arboviruses

Arboviruses are viruses transmitted to vertebrate hosts by arthropod vectors, most commonly mosquitoes and ticks. The term arbovirus is an umbrella for several virus groups in different families, including flaviviruses (such as dengue, Zika, West Nile and yellow fever), togaviruses (notably chikungunya and the alphaviruses), and some bunyaviruses (such as Crimean-Congo hemorrhagic fever and phenuiviruses). Transmission cycles typically involve a vertebrate reservoir and a vector. In enzootic cycles, non-human animals maintain the virus in nature; in urban cycles, human infections occur when a competent vector, especially Aedes or Culex mosquitoes, feeds on an infected person and then on another person. Tick-borne arboviruses follow similar patterns with Ixodes and other tick species as vectors, often involving wildlife reservoirs.

Clinical outcomes vary widely. Many infections produce a self-limited febrile illness; others cause severe disease such as acute encephalitis, meningitis, or hemorrhagic fever. Neurological disease is a hallmark of several tick-borne and West Nile virus infections, while dengue and chikungunya can cause intense joint pain and hemorrhagic manifestations in some cases.

Diagnosis relies on clinical suspicion supported by laboratory testing, including virus detection by PCR during acute infection and serology for past or recent exposure. Prevention centers on vector control and personal protection; vaccines exist for a subset of arboviruses, including yellow fever, Japanese encephalitis, tick-borne encephalitis, and dengue in certain settings. There are no universal antiviral treatments for arboviruses, so management is generally supportive.

Outbreaks are influenced by ecological and social factors such as climate, urbanization, travel, and vector control efforts. Surveillance, rapid diagnosis, and vaccination programs where available are essential for reducing disease burden.