Arboviruses, arenaviruses, and filoviruses are viruses that are spread from animals to people and, with some viruses, from people to people. The animal involved depends on the type of virus.
Many of these viruses do not cause symptoms. For some of these viruses, symptoms are mild and vague and resemble flu symptoms. For others, symptoms may progress and cause swollen lymph glands, rashes, and joint pain. However, some virus infections may be more serious and infect the tissues that cover the brain and spinal cord (meningitis) or the brain (encephalitis). Some cause fever with a tendency to bleed easily (called hemorrhagic fever), which can be life threatening.
Arboviruses
Arboviruses are arthropod-borne viruses. Scientists apply the name arbovirus to over 250 different viruses from many different families of virus that are spread to people or animals by certain arthropods that feed on blood. Arthropods include insects (such as flies and mosquitoes) and ticks. At least 80 arboviruses can cause disease in people.
Most arboviruses are transmitted by mosquitoes, but some are transmitted by ticks, and a few by midges or sand flies. Arboviruses are spread when an insect or tick bites an infected animal, then bites another animal or a person. Most arbovirus infections are not spread from person to person. Also, Zika virus can be spread during sexual activity. Uncommonly, dengue, chikungunya, and Zika viruses have been spread by blood transfusion or organ donation or from mother to newborn at birth. Casual everyday contact has not been shown to transmit arboviruses from person to person.
Many arboviruses that were once present in only a few parts of the world are now spreading. These viruses include chikungunya virus, West Nile virus, and Zika virus. Also, travelers may be infected in areas where the virus is common, then return home and be bitten by a mosquito, which spreads the virus to other people.
Arenaviruses
Arenaviruses are spread by rodents. Infections caused by these viruses include lymphocytic choriomeningitis and Lassa fever. Lassa fever can also be spread from person to person through contact with body fluids (such as saliva, urine, feces, or blood). Arenavirus infections are relatively common in people in some areas of the world and can cause severe disease.
Filoviruses
Filoviruses can cause severe hemorrhagic fever in people and other primates (such as apes and monkeys). So far, only 2 members of this group of viruses have been identified:
Ebola virus (with 5 species)
How filoviruses first spread to people has not been identified. However, experts think that the first person was infected by handling or eating an infected animal, such as a fruit bat or primate. These viruses spread readily from person to person.
Diagnosis
Blood tests
Culture of blood or infected tissue
To diagnose these infections, doctors may do blood tests and cultures. Blood may be tested for antibodies to or antigens of a virus. (Antibodies are proteins produced by the immune system to help defend the body against a particular attack. Antigens are proteins on or in viruses that trigger the body’s defenses.) Culture involves growing microorganisms in the laboratory from samples of blood, body fluid, or other material taken from an infected area until there are enough to identify.
Polymerase chain reaction (PCR) techniques may be used to make many copies of the virus's genetic material. This technique enables doctors to rapidly and accurately identify the virus.
Tests are sometimes done quickly—for example, when the infection is a serious threat to public health or when symptoms are severe.
A sample of blood or other tissues is sometimes examined with an electron microscope, which provides high magnification with clear resolution to visualize the virus.
Treatment
Supportive care
Sometimes ribavirinSometimes ribavirin
Treatment of most of these infections focuses on relieving symptoms and maintaining vital functions. For example, transfusions may be given if bleeding is severe.
The antiviral medication ribavirin may be used to treat hemorrhagic fever, as may occur in The antiviral medication ribavirin may be used to treat hemorrhagic fever, as may occur inLassa fever.
Prevention
Because there are so many different arboviruses, it is often most effective to control arbovirus infections by controlling the arthropods that spread them and preventing exposure to the virus (including preventing mosquito and tick bites).
Controlling mosquitoes is difficult, but new approaches are being developed and tested. In addition to using chemical pesticides, scientists are genetically modifying mosquitoes, releasing sterilized male mosquitoes into the environment, or infecting mosquitoes with a bacteria that blocks virus infection in the mosquitoes.
Preventing exposure to a virus
Infections spread by mosquitoes or ticks can often be prevented by avoiding exposure to the mosquito or tick as much as possible, with the following strategies:
Wear clothing that covers as much of the body as possible
Stay in places that have air conditioning or that use window and door screens to keep mosquitoes out
Sleep under a mosquito net in places that are not adequately screened or air-conditioned
Use insect repellants, such as DEET (diethyltoluamide)
Wear clothing that has been coated with the insecticide permethrinWear clothing that has been coated with the insecticide permethrin
To help prevent mosquito bites, people can limit the time they spend outdoors in wet areas.
For children, the following precautions are recommended:
Do not use insect repellent on infants under 2 months old.
Do not use products containing oil of lemon eucalyptus (para-menthane-diol) on children under 3 years old.
For older children, adults should spray repellent on their own hands and then apply it to the children's skin.
Dress children in clothing that covers their arms and legs, or cover the crib, stroller, or baby carrier with mosquito netting.
Do not apply insect repellent to the hands, eyes, mouth, or cut or irritated skin of children.
For ticks, the following can help:
Stay on paths and trails
Tuck trousers into boots or socks
Wear long-sleeved shirts (see sidebar Tick Bite Prevention)
Infections spread by mice or other rodents usually result from exposure to their urine, feces, or another body fluid, which contains the virus. The following can help prevent such exposure:
Before cleaning, air out closed spaces where mice may have been.
Before sweeping or cleaning, wet surfaces with a solution that has 10% bleach.
Avoid stirring up dust.
Seal openings where rodents could enter homes.
Put food in rodent-proof containers.
Eliminate potential nesting sites around the home.
Prevention of exposure to Ebola or Marburg virus requires strict quarantine of infected people and use of isolation measures because these viruses spread readily from person to person.
Vaccination
Effective vaccines are available, including in the United States, for Ebola, yellow fever virus, Japanese encephalitis virus, tick-borne encephalitis, chikungunya virus, and dengue. Vaccines for dengue are only somewhat effective and are given only to people who had a prior dengue infection.
More Information
The following English-language resource may be useful. Please note that The Manual is not responsible for the content of this resource
Centers for Disease Control and Prevention: Preventing Mosquito Bites. August 28, 2024.
Centers for Disease Control and Prevention: How to Clean Up After Rodents. April 8, 2024.
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