La Crosse Encephalitis is transmitted by which species?

• A. Ochlerotatus triseriatus
• B. Culiseta melanura
• C. Anopheles quadrimaculatus
• D. Culex quinquefasciatus

Answer: (A)

La Crosse Encephalitis virus is transmitted mainly by the eastern treehole mosquito, Ochlerotatus triseriatus (also known as Aedes triseriatus). This species is the principal vector in the Lacrosse virus transmission cycle, breeding in tree holes and artificial containers and feeding on small mammals such as chipmunks and squirrels, with humans occasionally becoming infected. The other mosquitoes listed are associated with different diseases: Culiseta melanura is a common vector for Eastern Equine Encephalitis, Anopheles quadrimaculatus transmits malaria, and Culex quinquefasciatus can transmit West Nile virus. Therefore, the species most responsible for La Crosse Encephalitis transmission is Ochlerotatus/Aedes triseriatus.