For many years, the Los Angeles County Department of Health Services provided mosquito control in the San Gabriel Valley for cities not covered by a mosquito abatement district. The formation of our District was a direct result of a mosquito transmitted disease called St Louis encephalitis (SLE).

In 1983 this disease was reported in Los Angeles County for the first time since the 1940s. In 1984, an epidemic of SLE occurred; sixteen cases and one death were reported. In 1986 three more cases were reported. In order to reduce the threat SLE posed to public health, the San Gabriel Valley Mosquito Abatement District was formed in August 1989 as an independent special district.

The District covers 287 square miles and includes 26 cities and parts of unincorporated Los Angeles County. The unincorporated areas of Altadena and Kinneloa were annexed to the District in 2002. Pasadena, South Pasadena, and Baldwin Park were annexed in 2018.

As the District has evolved, our services have increased to include the following:

• 1995 - Africanized honey bee control program.
• 1996 - Surveillance and control of black flies.
• 1997 - Full vector surveillance and control program adopted and we changed our name to San Gabriel Valley Mosquito & Vector Control District. 
• 2011 - Increased surveillance, operations, and education to respond to invasive Aedes mosquito threats

In 2014 the district reached a milestone as it celebrated 25 years of protecting the San Gabriel Valley from vector-borne diseases.