Mosquitoes and Disease

Bacteria and viruses enter the mosquito's body and multiply there before they are transferred to other animals by the mosquito's bite. The protozoan that causes malaria must go through part of its life cycle in a mosquito before it can infect humans.

Eliminating marshes, swamps, and other breeding places has helped control mosquito populations. Eliminating marshes and swamps is often undesirable, however, because many are valued as wildlife habitats. Another control measure is spraying a larvicide on water surfaces where eggs are laid. Adult mosquitoes are killed with such insecticides as malathion. Some drug-resistant strains of mosquitoes have developed, and researchers constantly seek new insecticides. Screens on doors and windows, and mosquito netting over beds, provide protection from these insect pests. Repellents containing a chemical substance called DEET (diethylmeta-toluamide) are effective when applied to the skin and clothing.

Mosquitoes belong to the family Culicidae of the order Diptera. The most common house mosquito in the United States is Aedes vexans; in the tropics, Culex pipiens. The three species of mosquitoes that transmit encephalitis in the United States are Aedes triseriatus, Culex nigripalpus, and C. quinque-fasciatus. The two species of mosquitoes that carry malaria in the United States are Anopheles freeborni and A. quadrimaculatus.