Vector Control

West Nile Virus Fact Sheet

Mosquito and Vector Control Association of California (MVCAC ) strives to provide quality public information, comprehensive mosquito and vector-borne disease surveillance, training to high professional standards, and effective legislative advocacy on behalf of California mosquito and vector control agencies.  

More than 65 mosquito and vector control agencies throughout the State are members of MVCAC.  

Mosquito control in California has been very successful at preventing major outbreaks of diseases for more than 60 years. These diseases include West Nile virus, malaria and encephalitis. Mosquito control and disease surveillance all over the world continues to protect public health against emerging vector-borne diseases such as Chikungunya, dengue fever and yellow fever.  

West Nile virus (WNV) is primarily transmitted through the bite of infected mosquitoes.  

There is no effective treatment for West Nile virus.  

Prevention of mosquito bites is the best defense against mosquito-transmitted diseases:

• Public education and awareness are critical to protect public health.
• Proactive mosquito management and control by vector control agencies reduces vector populations and disease risk.

The Three D’s of mosquito prevention are precautionary steps to protect against mosquito bites and mosquito breeding around the home.

1. Dump/Drain standing water where mosquitoes breed.
2. Dusk/Dawn - Stay indoors when mosquitoes are most active.
3. Defend - Wear approved insect repellent and long-sleeved shirts and pants.

Mosquito control using Integrated Vector Management methods are proven to be effective in reducing mosquito populations, human WNV cases, and risks for disease transmission.

Backyard and Urban Sources: Excessive rain can fill neglected swimming pools, spas, backyard containers, trash, retention basins, ditches and wetland areas, often resulting in prime mosquito breeding habitat. Local mosquito control experts inspect and abate known mosquito breeding sources, and depend on the community to help them identify problem backyards and neighborhood sources. Not only will mosquito control experts conduct property inspections, they can also provide mosquito fish for certain water sources to help aid in the reduction of mosquito populations.

Foreclosures and the Market Demand Conundrum: Record home foreclosures, a lack of qualified buyers and restrictive lending practices means homes are left unoccupied for greater periods of time, increasing the likelihood of pestiferous infestations. As a result, abandoned swimming pools and backyard mosquito breeding sources need to be monitored and treated for longer periods of time. Residents can help prevent mosquito breeding by reporting empty or green swimming pools to their local mosquito control agency. Keep in mind that a single, neglected backyard swimming pool can produce millions of mosquitoes.

Snowmelt: During years with record snow pact levels, stream, river, and wetland volume can increase. Increased springtime water volume can create stagnant pools along waterways when water levels return to normal in the early summer months. Residents are encouraged to take extra precautions when visiting these areas to avoid exposure to vector-borne illnesses.