By the Mosquito and Vector Control Association of California
Mosquito experts say that warm spring temperatures are prompting an early mosquito season and that drought conditions may lead to increased West Nile virus activity.
According to the U.S. Environmental Protection Agency, mild winters and drought have been associated with West Nile virus disease outbreaks.
West Nile virus, spread by Culex mosquitoes, is the most prevalent and serious mosquito-borne disease in California. There is no human vaccine for West Nile virus, a disease which can cause debilitating cases of meningitis, encephalitis, and even death. In 2021, there were 127 human West Nile virus disease cases from 28 counties in California, including 12 human deaths. Since 2003, more than 7,000 human disease cases have been reported, including more than 300 deaths.
In addition, as California residents brace for a third year of drought, mosquito experts are concerned that the lack of water is also conducive to the spread of invasive Aedes mosquitoes, whose eggs are resistant to drying out and can survive for many months. These mosquitoes are
particularly hard to control and pose a public health threat because they have the potential to spread serious diseases like Zika, dengue, chikungunya, and yellow fever to people, and even animal heartworm to pets.
“Climate change is magnifying the spread of invasive species, and we are seeing the effects first hand as invasive Aedes mosquitoes continue to spread throughout the state, ” said Ken Klemme, president of the Mosquito and Vector Control Association of California. “As drought
mitigation measures are put into place, it is important for residents to remember that mosquito production can occur in water sources as small as a bottle cap. Water storage containers need to be sealed properly, and swimming pools and ornamental ponds should not be left unattended.”
To raise awareness and educate Californians about the public health threat mosquitoes pose to our communities, Mosquito Awareness Week is observed April 17 – 23, 2022.
Mosquito experts say the future of mosquito control requires innovation to protect the public from mosquito-borne disease risks. Specifically, mosquito and vector control agencies in California are exploring the potential use of three innovative technologies: self-limiting
mosquitoes, Wolbachia, and irradiation. More information about the need for innovative technologies and how they work is available on the MVCAC website.
Everyone can do their part to help prevent mosquito bites:
- Apply insect repellent containing an EPA-registered active ingredient, including DEET, picaridin, oil of lemon eucalyptus, or IR3535, to clothes and exposed skin according to label instructions. Repellents keep mosquitoes from biting. It is important to follow EPA and CDC guidelines for the safe use of repellents on children.
- Dress in long sleeves and pants, especially if outside at dawn and dusk when mosquitoes that can spread West Nile virus are most active.
- Install screens on windows and doors and keep them in good repair to keep mosquitoes out of your home.
- Eliminate all sources of standing water on your property, including in flowerpots, old tires, buckets, pet dishes, and trash cans. Mosquitoes lay their eggs in very small amounts of standing water.
- Repair leaking faucets and broken sprinklers that can contribute to standing water around your home.
- Clean rain gutters clogged with leaves.
- Report neglected swimming pools and day-biting mosquitoes to your local mosquito and vector control agency.
To learn more, check out the videos on the MVCAC website, and for additional information on mosquitoes and mosquito-borne diseases, please visit the California Department of Public Health Mosquitoes and Mosquito-Borne Diseases webpage.
About the author: The Mosquito and Vector Control Association of California (MVCAC) is the statewide voice for mosquito and vector control professionals. The association provides public health information, expertise, mosquito and vector-borne disease surveillance, innovative research, professional training, effective legislative and regulatory advocacy on behalf of California public agencies.