Arboviruses (
arthropod-
borne viruses) are a large group of viruses that are spread by certain invertebrate animals (arthropods) -- in particular, blood-sucking insects. In the United States, they are most commonly spread by
mosquitoes. Birds are often the source of infection for mosquitoes, which can then transmit the infection to horses, other animals, and people.
Most people infected with arboviruses have few or no symptoms, but these organisms can cause serious and potentially fatal inflammation of the brain (
encephalitis) as well as other complications.
Prevention depends mainly on public health action to control mosquitoes and on individual action to avoid mosquito bites.
Life Cycle of an Arbovirus
Because people are not important in the life cycle of most arboviruses, infections are generally rare in humans. When people are part of the natural cycle and are necessary for transmitting infection, such as for dengue and urban
yellow fever viruses, then infection in people is more common.
Most cases of arboviral encephalitis occur from June through September, when biting insects are most active. In parts of the country with mild weather, cases can occur into the winter months.
Where Are Arboviruses Found?
These viruses are found throughout the world. The presence of an arbovirus in a particular area depends on the availability of specific types of mosquitoes that can carry it and specific birds or animals that can be infected.
