Arboviruses, a particular type of virus, are spread primarily by blood-sucking insects, like mosquitoes and ticks. In the United States, the viruses are most commonly spread by mosquitoes. While most infected people experience few symptoms, arboviruses can cause a potentially fatal inflammation of the brain.
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.
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.