Arboviruses are viruses transmitted by arthropods, the phylum of animals that includes insects. The word arbovirus is a shortened form of arthropod-borne virus. Many medically important arboviruses are transmitted by mosquitoes, ticks, and phlebotominae or sand flies. The insects cause infection through their bite, introducing the virus to the bloodstream. The arbovirus families are the Bunyaviridae, the Flaviviridae, the Reoviridae, and the Togaviridae.
Most arboviruses do not affect humans or cause only mild effects, such as rash or fever. However, some forms of arbovirus can cause very serious infection and may even result in death. Many forms of arbovirus that affect humans are also common among domesticated animals, and insects are responsible for transmitting the disease between animals and humans.
Some common arboviruses that can cause encephalitis, or swelling of the brain, include West Nile virus, the different strains of equine encephalitis virus, and St. Louis encephalitis virus, all transmitted by mosquitoes. As its name suggests, equine encephalitis virus also commonly infects horses. Tick-borne encephalitis virus causes similar symptoms to the mosquito-born encephalitic arboviruses.
Other arboviruses cause viral hemorrhagic fever (VHF), an illness characterized by high fever, bleeding disorders, hallucinations, vomitting, and diarrhea. Examples are Dengue or breakbone fever, and yellow fever, both carried by mosquitoes, and Crimean Congo hemorrhagic fever and Colorado fever, both carried by ticks. Arboviruses carried by the plebotominae, commonly called the sand flies, are collectively classified as phleboviruses. One of the better known phleboviruses is the Toscana virus, which has symptoms ranging from fever to encephalitis and meningtis, the inflammation of the meninges, membranes that surround the brain.
Children, the elderly, and immunocompromised individuals are often especially susceptible to arbovirus infection. Some arboviruses currently have no cure, though the immune system can often defend against the disease. Arbovirus infection can be prevented by using insecticides and insect repellent, wearing protective clothing, and eliminating the breeding grounds of arbovirus-carrying insects.