Yellow fever.2C dengue and other arboviruses Social history of viruses

aedes aegypti feeding on human blood

arboviruses viruses transmitted humans , other vertebrates blood-sucking insects. these viruses diverse; term arbovirus  – derived arthropod-borne virus  – no longer used in formal taxonomy because many species of virus known spread in way. there more 500 species of arboviruses, in 1930s 3 known cause disease in humans: yellow fever virus, dengue virus , pappataci fever virus. more 100 of such viruses known cause human diseases including encephalitis.

yellow fever notorious disease caused flavivirus. last major epidemic in occurred in 1905. during building of panama canal thousands of workers died disease. yellow fever originated in africa , virus brought americas on cargo ships, harbouring aedes aegypti mosquito carries virus. first recorded epidemic in africa occurred in ghana, in west africa, in 1926. in 1930s disease re-emerged in brazil. fred soper, american epidemiologist (1893–1977), discovered importance of sylvatic cycle of infection in non-human hosts, , infection of humans dead end broke cycle. although yellow fever vaccine 1 of successful ever developed, epidemics continue occur. in 1986–91 in west africa, on 20,000 people infected, 4,000 of whom died.

in 1930s, st. louis encephalitis, eastern equine encephalitis , western equine encephalitis emerged in us. virus causes la crosse encephalitis discovered in 1960s, , west nile virus arrived in new york in 1999. of 2010, dengue virus prevalent arbovirus , increasingly virulent strains of virus have spread across asia , americas.