Mosquitoes that feed on poultry blood usually belong to the genera Culex, Aedes, or Psorophora. Large numbers can decrease egg production or cause death. Mosquitoes transmit Plasmodium gallinaceum (chicken malaria), P hermani (in turkeys), and other Plasmodium species causing avian malaria. They also transmit many viruses, including Eastern and Western equine encephalomyelitis, St. Louis encephalitis, fowlpox, and West Nile viruses. West Nile virus is transmitted from infected birds to other birds primarily by mosquitoes, particularly Culex spp in the USA, and has been found in >200 species of birds in America, including chickens, turkeys, pigeons, budgerigars, cockatiels, ducks, finches, and birds of prey. (Also see West Nile Virus Infection in Poultry.)
Removal of mosquito-breeding habitats by emptying water-filled containers, clearing pool and pond edges of emergent vegetation, draining swampy areas, and filling low areas that collect water are the best physical control measures. Insecticidal control involves chemicals such as malathion, propoxur, permethrin, chlorpyrifos, or temephos. Insect growth regulators such as methoprene and diflubenzuron are also effective. Microbial control of mosquito larvae uses Bacillus thuringiensis israelensis and, against Culex spp, Bacillus sphaericus. Screening to prevent mosquito entry, residual wall sprays, and fogging within poultry houses also aid in control.