La-crosse-virus
Guides
Aedes japonicus
Asian bush mosquito, Asian rock pool mosquito
Aedes japonicus is an invasive mosquito species native to East Asia, first described from Tokyo in 1901. It has established populations in North America, Europe, and Hawaii through human-mediated transport of eggs in used tires and containers. The species is a competent vector for West Nile virus, La Crosse virus, Japanese encephalitis virus, and St. Louis encephalitis virus, with experimental evidence for dengue and chikungunya viruses. Its cold-hardiness, ecological plasticity, and ability to exploit diverse container habitats contribute to its invasive success.
Ochlerotatus hendersoni
Ochlerotatus hendersoni is a mosquito species closely related to Ochlerotatus triseriatus, with which it can produce viable interspecific hybrids. Unlike its congener O. triseriatus, which is an efficient vector for La Crosse virus, O. hendersoni transmits this virus only at very low rates. Genetic studies have identified quantitative trait loci associated with this refractory vector competence, with some regions containing genes from O. hendersoni that paradoxically increase transmission ability in hybrid offspring, likely due to epistatic interactions. The species is present in North America, including the northeastern United States.
Ochlerotatus triseriatus
eastern treehole mosquito, treehole mosquito
Ochlerotatus triseriatus, the eastern treehole mosquito, is a container-breeding mosquito native to North America. It is the primary enzootic vector of La Crosse virus, the leading cause of arboviral encephalitis in children in the United States. Larvae develop in natural tree holes and artificial water-holding containers, feeding on microbial communities associated with decaying organic matter. The species exhibits strong density-dependent survival, with larval crowding significantly reducing per-capita survival rates—a trait that has important implications for mosquito control strategies.