Mosquito Awareness Week, observed April 16 - 22, 2023, educates California residents about mosquitoes and how to help prevent the spread of mosquito-transmitted diseases.
One of the wettest years in history has left standing water across the state, creating perfect conditions for mosquitoes to develop. Stagnant water creates havens for disease-spreading mosquitoes, and mosquito experts are concerned this could be a long and intense mosquito season.
“After record amounts of rainfall this year, it is really important for all Californians to dump and drain standing water that has accumulated in their yards, porches, and patios,” said Assemblymember Jim Wood, who authored the state resolution recognizing California Mosquito Awareness Week. “It only takes a small amount of water for mosquitoes to develop so removing all stagnant water is a simple but very effective way to help to eliminate mosquitoes from our community. Not only are mosquitoes a nuisance, but they can transmit deadly diseases. Let's all work together to fight the bite!”
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 2022, there were 209 human West Nile virus disease cases from 28 counties in California, including 13 human deaths.
In addition, invasive Aedes mosquitoes continue to spread throughout the state. First detected in 2013, they have spread to 25 counties and 300 cities and towns. These mosquitoes are very hard to control and pose a serious public health threat because they can spread diseases like Zika, dengue, chikungunya, and yellow fever to people and animal heartworm to pets.
According to the California Department of Public Health, since 2016 there have been nearly 900 California residents with travel-associated dengue infections. While there has not yet been local transmission of dengue in the state, it is occurring at California's borders, making the threat even more real. In 2022, the border state of Sonora, Mexico had more than 9,000 cases with 91 people dying from dengue. In December 2022 in Maricopa County, Arizona, two individuals tested positive for dengue, which they acquired locally from a mosquito bite.
“While all of the rain has been great for the drought, it provides mosquitoes with more places to lay their eggs,” said Wakoli Wekesa, PhD, president of the Mosquito and Vector Control Association of California. “As we work to keep Californians safe from mosquito-transmitted diseases and combat the spread of invasive Aedes, it's critical that residents take simple precautions to protect themselves and keep their communities mosquito-free.”
Mosquito experts say the future of mosquito control requires innovation to protect the public from mosquito-borne diseases. 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:
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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.
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Dress in long sleeves and pants, especially if outside at dawn and dusk when mosquitoes that can spread West Nile virus are most active.
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Install screens on windows and doors and keep them in good repair to keep mosquitoes out of your home.
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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.
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Repair leaking faucets and broken sprinklers that can contribute to standing water around your home.
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Clean rain gutters clogged with leaves.
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Report neglected swimming pools and day-biting mosquitoes to your local mosquito and vector control agency (agency information can be found at www.mvcac.org)
To learn more, please visit the MVCAC website or the California Department of Public Health Mosquitoes and Mosquito-Borne Diseases webpage.
About MVCAC
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.
[Shared from the Mosquito and Vector Control Association of California. View UC IPM's Pest Notes: Mosquitoes for more information.]
From UC IPM Pests in the Urban Landscape blog.
According to Gary Goodman, District Manager of Sacramento Yolo Mosquito and Vector control, many residents are anxious and excited to get outside and enjoy the warm weather so it's important to protect yourself from mosquito bites by wearing a good mosquito repellent.
The Centers for Disease Control and Prevention (CDC) recommend using an insect repellent that contains the active ingredients DEET, Picaridin, IR3535 or the plant-based oil of lemon eucalyptus.
Aside from personal protection against mosquito bites, it's important to ensure mosquitoes are not breeding at home. Drain stagnant water from sprinklers, irrigation, and rainstorms. Be sure to check your backyard and dump any water in flower pots, kiddie pools, tires, pet dishes, bird baths and other common household containers that can hold water.
Another ongoing concern is the invasive mosquito Aedes aegypti which has been detected in several counties throughout Southern California and the Central Valley. For county level information, see this map. Invasive mosquitoes pose a significant health threat because they can transmit dangerous viruses including Zika, dengue fever and chikungunya. Surveillance efforts have continued since the initial detection last August. To date, no cases of Zika virus have been reported in California.
For more information on mosquito identification and management, see our recently revised Pest Notes: Mosquitoes. Additional information on vector-borne diseases is available on the California Department of Public Health website.
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- Author: Anne E Schellman
In Part I, we discussed why mosquitoes bite, and which mosquito species can spread West Nile and Zika virus. Now, let's talk about what mosquitoes need to reproduce, how to prevent them from breeding around your home, and best methods to protect yourself and your family while outdoors.
What do Mosquitoes Need to Breed?
The mosquitoes that spread West Nile virus and Zika need water to lay their eggs. Female mosquitoes can lay their eggs in even the smallest amount of water. Places in your yard that appeal to them include standing water found in ponds, garden pots, children's toys, or even pet water bowls. Eliminating these possible breeding spaces is key to mosquito control.
Watch the video “Don't Let Mosquitoes Breed in your Yard” from UC IPM for helpful tips.
Protect Yourself from Mosquito Bites
There's a plethora of mosquito control and prevention items for sale, but many are ineffective.
When outdoors, protect your skin by wearing long-sleeved pants and shirts, long socks, and a hat. Be aware that mosquitoes can bite through a thin layer of clothing. Also, choose and apply an effective EPA-registered mosquito repellent that contains DEET, picardin, IR3535, or oil of lemon eucalyptus to exposed skin.
You may be tempted to use outdoor sprays to battle mosquitoes. However, this method is only temporary and doesn't help control the source of the problem. The best way to avoid bites are prevention and protection.
Resources: UC IPM Pests in the Urban Landscape. Zika, Mosquitoes, and Repellents. https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=21923
- Author: Anne E Schellman
You've probably read a lot lately in the news about West Nile virus and Zika virus. In mid-June, the first human case of West Nile virus in Stanislaus County was diagnosed. This past week, mosquitoes that can carry the Zika virus were found in our county.
Why do mosquitoes bite?
It may surprise you to learn that mosquitoes get most of their food from flower nectar. However, female mosquitoes need a blood meal to produce eggs. If she bites someone while carrying a virus, it can infect that person.
What is the difference between West Nile virus and Zika virus?
West Nile virus is carried by Culex tarsalis or the Western encephalitis mosquito. This species is most active just after sunset. It feeds on birds and other mammals, including humans.
Eighty percent of people infected with West Nile virus do not show symptoms. The other twenty percent may have mild symptoms including fever, headache, body aches, nausea, vomiting, and sometimes swollen lymph glands or a skin rash. One in 150 people infected will develop a neurological illness that may result in death.
Zika virus is transmitted by several species of Aedes mosquitoes. These mosquitoes bite people during the day. Women infected with Zika during pregnancy may have an infant born with microcephaly and other severe brain defects.
Although this mosquito has been found in Stanislaus County, the virus has not been found in California. Aedes mosquitoes can only transmit Zika if they carry the virus.
How can I protect myself and my family?
Stay tuned tomorrow for part II of this blog post, with helpful tips for prevention and protection from mosquitoes.
Resources:
University of California Agriculture and Natural Resources. UC IPM Pest Notes: Mosquitoes. Taken from http://ipm.ucanr.edu/PMG/PESTNOTES/pn7451.html on August 5, 2019.
Vector Disease Control International. Culex tarsalis-the Western Encephalitis mosquito. Taken from http://www.vdci.net/blog/mosquito-of-the-month-culex-tarsalis-western-encephalitis-mosquito on August 5, 2019.
California Department of Public Health. Zika: What Californians Need to Know. Taken from https://www.cdph.ca.gov/Programs/CID/DCDC/Pages/Zika.aspx on August 5, 2019.
July 10, 2019
WEST NILE VIRUS
Elk Grove, Ca.—The Sacramento-Yolo Mosquito and Vector Control District confirmed today that the first mosquito sample of the season has tested positive for West Nile virus (WNV). The mosquito sample was collected near the Florin area of south Sacrament County. “As we expected, after finding the first positive bird earlier in the week, now we are finding virus in the mosquito populations, “ said Gary Goodman, District Manager. “With the very warm weather expected over the next few days, we expect WNV activity to quickly ramp up,” he added. The District encourages residents to take these findings seriously and do everything they can to protect themselves. Last year in California there were 211 confirmed human cases of the disease, including 11 fatalities.
The detection of this recent WNV activity is evidence that the disease is present and the public should take proper precautions to stay protected. “As more people enjoy outdoor activities during the warm summer evenings, it's important to remember that the best protection against mosquito bites is an effective insect repellent” said Goodman. Residents are also encouraged to report dead birds, neglected pools and other mosquito problems.
As a response to the finding of WNV, the District will increase its mosquito trapping and monitoring in the area to find sources where mosquitoes may be breeding. Targeted ground spraying may also be conducted to rapidly decrease the numbers of adult mosquitoes.
For current information about District activities, please visit www.FIGHTtheBITE.net. Residents may also subscribe to mailing lists to receive email notifications for upcoming mosquito treatments by zip code. To sign up, go to Spray Notifications on the website.
2019 West Nile virus activity update:
Sacramento County: 1 mosquito sample and 1 dead bird have tested positive for West Nile virus to date.
Yolo County: No activity has been detected to date.
Practice the District D's of Mosquito Prevention:
DRAIN standing water that may produce mosquitoes.
DAWN and DUSK are times to avoid being outdoors.
DRESS appropriately be wearing long sleeves and pants when outside.
DEFEND yourself by using an effective insect repellent. Make sure to follow label directions!
DOOR and window screens should be in good working condition.
DISTRICT personnel are also available to address any mosquito problems. Call them at 1-800-429-1022 or visit www.FIGHTtheBITE.net