Overview

The Problem. Mosquitoes have long impacted the lives of California residents. Decades before California became a state in 1850, unmitigated mosquito breeding in the lowlands, marshes and other wetlands, especially during seasonal flooding, created problems for the first inhabitants, the Native Americans. Mosquito-borne diseases also flourished among the pioneers and gold seekers in the 1850s. Species of Anopheles attacked the burgeoning population, resulting in malaria epidemics. (Thanks to mosquito surveillance, research and control, malaria has erupted only occasionally since World War II, appearing in small, scattered outbreaks.)

Mosquito Control Origins. The origins of organized mosquito control in California began in the Bay Area in the early 1900s. Salt marshes ringed the San Francisco Bay, producing massive numbers of mosquitoes that disrupted the lives of residents. Mosquitoes so infested the area that commuters wore head nets while waiting for the Marin-San Francisco ferry. Businesses set out smudge pots to discourage the insects. Initially, control efforts focused on constructing drainage canals and ditches in these marsh areas.

Malaria and West Nile Disease. In 1909, malaria claimed 112 lives in California, resulting in more attention toward mosquito abatement. Research showed that mosquito-borne diseases could be managed by implementing mosquito control methods. The mosquito-borne disease, West Nile virus (WNN). was first reported in the United States (New York) in 1999 and in California in 2002. Since 1999, WNV has caused more than 16,000 cases of human illness, including more than 650 deaths in the United States. In 2005, 18 Californians died of the disease, and more than 900 others were infected. Sacramento County last year showed more incidences of the disease than any other county in the United States.

Mosquito Abatement Act. On May 25, 1915, the California State Legislature passed the Mosquito Abatement Act, giving local governments the power to obtain revenues and form special districts to protect the public from the hazards of mosquito bites and mosquito-borne diseases. That same year a small group of districts formed. Today more than 60 organized mosquito control agencies serve the residents of California.

Mosquito and Vector Control Association of California (MVCAC). MVCAC represents some 63 mosquito and vector control programs covering more than 32 million California residents inside 38,000 square miles. The state’s mosquito control program, widely regarded as one of most effective in the world, has greatly limited or eliminated the transmission of once-common mosquito-borne diseases, including malaria.

The California districts incorporate a three-pronged attack —surveillance, public education and mosquito control.

Surveillance determines the presence of the pathogen before human transmission becomes epidemic, and helps target control efforts.

Public education includes how to design, set up and manage large mosquito control programs. Among the logistics: financial, managerial, personnel and legal issues.

Mosquito control employs the latest physical, biological and chemical means to reduce mosquito populations near population centers. Tailored for a wide variety of landscapes, wetlands and population centers, the control methods include the use of mosquito fish; sensible irrigation practices and landscape alterations to reduce breeding sources; larvicides; and ground-based or aerial pesticide applications.