Comparative attractiveness of two chicken breeds to mosquitoes in southern California.

Each transmission season (April-October), mosquito control districts deploy more than 2,000 white leghorn hens as sentinels in California's arbovirus surveillance program. In 2002, Rhode Island red hybrids were used instead, because of insufficient availability of leghorns. Although arboviral seroconversions occurred in both breeds, their attractiveness to host-seeking mosquitoes was not compared. During August and September 2004, Florida Medical Entomology Laboratory traps, each containing 1 hen, were deployed twice weekly at each of 4 fixed locations at a southern California wetland area. The breed at each location was alternated each trap-night to account for intersite variation in the mosquito population. Six chickens of each breed were rotated through the traps to account for interchicken variation in mosquito attractiveness. Although the mosquito counts varied significantly among trap locations, no significant difference was found between the 2 breeds. Sera collected biweekly detected seroconversions to Flavivirus in 4 of 6 red and 1 of 6 white chickens, not a statistically significant difference. Larger sample sizes or experimental infection of different chicken breeds may identify differences in their response to arbovirus infection.