Disease in Humans | Causative Organism | Animals Involved | Geographic Distribution | Probable Means of Transmission to Humans | Clinical Manifestations in Humans |
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Viral Diseases | |||||
Alkhurma (Alkhumra) hemorrhagic fever | Alkhurma (=Alkhumra) virus (family Flaviviirdae, genus Flavivirus); variant of Kyasanur Forest virus Haemaphysalis spp Few of the currently recognized 167 species of Haemaphysalis parasitize livestock, but those that do are economically important in Eurasia, Africa, Australia, and New Zealand. Some haemaphysaline... read more ; member of tickborne encephalitis virus serocomplex | Sheep, goats, camels | Middle East | 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; encephalitic/neurologic and hemorrhagic signs in some; early reports suggested case fatality up to 25% but probably lower, recently < 1%; subclinical infections may be common |
Barmah Forest virus infection; epidemic polyarthritis | Barmah Forest virus (family Togaviridae, genus Alphavirus) | Natural hosts unknown; horses, brushtail possums, kangaroos might hosts | Australia, Papua New Guinea | Mosquito bites; Culex and Aedes spp implicated; also found in Culicoides midges | Resembles disease due to Ross River virus Etiology and Epidemiology Equine arboviral encephalomyelitis is due to infection with arthropod-borne viruses typically belonging to the families Togaviridae (genus Alphavirus) or Flaviviridae (genus Flavivirus)... read more ; fever, rash, and nonspecific clinical signs; myalgia and polyarthralgia can persist for months |
Buffalopox | Vaccinia virus, Buffalopox virus strain (family Poxviridae, genus Orthopoxvirus) | Water buffalo, cattle | Indian subcontinent (south Asia), Indonesia, parts of Middle East | Skin contact with infected animals, often when milking | Pox skin lesions mainly on hands, face, legs, buttocks; occasionally lymphadenopathy, fever, malaise |
California encephalitis virus serogroup (California serogroup) infections | California encephalitis virus serogroup (family Bunyaviridae, genus Orthobunyavirus); includes California, La Crosse, Tahyna, Inkoo, Jamestown Canyon, Morro Bay, Snowshoe hare, Guaroa, Lumbo, Chatanga, and other viruses | Many wild and domestic mammals; major reservoirs and amplifying hosts can differ between viruses | North and South America, Europe, Africa, Asia; possibly worldwide; distribution of each virus varies | Mosquito bites | Syndromes, severity vary with the virus; flu-like illness, meningitis, or encephalitis common with North American viruses |
—La Crosse encephalitis | La Crosse virus (California encephalitis virus serogroup) | Chipmunks, squirrels are major amplifying hosts; 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 |
—Tahyna fever | Tahyna virus (California encephalitis virus serogroup) | Hares, rabbits, rodents, hedgehogs, and other mammals | Europe, Asia, Africa | Mosquito bites (culicine and anopheles) | Influenza-like illness, sometimes including GI signs; arthritis or respiratory signs, including bronchopneumonia in some; meningitis possible but appears uncommon; most often in children; does not appear to cause fatal disease |
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 |
Chikungunya | Chikungunya virus (family Togaviridae, genus Alphavirus) | Sylvatic cycle in nonhuman primates, possibly rodents in Africa; Asian lineage virus thought to be maintained in humans; however, sylvatic cycle may also exist in some locations | Asia, Africa, Europe, South America | Mosquito bites (especially Aedes spp) | Febrile illness, may have rash and/or GI signs; arthralgia, especially in small joints, and myalgia 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 and California hare coltivirus may be variants | Rodents and small mammals and other mammals can also be infected | Some regions in western 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 |
Orf virus (family Poxviridae, genus Parapoxvirus) | Sheep, goats, camelids, wild ungulates; rare cases in dogs and cats | Worldwide | Occupational exposure via contact with broken skin (both live animals and meat processing) | Papule(s) that umbilicate and ulcerate, usually on hands; dissemination rare but has occurred in humans with atopic dermatitis; large lesions refractory to treatment can occur in immunosuppressed | |
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 humans; more extensive or generalized disease may occur in children, humans with eczema, immunocompromised; severe cases can involve respiratory mucosa; rare fatal cases (eg, complications of encephalitis) | |
Crimean-Congo hemorrhagic fever virus (family Bunyaviridae, genus Orthonairovirus) | Cattle, water buffalo, rodents, sheep, goats, hares, other mammals, rarely in birds (eg, ostriches) | Africa, Middle East, Asia, parts of Europe where Hyalomma ticks occur | Tick bites, especially Hyalomma but other genera may also transmit; skin, mucous membrane contact with blood or tissues of animals or crushed ticks; ingestion of unpasteurized milk and possibly uncooked animal tissues; rarely airborne; person-to-person transmission occurs, especially via hemorrhage and during close contact | Febrile flu-like signs, GI symptoms; hemorrhagic signs may begin with petechial rash; hepatitis, abortion, other organ involvement in some cases; asymptomatic or mild in some; case fatality rate usually 3%–30% but can be higher | |
Eastern equine encephalomyelitis virus (EEEV), Madariaga virus (former South American EEEV lineages) (family Togaviridae, genus Alphavirus) | Birds are principal reservoir hosts, small mammals might also amplify, snakes might have role in overwintering virus; small mammals (eg, rodents), marsupials might be reservoir hosts for Madariaga virus; clinical cases in equids and occasionally other mammals and birds but domestic animals are almost always dead-end hosts | Americas | Mosquito bites; Culiseta melanura important in EEEV maintenance cycle; Culex spp might be important for Madariaga virus; various mosquito species (Aedes, Coquillettidia, Culex) can transmit to humans | EEEV causes nonspecific febrile illness, which may be followed by severe encephalitis; neurologic sequelae common after encephalitis; case fatality rate 30%–70%;more severe in infants and elderly; Madariaga virus causes similar signs but seems less severe | |
Ebola hemorrhagic fever | Zaire ebolavirus, Sudan ebolavirus, Tai Forest ebolavirus (formerly Ivory Coast ebolavirus), Bundibugyo ebolavirus (family Filoviridae, genus Ebolavirus); Reston ebolavirus does not seem to affect humans | Bats are reservoir hosts for Zaire ebolavirus and suspected reservoir hosts for others; primates, duikers, pigs, possibly other mammals can be infected | Africa | Contact with infected tissues (especially nonhuman primates and duikers), blood; probable transmission from bats in caves; person-to-person transmission occurs | Initially nonspecific febrile illness; maculopapular rash with desquamation; various oral/ pharyngeal mucosal lesions possible; signs of increased vascular permeability, mild to severe bleeding tendency, various other signs (eg, neurologic signs, dyspnea, multiorgan dysfunction) develop a few days after onset; mortality rate 36%–90%, varies with isolate |
Encephalomyocarditis | Encephalomyocarditis virus (family Picornaviridae, genus Cardiovirus); implicated as zoonotic pathogen but few confirmed cases | Rodents, possibly wild boar, may be reservoir hosts; also found in wild and domestic mammals (including swine, nonhuman primates), and wild birds | Worldwide in animals | Probably ingestion of contaminated food or water | Nonspecific febrile illness, sometimes with GI signs, and/or decreased reflexes have been reported in adults, with recovery within several days; implicated in CNS signs, including paralysis in children; most infections may be asymptomatic or mild |
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, typically in laboratories or other high concentrations of virus; broken skin or drinking virus-contaminated unpasteurized milk are recognized routes | Humans may become temporary nasal carriers after field exposure to virus but do not usually become ill; mild influenza-like disease and vesicular lesions (including lesions at site of skin entry) occur very rarely, mostly laboratory associated | |
Hantaviral diseases | |||||
—Hantaviral pulmonary syndrome | Sin Nombre, Black Creek Canal, Bayou, Andes, Choclo, Laguna Negra, and Cano Delgadito viruses, others (family Bunyaviridae, genus Hantavirus) | Reservoirs are rodents, insectivores; each virus tends to be associated with one to a few reservoir hosts; occasionally infect other hosts | North and South America | Aerosols from rodent excretions and secretions; contact with broken skin and mucous membranes; rodent bites; person-to-person transmission reported for Andes virus | Prodromal stage with nonspecific febrile illness; followed by respiratory failure, cardiac abnormalities; hemorrhagic signs possible, mainly with South American viruses; notable kidney disease uncommon; milder illnesses also possible; case fatality rate for most viruses approx. 25%–-40% in classical syndrome |
—Hemorrhagic fever with renal syndrome | Hantaan, Dobrava-Belgrade, Puumala, Seoul, and Amur-Soochong viruses, others (family Bunyaviridae, genus Hantavirus) | Reservoirs are rodents, insectivores; each virus tends to be associated with one to a few reservoir hosts; occasionally infect other hosts | Europe, Asia, Africa; Seoul virus is worldwide | Aerosols from rodent excretions and secretions; contact with broken skin and mucous membranes; rodent bites | Prodromal stage with nonspecific febrile illness; followed by hypotension, renal signs to renal failure with oliguria; hemorrhagic signs, other syndromes (including respiratory) in some; milder illnesses also possible; case fatality rate varies from < 1% (Puumala virus) to 5% (Hantaan virus), and up to 10%–-15% in the past |
Heartland virus disease | Heartland virus (family Bunyaviridae, genus Phlebovirus) | Not known | North America | Vector appears to be Amblyomma americanum tick | Febrile illness with headache, myalgia, arthralgia, diarrhea, thrombocytopenia; some cases fatal (may be associated with comorbidities) |
Hendra virus (family Paramyxoviridae, genus Henipavirus) | Fruit bats are normal reservoir host; horses can be infected | Australia | Direct contact with infected animals (all human cases have been linked with horses) or contaminated tissues | Respiratory infection, encephalitis (including recurrent encephalitis); few cases described but several were fatal | |
Hepatitis E | Hepatitis E virus, mammalian isolates (family Hepeviridae, genus Hepevirus); genotypes 3 and 6, possibly others, are zoonotic; genotypes 1 and 2 maintained in humans | Humans, 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 transmission; 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 |
Herpes B virus disease | Cercopithecine herpesvirus 1 (McHV, Herpesvirus simiae, B virus) (family Herpesviridae, genus Simplexvirus) | Carried in genus Macaca (Old World macaques), with lifelong latency and potential for periodic shedding 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; very high mortality rate in untreated cases |
Influenza virus infections | |||||
—Avian influenza | Influenza A virus (family Orthomyxoviridae, genus Influenzavirus A); avian influenza viruses; many severe human cases linked to Asian lineage H5N1 highly pathogenic avian influenza (HPAI) or H7N9 LPAI viruses; however, other viruses also cause illness | Avian influenza viruses in wild and domestic birds, especially poultry; uncommon in mammals | Worldwide, distribution of strains varies | Usually by contact with infected poultry; avian viruses may be shed in respiratory secretions and 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 | 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 |
Japanese encephalitis (Japanese B encephalitis) | Japanese encephalitis virus (family Flaviviridae, genus Flavivirus) | Swine, wild birds are important maintenance and amplifying hosts; horses ill but epidemiologically unimportant in amplification; other mammals, reptiles, amphibians may be infected, usually subclinically | Asia, parts of western Pacific islands and Australia | Mosquito bites especially Culex; Culex tritaeniorhynchus important in maintenance cycle; also through broken skin or mucous membranes after direct contact with infected tissues | Nonspecific febrile flu-like illness can progress to severe encephalitis or less common neurological syndromes (eg, flaccid paralysis) in some; neurologic sequelae very common in survivors of encephalitis; reported case fatality rates < 5%–40% |
Kyasanur Forest disease | Kyasanur Forest virus (family Flaviviridae, genus Flavivirus); member of tickborne encephalitis virus serocomplex | Rodents, shrews, other small mammals, ground-feeding birds thought to be reservoirs; affects monkeys; possible infections in other mammals, birds | India | Tick bites (especially Haemaphysalis spp, also others) | Nonspecific febrile illness; characteristic papulovesicular eruption on upper soft palate in some; 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% |
Lassa fever | Lassa virus (family Arenaviridae, genus Mammarenavirus) | Wild rodents, multimammate mouse is major host | West Africa | Contact with rodent excretions, secretions, or tissues; aerosols | 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 15%–20% among hospitalized patients |
Louping ill ( Ovine encephalomyelitis Louping Ill ) | Louping ill virus (family Flaviviridae, genus Flavivirus) | Sheep and red grouse are primary reservoirs; also reported in goats, South American camelids, cattle, horses, dogs, farmed cervids, other domestic and wild mammals; some birds related to grouse (eg, ptarmigan) are susceptible to experimental infection | UK, Northern Ireland; also reported in Norway, Denmark (island of Bornholm), part of eastern Russia; similar viruses in Spain, Greece, Turkey; historically in Bulgaria and possibly Japan | Usually tick bites (Ixodes ricinus) in animals but this route appears uncommon in humans; aerosol exposure in laboratory; contamination of skin wounds and mucous membranes after contact with cultures, infected animals or their tissues; possibly ingestion of milk; human illnesses seem to be rare and mostly laboratory associated | Biphasic influenza-like illness, sometimes followed by meningitis or meningoencephalitis, or polio-like paralytics, syndrome in second phase; case fatality rate appears low |
Lymphocytic choriomeningitis | Lymphocytic choriomeningitis virus (family Arenaviridae, genus Mammarenavirus) | Reservoir mainly house mouse; can be maintained in some other mice, hamster populations; also infects guinea pigs, chinchillas, rats, nonhuman primates, some other mammals | Worldwide | Direct or indirect contact with host excretions and secretions (via mucous membranes, broken skin, aerosols); bites; possibly ingestion | Ranges from mild flu-like illness to biphasic with meningitis in second phase; complications (eg, arthritis of hands, parotitis, orchitis) possible; can cause congenital defects (CNS defects, chorioretinitis, and other ocular lesions) or abortion; rarely fatal in immunocompetent (overall case fatality rate < 1%); serious and life-threatening multisystemic disease in transplant patients |
Marburg hemorrhagic fever | Marburg virus, Ravn 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; signs of increased vascular permeability, mild to severe bleeding tendency, various organ dysfunctions develop a few days after onset; mortality rate 20%–88%, varies with isolate |
Menangle virus infection | Menangle virus (family Paramyxoviridae) | Fruit bats are normal reservoir host; pigs can also be reservoir | Australia | Close direct contact with tissues, amniotic fluid or blood of pigs reported in human cases | Severe illness with fever, severe headache, myalgia, lymphadenopathy, drenching sweats, macular rash |
Middle East respiratory syndrome (MERS) | MERS coronavirus | Dromedary camels source of virus for many cases in humans; bats might be a reservoir | Middle East; serologic evidence for virus in Africa | Contact with nasal secretions from camels; evidence for virus in unpasteurized camel milk, various tissues; possibly other virus sources | Asymptomatic or mild upper respiratory signs or flu-like illness to pneumonia; more severe in humans with coexisting illness or immunosuppression, elderly, but also in healthy; multiorgan failure possible; reported case fatality rates 20% or higher in confirmed cases but serologic evidence suggests milder cases probably missed |
Pseudocowpox virus (family Poxviridae, genus Parapoxvirus) | Cattle | Worldwide | 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 | 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, dogs, some other mammals (eg, 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 |
Murray Valley encephalitis | Murray Valley encephalitis virus (family Flaviviridae, genus Flavivirus) | Wild water birds are reservoirs; rabbits, kangaroos may also amplify virus; some other mammals (eg, horses), dead-end hosts | Australia, New Guinea | Mosquito bites, especially Culex annulirostris | Asymptomatic or mild nonspecific febrile illness in majority; encephalitis, often with neurologic sequelae, or poliomyelitis-like flaccid paralysis in small number of patients; case fatality rate 15%–30% in encephalitic form |
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 US | Occupational exposure, usually after contact with large amounts of virus | Highly virulent (velogenic) strains can cause self-limiting conjunctivitis, possibly other syndromes (eg, mild influenza-like disease); fatal pneumonia in a severely immunocompromised person |
New World hemorrhagic fever (Argentinean, Bolivian, Venezuelan and Brazilian hemorrhagic fevers) | Arenaviruses in Tacaribe complex (family Arenaviridae, genus M Ammarenavirus): Juin virus (Argentine hemorrhagic fever), Machupo virus (Bolivian hemorrhagic fever), Guanarito virus (Venezuelan hemorrhagic fever), Sabiá virus (Brazilian hemorrhagic fever), Chapare virus; possibly others | Rodents | South America | Viruses found in rodent excretions, secretions, tissues; inhalation of aerosolized virus or direct contact with mucous membranes or broken skin | Gradual onset of nonspecific clinical signs, including myalgia, headache, and fever; may develop petechial or ecchymotic hemorrhages, bleeding, CNS signs, hypotension/shock; case fatality rates differ between viruses |
Nipah virus (family Paramyxoviridae, genus Henipavirus) | Fruit bats of the genus Pteropus are normal reservoir; swine can be reservoir; occasionally in other mammals (spillover hosts) | Malaysia, Bangladesh, Northern India; apparent outbreak (or closely related virus) in Philippines; virus is probably endemic in southeast Asia; however, 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; outbreak in Philippines linked to contact with horses; person to person transmission occurs | 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 38%–75% | |
Omsk hemorrhagic fever | Omsk hemorrhagic fever virus (family Flaviviridae, genus Flavivirus); member of tickborne encephalitis virus serocomplex | Voles, muskrats; also found in other animals | Siberia | Tick bites (Dermacentor spp); direct contact with body fluids or carcasses of muskrats and possibly other animal hosts | Biphasic febrile illness with headache, GI signs, ± hemorrhages (nose, gums, lungs, uterus); CNS signs in minority of patients; mortality rate < 3% |
Powassan virus encephalitis | Powassan virus (family Flaviviridae, genus Flavivirus); member of tickborne encephalitis serocomplex | Rodents and other small mammals thought to be reservoirs; evidence for infection in many other mammals, some birds | North America, eastern Russia | Tick bites, especially Ixodes spp, possibly other routes of transmission | Nonspecific febrile illness; may progress to neurologic signs, which can sometimes be severe; some cases fatal |
Lyssaviruses:rabies virus (family Rhabdoviridae, genus Lyssavirus) and related lyssaviruses, Duvenhage virus, Mokola virus, Australian bat lyssavirus, European bat lyssaviruses 1 and 2, Irkut virus, possibly others | Wild and domestic canids, Mustelidae, Viverridae, Procyonidae, and order Chiroptera (bats) are important reservoir hosts for rabies; bats are reservoir hosts for the rabies-related viruses except Mokola virus, which might be carried in rodents and shrews; probably all mammals are susceptible | Rabies is worldwide with a few exceptions: rabies-related lyssaviruses are found only in eastern hemisphere (distribution varies) | Exposure to saliva of diseased animals through broken skin or mucous membranes, often in bites; 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 in clinical cases thought to be very rare | |
Rift Valley fever virus (family Bunyaviridae, genus Phlebovirus) | Sheep, goats, cattle, water buffalo, African buffalo, camels, nonhuman primates; squirrels and other rodents; puppies and kittens | Africa | Mosquito bites; contact with animal tissues, aerosolized virus in laboratories or animal slaughter | Influenza-like febrile illness in most; complications can include renal disease, meningoencephalitis, ocular disease or hemorrhagic syndrome with liver involvement; death uncommon except with hemorrhagic syndrome | |
Ross River virus infection, Ross River fever; epidemic polyarthritis | Ross River virus (family Togaviridae, genus Alphavirus) | Marsupials, important amplifying hosts; possibly also amplified by horses, other mammals during epizootics | Australia, South Pacific Islands | Mosquito bites (especially Culex annulirostris and Aedes spp) | Mild fever, arthralgia ± arthritis, headache, rash; small joints most affected but large joints can also be involved; arthralgia, myalgia, lethargy may persist for months |
St. Louis encephalitis | St. Louis encephalitis virus (family Flaviviridae, genus Flavivirus) | Wild birds are major hosts; mammals (eg, rodents, bats) might also be involved in some locations | Western hemisphere | Mosquito bites, especially Culex spp | Flu-like illness sometimes followed by meningitis or encephalitis, focal neurologic signs; more severe in elderly and those with debilitating diseases; case fatality rate of 5%–20% reported in epidemics |
Severe acute respiratory syndrome (SARS) | SARS coronavirus (family Coronaviridae, genus Coronavirus) | Bats are thought to be reservoir hosts; can also infect palm civets, raccoon dogs, cats, pigs, ferrets, rodents, nonhuman primates, other mammals; palm civets might have role in transmission to humans but uncertain | China, southeast Asia | Contamination of mucous membranes with respiratory droplets or virus on fomites; possibly aerosol transmission | Mild upper respiratory or flu-like illness (sometimes with diarrhea) to severe pneumonia; generally more severe in people with comorbidities, elderly or immunocompromised, but also severe in some healthy people; multiorgan failure possible; fatality rate among known cases ranged from 6%– 17% in different areas |
Severe fever with thrombocytopenia syndrome (SFTS) | SFTS virus (family Bunyaviridae, genus Phlebovirus); agent appears related to heartland disease virus | Reservoir host unknown; antibodies or viral RNA found in various domestic and wild mammals | Asia | Tick bites (Haemaphysalis longicornis and members of other genera) | Febrile illness with GI signs; thrombocytopenia; multiple organ failure possible; some cases fatal |
Sindbis virus disease | Sindbis virus (family Togaviridae, genus Alphavirus) | Birds (passeriformes are main reservoirs or amplifying hosts); occasionally found in other vertebrates | Virus widespread in Eastern hemisphere; outbreaks tend to occur in limited locations but sporadic cases can occur anywhere | Mosquito bites; Culex and Culiseta, also others (eg, Aedes that act as bridge vectors) | 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; fatalities appear absent or very rare |
Tanapox | Tanapox virus (family Poxviridae, genus Yatapoxvirus); Yaba-like disease virus may be a variant of tanapox virus | Nonhuman primates | Africa, and in monkey colonies | Direct contact through broken skin; mosquitoes suspected to be vector in Africa | Nonspecific febrile illness followed by self- limited papulovesicular or nodular lesions (may be pruritic or tender), often on extremities; number of lesions varies but often 1–2 |
Tickborne encephalitis (far eastern tickborne encephalitis, Russian spring-summer encephalitis, central European tickborne encephalitis) | Tickborne encephalitis virus (TBEV) (family Flaviviridae, genus Flavivirus); three major subtypes: European (TBEV-Eu [least virulent]), Siberian (TBEV-Sib), Far Eastern (TBEV-FE) | Small mammals especially rodents; important in maintaining virus; ruminants, dogs, horses, and other mammals; birds can be infected | 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 unpasteurized milk and milk products | 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; cases with hemorrhagic signs reported in parts of Russia; case fatality rate in Europe (mainly TBEV-Eu) < 1% but some subtypes seem to have higher mortality |
Usutu virus infections | Usutu virus (family Flaviviridae, genus Flavivirus) | Birds are reservoir hosts; infections also occur in various mammals including horses, dogs, suids, rodents | Africa, Europe, Middle East | Mosquito bites, mainly Culex spp | Febrile flu-like illness, sometimes with rash; jaundice possible; encephalitis or meningoencephalitis in some; neurologic complications might occur mainly in people with comorbidities or immunosuppression; many cases might be mild/asymptomatic |
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 |
Venezuelan equine encephalomyelitis | Venezuelan equine encephalitis virus (VEEV) complex (family Togaviridae, genus Alphavirus) | Enzootic VEEV maintained in rodents, other small mammals, bats, not amplified in equids; epizootic viruses amplified in equids; occasionally in other mammals and birds | Western Hemisphere; enzootic strains probably Florida to South America; epizootic strains emerge in South America, spread, including to North America | Mosquito bites (epizootic VEEV mainly Culex; enzootic VEEV by multiple genera); epizootic viruses possibly also by mechanical vectors including blackflies; exposure to aerosolized debris from infected laboratory rodents; laboratory accidents | Most have nonspecific febrile illness, can be followed by neurologic signs in a small percentage of cases, especially children and to a lesser extent the elderly; encephalitis has case fatality rate of 10%–35% with highest rates in children < 5 yr old; fetal losses in some pregnant women |
Vesicular stomatitis | Vesicular stomatitis Indiana virus, vesicular stomatitis New Jersey virus, vesicular stomatitis Alagoas virus, and Cocal virus (family Rhadboviridae, genus Vesiculovirus) | Equids, swine, cattle; occasionally in South American camelids, sheep, and goats; also rodents; serologic evidence of infection in many wild mammals | North and South America; most likely not endemic north of Mexico but sporadic outbreaks | Contact with animals (lesions, secretions) or in laboratory, probably also from insect bites, including mosquitoes and biting flies (Lutzomyia spp, Culicoides midges, and blackflies) | Usually asymptomatic; may develop acute, self-limited, febrile flu-like illness; vesicles sometimes found in mouth, pharynx, or inoculation site (eg, hands); one case of encephalitis in young child attributed to VSV |
Wesselsbron fever | Wesselsbron virus (family Flaviviridae, genus Flavivirus) | Ruminants, especially sheep, goats; also evidence of infection in other mammals, including rodents; lemurs; can infect birds | Africa | Mosquito bites (mainly Aedes spp, possibly others); also by contact with contaminated material especially in the laboratory | Nonspecific febrile illness ± maculopapular rash or ocular signs in some; few cases described but seems to be self-limiting; one case of encephalitis after accidental laboratory exposure of eye |
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 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; < 1% develop neurologic disease but case fatality rate ~10% in all patients with this form and higher in the elderly | |
Western equine encephalomyelitis virus (family Togaviridae, genus Alphavirus) | Birds are reservoir hosts, may also cycle in jackrabbits; equids and other mammals are dead-end (incidental) hosts and do not amplify; reptiles might help overwinter | Americas | Mosquito bites; Culex tarsalis important in maintenance cycle in birds in North America; also transmitted by other genera especially Aedes | Nonspecific febrile illness may be followed by encephalitis in infants and children, uncommonly in healthy adults; case fatality rate 3%–4% | |
Yellow fever | Yellow fever virus (family Flaviviridae, genus Flavivirus); only sylvatic cycle is zoonotic (humans are reservoir for urban cycle) | Nonhuman primates | South America, Africa | Mosquito bites (Haemagogus spp and Sabethes spp in sylvatic cycles in South America, Aedes spp in sylvatic 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; can be fatal |
Zika virus infection | Zika virus (family Flaviviridae) | Nonhuman and human primates are likely the main reservoirs of the virus | Africa, the Americas, Southern Asia, Western Pacific | Mosquito bites (infected Aedes mosquitoes [A aegypti and A albopictus]) | Many people are asymptomatic; acute onset of fever with maculopapular rash, arthralgia, conjunctivitis, myalgia, headache; there have been cases of Guillain-Barré syndrome reported in patients following suspected Zika virus infection; infection during pregnancy is a cause of microcephaly and other severe fetal brain defects |
Prion Disease | |||||
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 |