The deluge of rain that fell in the Central Valley this winter and spring did much to help the state out of the drought, but it also created optimal breeding conditions for mosquitoes that officials are warning could prompt a bevy of health concerns for residents.
According to the California Department of Water Resources, the San Joaquin Valley received nearly 125 percent of the average rainfall from October 2018 to February 2019. The heavy rainfall can lead to accumulated stagnant water, which in turn creates mosquito breeding sites. Mosquito experts throughout the state are stressing the need for Californians to dump and drain all standing water.
“Warm weather coupled with large amounts of stagnant water from recent rain events create the perfect conditions for mosquito breeding,” said Dave Heft, general manager for Turlock Mosquito Abatement District. “Mosquitoes can lay their eggs in a wide range of water holding sources and can complete their life cycle, from egg to adult, in about a week. Residents must do their part to help protect public health by dumping and draining all standing water to eliminate mosquitoes from their communities.”
In addition to being a nuisance, mosquitoes
pose a serious public health risk as infected mosquitoes can spread viruses,
which can cause debilitating cases of meningitis, encephalitis, and even death.
West Nile Virus activity was detected in 41 counties in California in 2018 and
there were 215 human WNV cases reported, of which 153 were the more severe
neuroinvasive form. There were also five human Saint Louis Encephalitis Virus
Cases in the state.
During 2018 in Stanislaus county, there were 15 human cases of West Nile Virus and one case of Saint Louis Encephalitis Virus.
Mosquitoes become infected with West Nile
Virus when they feed on infected birds. Infected mosquitoes can then spread
West Nile Virus to humans and other animals when they bite, according to the
Centers for Disease Control.
Approximately 1 in 5 people who are infected with West Nile virus will develop symptoms such as fever, headache, body aches, joint pains, vomiting, diarrhea, or rash. Less than 1 percent will develop a serious neurologic illness such as encephalitis or meningitis (inflammation of the brain or surrounding tissues). About 10 percent of people who develop neurologic infection due to West Nile virus will die, according to the CDC. People over 50 years of age and those with certain medical conditions, such as cancer, diabetes, hypertension, kidney disease, and organ transplants, are at greater risk for serious illness.
There are no medications to treat or vaccines to prevent West Nile Virus infection. People with milder illnesses typically recover on their own, although symptoms may last for several weeks or months. In the neuroinvasive forms, patients can suffer severe and sometimes long-term symptoms.
All signs are pointing to an early and active mosquito season. To raise awareness and educate Californians about the public health threat mosquitoes pose, the California Legislature declared April 21-27, 2019 as Mosquito Awareness Week.
“Many of us, including myself, have lost dear
friends and loved ones to mosquito-transmitted diseases like West Nile virus
infection. The risks are all too real, and awareness is one critical tool we
can use to save lives,” said Senator Henry Stern. “All Californians play an
important role in protecting public health and should take simple measures to
reduce the risk of mosquito- transmitted diseases in their community.”
The Turlock and Eastside Mosquito Abatement Districts also want to remind the public to be aware of the new invasive mosquito species which have been making their way around California. Though not yet detected in Stanislaus County, officials are concerned it’s only a matter of time. These species are aggressive day-biting mosquitoes found in urban areas. Anyone experiencing daytime biting mosquitoes in town, should contact their District.
The invasive Aedes mosquitoes, are able to spread zika, dengue, chikungunya and yellow fever viruses. These mosquitoes continue to spread and are now established in 12 counties in the Central Valley and Southern California. With thousands of international travelers arriving or returning to California each year from areas where these viruses regularly occur, the potential for local transmission of imported diseases in the state is increasing. The arrival of a single traveler with an active infection into an area with invasive mosquitoes opens the door for these diseases to spread.
The Turlock Mosquito Abatement District will be conducting aerial photography to identify neglected pools, will be occurring the week of April 22. This service aids the District in identifying pools which can potentially produce mosquitoes capable of transmitting viruses.
There are two mosquito abatement districts to serve residents in Stanislaus County. Residents north of the Tuolumne River should contact the Eastside Mosquito Abatement District at (209) 522-4098. Residents south of the Tuolumne River should contact the Turlock Mosquito Abatement District at turlockmosquito.org or (209) 634-1234.
To minimize exposure to mosquitoes, people are advised to:
• 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
• Dress in loose-fitting long sleeves and pants.
• Install screens on windows and doors and keep them in good repair.
• Eliminate all sources of standing water on your property, including in flower pots, old tires, buckets, pet dishes and trash cans.
• Repair leaking faucets and broken sprinklers.
• Clean rain gutters clogged with leaves.
• Report neglected swimming pools and day-biting mosquitoes to your local mosquito and vector control agency.