Antibody response to Culex tarsalis salivary gland antigens among sentinel chickens in California.

The arboviral surveillance program in California depends in part on sentinel chickens to detect western equine encephalomyelitis virus, St. Louis encephalitis virus, and West Nile virus activity. From 2000 through 2002, 1,578 serum specimens from 34 sentinel flocks in northern and southern California were tested for antibodies to Culex tarsalis salivary gland antigens. Sentinel chickens that were seropositive for mosquito salivary gland antigens were more likely to seroconvert to St. Louis encephalitis virus than those seronegative for salivary gland antigens. Flocks with mosquito traps located < 50 feet away had a reduced antibody response to mosquito salivary gland antigens. The use of sentinel chickens and mosquito traps for arboviral surveillance should be standardized to ensure that surveillance data from different sites are comparable and that flocks have comparable opportunities for mosquito exposure. Sentinel chickens should be accessible to potential mosquito vectors to maximize their sensitivity for detecting arboviral activity.