Find information on medical topics, symptoms, drugs, procedures, news and more, written for the health care professional.

* This is a professional Version *

Overview of Arbovirus, Arenavirus, and Filovirus Infections

by Craig R. Pringle, BSc, PhD

Arbovirus (arthropod-borne virus) applies to any virus that is transmitted to humans and/or other vertebrates by certain species of blood-feeding arthropods, chiefly insects (flies and mosquitoes) and arachnids (ticks). Arbovirus is not part of the current viral classification system, which is based on the nature and structure of the viral genome. Families in the current classification system that have some arbovirus members include

  • Bunyaviridae (comprising the bunyaviruses, phleboviruses, nairoviruses, and hantaviruses)

  • Flaviviridae (comprising only the flaviviruses)

  • Reoviridae (comprising the coltiviruses and orbiviruses)

  • Togaviridae (comprising the alphaviruses)

Most viruses associated with hemorrhagic fevers are classified in the families Arenaviridae and Filoviridae. However, some flaviviruses (yellow fever, dengue viruses), some Bunyaviridae (Rift Valley fever virus, Crimean-Congo hemorrhagic fever virus, and the hantaviruses) may be associated with hemorrhagic symptoms.

Arboviruses number > 250 and are distributed worldwide; at least 80 cause human disease. Birds are often reservoirs for arboviruses, which are transmitted by mosquitoes to horses, other domestic animals, and humans. Most arboviral diseases are not transmissible by humans, perhaps because the typical viremia is inadequate to infect the arthropod vector; exceptions include dengue fever, yellow fever, and chikungunya disease, which can be transmitted from person to person via mosquitoes. Some infections (eg, West Nile virus, Colorado tick fever, dengue) have been spread by blood transfusion or organ donation. Reservoirs for bunyaviruses include insects and vertebrates, often rodents. These viruses spread to humans directly from their reservoirs, but human-to-human transmission may occur.

The Arenaviridae includes lymphocytic choriomeningitis virus, Lassa fever virus, Mopeia virus, Tacaribe virus, Junin virus, Lujo virus, and Guaroa virus; all are transmitted by rodents and thus are not arboviruses. Lassa fever can be transmitted from person to person.

The Filoviridae consists of 2 genera: Ebolavirus (consisting of 5 species) and Marburgvirus (consisting of 2 species). The specific vectors of these viruses have not been confirmed, but fruit bats are the prime candidates; thus, Filoviridae are not arboviruses. Human-to-human transmission of Ebola virus and Marburg virus occurs readily.

Many of these infections are asymptomatic. When symptomatic, they generally begin with a minor nonspecific flu-like illness that may evolve to one of a few syndromes (see Table: Arbovirus, Arenavirus, and Filovirus Diseases). These syndromes include lymphadenopathy, rashes, aseptic meningitis, encephalitis, arthralgias, arthritis, and noncardiogenic pulmonary edema. Many cause fever and bleeding tendencies (hemorrhagic fever). Decreased synthesis of vitamin K–dependent coagulation factors, disseminated intravascular coagulation, and altered platelet function contribute to bleeding.

Laboratory diagnosis often involves viral cultures, PCR, electron microscopy, and antigen and antibody detection methods where available.

Arbovirus, Arenavirus, and Filovirus Diseases

Distinguishing Symptoms

Viral Agent or Disease

Family

Vector

Major Distribution*

Fever, malaise, headaches, myalgias

Additional features: none

Colorado tick fever

Reoviridae ( Coltivirus)

Ticks

Dermacentor sp

Western US, western Canada

Phlebotomus fever

Bunyaviridae ( Phlebovirus)

Sand flies

Phlebotomus sp

Mediterranean basin, Balkans, Middle East, Pakistan, India, China, eastern Africa, Panama, Brazil

Venezuelan equine encephalitis

Togaviridae ( Alphavirus)

Mosquitoes

Culex sp

Argentina, Brazil, northern South America, Panama, Mexico, Florida

Rift Valley fever

Bunyaviridae ( Phlebovirus)

Mosquitoes

Several species

South Africa, eastern Africa, Egypt

Lymphadenopathy, rash

Dengue fever

Flaviviridae

Mosquitoes

Aedes sp

Southeast Asia, West Africa, Oceania, Australia, South America, Mexico, Caribbean, US

West Nile fever

Flaviviridae

Mosquitoes

Culex sp

Africa, Middle East, southern France, Russia, India, Indonesia, US

Arthralgia, rash

Chikungunya disease

Togaviridae ( Alphavirus)

Mosquitoes

Aedes sp

Africa, India, Guam, Southeast Asia, New Guinea, limited areas of Europe

Mayaro virus

Togaviridae ( Alphavirus)

Mosquitoes

Haemogus sp

Brazil, Bolivia, Trinidad

Ross River virus

Togaviridae ( Alphavirus)

Mosquitoes

Aedes sp

Australia, New Guinea, Solomon Islands, Samoa, Cook Islands

Barmah Forest virus

Togaviridae ( Alphavirus)

Mosquitoes

Aedes sp

Australia

Sindbis virus disease (Ockelbo disease, Karelian fever)

Togaviridae ( Alphavirus)

Mosquitoes

Culex sp

Africa, Australia, former Soviet Union, Finland, Sweden

Hemorrhagic signs

Yellow fever

Flaviviridae

Mosquitoes

Aedes spp

Central and South America, Africa

Dengue hemorrhagic fever

Flaviviridae

Mosquitoes

Aedes sp

Southeast Asia, West Africa, Oceania, Caribbean

Kyasanur Forest disease

Flaviviridae

Ticks

Haemaphysalis sp

India

Omsk hemorrhagic fever

Flaviviridae

Ticks

Dermacentor spp

Russia

Crimean-Congo hemorrhagic fever

Bunyaviridae ( Nairovirus)

Ticks

Hyalomma sp

Africa, southern and eastern Europe, India, China, Middle East, former Soviet Union

Hantaan virus

Bunyaviridae ( Hantavirus)

Rodent

Korea, Japan, China, Southeast Asia, Europe

Seoul virus

Bunyaviridae ( Hantavirus)

Rodent

Korea, Japan, Europe

Puumala virus (nephropathia epidemica)

Bunyaviridae ( Hantavirus)

Rodent

Scandinavia, former Soviet Union

Machupo virus

Arenaviridae

Rodent

Bolivia

Junin virus

Arenaviridae

Rodent

Argentina

Guanarito virus

Arenaviridae

Rodent

Venezuela

Lassa fever virus

Arenaviridae

Rodent

Mastomys sp

West Africa

Lujo virus

Arenaviridae

Unknown

Zambia

Marburg virus

Filoviridae

Human to human

Monkey

Bat

Zimbabwe, Kenya, Uganda, Democratic Republic of Congo, South Africa

Ebola virus

Filoviridae

Human to human

Monkey

Bat

Zaire, Sudan Guinea, Liberia, Sierra Leone, Democratic Republic of Congo, Gabon, Côte d'Ivoire, Uganda

Noncardiogenic pulmonary edema

Hantavirus: Sin Nombre, Black Creek Canal, Bayou, New York-1, Rio Mamore

Bunyaviridae ( Hantavirus)

Rodent

US (west of Mississippi River), Canada, Brazil, Bolivia, Paraguay, Argentina

Severe fever with thrombocytopenia syndrome (SFTS)

SFTS virus

Bunyaviridae

Ticks

China, Korea, Japan

Fever and CNS involvement

Eastern equine encephalitis

Togaviridae ( Alphavirus)

Mosquitoes

Culex sp

Atlantic and Gulf coasts of US, Caribbean, upper New York, western Michigan

Western equine encephalitis

Togaviridae ( Alphavirus)

Mosquito

US, Canada, Central and South America

West Nile virus

Flaviviridae

Mosquitoes

Culex sp

Africa, Middle East, southern France, former Soviet Union, India, Indonesia, US

St. Louis encephalitis

Flaviviridae

Mosquitoes

Culex sp

US, Caribbean

Venezuelan equine encephalitis

Togaviridae ( Alphavirus)

Mosquitoes

Culex sp

Argentina, Brazil, northern South America, Panama, Mexico, Florida

La Crosse encephalitis

Bunyaviridae

Mosquitoes

Aedes spp.

North Central States, New York

Japanese encephalitis

Flaviviridae

Mosquitoes

Culex sp

Japan, Korea, China, India, Philippines, Southeast Asia, Russia

Powassan virus

Flaviviridae

Tick

Eastern Canada, New York

Murray Valley encephalitis

Flaviviridae

Mosquitoes

Culex sp

Australia, New Guinea

Kyasanur Forest disease

Flaviviridae

Ticks

India

Tick-borne encephalitis

Flaviviridae

Ticks

Haemaphysalis sp

Europe, Balkans, Russia

Lymphocytic choriomeningitis

Arenaviridae

Rodents

Organ transplantation

US, Argentina, Germany, Balkans

*Changes in climatic conditions can affect the geographic range of arboviruses by extending or contracting the habitats of their vectors.

Rift Valley fever also causes hemorrhage, meningoencephalitis, and ocular disorders.

The Seoul, Puumala, Dobrava, and Hantaan hantaviruses cause hemorrhagic fever with renal syndrome.

Treatment

  • Supportive care

  • Sometimes ribavirin

Treatment for most of these infections is supportive. In hemorrhagic fevers, bleeding may require phytonadione (vitamin K 1 —see Treatment under Vitamin K Deficiency). Transfusion of packed RBCs or fresh frozen plasma may also be necessary. Aspirin and other NSAIDs are contraindicated because of antiplatelet activity.

Ribavirin 30 mg/kg IV (maximum, 2 g) loading dose followed by 16 mg/kg IV (maximum, 1 g/dose) q 6 h for 4 days, then 8 mg/kg IV (maximum, 500 mg/dose) q 8 h for 6 days is recommended for hemorrhagic fever caused by arenaviruses or bunyaviruses including Lassa fever, Rift Valley fever, and Crimean-Congo hemorrhagic fever. For dosage in hemorrhagic fever with renal syndrome, see Hemorrhagic Fever With Renal Syndrome (HFRS) : Treatment. Antiviral treatment for other syndromes has not been adequately studied. Ribavirin has not been effective in animal models of filovirus and flavivirus infections.

Prevention

The abundance and diversity of arboviruses means that it is often easier and cheaper to control arbovirus infections by destroying their arthropod vectors, preventing bites, and eliminating their breeding habitats than by developing specific vaccines or drug treatments. At present, there are effective vaccines only for Yellow fever virus and Japanese encephalitis virus. Vaccines for tick-borne encephalitis are available in Europe, Russia and China but are not available in the US.

Diseases transmitted by mosquitoes or ticks can often be prevented by wearing clothing that covers as much of the body as possible, using insect repellants (eg, DEET [diethyltoluamide]) and minimizing the likelihood of exposure to the insect (eg, for mosquitoes, limiting time outdoors in wet areas; for ticks, see Tick Bite Prevention).

Diseases transmitted by rodent excreta can be prevented by sealing sites of potential rodent entry into homes and nearby buildings, preventing rodent access to food, and eliminating potential nesting sites around the home. Guidelines for cleaning up after rodents and working in areas with potential rodent excreta are available through the Centers for Disease Control and Prevention (CDC).

Because transmission of the filoviruses Ebola virus and Marburg virus is predominantly from person to person, prevention of spread requires strict quarantine measures.

Resources In This Article

Drugs Mentioned In This Article

  • Drug Name
    Select Trade
  • VIRAZOLE
  • MEPHYTON
  • No US brand name

* This is a professional Version *