Enlarged view of an Aedes triseriatus mosquito larva

This is an enlarged view of an Aedes triseriatus mosquito larva. The A. triseriatus mosquito is known as one of the many arthropodal vectors responsible for spreading the arboviral encephalitis, West Nile virus (WNV) to human beings through their bite when obtaining a blood meal.
WNV is maintained in nature in a transmission cycle that involves primarily birds and mosquitoes.
The main route of human infection is through the bite of an infected mosquito.

Mosquitoes become infected when they feed on infected birds, which may circulate the virus in their blood for a few days. Infectious mosquitoes carry virus particles in their salivary glands and infect susceptible bird species during blood-meal feeding. Bird reservoirs will sustain an infectious viremia for 1 to 4 days after exposure, after which the hosts that survive develop life-long immunity.