Record Rainfalls and Warm Temperatures Could Mean an Explosion of Mosquitoes

Press release by Mosquito and Vector Control Association of California (MVCAC). Source

National Mosquito Control Awareness Week is a Reminder to Californians to Protect Themselves

SACRAMENTO, June 22, 2017 – While California’s wettest winter in 122 years ended the state’s historic drought, the surge in rainfall could contribute to another threat: an active mosquito season with the potential for increased mosquito-borne virus transmission to people.

Heavy rains over the past six months have produced new sources of standing water throughout the state. As the weather heats up, these sources become ideal breeding grounds for mosquitoes which could result in tens of thousands of potential virus transmitters, posing a health risk to Californians.

Mosquitoes in California actively transmit West Nile virus and Saint Louis encephalitis each year, and invasive mosquitoes detected in the state have the potential to transmit even more viruses such chikungunya, dengue, yellow fever, and Zika.

“Californians have the power to significantly reduce the mosquito threat and help protect residents and communities from potentially fatal diseases,” said Jamie Scott, President of the Mosquito and Vector Control Association of California (MVCAC). “Mosquito control is a community effort and we urge everyone to take time at least once a week to inspect their yard and get rid of any standing water – the breeding grounds for the world’s deadliest animal.”

June 25 – July 1 is National Mosquito Control Awareness Week and aims to educate the public about the significance of mosquitoes in their daily lives and the important service provided by mosquito control workers around the world.

West Nile virus continues to be a threat to Californians with more than 2,000 cases in just the last three years, including a record number of deaths (53) in 2015. Of these reported cases, there has been an increase of people developing the more serious neuroinvasive form of the disease. In recent years invasive Aedes mosquitoes have established in more than 124 cities and communities across the state posing an additional threat. An aggressive day-time biter, theses mosquitoes are not only ruining the quality of life of many Californians with their incessant biting, but also are capable of infecting people with diseases not currently transmitted in the state by mosquitoes. The threat of local transmission of viruses such as Zika, dengue, and chikungunya becomes greater as the population of these invasive Aedes grows and people who visit areas where these diseases are present visit or return home to California.

Since 2015, California has reported 561 travel-associated cases of Zika virus, including 131 infections in pregnant women and six infants born with complications. Mosquito control agencies throughout the state and the nation are of key importance to increasing awareness and protecting public health year-round. However, it is equally critical that local residents understand how to protect themselves and their families from mosquito-borne illness during the upcoming summer months.

The MVCAC’s new website at is a new resource for the public to keep up-to-date on mosquito threats and find prevention and protection best practices.

To minimize exposure to mosquito bites:

  1. Before going outdoors:
    a. Apply insect repellent containing EPA-registered active ingredients, including DEET, picaradin, oil of lemon eucalyptus, or IR3535 according to label instructions. Repellents keep mosquitoes from biting. DEET can be used safely on infants and children 2 months of age and older.
    b. Dress in long sleeves and pants and closed shoes.
  2. At home:
    a. Install screens on windows and doors and keep them in good repair.
    b. Eliminate all sources of standing water on your property, including in flower pots, old tires, and buckets. Remember: mosquitoes can lay their eggs in sources of water as small as a bottle cap.
    c. If you are being bitten by mosquitoes during the day, please contact your local mosquito and vector control agency.

For additional information on mosquitoes and mosquito-borne diseases:

Travelers should refer to the CDC’s Travel Advisories:

About MVCAC:

MVCAC represents more than 65 special districts and other subdivisions of state and local government which are responsible for mosquito and vector control, surveillance of WNV and other vector-borne diseases, and public education programs to help Californians protect themselves from mosquito-borne disease. Approximately half the land area and 85 percent of the population of California are within the boundaries of a mosquito control program. To these ends, MVCAC advocates safe, effective, and environmentally friendly methods of mosquito and vector control.