-borne typhus

Rickettsia typhi(R mooseri) and related species

Rats, cats, opposums; other species can also be infected


Infected rodent fleas, possibly cat fleas

Fever, severe headache, central rash, arthralgia, cough, nausea/vomiting; mortality rate 4% without treatment

—Scrub typhus; Chigger-borne rickettsiosis

Orientia tsutsugamushi and related species

Rodents, insectivores

Asia, Australia, islands of southwestern Pacific Ocean; cases are usually concentrated regionally in “typhus islands”

Bite of infected larval trombiculid mites (chiggers)

Eschar in some; rash, headache, fever, painful lymphadenopathy, body aches, interstitial pneumonitis, pneumonia, neurologic signs or cardiac complications in some; mild to severe; convalescence prolonged; case fatality rate 35–50% if untreated


R prowazekii

Flying squirrels

Eastern USA

Squirrel lice or fleas suspected

Fever, headache, muscle aches, rash; GI signs in some; sepsis possible; appears to be somewhat milder than non-zoonotic typhus, which has a mortality rate of 20–40% if untreated


Fungal Diseases

Aspergillosis; Allergic bronchopulmonary aspergillosis (see Aspergillosis)

Aspergillus spp

Birds and mammals


Environmental exposure (decaying vegetation or grains); infection common to humans and animals, insignificant as zoonosis

Allergic respiratory signs, especially in people with asthma or cystic fibrosis; allergic sinusitis; pneumonia with dissemination in immunocompromised (can be fatal); chronic pulmonary disease ± aspergilloma (fungus ball)

Blastomycosis (see Fungal Infections: Blastomycosis)

Blastomyces dermatitidis

Dogs, cats, horses, sea mammals; other mammals

Worldwide; focal distribution

Environmental exposure most common (moist soil); infection common to humans and animals; also reported rarely by animal exposure

Acute to chronic pulmonary disease; skin or bone lesions; meningitis, other syndromes, disseminated disease possible; some cases fatal

Coccidioidomycosis (see Fungal Infections: Coccidioidomycosis)

Coccidioides immitis

Cattle, sheep, horses, llamas, dogs, many other mammals

Southwestern USA, Mexico, Central and South America; in arid or semiarid foci

Principally environmental exposure (inhalation of arthrospores) including fungal cultures; infection common to humans and animals, one unusual case reported after autopsy of horse with disseminated disease

Self-limited febrile flu-like illness, sometimes with cough, chest pain in healthy host; serious, possibly life-threatening pulmonary disease or disseminated infection with cutaneous/subcutaneous lesions, persistent meningitis or osteomyelitis, especially in immunocompromised

Cryptococcosis (see Fungal Infections: Cryptococcosis)

Cryptococcus neoformans var grubii, C neoformans var neoformans, C neoformans var gattii

Birds including pigeons, psittacines; cats, other mammals


Principally environmental exposure, especially pigeon nests; via inhalation or through the skin; infection common to humans and animals, insignificant as zoonosis

Pulmonary granulomas, usually self-limiting in healthy host; skin lesions; CNS disease and dissemination most often in immunocompromised

Histoplasmosis (see Fungal Infections: Histoplasmosis)

Histoplasma capsulatum var capsulatum

Dogs, cats, bats, cattle, sheep, horses, many other domestic and wild mammals


Principally environmental exposure, avian or bat feces encourage growth of organism; infection common to humans and animals; insignificant as zoonosis

Flu-like, febrile illness, usually self-limiting in healthy hosts; skin lesions; chronic pulmonary disease, usually with pre-existing lung disease; dissemination in very young, elderly, immunocompromised


H capsulatum var duboisii

As above


As above

Usually skin and subcutaneous lesions, osteolytic bone lesions, but can disseminate

Malassezia dermatitis

Malassezia spp

Dogs, cats, other animals


Exposure to symptomatic animals; normal levels on skin not thought to be a risk

Exfoliative dermatitis

Ringworm (Dermatophytosis, see Dermatophytosis)

Microsporum and Trichophyton spp

Dogs, cats, cattle, sheep, goats, horses, rodents, other animals


Direct skin/hair contact with infected animals, fomites

Skin and hair lesions, usually pruritic; rare skin dissemination in immunocompromised

Sporotrichosis (see Fungal Infections: Sporotrichosis)

Sporothrix schenckii

Horses, cats, other mammals, birds


Primarily environmental in vegetation, wood, soil; inoculation from environment in penetrating wounds (splinters, thorns, bites, pecks) skin contact with lesions, especially in cats; inhalation rare

Papules, pustules, nodules, ulcerative skin lesions, may follow course of draining lymphatics; disseminated disease can occur in immunocompromised; acute or chronic pulmonary disease resembling tuberculosis after inhalation, especially with underlying lung disease (rare)


Parasitic Diseases—Protozoans

Babesiosis (see Blood Parasites: Babesiosis)

Babesia microti complex, B duncani (formerly WA-1), and possibly other species

Rodents, insectivores, some other mammals

B microti worldwide; B duncani in Asia, Africa, North America

Bite of infected Ixodes ticks

Fever, myalgia, fatigue; mild to severe hemolytic anemia, especially severe in immunocompromised and elderly; recurrent or chronic infection may develop; dual infection with B burgdorferi may worsen both diseases; death uncommon


B divergens

Cattle; B divergens or closely related organism in reindeer, other mammals

Europe, possibly North Africa

Tick (Ixodes ricinus) bites

Usually in splenectomized; acute, severe hemolysis; persistent high fever, headache, myalgia, abdominal pain, sometimes GI signs; shock and renal failure; cases progress rapidly; case fatality rate 40% with effective treatment, usually fatal if untreated


B bovis; uncertain zoonosis; some historical cases were probably B divergens

Cattle, water buffalo, African buffalo, possibly other species

Africa, Asia, Central and South America, Mexico, Australia, parts of Europe

Tick (Rhipicephalus microplus and R annulatus) bites



Balantidium coli and related species

Swine, rats, nonhuman primates, other animals

Worldwide; low incidence

Ingestion, especially of water contaminated with feces

Asymptomatic to mucoid, bloody stool; intestinal hemorrhage and perforation possible; rare extrain-testinal cases

Chagas' disease (American trypanosomiasis, see Blood Parasites: Chagas' Disease)

Trypanosoma cruzi

Opossums, lagomorphs, rodents, armadillos, dogs, cats, other wild and domestic mammals

Western hemisphere—Southern USA, Mexico, Central and South America

Fecal material of reduviid bug in family Triatomidae contaminates bite wounds, abrasions, or mucous membranes

Acute disease—erratic fever, adenopathy, headache, myalgia, hepatosplenomegaly, swelling at inoculation site and eyelid; myocarditis, or encephalitis in some; worse in immunocompromised

Chronic form (in 10–30% of patients)—cardiomyopathy, megaesophagus, megacolon, other forms; reported annual mortality rate in chronic form 0.2%–19% (higher rates from studies that include only cardiac patients)

Cryptosporidiosis (see Cryptosporidiosis)

Cryptosporidium parvum; less often C canis, C felis, C meleagridis, C muris, and other species; (C hominis is adapted mainly to humans)

Cattle and other ruminants (C parvum), other domestic and wild mammals, birds (C meleagridis), reptiles, fish


Fecal-oral; ingestion of contaminated food and water; inhalation

Self-limiting gastroenteritis in healthy; can be cholera-like and persistent in immunocompromised, with weight loss, wasting; cholecystitis; respiratory signs, mainly in immunosuppressed

Giardiasis (see Giardiasis)

Giardia intestinalis (also known as G lamblia)

Many domestic and wild mammals including dogs, cats, ruminants, beavers, porcupines


Ingestion of water and less often food; fecal-oral (hands or fomites)

Gastroenteritis, may be persistent


—Visceral (Kalaazar see Leishmaniosis)

Leishmania donovani, Leishmania infantum and other species

Wild canids and dogs, cats, horses, rodents; humans are main reservoir in India

Asia, South America, Caribbean, Africa, the Middle East, Mediterranean coast, North America

Bite of sand flies Phlebotomus and Lutzomyia spp

Undulating fever, hepatosplenomegaly; some have cough, diarrhea, lymphadenopathy, weight loss, petechiae or hemorrhages on mucous membranes, nodular lesions or darkening of skin; pancytopenia; almost always fatal if untreated; case fatality rate 10% or higher in treated

—Cutaneous and mucocutaneous

L tropica complex, L braziliensis complex, L mexicana complex, others

Canids, horses, cats, marsupials, sloths, wild mammals, rodents

Mediterranean, Asia, Africa, Middle East, Mexico to South America, Caribbean

As above

Papules to ulcers or nodules on skin ± mucous membranes; single or multiple lesions; localized or disseminated; may persist or recur; atypical forms in immunosuppressed

Malaria of nonhuman primates

At least 20 species of Plasmodium including P knowlesi; all may not be zoonotic

Old and New World monkeys, apes

Central and South America, Asia, Africa

Bite of Anopheline mosquitoes

Fever, chills; headache, myalgia, malaise, cough, nausea, vomiting and other symptoms in some; some cases fatal


Microsporidia of Enterocytozoon bieneusi, Encephalitozoon cuniculi, E intestinalis, E hellem, others

Widespread in vertebrates including primates, rabbits, rodents, dogs, cattle, pigs, goats, birds, fish; also in invertebrates


Fecal-oral; direct contact; ingestion of contaminated food or water; aerosols; possibly vector-transmitted

Keratitis; acute diarrhea (traveler's diarrhea); chronic diarrhea in immunocompromised; may disseminate to systemic disease with variable symptoms in immunocompromised

Rhinosporidiosis (see Fungal Infections: Rhinosporidiosis)

Rhinosporidium seeberi; some strains may be host specific

Horses, cattle, mules, dogs, cats, and birds

Worldwide, endemic in South Asia and Africa

Environmental exposure (unidentified reservoirs)

Nasal and other mucous membrane masses and polyps; may cause obstruction; rare disseminated disease with osteolytic lesions or affecting viscera; rare skin and subcutaneous lesions

Sarcocystosis (Sarcosporidiosis, see Sarcocystosis)

Sarcocystis suihominis

Humans, nonhuman primates are definitive hosts; swine are intermediate host


Ingestion of raw pork

Gastroenteritis, usually mild, or asymptomatic

Sarcocystosis (continued)

S hominis

Humans, nonhuman primates are definitive hosts; cattle are intermediate host


Ingestion of raw beef

Gastroenteritis, usually mild or asymptomatic


Sarcocystis spp

Humans are intermediate host; species of Sarcocystis and definitive host(s) are often unknown

Worldwide; symptomatic cases mainly Asia, probably due to distribution of definitive host

Assumed to be ingestion of oocysts or sporocysts shed in feces of definitive host(s)

Main syndrome is myositis, acute and self-limited to chronic, moderately severe; also cough, arthralgia, transient pruritic rashes, headache, malaise, lymphadenopathy in some

Toxoplasmosis (see Toxoplasmosis)

Toxoplasma gondii

Felidae including domestic cat are definitive hosts; birds and mammals including sheep, goats, swine, and humans are intermediate hosts


Ingestion of oocysts shed in feces of infected cats (including contaminated soil, food, water) or ingestion of tissue cysts in undercooked meat or unpasteurized milk

Lymphadenopathy or mild, febrile, flu-like syndrome or uveitis in immunocompetent, nonpregnant host; often severe in immunocompromised, with neurologic disease, chorioretinitis, myocarditis, pneumonitis or disseminated disease; infection of fetus may result in CNS damage or generalized infection; abortions and stillbirths

Trypanosomiasis (African sleeping sickness, see Blood Parasites: Trypanosomiasis)

Trypanosoma brucei;T brucei rhodesiense is zoonotic; T brucei gambiense is primarily a human pathogen, although some animals can be infected

T brucei rhodesiense reservoirs include cattle, sheep, antelope, hyenas, lions, humans; also isolated from other mammals

Africa; common below the Sahara desert

Bite of infected tsetse fly (Glossina spp)

Painful chancre at bite site; intermittent fever, headache, adenopathy, rash, arthralgia; neurologic signs such as somnolence, seizures; cardiac complications possible; gambiense disease may last years; rhodesiense disease may last weeks; both usually fatal without treatment


Parasitic Diseases—Trematodes (Flukes)


Clonorchis sinensis (Chinese liver fluke)

Dogs, cats, swine, rats, other mammals are definitive hosts; fish (and snails) are intermediate hosts


Ingestion of undercooked infected freshwater fish or shrimp containing encysted larvae

Cholecystitis symptoms, indigestion, diarrhea, mild fever; chronic infections associated with cirrhosis, pancreatitis or cholangiocarcinoma


Dicrocoelium dendriticum, rarely D hospes (lancet flukes)

Ruminants especially sheep, goats, cattle, occasionally other mammals are definitive hosts; land snails (1st) and ants (2nd) are intermediate hosts

D dendriticum worldwide; D hospes in Africa south of Sahara desert

Ingestion of infected ants

Abdominal discomfort, flatulent indigestion; occasionally alternating diarrhea/constipation, vomiting, pain


Echinostoma ilocanum, E hortense, and other Echinostoma spp; Echinochasmus japonicus and other members of Echinostomatidae can also be zoonotic

Cats, dogs, rodents, other mammals; birds (ducks, geese, fowl) are definitive hosts; fish, shellfish, tadpoles, snails are intermediate hosts

Most human cases in Asia, Western Pacific; parasites are widely distributed including Europe, Americas

Ingestion of undercooked fish, shellfish, snails or amphibians (frogs)

Abdominal discomfort; diarrhea, especially in heavy infestation; anemia, edema may occur in children


Fasciola hepatica

Cattle, sheep, water buffalo, horses, rabbits, other herbivores are definitive hosts; snails are intermediate hosts

Worldwide or nearly worldwide; in temperate areas

Ingestion of contaminated greens, eg, watercress, or water that contains metacercariae

Gastroenteritis, hepatomegaly, fever, urticaria possible acutely; biliary colic and obstructive jaundice in chronic cases; aberrant migration with extrahepatic signs (pulmonary infiltrates, meningitis, lymphadenopathy, skin lesions or subcutaneous swelling) in some


F gigantica

Cattle, buffalo, goats, sheep, zebras, other mammals are definitive hosts; snails are intermediate hosts

Mainly in tropical areas: Africa, Asia, Middle East and western Pacific

As above

Signs resemble fascioliasis caused by F hepatica


Fasciolopsis buski

Swine, humans are definitive hosts; snails are intermediate hosts

Asian pig-raising regions

Ingestion of aquatic vegetables or contaminated drinking water containing metacercariae

Often asymptomatic; gastroenteritis; intestinal obstruction possible; facial, abdominal, extremity edema may occur


Gastrodiscoides hominis; uncertain whether humans and swine carry the same strains

Swine, humans, nonhuman primates, rodents, other mammals are definitive hosts; snails are intermediate hosts

Asia (including the Philippines), Africa

Possibly ingestion of water or aquatic plants

Mild diarrhea if high parasite burden


Heterophyes spp and other heterophids

Cats, dogs, foxes, wolves, fish-eating birds are definitive hosts; fish (and snails) are intermediate hosts

Middle East (especially Nile delta), Turkey, Asia

Ingestion of undercooked fish containing encysted larvae

Diarrhea with mucus, colicky pain; heart or CNS involvement possible


Metagonimus yokogawai and other Metagonimus spp

Cats, dogs, rats, other fish-eating mammals, pelicans are definitive hosts; fish (and snails) are intermediate hosts

Asia, Europe, Siberia

Ingestion of undercooked freshwater fish containing encysted larvae

Diarrhea with mucus, anorexia, mild epigastric pain or abdominal cramps; malabsorption, weight loss if high parasite burden


Metorchis conjunctus, Canadian liver fluke

Dogs, foxes and other canids, cats, raccoons, muskrats, mink, other fish-eating mammals are definitive hosts; fish (and snails) are intermediate hosts

North America; human infection rare

Ingestion of undercooked freshwater fish containing encysted larvae

Fever, abdominal pain (mainly epigastric), anorexia during acute stage; effects of chronic infection uncertain


Troglotrema salmincola (synonym Nanophyetus salmincola)

Raccoons, foxes, dogs, cats, skunks, and other fish-eating mammals and birds are definitive hosts; salmonid and non-salmonid fish (and snails) are intermediate host

North America along Pacific coast, Russia

Ingestion of undercooked fish or roe

Mild gastroenteritis


Opisthorchis felineus (cat liver fluke)

Cats, dogs, foxes, swine, seals, other fish-eating mammals are definitive hosts; fish (and snails) are intermediate hosts

Europe, Asia, Siberia

Ingestion of undercooked freshwater fish containing encysted larvae

Acute febrile illness with arthralgia, lymphadenopathy, skin rash; suppurative cholangitis and liver abscess in subacute, chronic stages; possible increased risk of cholangiocarcinoma


O viverrini (small liver fluke)

Dogs, cats, rats, pigs, fish-eating mammals are definitive hosts; fish (and snails) are intermediate hosts

Southeast Asia

Ingestion of undercooked freshwater fish containing encysted larvae

Upper abdominal pain, diarrhea, fever, jaundice possible acutely; chronic infections with cirrhosis, pancreatitis, high incidence of cholangiocarcinoma


Amphimerus pseudofelineus

Dogs, cats, coyotes, opossums are definitive hosts; fish suspected as intermediate hosts

North and South America

Undetermined, but probably ingestion of intermediate host


Paragonimiasis (Lung fluke disease)

Paragonimus westermani, P heterotremus, P africanus, P mexicanus, and other species

Dogs, cats, swine, wild carnivores, opposums, and other mammals are definitive hosts; snails and freshwater crustaceans are intermediate hosts; wild boars, sheep, goats, rabbits, birds, other animals are paratenic hosts

Flukes are worldwide (distribution varies with species); most human infections in Asia, Africa, tropical America

Ingestion of undercooked, infected freshwater crustaceans (crabs, crayfish); or metacercariae on contaminated hands, fomites after preparing crustaceans; or undercooked meat from paratenic hosts such as wild boars

Chills, fever possible during migration to lungs; pulmonary disease resembling tuberculosis; with cough, blood-tinged sputum; abdominal form with dull pain, tenderness, possibly diarrhea; less often, neurologic signs, migratory skin nodules, other organ-specific symptoms; predominant signs vary with species of fluke

Schistosomiasis, intestinal and hepatic

Schistosoma japonicum

Many mammals including cattle, water buffalo, swine, dogs, cats, deer, rodents are definitive hosts; snails are intermediate hosts

China, Indonesia, Philippines

Penetration of unbroken skin by cercariae from infected snails in water

Acute disease (Katayama fever), especially after first infection; febrile illness, sometimes with cough, diarrhea, abdominal pain, hepatosplenomegaly and/or rash/urticaria; apparent clinical recovery may be followed by chronic intestinal schistosomiasis with abdominal pain/discomfort, diarrhea with or without blood; chronic hepatic schistosomiasis with hepatosplenomegaly followed by liver fibrosis, ascites, portal hypertension with hematemesis and/or melena, portocaval shunting with pulmonary signs; ectopic parasites can cause seizures, paralysis, meningoencephalitis; intestinal and hepatic lesions tend to progress rapidly; death can occur


S mansoni

Humans, nonhuman primates are major reservoir (definitive) hosts; also in rodents, insectivores, cattle, dogs; snails are intermediate hosts

Africa, Middle East, South America, Caribbean

Penetration of unbroken skin by cercariae from infected snails in water

Acute disease in some; intestinal and hepatic schistosomiasis similar to S japonicum, but not as rapidly progressive; glomerulonephritis a possible complication; ectopic CNS parasites tend to cause transverse myelitis; also causes genital schistosomiasis with reproductive problems; death can occur


S mattheei

Cattle, sheep, goats, waterbuck, wildebeest, antelope, buffalo, other mammals are definitive hosts; snails are intermediate hosts

Southern Africa

Penetration of unbroken skin by cercariae from infected snails in water

Intestinal and hepatic schistosomiasis; death can occur


S mekongi

Humans are reservoir (definitive) hosts; also found in dogs, pigs; snails are intermediate hosts

Southeast Asia

Penetration of unbroken skin by cercariae from infected snails in water

Acute disease absent or very rare; intestinal and hepatic schistosomiasis; death can occur


S intercalatum

Cattle, sheep, antelope, goats, primates, rats are definitive hosts; snails are intermediate hosts

Central Africa

Penetration of unbroken skin by cercariae from infected snails in water

Intestinal schistosomiasis only, often mild or asymptomatic; occasionally bloody feces, diarrhea

Schistosomiasis, urinary

S haematobium

Humans are the main reservoir (definitive host); occasionally infects nonhuman primates, pigs, sheep, rodents, or other mammals; snails are intermediate hosts

Africa (including Madagascar, Mauritius), the Middle East

Penetration of unbroken skin by cercariae from infected snails in water

Acute disease in some; chronic disease—hematuria, dysuria, kidney failure; calcification of bladder wall, ureter, and bladder can lead to bladder cancer; ectopic CNS parasites tend to cause transverse myelitis; genital schistosomiasis; death can occur

Swimmer's itch (Cercarial dermatitis)

Schistosome cercariae from Schistosoma spp (mammals); Gigantobilharzia, Trichobilharzia, and Austrobilharzia spp (birds)

Birds, mammals are definitive hosts; snails are intermediate hosts


Penetration of unbroken skin by cercariae from infected snails in fresh- and saltwater

Self-limiting urticaria, pruritus, rash


Parasitic Diseases—Cestodes (Tapeworms)


Bertiella studeri, B mucronata

Nonhuman primates are usual hosts; other mammals including dogs, humans can be infected

Asia, South America, Africa; can occur in imported primates in other areas

Ingestion of infected oribatid mites in food

Most cases asymptomatic; abdominal pain, vomiting, diarrhea, constipation, weight loss

Coenuriasis (Coenurosis)

Taenia multiceps

Definitive hosts are canids; intermediate hosts are sheep, other herbivores

Worldwide in scattered foci

Ingestion of tapeworm eggs in canine feces, may be via water, vegetables, soil

Painless skin swelling; possible CNS involvement (signs of mass lesion in brain) or larva in eye


T serialis

Definitive hosts are canids; intermediate hosts are lagomorphs, occasionally other mammals

Africa, Europe, North America; rare in humans

As above

Painless skin swelling; also in muscles and retroperitoneally; CNS involvement possible


T brauni

Definitive hosts are canids; intermediate hosts are gerbils, wild rodents, also humans


As above

Most often in subcutaneous tissues (skin swelling) or eye


Taenia solium (see also Taeniasis)

Humans are definitive hosts; swine, other mammals are intermediate hosts; (humans can be both definitive and intermediate hosts)

Worldwide where swine are reared; most cases occur in Africa, Asia, Central and South America

Ingestion of eggs (including autoinfection from adult parasite in human intestine)

Inflammation in CNS caused by death of larva (years after infection) can cause seizures, other CNS signs; less often in eye or heart


T crassiceps

Foxes, occasionally other canids are definitive hosts; rodents, insectivores, occasionally other mammals are intermediate hosts

North America, Europe, and other areas where foxes are present

Ingestion of eggs

Very rare; one case involved only the eye; one resembled tumor in arm; one paravertebral pseudohematoma with local bleeding

Diphyllobothriasis (Fish tapeworm infection)

Diphyllobothrium latum (Dibothriocephalus latus), D pacificum, D dendriticum, and other Diphyllobothrium spp

Dogs, bears, seals, sea lions, gulls, and other fish-eating mammals and birds are definitive hosts; freshwater or marine fish (and copepods) are intermediate hosts


Ingestion of undercooked infected fish

Usually asymptomatic; may cause mild abdominal distress; rare megaloblastic anemia

Dipylidiasis(Dog tapeworm infection)

Dipylidium caninum

Dogs, cats are definitive hosts; fleas are intermediate hosts


Ingestion of dog or cat fleas

Usually in children; asymptomatic or mild abdominal distress; proglottids in stool resemble cucumber seeds


Echinococcus granulosus

Dogs, hyenas, and other canids are definitive hosts; sheep, cattle, swine, rodents, deer, moose, other mammals are either intermediate or aberrant hosts


Ingestion of tapeworm eggs in food, water; to mouth on hands; eggs stick to fur and hands

Cause space-occupying lesions of organs, especially lung, liver, also other organs, rarely CNS; cyst grows slowly, can cause death if untreated


E multilocularis

Dog, cats, wild canids and felids are definitive hosts; many species of small mammals including microtine rodents, insectivores are intermediate hosts

North America (Canada to northern states of USA), northern and central Eurasia

Ingestion of tapeworm eggs in food, water; to mouth on hands; eggs stick to fur and hands

Usually involves liver with mass lesions, occasionally lung or CNS; primary lesion can metastasize to many organs; very serious, 29% survive 10 yr after diagnosis if untreated, few/none survive 15 yr


E oligarthrus

Wild felids are definitive hosts; agouti, pacas, spiny rats are intermediate hosts

Central and South America; rare in humans

Ingestion of tapeworm eggs in food, water; to mouth on hands; eggs stick to fur and hands

Has occurred in a variety of internal organs, eyes


E vogeli

Bush dogs and dogs are definitive hosts; agouti, pacas, nonhuman primates are intermediate hosts

Central and South America

Ingestion of tapeworm eggs in food, water; to mouth on hands; eggs stick to fur and hands

Usually involves liver, may invade adjacent tissues; mortality high in advanced cases, even with treatment (22% in one study)


Hymenolepis nana (dwarf tapeworm); most human infections probably from strains adapted to humans, but zoonoses possible

Humans, nonhuman primates, rodents are definitive hosts; insects including fleas, flour beetles, cereal beetles are intermediate hosts


Accidental ingestion of tapeworm eggs or infected insects; autoinfection possible

Mainly in children; mild abdominal distress, decreased appetite, irritability are most common; weight loss, flatulence, diarrhea possible


H diminuta (mouse tapeworm, rat tapeworm)

Rats, mice are definitive hosts; insects including fleas and cereal beetles are intermediate hosts


Ingestion of infected insects in food

Mild abdominal symptoms of short duration

Inermicapsifer infection

Inermicapsifer madagascariensis

Rodents, humans are definitive hosts in Africa; humans may be exclusive host outside Africa

Africa, southeast Asia, tropical America

Probably ingestion of infected arthropods

Mild abdominal symptoms, if any

Raillietina infection

Raillietina celebensis, R demerariensis; most Raillietina spp have not been reported in humans

Rodents, nonhuman primates are definitive hosts for R celebensis, R demerariensis; other species in birds, mammals; arthropods including ants are intermediate hosts

R demerariensis in tropical America (human cases mainly Ecuador, Cuba, Guyana, Honduras); R celebensis in Asia, Australia, Africa

Probably ingestion of infected arthropods in food

Vague discomfort, many asymptomatic; gastroenteritis, possibly other signs; mainly in children


Spirometra spp (pseudophyllidean tapeworms, second larval stage)

Dogs, cats, wild canids and felids are definitive hosts; copepods are first intermediate host; primates, pigs, weasels, rodents, insectivores, other mammals, birds, reptiles, amphibians, fish are second intermediate hosts

Worldwide; human cases mainly in Thailand

Ingestion of infected cyclops (in water) or undercooked intermediate host; application of contaminated tissues to skin (eg, as poultice)

Nodular, itchy skin lesions that can migrate; conjunctival and eyelid lesions; urticaria, painful edema; other organ involvement including CNS



—Asian taeniasis

Taenia taiwanensis, Taenia asiatica or T saginata asiatica

Domestic and wild pigs, occasionally cattle, goats, monkeys are intermediate hosts; humans are definitive hosts

East and southeast Asia, Africa

Ingestion of undercooked animal products, usually visceral organs such as liver and lung

Vague abdominal complaints and proglottid passage; anal pruritus; ingestion of eggs followed by larval migration and disseminated disease appears unlikely but has not been ruled out

—Beef tapeworm disease

T saginata

Cattle, water buffalo, llamas, reindeer, camels, other domestic and wild ruminants are intermediate hosts; humans are definitive host


Ingestion of undercooked meat containing larvae

Mild abdominal discomfort and proglottid passage; gravid proglottids may travel to ectopic sites and cause symptoms; eggs do not cause disseminated disease

—Pork tapeworm disease; Cysticercosis and neurocysticercosis

T solium

Humans are definitive host; swine, occasionally other mammals including humans are intermediate hosts

Worldwide where swine are reared; most cases occur in Africa, Asia, Central and South America

Ingestion of undercooked pork containing larvae causes taeniasis; ingestion of eggs (including autoinfection from adult worm in intestine) causes cysticercosis

Adult stage in intestine (taeniasis) mild or asymptomatic; cysticercosis usually asymptomatic for years until death of cysticerci result in inflammation in CNS (seizures, other CNS signs) or less often in eye or heart


Parasitic Diseases—Nematodes (Roundworms)


Parastrongylus costaricensis

Cotton rats and other rodents are definitive hosts; slugs are intermediate hosts

North and South America, Caribbean

Accidental ingestion of slugs or plants contaminated by their secretions

Abdominal angiostrongyliasis; resembles appendicitis, especially in children


Angiostrongylus cantonensis

Rodents (including Rattus and Bandicota spp) are definitive hosts; snails, slugs, and land planarians are intermediate hosts; fish, crustaceans (crabs, shrimp, prawns), amphibians are paratenic hosts


Ingestion of undercooked intermediate host, paratenic host, or plant contaminated by the intermediate host's secretions

Eosinophilic meningitis or meningoencephalitis, spinal cord involvement; ocular involvement with decreased vision; abdominal pain, pruritus in some; most cases relatively mild and self-limiting, but some fatal


Anisakis and Pseudoterranova spp

Marine mammals (cetaceans and pinnipeds) and fish-eating birds are definitive hosts; fish, crustaceans, and cephalopod mollusks are intermediate or paratenic hosts

Worldwide, but many cases in northern Asia and western Europe

Ingestion of undercooked marine fish, squid, octopus

Gastroenteritis with upper quadrant pain; rarely in sites other than stomach; oropharyngeal worm can cause hematemesis, cough; urticaria and other allergic signs after ingestion of live or dead worms



—Hepatic capillariasis

Capillaria hepatica, (synonym Calodium hepaticum)

Rodents, other wild and domestic mammals

Worldwide in scattered foci

Ingestion of embryonated eggs in soil

Acute or subacute hepatitis with marked eosinophilia; subclinical to fatal

—Intestinal capillariasis

C philippinensis

Aquatic birds, humans can be definitive hosts; freshwater fish are intermediate host

Philippines, Thailand, east Asia, Middle East

Ingestion of undercooked infected fish

Enteropathy with protein loss and malabsorption; diarrhea, abdominal pain

—Pulmonary capillariasis

C aerophila, (synonym Eucoleus aerophilus)

Dogs, cats, other carnivores

Worldwide; rare in humans

Accidental ingestion of infective eggs in soil or contaminated food

Fever, cough, bronchospasm, bronchitis, dyspnea; can mimic bronchial carcinoma

Dioctophymosis (Giant kidney worm infection)

Dioctophyma renale

Mink, dogs, and other carnivores are definitive hosts; annelids are intermediate hosts; frogs, fish are paratenic hosts

Europe, Asia, North and South America; rare

Ingestion of infected fish or frog's liver and mesentery

Renal colic, hematuria, pyuria, ureteral obstruction

Dracunculiasis (Guinea worm infection)

Dracunculus medinensis

Humans, nonhuman primates, domestic and wild carnivores, horses, cattle are definitive hosts; copepods are intermediate hosts

Asia (mainly Indian subcontinent) and Africa

Ingestion of infected cyclops in water

No symptoms until just before larviposition (~1 yr); papule to vesicular skin lesion to ulcer that opens in water to reveal worm; allergic reaction common at this time and secondary infection may occur




Dirofilaria immitis

Dogs, cats, wild mammals especially carnivores, mustelids, primates are definitive hosts; mosquitoes are intermediate hosts


Bite of infected mosquitoes

Fever, cough acutely, resulting in infarct or coin lesion in the lungs; often asymptomatic; rarely involves eye


D tenuis, D repens, possibly other species

D tenuis in raccoons; D repens in dogs, cats

D tenuis in North America; D repens in Asia, Europe, Africa

Bite of infected mosquitoes

Subcutaneous nodule or submucosal swelling, some migratory and/or painful; subconjunctival; internal location (mainly lung) possible

—Malayan filariasis

Brugia malayi; subperiodic form is zoonotic; periodic form is exclusive to humans

Cats, wild felids, pangolins, other carnivores, nonhuman primates

Asia; subperiodic form is limited to peninsular Malaysia, Thailand, and parts of Indonesia, Vietnam, and the Philippines in swamp-forest environments

Bite of infected mosquitoes, mainly Brugia malayi, Mansonia spp

Recurrent painful lymphadenitis, lymphangitis, often preceded by prodromal illness with malaise or urticaria; may progress to elephantiasis, usually of legs; hypersensitivity syndrome with cough, chest pain, asthmatic attacks especially at night


Gnathostoma spinigerum and other Gnathostoma spp

Dogs, cats, wild carnivores, are definitive hosts; copepods, freshwater fish, frogs, snakes, chickens, snails, pigs are intermediate hosts

Worldwide; most human cases from Asia; emerging along Pacific coast of Mexico, Ecuador, Peru, Argentina

Ingestion of undercooked fish, poultry, or other intermediate host, rarely in drinking water

Fever, malaise, gastroenteritis, urticaria, soon after ingestion; migratory skin lesions (intermittent swelling, often painful or pruritic) after weeks to years; may involve viscera, eye, or CNS


Gongylonema pulchrum

Ruminants, domestic and wild swine, other mammals are definitive hosts; beetles, cockroaches are intermediate hosts

Worldwide; rare in humans

Ingestion of infected beetles, probably on vegetables; possible inhalation of small beetles

Movement of parasite in submucosa of mouth is sensed; local irritation; pharyngitis, stomatitis possible

Larva migrans, cutaneous (See alsognathostomiasis, above.)

Ancylostoma braziliense, A caninum, Uncinaria stenocephala

Cats, dogs, wild carnivores

Worldwide; distribution varies with the species

Contact with infective larvae that penetrate skin, usually via soil

Itchy, serpiginous, migrating skin lesions; papules, nonspecific dermatitis, vesicles; wheezing, cough, and urticaria may occur; myositis or ocular lesions possible; eosinophilic enteritis after ingestion of A caninum


Bunostomum phlebotomum


Temperate regions

As above

As above


Strongyloides stercoralis and other Strongyloides spp found in animals

S stercoralis in dogs, cats, primates including humans; other species in swine, sheep, goats, cattle, horses, raccoons and other domestic and wild mammals

Worldwide, more common in tropics and subtropics

Contact with infective larvae that penetrate skin, from soil or direct contact with feces; autoinfection possible with S stercoralis

Larva currens (linear, serpiginous urticarial inflammation, often rapidly progressive); S stercoralis may also mature in intestine, causing enteritis and other signs (see below)

Larva migrans, visceral (See alsoangiostrongyliasis and anisakiasis, above)

Toxocara canis, T cati, possibly others

Dogs and wild canids (T canis), cats (T cati) are definitive hosts; many species can be paratenic hosts


Ingestion of embryonated eggs shed in feces of dogs and cats; via soil, water, food, fomites

Fever, wheezing cough, upper abdominal discomfort; nodular rash on trunk and extremities; may wax and wane for months; eye involvement (ocular migrans) may resemble retinoblastoma


Baylisascaris procyonis

Raccoons are definitive host; dogs can be definitive or intermediate host; many mammals (including humans) and birds are intermediate hosts

North America, Europe, Japan

Accidental ingestion of embryonated eggs in soil, water, or fecal-contaminated material

Nonspecific signs including fever, lethargy; hepatomegaly, pneumonitis, parasitic meningoencephalitis (may be fatal in infants, young children), ocular disease; other syndromes including cardiac disease

Oesophagostomiasis, Ternidensiasis

Oesophagostomum spp, Ternidens deminutus

Primates, including humans

Africa, Asia, South America (Brazil)

Ingestion of infective larvae in soil, often in food or water

Abdominal pain (may be right lower quadrant) and one or more masses ± mild fever; intestinal obstruction or abscessation possible; multinodular form (less common) with abdominal pain, persistent diarrhea, weight loss; rarely ectopic in omentum, liver, or skin


Strongyloides stercoralis (canine and primate-adapted S stercoralis probably exist, and zoonotic infections from dogs may rarely mature in humans)

S stercoralis in dogs, cats, foxes, primates including humans

S stercoralis worldwide; more common in tropical and subtropical climates

Contact with infective larvae that penetrate skin, in soil or direct contact with feces; autoinfection possible

Frequently asymptomatic in healthy; possible larva currens (seelarva migrans, above); respiratory signs in some (cough to bronchopneumonia) especially in elderly, immunocompromised; abdominal pain, diarrhea, sometimes with periodic urticarial or maculopapular rash; disseminated strongyloidiasis, neurologic complications, septicemia, and death may occur in immunocompromised

Strongyloidiasis (continued)

S fuelleborni

Primates including humans

Africa, Asia, and in captive primates in other areas

As above

Associated with abdominal pain, occasional diarrhea, not well studied

Thelaziasis (Eyeworms)

Thelazia callipaedia, T californiensis, possibly T rhodesii

Definitive hosts are dogs and other canids, cats, rabbits (T callipaedia); dogs, wild mammals, occasionally cats, sheep (T californiensis); flies are intermediate hosts

T callipaedia in Asia, Europe; T californiensis in North America (western USA); rarely in humans

Flies release parasite larvae on conjunctiva

Conjunctivitis; corneal scarring, opacity in chronic cases

Trichinosis (Trichinellosis)

Trichinella spiralis and subspecies, T nativa, T britovi, T nelsoni, T pseudospiralis, possibly others

Main reservoir may be wild carnivores (foxes, badgers, wolves, lynx), omnivores (bears, boars); also in any mammal that eats (or is fed) meat including domestic swine, rodents, cats, dogs, horses, marine mammals; also birds (T pseudospiralis)

Worldwide, especially subarctic region; some species are limited in their distribution

Ingestion of undercooked pork, horse meat, game, and other tissues containing viable cysts

Gastroenteritis in some; followed by fever, headache, severe myalgia, facial swelling (especially eyelids); ocular pain, rashes, or pruritus possible; pneumonitis, CNS, or myocardial involvement can occur; inapparent to fatal


Trichostrongylus spp

Cattle, sheep, other domestic and wild ruminants, sometimes other mammals


Ingestion of infective larvae on vegetables or in contaminated water, soil

Asymptomatic or mild gastroenteritis

Trichuriasis (Whipworm infection)

Trichuris vulpis, T suis, and possibly other species; T spp, T trichiura occurs mainly in humans and zoonotic infections are unusual

T vulpis in canids; T suis in domestic and wild swine

Worldwide, especially warm, humid climates

Ingestion of embryonated eggs on plant foods, water, or in soil

Asymptomatic or mild to moderate gastroenteritis; bloody diarrhea possible; rarely, larva migrans from T trichiura , T vulpis


Parasitic Diseases—Acanthocephalans

Acanthocephaliasis, Macracanthorhynchosis

Macracanthorhynchus hirudinaceus and other species

Hosts vary with parasite species; definitive hosts include domestic and wild pigs, rodents, muskrats, arctic foxes, dogs, sea otters, other terrestrial and marine mammals; intermediate hosts are beetles, cockroaches, crustaceans; fish are paratenic hosts


Ingestion of infected beetles, other intermediate hosts, or fish

Gastroenteritis, may lead to gut perforation or intestinal obstruction; some cases asymptomatic


Parasitic Diseases—Annelids (Leeches)

Hirudiniasis (internal)

Limnatis nilotica and other aquatic leeches

Cattle, buffalo, other domestic and wild mammals, probably frogs

Africa, Asia, southern Europe, Middle East

Drinking unfiltered water (leech enters nares or mouth), wading in deep water (enters genitourinary tract)

Attaches to nasopharynx, pharynx, esophagus, occasionally deeper in respiratory tract, or in genitourinary tract; pressure and/or pain at attachment site; bleeding (eg, hemoptysis, hematemesis, epistaxis, vaginal bleeding), anemia (can be severe); other signs depend on location, may include persistent headache, cough, dyspnea, chest pain


Arthropod Diseases

Acariasis (Mange)

Mites of Sarcoptes, Cheyletiella, Dermanyssus, and Ornithonyssus spp

Mammals and birds


Contact with infected animals, fomites

Itchy skin lesions


Cochliomyia hominivorax and Chrysomya bezziana (screw-worms)

Mammals; rare in birds

C hominivorax in South America, Caribbean; C bezziana in Asia, Africa, possibly Middle East

Flies lay eggs on host, larvae enter wounds (as small as a tick bite), mucous membranes

Painful, pruritic, foul-smelling enlarging dermal and subdermal wounds or nodules, often with serosanguineous discharge; some infestations in cavities including nasal cavity; larvae can invade living tissue, locally destructive (including bone, eye, sinuses, or cranial cavity); can be fatal if untreated


Cordylobia anthropophaga, rarely C rodhaini(Tumbu flies)


Africa, Saudi Arabia

Larvae from environment invade unbroken skin

Furuncular swelling at site of invasion, often feet


Cuterebra spp

Rodents, lagomorphs, occasionally other mammals

North America

Larvae from vegetation enter host in natural cavities or invade intact skin

Subcutaneous furunculoid nodules; creeping skin eruption (uncommon); ocular lesions; rarely larvae in upper respiratory tract


Dermatobia hominis (human bot fly)

Mammals, some birds

South and Central America, Mexico

Eggs carried by other insects; larvae hatch and penetrate skin of mammalian host when insect lands

Nonmigratory larvae in furuncles; pain, intense pruritus, sometimes with lymphangitis or lymphadenitis; can invade eyelids, eye sockets, mouth, especially in children


Gasterophilus spp (equine bot fly)

Equids, occasionally other mammals


Accidental exposure to larvae

Serpiginous, pruritic red stripes on skin resembling cutaneous larva migrans; rarely gastric with nausea and vomiting


Hypoderma lineatum, H bovis (warbles), and other Hypoderma spp

H bovis and H lineatum in cattle, sometimes other mammals; other species primarily parasites of deer, caribou, or yaks

North America, Europe, Asia; species distribution varies

Eggs laid on host, larvae invade skin

Usually subcutaneous (slowly moving furuncles that can appear and disappear) or similar to cutaneous larva migrans; endophthalmia uncommon; H lineatum may also cause fever, muscle pain, eosinophilia, sometimes respiratory, cardiac, or neurologic signs


Oestrus ovis, Rhinoestrus purpurensis

O ovis mainly in sheep, goats, also other mammals; R purpurensis mainly in equids

O ovis worldwide; R purpurensis in Asia, Africa, Europe

Larvae are deposited in nares, conjunctiva, occasionally lips/mouth by adult fly

Conjunctival form, with lacrimation and sensation of irritating foreign body in eye, ocular destruction is rare; nasal form with localized pain or pruritus, congestion, headache; also in pharynx (inflammation, vomiting, dysphagia), rarely ear; usually self-limiting (except inside eye), as larvae cannot develop beyond first stage in humans


Wohlfahrtia spp, Wohlfahrtia vigil, W magnifica

W vigil in rabbits, mink, foxes, dogs, and other carnivores; W magnifica in sheep, cattle, other mammals, some birds, especially geese

W vigil in North America; W magnifica in Europe (mainly Mediterranean), north Africa, Asia

Larvae deposited on host or nearby, penetrate lesions (both agents) or intact skin (W vigil) and natural orifices

W vigil causes subcutaneous abscesses, furuncles; W magnifica has been reported from skin, eye, vulva, ear, orotracheal region

Pentastomid infections

Armillifer spp (tongue worms)

Definitive hosts are snakes; intermediate hosts are rodents and other wild animals

Africa, Asia

Ingestion, via water or vegetables contaminated with eggs (from feces or saliva of snakes); undercooked snake meat; contaminated hands, fomites after handling snake meat

Usually asymptomatic; large numbers of parasites can cause multifocal abscesses, masses, or obstruction of ducts in internal organs; symptoms vary with location


Linguatula serrata

Definitive hosts are dogs and other canids, felids; intermediate hosts are herbivores, especially sheep, goats, lagomorphs, and including humans


Ingestion of water or vegetables contaminated with eggs (from feces, saliva, or nasal discharge of definitive host); ingestion of larvae in undercooked liver or lymph nodes from intermediate hosts

Ingestion of eggs—usually asymptomatic; ocular or pulmonary signs, abdominal pain, icterus, and other symptoms possible from invasion of internal organs

Ingestion of larvae—throat irritation, pain; edema, congestion of nasopharynx may cause dyspnea, difficulty swallowing; most severe cases are probably in people who have been sensitized

Tick paralysis (see Tick Paralysis)

Dermacentor andersoni, D variabilis, and sometimes Ixodes, Haemaphysalis, Rhipicephalus, Argas, and Hyalomma spp ticks

Various animals


Tick attachment, especially on back of neck or along spinal column

Elevated temperature, ascending flaccid paralysis; can cause respiratory paralysis, also paresthesia; ends when tick is removed, but recovery slow; death possible

Tunga infections

Tunga penetrans (sand fleas, jiggers)

Humans, dogs, pigs, other mammals

Africa, Central and South America, Caribbean, south Asia

Skin contact with contaminated soil

Penetration of skin and burrowing result in pain and itching around discrete sores, often on feet; may be secondarily infected


Viral Diseases

Alkhurma virus infection

Alkhurma virus; may be a variant or strain of Kyasanur Forest virus

Sheep, goats, camels

Mainly in Saudi Arabia; virus may exist throughout Arabian peninsula

Direct contact including transmission via broken skin, ingestion of unpasteurized camel milk, mosquito bites

Fever, headache, myalgia, anorexia, vomiting; encephalitic and hemorrhagic signs; case fatality rate 25%

Barmah Forest virus infection

Barmah Forest virus, (Family Togaviridae, genus Alphavirus)

Natural hosts unknown; horses, brushtail possums may amplify virus


Mosquito bites; Culex annulirostris and Aedes spp implicated

Identical to disease caused by Ross River virus (see p 2814), but persists longterm in fewer patients

Buffalopox virus infection

Vaccinia virus, Buffalopox virus strain (Family Poxviridae, genus Orthopoxvirus)

Water buffalo, cattle

Indian subcontinent (south Asia), Egypt, Indonesia

Skin contact with infected animals, often when milking

Pox skin lesions mainly on hands, face, legs, buttocks; occasionally lymphadenopathy

California encephalitis virus (California serogroup) infections

California encephalitis virus (Family Bunyaviridae, genus Orthobunyavirus); includes California, La Crosse, Tahyna, Inkoo, Jamestown Canyon, Morro Bay, Snowshoe hare, Chatanga, and other strains

Many wild and domestic mammals

North and South America, Europe, Africa, Asia; possibly worldwide; distribution of each strain varies

Mosquito bites

Syndromes, severity vary with the strain; flu-like illness, meningitis, or encephalitis are common with North American strains

—La Crosse encephalitis

La Crosse strain of California encephalitis virus (La Crosse virus)

Chipmunks, squirrels are major amplifying hosts; rabbits, foxes, and other mammals can be infected

North America

Mosquito bites

Many cases mild and flu-like; meningitis or encephalitis with seizures, paralysis, and focal neurologic signs possible; most cases in children; estimated case fatality rate in cases with encephalitis is 0.3%

—Tahyna fever

Tahyna strain of California encephalitis virus (Tahyna virus)

Hares, rabbits, rodents, hedgehogs and other mammals

Europe, Asia, Africa

Mosquito (culicine) bites

Influenza-like illness, sometimes including GI signs; respiratory signs including bronchopneumonia in some; meningitis possible; most often in children; does not appear to cause fatal disease

Chikungunya virus infection

Chikungunya virus (Family Togaviridae, genus Alphavirus)

Sylvatic cycle in nonhuman primates in Africa; virus thought to be maintained in humans in Asia

Southeast Asia, Africa

Mosquito (especially Aedes spp) bites

Febrile illness, may have rash; arthralgia, especially in small joints, is prominent, may persist for months; myocarditis, neurologic signs, hemorrhages reported in a few cases

Colorado tick fever

Colorado tick fever virus (Family Reoviridae, genus Coltivurus; Salmon River virus may be a variant

Rodents (ground squirrels, chipmunks, mice, rats), porcupines, lagomorphs, deer, elk, and other mammals

Rocky Mountain region of North America

Tick (Dermacentor andersoni) bites

Febrile illness with headache, myalgia, abdominal and retroorbital pain, other signs; biphasic or triphasic in some; neurologic signs, hemorrhages, pericarditis, myocarditis, or orchitis occasionally in severe cases; case fatality rate low

Contagious ecthyma (Orf, see Contagious Ecthyma)

Orf virus (Family Poxviridae, genus Parapoxvirus)

Sheep, goats, camelids, reindeer, wild ungulates; rare cases in dogs


Occupational exposure via contact with broken skin

Papule(s) that umbilicate and ulcerate, usually on hands; dissemination rare; large lesions refractory to treatment can occur in immunosuppressed

Cowpox (see Pox Diseases)

Cowpox virus (Family Poxviridae, genus Orthopoxvirus)

Rodents are usual reservoir host; also in domestic and wild cats, occasionally cattle, other mammals

Parts of Europe and Asia

Contact exposure via broken skin, bites, scratches

Vesicles that become pustular, to ulcerative nodules, scars; single or multiple lesions, often on hands; regional adenopathy and malaise, flu-like symptoms in some; lesions remain localized in healthy people; generalized disease may occur in immunocompromised, can include eye

Crimean-Congo hemorrhagic fever (see Crimean-Congo Hemorrhagic Fever)

Crimean-Congo hemorrhagic fever virus (Family Bunyaviridae, genus Nairovirus)

Cattle, rodents, sheep, goats, hares, other mammals, some birds

Africa, Middle East, central Asia, eastern Europe

Tick bites, especially Hyalomma but also -Rhipicephalus, Dermacentor, other species; skin contact with animal or human blood or tissues or crushed ticks; ingestion of unpasteurized milk

Fever, headache, pharyngitis, abdominal symptoms, petechial rash, hemorrhage, hepatitis; very severe in pregnant women; case fatality rate 30–50%

Eastern equine encephalomyelitis (see Equine Viral Encephalomyelitis)

Eastern equine encephalomyelitis virus (Family Togaviridae, genus Alphavirus); North American variant more virulent than South American variant

Birds are principal reservoir hosts; clinical cases occur in equids and occasionally other mammals and birds; mammals are almost always dead-end hosts

Western hemisphere

Mosquito bites; Culiseta melanura important in maintenance cycle in birds; many genera can transmit to humans

Nonspecific febrile illness may be followed by severe encephalitis, especially with North American variant; neurologic sequelae common after encephalitis; case fatality rate 30–70% with North American variant

Ebola hemorrhagic fever

Zaire ebolavirus, Sudan ebolavirus, Ivory Coast ebolavirus, Bundibugyo ebolavirus (Family Filoviridae, genus Ebolavirus)

Bats are reservoir hosts for Zaire ebolavirus and suspected reservoir hosts for others; primates, duikers, possibly other mammals can be infected


Contact with infected tissues (especially nonhuman primates and duikers); probable transmission from bats in caves

Initially nonspecific febrile illness; maculopapular rash with desquamation; mild to severe bleeding tendency develops a few days after onset; mortality rate 36–90%, varies with the isolate


Encephalomyocarditis virus (Family Picornaviridae, genus Cardiovirus)

Rodents may be reservoir hosts; also in swine, nonhuman primates, elephants, other mammals, and wild birds

Worldwide in animals; uncommon in humans


Fever, severe headache, pharyngitis, neck stiffness, abdominal pain, vomiting and/or decreased reflexes have been reported in adults, with recovery within several days; CNS signs, including paralysis, can occur in children

Foot-and-mouth disease (see Foot-and-Mouth Disease)

Foot-and-mouth disease virus (Family Picornaviridae, genus Aphthovirus, types A, O, C, SAT 1, SAT 2, SAT 3, and Asia 1)

Cattle, swine, sheep, goats, other cloven-hoofed animals (Artiodactyla), a few mammals in other orders

Asia, Africa, Middle East, South America

Contact exposure

Humans can carry virus but do not usually become ill; mild influenza-like disease with vesicular lesions occurs very rarely

Hantaviral diseases


—Hantaviral pulmonary syndrome

Sin Nombre, Black Creek Canal, Muleshoe, Bayou, Andes, Bermejo, Choclo, Araraquara, Juquitiba, Maciel and Castelo dos Sonhos viruses, others (Family Bunyaviridae, genus Hantavirus)

Rodents; each virus tends to be associated with a single reservoir host

North and South America

Aerosols from rodent excretions and secretions; contact with broken skin and mucous membranes; rodent bites

Prodromal stage with nonspecific febrile illness; followed by respiratory failure, cardiac abnormalities; hemorrhagic signs possible with South American viruses; significant kidney disease uncommon; mortality rate varies with the virus, but can reach 40–60%

—Hemorrhagic fever with renal syndrome

Hantaan virus, Dobrava virus, Puumala virus, Seoul virus, others (Family Bunyaviridae, genus Hantavirus)

Rodents; each virus tends to be associated with a single reservoir host, but Seoul virus is carried by both Rattus norvegicus and R rattus

Europe, Asia; Seoul virus is worldwide

Aerosols from rodent excretions and secretions; contact with broken skin and mucous membranes; rodent bites

Prodromal stage with abrupt onset of fever, headache, back pain, petechiae, GI signs (may be severe); followed by hypotension, renal signs to renal failure with oliguria; hemorrhage in some; mortality rate varies with the virus, from <1% (Puumala virus) to 10–15% (Hantaan virus)

Hendra virus infection (see Hendra Virus Infection)

Hendra virus (Family Paramyxoviridae, genus Henipavirus)

Fruit bats are normal reservoir host; horses can be infected


Direct contact with infected animals or contaminated tissue

Respiratory infection, encephalitis; few cases described

Hepatitis E

Hepatitis E virus, mammalian isolates (Family Hepadnaviridae, genus Avihepadnavirus)

Humans, swine, deer, others


Fecal, oral spread; consumption of raw or undercooked meat and liver; waterborne

Mild, self-limiting hepatitis to liver failure, more severe in pregnancy; usually acute, but can be chronic in solid organ transplant patients; case fatality rate 1% in general population, 20% in pregnant

Herpes B virus disease

Cercopithecine herpesvirus 1 (Herpesvirus simiae, B virus) (Family Herpesviridae, genus Simplexvirus)

Carried in genus Macaca (Old World macaques), with lifelong latency after infection; other nonhuman primates susceptible; cell cultures

Worldwide, can be common, especially in closed groups of macaques; human cases rare

Monkey bites and scratches, contamination of mucous membranes with infected saliva, secretions

Influenza-like symptoms; vesicular skin lesions, pain, or itching around wound; followed by severe encephalitis with seizures, paralysis, coma; 85% mortality rate

Influenza virus infections


—Avian influenza

Influenza A virus (Family Orthomyxoviridae, genus Influenzavirus A); avian influenza viruses; avian viruses that cause severe zoonotic disease are usually high pathogenicity (HPAI) strains

Avian influenza viruses in wild and domestic birds; avian HPAI viruses generally found in poultry and rarely in wild birds; uncommon in mammals

Worldwide; HPAI avian influenza viruses eradicated from domestic poultry in many developed countries

Usually by contact with infected animals; avian viruses also in feces

Avian influenza viruses can cause conjunctivitis, human influenza-like illness, or severe disease with multiorgan dysfunction, death; severity of disease varies with influenza strain

—Swine influenza

Influenza A virus (Family Orthomyxoviridae, genus Influenzavirus A); swine influenza viruses

Usually in pigs; also turkeys; can infect mink, ferrets


Usually by contact with infected animals; swine influenza viruses occur in respiratory secretions

Seems to resemble human influenza; severity of disease varies

Japanese encephalitis (Japanese B encephalitis)

Japanese encephalitis virus (Family Flaviviridae, genus Flavivirus)

Swine, horses; wild birds are subclinical maintenance hosts; other mammals, reptiles, amphibians may be infected asymptomatically

Asia, Pacific islands from Japan to the Philippines

Mosquito (Culex tritaeniorhynchus, other Culex spp) bites; also through broken skin or mucous membranes after direct contact with infected tissues

Fever, chills, myalgia, severe headache, GI symptoms; can progress to severe encephalitis; neurologic sequelae very common in survivors of encephalitis; case fatality rate 15–30%

Kyasanur forest disease

Kyasanur forest virus (Family Flaviviridae, genus Flavivirus)

Rodents, shrews, monkeys, possibly other mammals, birds


Tick (Haemaphysalis spinigera) bites

Fever, headache, bradycardia, prostration, severe pain in extremities; course may be biphasic with remission followed by hemorrhagic signs (eg, ecchymoses, purpura, petechiae, GI bleeding, epistaxis); meningoencephalitis in some; case fatality rate 2–10%

Lassa fever

Lassa virus (Family Arenaviridae, genus Arenavirus)

Wild rodents, usually multimammate mouse


Contact with rodent excretions, secretions, or tissues

Gradual onset of nonspecific febrile illness, may be followed by chest pain, cough, GI signs, hepatitis; severe swelling of head and neck, hypotension/shock can develop; pleural/pericardial effusions; hemorrhagic syndrome less common; overall mortality rate 1% in endemic areas; case fatality rate can be up to 50% during epidemics

Louping ill (Ovine encephalomyelitis, see Louping Ill)

Louping ill virus (Family Flaviviridae, genus Flavivirus)

Sheep, goats, other domestic and wild mammals, grouse, ptarmigan

UK, Northern Ireland, Norway; rare

Tick (Ixodes ricinus) bites; aerosol exposure in laboratory, contamination of skin wounds; possibly ingestion of milk

Biphasic influenza-like illness, sometimes followed by meningitis or meningoencephalitis, paralysis, joint pain in second phase; not usually fatal

Lymphocytic choriomeningitis

Lymphocytic choriomeningitis virus (Family Arenaviridae, genus Arenavirus)

Reservoir mainly house mice; can be maintained in hamster populations; also infects guinea pigs, chinchillas, rats, nonhuman primates, some other mammals


Contact with host excretions and secretions; bites

Ranges from mild flu-like illness to biphasic with meningitis in second phase; arthritis, parotitis, and orchitis may occur; can be teratogenic (CNS) or cause abortion; rarely fatal in immunocompetent

Marburg hemorrhagic fever

Lake Victoria Marburgvirus (Family Filoviridae, genus Marburgvirus)

Bats are reservoir hosts; primates can be infected


Contact with infected tissues (especially nonhuman primates); probable transmission from bats in caves

Initially nonspecific febrile illness; maculopapular rash with desquamation; hepatitis; mild to severe bleeding tendency develops a few days after onset; mortality rate 20–88%, varies with the isolate

Menangle virus infection

Menangle virus (Family Paramyxoviridae)

Fruit bats are normal reservoir host; pigs can also be reservoir


Close direct contact with tissues, amniotic fluid, blood reported in human cases

Severe illness with fever, severe headache, myalgia, lymphadenopathy, drenching sweats, macular rash

Milker's nodules (Pseudocowpox, see Pox Diseases: Pseudocowpox)

Pseudocowpox virus (Family Poxviridae, genus Parapoxvirus)



Skin contact (especially broken skin) with lesions on cow's udder or mouth of calf; also from fomites

Papular to nodular red skin lesions; self-limiting


Monkeypox virus (Family Poxviridae, genus Orthopoxvirus)

Nonhuman primates; Gambian rats, other African rodents; prairie dogs, other pet rodents, squirrels

West and central Africa

Contact with lesions, blood or body fluids, fomites; bites; aerosols

Smallpox-like disease; flu-like symptoms followed by maculopapular rash, which develops into vesicles, pustules, scabs; lymphadenopathy prominent; respiratory signs, encephalitis possible; case fatality rate varies with strain, <1% to 10%; milder in those vaccinated for smallpox

Murray Valley encephalitis

Murray Valley encephalitis virus (Family Flaviviridae, genus Flavivirus)

Wild birds

Australia, New Guinea

Mosquito (Culex annulirostris) bites

Asymptomatic infection in >99%; when disease occurs it can be severe; encephalitis, often with neurologic sequelae; poliomyelitis-like flaccid paralysis in some; case fatality rate >40%

Newcastle disease

Newcastle disease virus/Avian paramyxovirus 1 (Family Paramyxoviridae, genus Avulavirus)

Domestic and wild birds

Mildly virulent (lentogenic, mesogenic strains) are found worldwide; highly virulent (velogenic) strains occur in Asia, the Middle East, Africa, Central and South America, parts of Mexico; also in cormorants in USA

Occupational exposure, usually after contact with large amounts of virus

Highly virulent (velogenic) strains can cause self-limiting conjunctivitis, possibly other syndromes

New World hemorrhagic fever (Argentinean, Bolivian, Venezuelan and Brazilian hemorrhagic fevers [HF])

Arenaviruses in Tacaribe complex (Family Arenaviridae, genus Arenavirus): Juin virus (Argentine HF), Machupo virus (Bolivian HF), Guanarito virus (Venzuelan HF), Sabiá virus (Brazilian HF); possibly others



Viruses occur in rodent excretions, secretions, tissues; inhalation of aerosolized virus or direct contact with mucous membranes or broken skin

Gradual onset of nonspecific signs including myalgia, headache, and fever; may develop petechial or ecchymotic hemorrhages, bleeding, CNS signs, hypotension/shock; case fatality rate in Bolivian hemorrhagic fever 5–30%, Argentine hemorrhagic fever 15–20%

Nipah virus infection (see Nipah Virus Infection)

Nipah virus (Family Paramyxoviridae, genus Henipavirus)

Fruit bats are normal reservoir; swine can be reservoir; occasionally in other mammals (spillover hosts)

Malaysia, Bangladesh and Northern India; virus is probably endemic in southeast Asia, but outbreaks seem to cluster in certain geographic areas

Direct contact with infected pigs or contaminated tissue; direct or indirect (eg, contaminated fruit juice) bat-to-human transmission

Initial signs flu-like with fever, headache, myalgia, sometimes vomiting; encephalitis; respiratory disease including acute respiratory distress syndromes in some; septicemia; other complications in severely ill; case fatality rate 33–75%

Omsk hemorrhagic fever

Omsk hemorrhagic fever virus (Family Flaviviridae, genus Flavivirus)

Voles, muskrats; also found in other animals


Tick (Dermacentor spp) bites; direct contact with body fluids or carcasses of muskrats

Biphasic febrile illness with headache, vomiting, papulovesicular rash on soft palate ± hemorrhages (nose, gums, lungs, uterus); CNS disease is uncommon; mortality rate <3%

Rabies and rabies-related infections (see Rabies)

Rabies virus (Family Rhabdoviridae, genus Lyssavirus) and the related lyssaviruses, Duvenhage virus, Mokola virus, Australian bat lyssa-virus, European bat lyssa-viruses; possibly others

Wild and domestic canids, Mustelidae, Viverridae, Procyonidae, and order Chiroptera (bats) are important reservoir hosts; all mammals are susceptible; bats are reservoir hosts for Duvenhage virus, Australian bat lyssavirus, and European bat lyssaviruses; Mokola virus carried in rodents and shrews

Rabies is worldwide except Australia, New Zealand, UK, Ireland, Scandinavia, Iceland, Japan, Taiwan; many smaller islands, including Hawaii, are free of infection

Bites of diseased animals; aerosols in closed environments

Paresthesias or pain at bite site; nonspecific prodromal signs such as fever, myalgia, malaise; mood changes progress to paresthesias, paresis, seizures, and many other neurologic signs; survival is extremely rare

Rift Valley fever (see Rift Valley Fever)

Rift Valley fever virus (Family Bunyaviridae, genus Flavivirus)

Sheep, goats, cattle, buffalo, camels, nonhuman primates; squirrels and other rodents; puppies and kittens


Mosquito (Aedes spp) bites; contact with tissues

Influenza-like febrile illness in most; complications including hemorrhagic fever, meningoencephalitis, or ocular disease in <5%; death uncommon

Ross River virus infection, Ross River fever

Ross River virus (Family Togaviridae, genus Alphavirus)

Wallaby and dusky rats proposed as natural hosts; humans, horses may also be a source of virus during epidemics

Australia, South Pacific Islands

Mosquito (Culex annulirostris and Aedes spp) bites

Mild fever, arthralgia +/– arthritis, headache, rash; small joints most affected; arthralgia, myalgia, lethargy may persist for months

St. Louis encephalitis

St. Louis encephalitis virus (Family Flaviviridae, genus Flavivirus)

Wild birds, domestic fowl; bats may also maintain virus

Western hemisphere

Mosquito (Culex tarsalis, C pipiens-quinquefasciatus complex, C nigripalpus) bites

Flu-like illness sometimes followed by meningitis or encephalitis, focal neurologic signs, dysuria; more severe in elderly and those with debilitating diseases; overall case fatality rate 7%, but higher in elderly

Severe acute respiratory syndrome (SARS)

SARS coronavirus (Family Coronaviridae, genus Coronavirus)

Bats are probable reservoir hosts; can also infect palm civets, raccoon dogs, cats, pigs, ferrets, rodents, nonhuman primates, other mammals

China, southeast Asia

Contamination of mucous membranes with respiratory droplets or virus on fomites; possibly aerosol transmission

Fever, myalgia, headache, diarrhea, cough; viral pneumonia with rapid deterioration; case fatality rate 15%

Sindbis virus disease

Sindbis virus (Family Togaviridae, genus Alphavirus)

Birds (mainly passeriforms); can be found in rodents, amphibians

Eastern hemisphere; rare in humans

Mosquito bites; many species can transmit

Fever, arthritis, rash, prominent myalgia; nausea, vomiting, mild jaundice in some; joint pain can persist for months


Tanapox virus (Family Poxviridae, genus Yatapoxvirus); Yaba-like disease virus may be a variant of tanapox virus

Nonhuman primates

Asia, Africa, and in monkey colonies

Direct contact through broken skin; mosquitoes suspected to be vector in Africa

Fever, severe backache, lymphadenopathy, and papulovesicular, pruritic lesions, often on extremities; rarely more than 1–2 skin lesions

Tick-borne encephalitis (Far eastern tickborne encephalitis; (Russian spring- summer encephalitis, Central European tickborne encephalitis)

Tick-borne encephalitis virus (TBEV) (Family Flaviviridae, genus Flavivirus); three subtypes—European (TBEV-Eu; least virulent), Siberian (TBEV-Sib), Far Eastern (TBEV-FE)

Small mammals especially rodents; goats, sheep, dogs, and other mammals; birdsvb

Eurasia; TBEV-Eu mainly Europe to former USSR; TBEV-FE mainly Asia to former USSR; TBEV-Sib mainly in Siberia

Tick (mainly Ixodes ricinus and I persculatus; also other species) bites; may be ingested in milk

Often biphasic, with flu-like febrile illness in initial stage; neurologic signs from mild meningitis to severe encephalitis in some; myelitis or flaccid poliomyelitis-like paralysis (usually arms, shoulders, levator muscles of head); possibility of chronic and progressive forms, especially with TBEV-Sib; case fatality rate is <2% (TBEV-Eu), 2–3% (TBEV-Sib); case fatality rate of 20–30% in TBEV-FE may be based on severe cases

Venezuelan equine encephalomyelitis

Venezuelan equine encephalitis virus (Family Togaviridae, genus Alphavirus)

Rodents, birds, equids, occasionally in other mammals

Western hemisphere

Mosquito (Mansonia, Aedes, Culex spp) bites; exposure to aerosolized debris from infected laboratory rodents; laboratory accidents

Most have nonspecific febrile illness; <5% progress to encephalitis with case fatality rate of 10% (adults) to 35% (children)

Vesicular stomatitis

Vesicular stomatitis Indiana virus, Vesicular stomatitis New Jersey virus, Vesicular stomatitis Alagoas virus, and Cocal virus (Family Rhadboviridae, genus Vesiculovirus)

Swine, cattle, horses; occasionally in South American camelids, sheep, and goats; also, rodents; serologic evidence of infection in many wild mammals especially bats

North and South America

Contact with animals or in laboratory, probably also from insect bites, including mosquitoes and biting flies (Phlebotomus spp, Lutzomyia spp, and black flies)

Usually asymptomatic; may develop acute, febrile flu-like illness; vesicles can occur in mouth, pharynx, or inoculation site (eg, hands); self-limiting

Wesselsbron fever

Wesselsbron virus (Family Flaviviridae, genus Flavivirus)

Sheep; also cattle, lemurs, other mammals, and birds

Southern Africa, southeast Asia

Mosquito (Aedes spp and possibly others) bites; also by contact with contaminated material

Fever, headache, myalgia, arthralgia; hyperesthesia of skin ± maculopapular rash in some; self-limiting

West Nile fever and neuroinvasive disease (see Equine Viral Encephalomyelitis)

West Nile Virus (Family Flaviviridae, genus Flavivirus)

Birds, horses, other mammals, alligators, possibly other reptiles and amphibians

Eastern and Western hemisphere

Mosquito (primarily Culex univittatus, Culex spp) bites; also by handling infected birds or reptiles or their tissues

Nonspecific febrile illness, occasionally with rash; some cases progress to encephalitis, meningitis, and/or acute flaccid paralysis that resembles poliomyelitis; worse in elderly and immunocompromised; case fatality rate ~10% in all patients with neurologic disease, but higher in elderly

Western equine encephalomyelitis (see Equine Viral Encephalomyelitis)

Western equine encephalomyelitis virus (Family Togaviridae, genus Alphavirus)

Birds are reservoir hosts, also cycles in jackrabbits; equids, other mammals are incidental hosts; virus is also found in reptiles, amphibians

Western and Central USA, Canada, South America

Mosquito (Aedes spp, Culex spp) bites

Nonspecific febrile illness may be followed by encephalitis in infants and children, uncommonly in adults; case fatality rate 3–4%

Yellow fever

Yellow fever virus (Family Flaviviridae, genus Flavivirus); only jungle cycle is zoonotic (humans are reservoir for urban cycle)

Nonhuman primates

South America, Africa

Mosquito (Haemagogus spp and Sabethes spp in jungle cycles in South America, Aedes spp in jungle cycles in Africa) bites

Nonspecific, mild to severe febrile illness followed by liver and renal failure in 20–50%; hemorrhages (eg, epistaxis, hematemesis, melena, uterine hemorrhage) and often jaundice in severe cases; cases with hemorrhages are often fatal


Prion Diseases

Variant Creutzfeldt-Jakob disease

Bovine spongiform encephalopathy prion

Cattle are most important host; also infects other ruminants, cats and other felids, lemurs

Most cases in the UK, but also in many other countries

Ingestion of bovine products, especially those contaminated with CNS tissues

Neurodegenerative disorder similar to sporadic Creutzfeldt-Jakob disease, but often in younger patients and progresses more rapidly; always fatal

a Many proven zoonoses, including some relatively rare arthropodborne viral infections and helminth infections have been omitted, as well as those diseases caused by fish and reptile toxins.

b Enterotoxigenic, enteroinvasive, enteropathogenic, and enteroaggressive strains are not considered zoonotic.