Zoonotic Diseases

Bacterial Diseases

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; papule to 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)

Bordetellosis (see Respiratory Diseases of Pigs and Infectious Tracheobronchitis of Dogs)

Bordetella bronchiseptica

Dogs, rabbits, cats, pigs, guinea pigs, other mammals

Worldwide; uncommon in people

Exposure to saliva or sputum, aerosols

Sinusitis, bronchitis, pertussis-like illness; pneumonia and disseminated disease (eg, endocarditis, peritonitis, meningitis), usually in immunocompromised; wound infection

—Lyme disease

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

Wild rodents, insectivores, hedgehogs, hares, other mammals; birds are reservoirs for agent; deer are hosts for tick vector only (blood meals)

Agents exist worldwide where Ixodes ticks are found; human cases have been reported in North America, Europe, Australia, parts of Asia, Amazon region of South America

Ixodes spp bites

Nonspecific febrile illness early; target skin lesions in many; may progress to arthritis, neurologic, cardiac, and/ or skin signs (acrodermatitis chronica atrophicans); syndromes may vary with infecting agent

—Southern tick-associated rash illness

Etiology uncertain; various Borrelia spp suggested

USA; most cases in southeast

Tick bite (Amblyomma americanum)

Resembles Lyme disease

B melitensis

Goats, sheep, camels; other mammalian spillover hosts

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

Ingestion (including unpasteurized dairy products or undercooked meat), contact with mucous membranes and broken skin; Rev 1 vaccine

As above; this species highly pathogenic for people

B canis

Dogs; evidence of infection in wild canids including coyotes, foxes

Worldwide; rare in people

Probably via ingestion or contact with mucous membranes, broken skin; close contact, especially with animals that recently aborted or gave birth

Probably as above

Campylobacter enteritis (see Enteric Campylobacteriosis)

C jejuni, C coli, occasionally other species; some strains of C jejuni seem to have broader host ranges than others

Poultry, cattle, swine, dogs, cats, rodents, other mammals, wild birds

Worldwide

Foodborne (especially poultry and other meats, unpasteurized dairy products); waterborne; contact with infected animals (fecal/oral)

Gastroenteritis from mild cases to fulminating or relapsing colitis; occasional sequelae such as reactive arthritis; occasionally, other syndromes, including sepsis

Capnocytophaga infection

C canimorsus, C cynodegmi

Dogs, cats

Probably worldwide

Bites or scratches

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

Chlamydiosis (see also Psittacosis below)

Chlamydia ( Chlamydophila) abortus, C felis

C abortus in sheep, goats, cattle, other mammals; 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

C abortus: abortions, septicemia; C felis suspected agent of keratoconjunctivitis, also implicated in other conditions (controversial)

Clostridium perfringens, type A (most common), C, or D; environmental or endogenous source, with some potential for zoonotic transmission

Domestic and wild animals, people

Worldwide

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

Dermatophilosis (see Dermatophilosis)

Dermatophilus congolensis

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

Worldwide, especially in warmer regions

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

Pustular desquamative dermatitis, other skin lesions

Erysipeloid (see Erysipelothrix rhusiopathiae Infection)

Erysipelothrix rhusiopathiae

Swine, sheep, cattle, rodents, marine mammals; many other domestic and wild mammals and marsupials, birds (including poultry), reptiles, fish, mollusks, crustaceans

Worldwide

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

Localized cellulitis, usually self-limiting, often on hands; generalized skin lesions (uncommon); arthritis, often in finger joints near skin lesion; endocarditis (with high mortality, 38%); generalization with sepsis, other syndromes uncommon and often in immunocompromised

Helicobacter infection

H pullorum, H suis, other species suspected as zoonoses

Poultry (H pullorum), rodents (H pullorum and other species), pigs (H suis), dogs (H canis), many other mammals

Uncertain; possibly ingestion of undercooked meat or direct contact

Gastroenteritis or diarrhea, liver disease; bacteremia in immunosuppressed patients

Leptospirosis (see Leptospirosis)

Leptospira spp

Domestic and wild animals; reservoir hosts include rodents, dogs, cattle, pigs, farmed red deer, others

Worldwide

Occupational and recreational exposure, or exposure to rodent-contaminated material in urban locations; especially skin, mucous membrane contact with contaminated urine, infected fetuses, or reproductive fluids; water- and foodborne

Asymptomatic to severe, sometimes biphasic; nonspecific febrile illness followed by aseptic meningitis or icteric form (especially liver, kidney, CNS involvement, hemorrhages possible); pulmonary hemorrhage and edema, other syndromes; uveitis can be sequela; case fatality rate varies with syndrome (uncommon in aseptic meningitis, 5%–15% in icteric form, 30%–60% in severe pulmonary form)

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 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

Mycobacteriosis (see Tuberculosis and other Mycobacterial Infections)

Mycobacterium avium complex

Many species of mammals, some birds

Worldwide

Environmental, mainly from water, and/or soil; infection common to people and animals

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

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

Cattle, other ruminants; swine, cats, dogs, koalas, other mammals, amphibians, reptiles (uncommon), fish; predominant Mycobacterium spp vary with host

Worldwide; distribution varies with the organism

Environmental, from water and/or soil

Same syndromes as M avium complex; some organisms tend to be associated with certain syndromes (eg, M marinum, M ulcerans, with ulcerative or nodular dermatitis)

Pasteurellosis (see Pasteurellosis of Sheep and Goats and see Pasteurellosis)

Pasteurella multocida and other species

Many species of domestic and wild animals, including dogs, cats, livestock, rabbits, birds

Worldwide

Wounds, scratches, bites, close contact with mucus membranes

Wound infections, cellulitis most common; other syndromes possible, including osteomyelitis, septic arthritis, sepsis, meningitis, respiratory disease; systemic conditions more common in immunocompromised

Psittacosis and ornithosis (see Avian Chlamydiosis)

Chlamydia (Chlamydophila) psittaci

Psittacine birds (especially parakeets, cockatiels), pigeons, turkeys, ducks, geese, and other domestic or wild birds; mammalian strains of C psittaci also exist (zoonotic potential still undetermined)

Worldwide

Inhalation of respiratory secretions or dried guano

Influenza-like febrile illness with nonproductive cough that may progress to pneumonia; complications, including endocarditis, myocarditis, meningoencephalitis, hepatitis, glomerulonephritis, and other organ dysfunction; sepsis; some cases fatal if untreated, <1% with treatment

Spirillum minus

Rodents; might also be transmitted by carnivores, which are probably infected or transiently colonized from rodents

Organism is common only in Asia

Mainly bites and scratches

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

Streptococcal infections

Streptococcus spp, including S suis, S equi zooepidemicus, S canis, S iniae, possibly others

S suis in swine; S equi zooepidemicus in horses; S canis in dogs, cats; S iniae in fish; each species can also be found in other animals

Worldwide

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

Skin and soft-tissue infections; pharyngitis; other conditions, including pneumonia, meningitis, arthritis, endocarditis, streptococcal toxic shock syndrome, sepsis

Mycobacterium caprae

Mainly goats, also infects other ruminants; can occur in other mammals, including pigs, horses, cervids, camels, carnivores

Reported mainly in Europe

Thought to be ingestion or direct contact with livestock, similarly to M bovis

Extrapulmonary conditions, including skin lesions, meningitis, lymphadenitis, pericarditis, urinary, dissemination; also pulmonary disease

Tularemia (see Tularemia)

Francisella tularensis subsp tularensis more virulent, F tularensis subsp holarctica (F tularensis type B) less virulent, F tularensis subsp mediasiatica, F tularensis subsp novicida

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

F tularensis subsp tularensis almost exclusively in North America; F tularensis subsp holarctica in North America, Europe, Asia; F tularensis subsp mediasiatica in Central Asia; F tularensis subsp novicida reported in North America, Australia, Spain

Contact with mucous membranes, broken skin; insect bites (tabanids, mosquitoes, hard ticks); fomites; ingestion in food or water; inhalation

Nonspecific febrile illness, lymphadenitis; ulcerative skin lesions, exudative pharyngitis and stomatitis, conjunctivitis, gastroenteritis, respiratory signs or pneumonia, sepsis; case fatality rate 5% (localized disease, untreated) to >50% (untreated typhoidal form or severe respiratory disease)

V vulnificus

Marine shellfish, crustaceans (eg, shrimp), fish; also environmental in aquatic environments

Worldwide; human cases have been reported in North America, Europe, Asia

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 immunocompromised or those with liver disease, other debilitating illnesses; case fatality rate for sepsis >50%, and up to 25% for wound infections

V cholerae non-O1/O139 (nonepidemic strains)

Oysters, other seafood; also environmental in aquatic environments

Worldwide

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)

Y enterocolitica; not all serotypes are pathogenic

Many domestic and wild mammals, including rodents; some birds, reptiles, amphibians; zoonotic serotypes most common in pigs (major zoonotic source), pathogenic types also occur in dogs, cats

Worldwide; prevalence of human disease may vary between regions (commonly reported in Europe)

Ingestion

Gastroenteritis with watery diarrhea especially in young children, bloody feces uncommon; pseudoappendicitis; sequelae may include erythema nodosum, reactive arthritis; sepsis, other syndromes

Human ewingii ehrlichiosis (formerly granulocytic ehrlichiosis)

Ehrlichia ewingii

Dogs, deer proposed

Southeastern and south central USA; has been detected in South America

Ticks, including Amblyomma americanum

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

Human granulocytic anaplasmosis (formerly human granulocytic ehrlichiosis)

Anaplasma phagocytophilum (formerly Ehrlichia phagocytophilum and E equi)

Wild rodents, deer may be reservoirs in North America; livestock, wild ungulates, wild rodents may be reservoirs in Europe; many other animals (eg, equids, ruminants, dogs, cats, birds) can also be infected

Worldwide

Tick bites (Ixodes spp)

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

Q fever (Query fever, see Coxiellosis)

Coxiella burnetii

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

Worldwide

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

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

Spotted fever group of Rickettsia

—Mediterranean spotted fever; Boutonneuse fever; Tick bite fever;

R conorii subsp conorii

Dogs, rabbits implicated as reservoirs; other animals can be infected

Europe, especially Mediterranean; cases reported in sub-Saharan Africa

Bite of infected ticks (mainly Rhipicephalus sanguineus, also others), crushing tick

Nonspecific febrile illness; eschar (typically single) may or may not be present; rash, often maculopapular, in most; life-threatening disseminated disease or neurologic signs possible but uncommon; case fatality rate 1%–3% if untreated

—Fleaborne spotted fever; Cat flea typhus

R felis (synonym ELB agent)

Unknown; dogs have been suggested as possible amplifying hosts

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

Flea bites; mainly associated with Ctenocephalides felis (cat flea), also infects C canis and other fleas

Few clinical cases have been described but resembles other spotted fevers; febrile illness; rash in most; eschar may be uncommon; most cases seem to be mild but CNS involvement, pneumonia possible

—Rickettsial pox

R akari

Mice; also rats, Korean voles

Organism may be cosmopolitan; human cases seem to be uncommon

Bite of infected rodent mites, Liponyssoides sanguineus

Eschar (single) in most; febrile illness; maculopapular rash progresses to vesicular, pustular, resembles chickenpox; self-limiting

—Rocky Mountain spotted fever (see Rocky Mountain Spotted Fever)

R rickettsii

Rodents, rabbits, opossums, and other small mammals might amplify; dogs can be infected

Western hemisphere

Bite of infected ticks, especially Dermacentor variabilis, D andersoni (D variabilis in USA); Amblyomma cajennense, A aureolatum in South America; Rhipicephalus sanguineus in Arizona, Mexico, and South America; also from crushing tick

Moderate to severe febrile illness; macular to generalized petechial rash; edema in some; usually no eschar; neurologic, pulmonary, hemorrhagic, and kidney signs in some; sepsis; gangrene; case fatality rate 15%–30% or higher (up to 85%) if untreated, ~3% or less with treatment in North America but higher in parts of Brazil

—Other tickborne species in spotted fever group

R sibirica, R japonica, R helvetica, R honei, R heilongjiangensis, R aeschlimannii, R massiliae, R monacensi, R amblyommii, others

Various vertebrates

Worldwide; distribution varies by species

Bites of ixodid 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

—Murine typhus; Fleaborne typhus

R typhi (formerly R mooseri)

Rats are major reservoir; cats, opossums, possibly dogs, other species in peridomestic cycle

Worldwide, especially warmer regions

Infected rodent fleas, usually via flea feces; cat fleas seem to be involved in some cycles

Fever, severe headache, central rash (not always observed); other signs, including arthralgia, cough, nausea/vomiting in some; mortality rate 4% without treatment

—Typhus

R prowazekii

Flying squirrels

Eastern USA

Squirrel lice or fleas suspected

Nonspecific febrile illness, rash; GI signs in some; sepsis possible; appears to be somewhat milder than non-zoonotic typhus, which has a mortality rate of 20%–60% if untreated

Aspergillosis; Allergic bronchopulmonary aspergillosis (see Aspergillosis)

Aspergillus spp

Birds and mammals

Worldwide

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

Allergic respiratory signs, especially in people with certain respiratory conditions or immunodeficiencies; allergic sinusitis; pneumonia sometimes with dissemination in immunocompromised (can be fatal); chronic pulmonary disease ± aspergilloma (fungus ball); localized infections of other organs, tissues

Coccidioidomycosis (see Coccidioidomycosis)

Coccidioides immitis, C posadasii

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

Especially southwestern USA, Mexico, Central and South America; in arid or semiarid foci; some cases might be acquired outside usual foci

Principally environmental exposure (inhalation of arthrospores), including fungal cultures; infection common in people and animals, one unusual case reported after necropsy 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

Histoplasmosis (see Histoplasmosis)

Histoplasma capsulatum var capsulatum

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

Worldwide; clinical cases often cluster in regional foci

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

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

Malassezia infection

Malassezia spp

Dogs, cats, other animals

Worldwide

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

Dermatitis; zoonotic strains might be implicated in fungemia in preterm neonates, other immunocompromised

Sporotrichosis (see Sporotrichosis)

Sporothrix schenckii

Cats, other mammals, birds

Worldwide; epizootics in cats in South America

Primarily environmental in vegetation, wood, soil; inoculation from environment in penetrating wounds (splinters, bites, pecks), skin contact with lesions, especially in cats; bites, scratches, other close contact implicated during feline epidemics; inhalation rare

Papules, pustules, nodules, ulcerative skin lesions, may follow course of draining lymphatics; mucosa can be affected; extracutaneous involvement, especially bones, joints; disseminated disease (including meningitis) can be seen in immunocompromised; acute or chronic pulmonary disease resembling tuberculosis after inhalation, especially with underlying lung disease (rare)

Babesiosis (see Babesiosis)

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

Rodents, insectivores, lagomorphs, some other mammals; reservoirs uncertain for some species

Babesia spp worldwide in wild animals, many agents not identified to species; human illness due to B microti complex reported in North America (most), Europe, Asia, Australia

Bite of infected Ixodes ticks for B microti

Many immunocompetent patients may have mild to moderate flu-like, febrile illness; mild to severe hemolytic anemia, especially severe in immunocompromised and elderly; respiratory, hepatic, renal, and other organ dysfunction; recurrent or chronic infection may develop; dual infection with B burgdorferi may worsen both diseases; death possible in severe cases

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 bites (Rhipicephalus microplus and R annulatus)

Chagas’ disease (American trypanosomiasis, see 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; ingestion in contaminated food

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)

Giardiasis (see Giardiasis (Giardia))

Giardia intestinalis, also known as G duodenalis (formerly G lamblia); only some genotypes seem to have zoonotic potential

Many domestic and wild mammals, including dogs, cats, ruminants, aquatic mammals such as beavers

Worldwide

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

Gastroenteritis, may be persistent

—Cutaneous and mucocutaneous

L tropica complex (except L tropica, which is maintained in people), L braziliensis complex, L mexicana complex, others

Dogs (L peruviana), rodents, various wild mammals act as reservoir hosts; other mammals can be infected

Mediterranean, Asia, Africa, Middle East, Mexico to South America, Caribbean; localized focus in USA (Texas and Oklahoma)

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; cutaneous form rarely fatal, mucocutaneous form can be disfiguring and may be fatal if pharynx affected

Microsporidiosis

Microsporidia of Enterocytozoon bieneusi, Encephalitozoon cuniculi, E intestinalis, E hellem, others; both zoonotic and anthropnotic transmission reported for some agents

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

Worldwide

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

Sarcocystosis (Sarcosporidiosis, see Sarcocystosis)

Sarcocystis suihominis, also called S meischeriana

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

Worldwide

Ingestion of raw pork

Gastroenteritis, usually mild, or asymptomatic

Sarcocystis spp; S nesbitti may be one cause

People are intermediate host; species of Sarcocystis and definitive host(s) are often unknown; definitive host for S nesbitti thought to be snakes

Worldwide; symptomatic cases mainly in Asia, probably because of distribution of definitive host

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

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

Trypanosomiasis (African sleeping sickness, see Trypanosomiasis)

Trypanosoma brucei; T brucei rhodesiense is zoonotic; T brucei gambiense is primarily a human pathogen, although some animals (eg, pigs) can be infected and might serve as minor reservoirs

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

Africa; common below the Sahara desert

Bite of infected tsetse fly (Glossina spp)

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

Clonorchiasis

Clonorchis sinensis (Chinese liver fluke)

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

Asia

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

Echinostomiasis

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

Cats, dogs, rodents, pigs, other mammals; birds, including poultry, are definitive hosts; fish, shellfish, tadpoles, snails are intermediate hosts

Most human cases in Asia, Western Pacific; this group of parasites is widely distributed, including Europe, Americas, Middle East

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

Abdominal discomfort; diarrhea, especially in heavy infestation; malnutrition, anemia, edema may occur, especially in children; intestinal perforation has been reported

F gigantica

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

Thought to occur mainly in tropical areas: Africa, Asia, Middle East, and western Pacific

As above

Signs resemble fascioliasis caused by F hepatica

Gastrodiscoidiasis

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

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

Asia (including the Philippines), also reported in Africa, Volga delta in Russia

Possibly ingestion of water or aquatic plants

Mild diarrhea if high parasite burden

Metagonimiasis

Metagonimus yokogawai, M miyatai, M takahashii, and other Metagonimus spp

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

Human illness mainly in Asia, also reported in Siberia; parasites have been found in Europe

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

Nanophyetiasis

Troglotrema salmincola (also called Nanophyetus salmincola)

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

North America along Pacific coast, Russia

Ingestion of undercooked fish or roe

Mild gastroenteritis

O viverrini (small liver fluke); zoonotic transmission can occur, but people are important hosts

People, 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

Paragonimiasis (Lung fluke disease)

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

Dogs, cats, swine, wild carnivores, opossums, 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); 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

S mansoni

People, 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 (most often) and/or 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 mekongi

People 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

Schistosomiasis, urinary

S haematobium

People are main reservoir (definitive host); occasionally infects nonhuman primates, pigs, buffalo, 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

Parasitic Diseases—Cestodes (Tapeworms)

Coenuriasis (Coenurosis)

Taenia multiceps

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

Worldwide in scattered foci; mainly reported from Europe, Asia

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 brauni

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

Africa

As above

Most often in subcutaneous tissues (skin swelling) or eye, also CNS

T crassiceps

Foxes, also other canids and carnivores, including dogs, are definitive hosts; rodents, insectivores, rabbits, occasionally other mammals are intermediate hosts

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

Ingestion of eggs

Tissue invasion (mainly subcutaneous, muscle), ocular; one paravertebral pseudohematoma with local bleeding, one CNS larva; many but not all cases in immunocompromised

Dipylidiasis (Dog tapeworm infection)

Dipylidium caninum

Dogs, cats, wild canids, some other wild carnivores are definitive hosts; fleas are intermediate hosts

Worldwide; uncommonly reported in people

Ingestion of dog or cat fleas

Usually in children; asymptomatic or mild abdominal distress, diarrhea; proglottids in feces resemble cucumber seeds

E multilocularis

Foxes and other wild canids and felids are usual definitive hosts, but parasite can also mature in dogs, cats; intermediate hosts are usually rodents, insectivores, some other mammals

North America (mainly Canada to north central USA), northern and central Eurasia

Ingestion of tapeworm eggs in food or 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; without treatment, 70%–100% cases are fatal

E vogeli

Bush dogs are usual definitive host, can mature in other canids, including dogs; pacas, agouti, nutria, nonhuman primates, and other mammals can be intermediate hosts

Central and South America

Ingestion of tapeworm eggs in food or 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)

H diminuta (mouse tapeworm, rat tapeworm)

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

Worldwide

Ingestion of infected insects in food

Mild abdominal symptoms of short duration

Raillietina infection

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

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 cases asymptomatic; gastroenteritis, possibly other signs; mainly in children

Taeniasis

—Beef tapeworm disease

T saginata

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

Worldwide

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

Parasitic Diseases—Nematodes (Roundworms)

Angiostrongylus cantonensis, also called Parastrongylus cantonensis

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

Originated in Asia, spread to many other regions, mainly tropics, including Americas, Caribbean, Middle East, Australia

Ingestion of raw/undercooked intermediate or paratenic host (or accidental ingestion on vegetables); possibly ingestion of plants contaminated by secretions of intermediate host

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

Ascariasis

Ascaris suum; potentially zoonotic (controversial)

Pigs, also reported occasionally in other mammals, including nonhuman primates, sheep, cattle

Worldwide, prevalence varies

Ingestion of eggs from environment (shed in feces)

Visceral larva migrans (respiratory signs, fever during larval migration); GI signs

—Hepatic capillariasis

Capillaria hepatica (also called Calodium hepaticum)

Rodents major host, also in many 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

—Pulmonary capillariasis

C aerophila (also called Eucoleus aerophilus)

Dogs, cats, other carnivores

Worldwide; rare in people

Accidental ingestion of infective eggs in soil or contaminated food

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

Dracunculiasis (Guinea worm infection)

Dracunculus medinensis; people are most important host but possible role for zoonotic transmission in some locations

People, nonhuman primates are definitive hosts; infections have also been reported in animals, but parasite identification sometimes uncertain; domestic animals not thought to maintain parasite but possible exceptions (eg, dogs in Chad); 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

—Dirofilariasis

Dirofilaria immitis

Dogs, cats, other mammals especially carnivores, mustelids, primates are definitive hosts (mainly patent in dogs and wild canids); mosquitoes are intermediate hosts

Worldwide

Bite of infected mosquitoes

Fever, cough acutely, larvae result in infarct or coin lesion in the lungs; often asymptomatic; rarely involves eye or other body sites

—Malayan filariasis

Brugia malayi; subperiodic form is of uncertain origin, thought to be zoonotic or maintained in both animals and people; periodic form is exclusive to people

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

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

Bite of infected mosquitoes, Mansonia spp mainly associated with subperiodic form

Lymphatic filariasis: 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

Gnathostomiasis

Gnathostoma spinigerum, G binucleatum, and some other Gnathostoma spp

Dogs, cats, wild carnivores are definitive hosts (G doloresi and G hispidum in pigs and wild boars); copepods, freshwater fish, eels, frogs, snakes, chickens, snails, pigs are intermediate or paratenic hosts

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

Ingestion of undercooked fish, poultry, or other intermediate or paratenic host, drinking water contaminated with copepods containing larvae; handling meat that contains larvae

Fever, malaise, gastroenteritis, urticaria, soon after ingestion; migratory skin lesions (intermittent swelling, often painful or pruritic, or linear erythematous lesions) after weeks to years; may involve viscera, eye, or CNS; CNS involvement can be fatal or result in permanent damage with reported case fatality rates of 7%–25%

Larva migrans, cutaneous (see alsognathostomiasis, above)

Ancylostoma braziliense, A caninum, A ceylanicum, Uncinaria stenocephala

Cats, dogs, wild carnivores are definitive hosts

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; A ceylanicum can also become patent in intestine, causing GI signs, anemia

Strongyloides stercoralis and other Strongyloides spp found in animals

S stercoralis in dogs, cats, primates, including people; 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)

Baylisascaris procyonis, possibly other species of Bayliscascaris

Raccoons, kinkajous are definitive hosts; dogs can be definitive or intermediate host; many mammals (including people), marsupials, and birds are intermediate or paratenic 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

Onchocercosis

Onchocerca gutturosa, O cervicalis, O jakutensis, O dewittei japonica, O reticulata, O lupi, others

Definitive hosts include cattle, horses, cervids, wild boars, dogs and other canids, camels, other species

Distribution varies with species

Probably transmitted by black flies (Diptera: Simuliidae), possibly other vectors

Ocular disease, subcutaneous nodules

S fuelleborni

Primates, including people

Africa, Asia, and in captive primates in other areas

As above

Associated with abdominal pain, occasional diarrhea, not well studied

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); T zimbabwensis (zoonotic potential unknown) can infect reptiles

Worldwide, especially in temperate regions; 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

Trichuriasis (Whipworm infection)

Trichuris suis, possibly T vulpis and other species; main species in people is T trichiura, but 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

T suis can colonize people, who develop GI signs; rare larva migrans or intestinal infections suggested from T vulpis (controversial identification)

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

Worldwide

Ingestion of infected beetles, other intermediate hosts, or fish

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

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

Acariasis (Mange)

Mites of Sarcoptes, Cheyletiella, Dermanyssus, and Ornithonyssus spp, Notoedres cati, Trixacarus caviae, Liponyssoides sanguineus; possibly others (uncommon)

Mammals and birds

Worldwide

Contact with infected animals, fomites

Itchy skin lesions

Cordylobia anthropophaga, rarely C rodhaini (Tumbu flies)

Mammals, often found in dogs, rodents

Africa, Middle East; also reported in Mediterranean region of Europe

Larvae from environment invade unbroken skin

Furuncular swelling at site of invasion, often feet; fever, malaise, focal lymphadenopathy possible

Dermatobia hominis (human botfly)

Mammals, some birds

South and Central America, Mexico

Eggs carried by other insects (eg, mosquitoes); larvae hatch and penetrate skin of mammalian host when insect lands

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

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 an eosinophilic syndrome with fever, muscle pain, sometimes respiratory, cardiac, or neurologic signs

Wohlfahrtia spp, Wohlfahrtia vigil, W magnifica

W vigil in rabbits, rodents, mink, foxes, dogs, and other carnivores, other mammals; W magnifica in sheep, cattle, dogs, 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

Linguatula serrata

Definitive hosts are dogs and other canids, felids; intermediate hosts are herbivores (especially sheep, goats, lagomorphs) and people

Worldwide

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

Tunga infections

Tunga penetrans (sand fleas, jiggers)

People, 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

Alkhurma virus infection

Alkhurma virus (family Flaviviirdae, genus Flavivirus); may be a variant or strain of Kyasanur Forest virus

Sheep, goats, camels

Middle East, mainly reported in Saudi Arabia, also Egypt

Ticks (Ornithodoros and Hyalomma spp); direct contact with animal meat via broken skin or ingestion of unpasteurized camel milk linked to some cases

Febrile illness, often with GI signs (eg, vomiting, abdominal pain); encephalitic/neurologic and hemorrhagic signs in some; case fatality up to 25% in early reports, recently <1%

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, fever, malaise

—La Crosse encephalitis

La Crosse virus (California encephalitis virus serogroup)

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 <1% in cases with encephalitis

Camelpox

Camelpox virus

Old World camelids, possibly other species

Middle East, Asia, Africa, possibly other areas; human cases recently described in India in camel handlers, rare unconfirmed cases suggested in other locations

Direct contact

Skin lesions similar to cowpox, variola virus infections

Colorado tick fever

Colorado tick fever virus (family Reoviridae, genus Coltivurus; Salmon River virus and California hare coltivirus may be variants

Rodents; also found in porcupines, lagomorphs, deer, elk, and other mammals

Rocky Mountain region of North America

Tick bites (primary vector is Dermacentor andersoni)

Nonspecific febrile illness; pharyngitis, rash, or GI signs possible; biphasic or triphasic in some; complications (eg, neurologic signs, hemorrhages, pericarditis, myocarditis, orchitis) uncommon but can occur in severe cases; deaths rare

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

Papules, 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; more extensive or generalized disease may be seen in children, people with eczema,immunocompromised; severe cases can involve respiratory mucosa; rare fatal cases (eg, complications of encephalitis)

Eastern equine encephalomyelitis (see Equine Arboviral Encephalomyelitis)

Eastern equine encephalomyelitis virus (family Togaviridae, genus Alphavirus); North American lineage 1 strains more virulent than South American lineages

Birds are principal reservoir hosts in North America, snakes might have role in overwintering virus; rodents, marsupials might be reservoir hosts in South America; clinical cases seen 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 in North America; various mosquito species (Aedes, Coquillettidia, Culex) can transmit to people

Nonspecific febrile illness may be followed by severe encephalitis, especially with North American lineage; neurologic sequelae common after encephalitis; case fatality rate 30%–70% with North American lineage; more severe in infants and elderly

Encephalomyocarditis

Encephalomyocarditis virus (family Picornaviridae, genus Cardiovirus); thought to be zoonotic

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

Worldwide in animals

Uncertain

Nonspecific febrile illness, sometimes with GI signs, and/or decreased reflexes have been reported in adults, with recovery within several days; CNS signs, including paralysis, have been reported in children

Hantaviral diseases

—Hemorrhagic fever with renal syndrome

Hantaan virus, Dobrava virus, Puumala virus, Seoul virus, Saaremaa 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, sometimes petechiae, GI signs (may be severe); followed by hypotension, renal signs to renal failure with oliguria; hemorrhage, other syndromes in some; mortality rate varies with the virus, from <1% (Puumala virus) to 10%–15% (Hantaan virus)

Hepatitis E

Hepatitis E virus, mammalian isolates (family Hepeviridae, genus Hepevirus); genotypes 3 and 4 zoonotic; genotypes 1 and 2 maintained in people

People; animals, including swine, wild boar, deer, rabbits, ferrets, rats, mongoose, others; swine and probably other hosts are reservoirs for human infections

Worldwide; human and zoonotic genotypes may differ in prevalence between areas

Fecal-oral spread; consumption of raw or undercooked meat and liver; waterborne, contact with animal reservoirs

Mild, self-limiting hepatitis to liver failure, more severe in pregnancy and can result in abortion, death of newborn, premature birth; usually acute, but can be chronic in organ-transplant patients; case fatality rate <1% to 4% in general population, up to 20% in pregnant

Influenza virus infections

—Swine influenza

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

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

Worldwide

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

Seems to resemble human influenza; severity of disease varies; fatal cases have been reported uncommonly

Kyasanur Forest disease

Kyasanur Forest virus (family Flaviviridae, genus Flavivirus)

Rodents, shrews, other small mammals might be reservoirs (uncertain); affects monkeys; possible infections in other mammals, birds

India

Tick bites (especially Haemaphysalis spinigera, also others)

Nonspecific febrile illness; course may be biphasic; hemorrhagic signs (eg, ecchymoses, purpura, petechiae, GI bleeding, epistaxis) and/or neurologic signs possible in second stage; prolonged convalescence in many; case fatality rate ~3%

Louping ill (Ovine encephalomyelitis, see Louping Ill)

Louping ill virus (family Flaviviridae, genus Flavivirus)

Sheep, goats, also in llamas, cattle, horses, other domestic and wild mammals, grouse, ptarmigan

UK, Northern Ireland; also reported in Norway, Spain; uncommon in people

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

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

Marburg hemorrhagic fever

Marburg virus (family Filoviridae, genus Marburgvirus)

Bats are reservoir hosts; primates can be infected

Africa

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 isolate

Middle East respiratory syndrome (MERS)

MERS coronavirus

Unknown reservoir host, possibly bats; source of infection for people uncertain, camels implicated

Middle East

Pneumonia, more likely in people with coexisting illness or immunosuppression but also in healthy; ~50% of known cases were fatal

Monkeypox

Monkeypox virus (family Poxviridae, genus Orthopoxvirus); Congo Basin clade causes more severe illness than West African clade

Nonhuman primates, some wild and pet rodents, including Gambian rats, dormice, prairie dogs, African squirrels, some other mammals such as opossums; full host range uncertain

West and central Africa

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

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%–17% or higher; milder in those vaccinated for smallpox

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 found 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

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 and meningitis; respiratory disease, including acute respiratory distress syndromes in some; septicemia; other complications in severely ill; case fatality rate 33%–75%

Powassan virus encephalitis

Powassan virus (family Flaviviridae, genus Flavivirus); two closely related lineages in different reservoirs

Rodents (groundhog, squirrels, mice) and other small mammals thought to be reservoirs

North America, eastern Russia

Ixodes spp ticks, also found in Dermacentor andersoni

Nonspecific febrile illness; may progress to neurologic signs, which may be severe; some cases fatal

Rift Valley fever (see Rift Valley Fever)

Rift Valley fever virus (family Bunyaviridae, genus Flavivirus)

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

Africa, foci on Arabian peninsula, Indian subcontinent

Mosquito bites (Aedes spp and Culex triteniorynchus); contact with tissues

Influenza-like febrile illness in most; complications, including hemorrhagic fever, meningoencephalitis in <5%; ocular disease in 1%–10%; other syndromes include acute renal failure or thrombosis; death uncommon except with hemorrhagic syndrome

St. Louis encephalitis

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

Wild birds, domestic fowl; rodents, bats, other mammals might also maintain viruses in South America

Western hemisphere

Mosquito bites (Culex tarsalis, C pipiens-quinquefasciatus complex, C nigripalpus, also reported in other genera)

Flu-like illness sometimes followed by meningitis or encephalitis, focal neurologic signs, dysuria; more severe in elderly and those with debilitating diseases; case fatality rate of 5%–20% reported in epidemics

Sindbis virus disease

Sindbis virus (family Togaviridae, genus Alphavirus)

Birds (passeriforms suspected as main reservoirs/amplifying hosts); occasionally found in other vertebrates

Virus widespread in Eastern hemisphere; human cases tend to occur in limited geographic regions

Mosquito bites; Culex and Culiseta, also others

Fever, arthritis, rash, prominent myalgia; nausea, vomiting, mild jaundice in some; joint pain can persist for months; seems to be mild or asymptomatic in most children; no fatal cases reported

Tickborne encephalitis (Far eastern tickborne encephalitis, Russian spring-summer encephalitis, Central European tickborne encephalitis)

Tickborne 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; also in goats, sheep, dogs, and other mammals; birds

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

Tick bites (mainly Ixodes ricinus and I persculatus; also other species); 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 <2% (TBEV-Eu), 2%–3% (TBEV-Sib); case fatality rate 20%–30% in TBEV-FE may be based on severe cases

Vaccinia-related poxviruses

Vaccinia or vaccinia-like viruses (family Poxviridae, genus Orthopoxvirus) of uncertain origin

Reservoir uncertain; found in wild rodents, cattle, horses, nonhuman primates

Appear to be endemic in Brazil

Direct contact

Pox skin lesions (papules, pustules, ulcerative nodules), may be accompanied by fever, lymphadenopathy

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; most likely not endemic north of Mexico but sporadic outbreaks

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 be found in mouth, pharynx, or inoculation site (eg, hands); self-limiting

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

West Nile virus (family Flaviviridae, genus Flavivirus); lineage 1 and lineage 2 viruses are both pathogenic

Birds are primary reservoir hosts; also affects horses, other mammals, alligators, possibly other reptiles and amphibians

Eastern and Western hemisphere

Mosquito bites (primarily Culex univittatus, Culex spp); 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; occasionally other syndromes; worse in elderly and immunocompromised; case fatality rate ~10% in all patients with neurologic disease, but higher in elderly

Yellow fever

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

Nonhuman primates

South America, Africa

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

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

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