Merck Manual

Please confirm that you are a health care professional

Loading

Overview of Arbovirus, Arenavirus, and Filovirus Infections

By

Thomas M. Yuill

, PhD, University of Wisconsin-Madison

Last full review/revision Mar 2020| Content last modified Mar 2020
Click here for Patient Education
NOTE: This is the Professional Version. CONSUMERS: Click here for the Consumer Version
Topic Resources

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)

  • Togaviridae

  • Flaviviridae (comprising only the flaviviruses)

  • Reoviridae (comprising the coltiviruses and orbiviruses)

  • Togaviridae (comprising the alphaviruses)

Pearls & Pitfalls

  • Arbovirus is not a family of viruses; the term indicates only that a virus is transmitted by certain species of arthropods—arthropod-borne virus.

  • Members of many different viral families may be arboviruses.

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

Arbovirus species 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. Other reservoirs for arboviruses include arthropods and vertebrates (often rodents, monkeys, and humans). These viruses may spread to humans directly from nonhuman reservoirs, but human-to-human transmission may also occur by blood transfusion, organ transplantation, sexual contact, and from mother to child during birth depending on the specific virus involved. Human-to-human transmission of most arboviruses through casual, everyday contact has not been documented. Most arboviral diseases are not transmissible by humans, perhaps because the typical viremia is inadequate to infect the arthropod vector; exceptions include dengue, yellow fever, Zika virus infection, and chikungunya disease, which can be transmitted from person to person via mosquitoes. Also, Zika virus can be transmitted during sexual activity from infected symptomatic or asymptomatic men to their sex partners (male or female) or from infected women to their sex partner.

Some infections (eg, West Nile virus infection, Colorado tick fever, dengue, Zika virus) have been spread by blood transfusion or organ donation.

The Arenaviridae includes lymphocytic choriomeningitis virus, Lassa fever virus, Mopeia virus, Tacaribe virus, Junin virus, Lujo virus, and Machupo virus; all are transmitted by rodents and thus are not arboviruses. Lassa fever virus 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, polymerase chain reaction, electron microscopy, and antigen and antibody detection methods where available.

Table
icon

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 species

Western US, western Canada

Phlebotomus fever

Bunyaviridae (Phlebovirus)

Sand flies

Phlebotomus species

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

Venezuelan equine encephalitis

Togaviridae (Alphavirus)

Mosquitoes

Culex species

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

Heartland virus

Bunyaviridae (Phlebovirus)

Tick

Amblyomma americanum

US

Bunyaviridae (Phlebovirus)

Mosquitoes

Several species

South Africa, eastern Africa, Egypt, Yemen, Saudi Arabia

Oropouche virus

Bunyaviridae (Simbu virus)

Biting midge

Culicoides paraensis

South and Central America, Caribbean

Rash

Dengue fever

Flaviviridae

Mosquitoes

Aedes species

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

Usutu

Flaviviridae

Mosquitoes

Africa, Europe

Flaviviridae

Mosquitoes

Aedes species

Central and South

America, Mexico, Caribbean, US, Africa, Pacific Islands, Asia

Flaviviridae

Mosquitoes

Culex species

Africa, Middle East, southern Europe, Russia, India, Indonesia, US, southern Canada, Mexico, South America, Caribbean Islands.

Arthralgia, rash

Togaviridae (Alphavirus)

Mosquitoes

Aedes species

Africa, India, Pakistan, Guam, Southeast Asia, Reunion Island, New Guinea, limited areas of Europe, South and Central America, Mexico, US

Bourbon virus

Orthomyxoviridae (Thogotovirus)

Tick

Amblyomma americanum

US

Togaviridae (Alphavirus)

Mosquitoes

Haemagogus species

Brazil, Bolivia, Trinidad

Ross River virus

Togaviridae (Alphavirus)

Mosquitoes

Aedes species, Culex species

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

Barmah Forest virus

Togaviridae (Alphavirus)

Mosquitoes

Aedes species, Culex species

Australia

Sindbis virus disease (Ockelbo disease, Karelian fever)

Togaviridae (Alphavirus)

Mosquitoes

Culex species

Africa, Australia, Asia, former Soviet Union, Europe (including Finland and Sweden), Oceania

Hemorrhagic signs§

Flaviviridae

Mosquitoes

Aedes species

Panama, South America, Africa

Flaviviridae

Mosquitoes

Aedes species

Southeast Asia, South Asia, West and East Africa, Oceania, Caribbean, South and Central America, Mexico, US

Flaviviridae

Ticks

Haemaphysalis species

India

Flaviviridae

Ticks

Dermacentor species

Russia

Crimean-Congo hemorrhagic fever

Bunyaviridae (Nairovirus)

Ticks

Hyalomma species

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

Bunyaviridae (Hantavirus)

Rodent

Korea, Japan, China, Far Eastern Russia, the Balkans

Seoul virus

Bunyaviridae (Hantavirus)

Rodent

Nearly worldwide, including Korea, Japan, the Americas and Europe

Puumala virus (nephropathia epidemica)

Bunyaviridae (Hantavirus)

Rodent

Scandinavia, Russia, the Balkans

Dobrava-Belgrade virus

Bunyaviridae (Hantavirus)

Rodent

The Balkans, Slovakia, Czech Republic, Turkey

Machupo virus

Arenaviridae

Rodent

Bolivia

Junin virus

Arenaviridae

Rodent

Argentina

Guanarito virus

Arenaviridae

Rodent

Venezuela

Arenaviridae

Rodent

Mastomys species

West Africa, including Nigeria

Lujo virus

Arenaviridae

Unknown

Zambia

Filoviridae

Human to human

Monkey

Bat

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

Filoviridae

Human to human

Monkey

Bat

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

Severe fever with thrombocytopenia syndrome virus

Bunyaviridae

Ticks

Haemaphysalis longicornis

China, Korea, Japan

Noncardiogenic pulmonary edema

Hantavirus: Sin Nombre, Black Creek Canal, Bayou, Leguna Negra, Andes, Andes-like viruses Hu39694, Lechiguanas, Oran, Bermejo, Choclo

Bunyaviridae (Hantavirus)

Rodents

US, Canada, Brazil, Bolivia, Paraguay, Argentina, Chile, Panama

Fever and central nervous system involvement

Eastern equine encephalitis

Togaviridae (Alphavirus)

Mosquitoes

Culex species, Culiseta melanura

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

Western equine encephalitis

Togaviridae (Alphavirus)

Mosquito

Culex species

US, Canada, Central and South America

Flaviviridae

Mosquitoes

Culex species

Africa, Middle East, southern Europe, former Soviet Union, India, Indonesia, US, southern Canada, Mexico, South America, Caribbean Islands

St. Louis encephalitis

Flaviviridae

Mosquitoes

Culex species

US, Caribbean, South America

Usutu

Flaviviridae

Mosquitoes

Africa, Europe

Venezuelan equine encephalitis

Togaviridae (Alphavirus)

Mosquitoes

Culex species

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

La Crosse encephalitis

Bunyaviridae

Mosquitoes

Aedes species

North Central States, New York, Appalachian states

Jamestown Canyon virus

Bunyaviridae

Mosquitoes

Aedes species

US from the Rocky Mountains to the East Coast, southeastern Canada

Japanese encephalitis

Flaviviridae

Mosquitoes

Culex species

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

Flaviviridae

Tick

Ixodes species

Eastern Canada, New York, New England states, Wisconsin

Murray Valley encephalitis

Flaviviridae

Mosquitoes

Culex species

Australia, New Guinea

Flaviviridae

Ticks

Haemaphysalis

spinigera

India

Flaviviridae

Ticks

Ixodes species

Haemaphysalis species

Europe, Balkans, Russia

Lymphocytic choriomeningitis virus

Arenaviridae

Rodents

Americas, Europe, Australia, Japan

* 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.

West Nile virus also causes encephalitis.

§ 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 K1). Transfusion of packed red blood cells or fresh frozen plasma may also be necessary. Aspirin and other NSAIDs (nonsteroidal anti-inflammatory drugs) are contraindicated because of antiplatelet activity. For advanced cases of hantavirus cardiopulmonary syndrome, extracorporeal membrane oxygenation (ECMO) may be needed.

The following is recommended for hemorrhagic fever caused by arenaviruses or bunyaviruses including Lassa fever, Rift Valley fever, and Crimean-Congo hemorrhagic fever:

  • Ribavirin 30 mg/kg IV (maximum, 2 g) loading dose followed by 16 mg/kg IV (maximum, 1 g/dose) every 6 hours for 4 days, then 8 mg/kg IV (maximum, 500 mg/dose) every 8 hours for 6 days

Treatment of hemorrhagic fever with renal syndrome is with IV ribavirin: loading dose 33 mg/kg (maximum, 2.64 g), followed by 16 mg/kg every 6 hours (maximum, 1.28 g every 6 hours) for 4 days, then 8 mg/kg every 8 hours (maximum, 0.64 g every 8 hours) for 3 days.

Antiviral treatment for other syndromes has not been adequately studied. Ribavirin has not been effective in animal models of filovirus and flavivirus infections. However, the monoclonal antibody cocktail REGN-EB3 and the single monoclonal antibody mAb 114 reduced deaths in a field trial in the Ebola outbreak in the Democratic Republic of the Congo.

Prevention

  • Vector control

  • Prevention of vector bites

  • Sometimes vaccination

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.

Vector control and bite prevention

Diseases transmitted by mosquitoes or ticks can often be prevented by the following:

  • Wearing clothing that covers as much of the body as possible

  • Using insect repellants (eg, DEET [diethyltoluamide])

  • Minimizing the likelihood of exposure to the insect or tick (eg, for mosquitoes, limiting time outdoors in wet areas; for ticks, see sidebar Tick Bite Prevention)

  • There has been recent progress in reducing populations of Aedes aegypti through the release of sterile males or genetically modified males. Also, field trials are underway with introduction into the wild of Aedes aegypti mosquitoes that have been infected with Wolbachia bacteria. These bacteria do not reduce mosquito populations. Instead, they block infection of the mosquitoes by dengue, chikungunya, and Zika viruses, thus reducing transmission of disease. The Wolbachia are transmitted to the infected mosquito's offspring, thus multiplying the effectiveness of the technique.

Diseases transmitted by rodent excreta can be prevented by the following:

  • Before cleaning, ventilate for ≥ 15 minutes closed spaces where mice have been.

  • Wet down surfaces with a 10% bleach solution before sweeping or cleaning.

  • Avoid stirring up dust.

  • Seal sites of potential rodent entry into homes and nearby buildings.

  • Prevent rodent access to food.

  • Eliminate potential nesting sites in and around the home.

Guidelines for cleaning up after rodents and working in areas with potential rodent excreta are available from 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 and isolation measures.

Vaccination

At present, in the US there are effective vaccines only for Ebola virus, yellow fever virus and Japanese encephalitis virus. Vaccines for tick-borne encephalitis are available in Europe, Russia and China. A vaccine for dengue is approved in several countries outside the US, but efficacy is only moderate and varies by dengue immune status, serotype, and patient age; studies are ongoing.

Drugs Mentioned In This Article

Drug Name Select Trade
MEPHYTON
VIRAZOLE
No US brand name
Click here for Patient Education
NOTE: This is the Professional Version. CONSUMERS: Click here for the Consumer Version
Professionals also read

Also of Interest

Videos

View All
Overview of Mechanisms of Antimicrobial Resistance
Video
Overview of Mechanisms of Antimicrobial Resistance
3D Models
View All
SARS-CoV-2
3D Model
SARS-CoV-2

SOCIAL MEDIA

TOP