Vector Type
Mosquito
Vector Species Name
Culex tarsalis
Vector Common Name
Western Encephalitis Mosquito

Vector Information

Culex tarsalis are found from coast to coast throughout the United States, but are most common west of the Mississippi River and particularly abundant in California. Living in temperate climates, they primarily lay their eggs in newly flooded natural and artificial pools such as treeholes, catch basins, used tires, clogged gutters, and poorly maintained water features. A typical Cx. tarsalis breeding cycle (from egg, to larvae, to adult) takes two weeks but may occur more rapidly in warmer conditions. They frequently associate with human environments and are common near homes. Fertilized females overwinter in covered areas such as basements, sheds, caves, and culverts. They have an overall black body with a white band on the proboscis and white stripes on the middle and hind legs. Primarily zoophilic, Cx. tarsalis feed during the early overnight hours. Culex mosquitos are the primary vectors of West Nile virus from avian reservoirs to humans. Cx. tarsalis is also a vector of western equine encephalitis virus and St. Louis encephalitis virus. 

Found In
AL
AK
AZ
AR
CA
CO
CT
DE
FL
GA
HI
ID
IL
IN
IA
KS
KY
LA
ME
MI
MN
MS
MO
MT
NE
NV
NJ
NM
ND
OH
OK
OR
PA
SC
SD
TN
TX
UT
WA
WV
WI
WY

*Disease transmission varies locally. This map depicts where vectors can be found geographically and provides information about diseases these vectors might carry. Vectors might be present in a state or locality, however, and not be carriers of any particular disease. In addition, identified vectors may have a presence in a state, but may not be found throughout that state.