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By Gig Conaughton, County of San Diego Communications Office

July 23, 2018 (Santee) -West Nile virus made its first appearance of the summer in San Diego County this week when a batch of mosquitoes caught in routine trapping in Santee tested positive for the virus.

County officials reminded people they should follow the County’s “Prevent, Protect, Report” guidelines to protect themselves from all mosquitoes and the various diseases they can transmit, from West Nile virus to tropical diseases such as chikungunya, dengue and Zika.

“One of the most important things people can do is to find and dump out any standing water they see inside and outside their homes so mosquitoes can’t breed,” said Elise Rothschild, the County’s Director of Environmental Health.

No people, or birds — the main carriers of West Nile virus — have tested positive for West Nile virus in San Diego County this year. However, County Vector Control officials said West Nile virus has been present in the county since it arrived here in 2003. Only about 20 percent of people who get infected with West Nile virus suffer any symptoms, but it can be deadly in rare cases.

Last year, two San Diego County residents tested positive for West Nile virus; both recovered. But across the state of California in 2017, 600 people tested positive and 44 people died. In Los Angeles County alone, 268 people tested positive and 27 people died.

West Nile virus is mainly a bird disease, but it can be transmitted to humans by a number of species of mosquitoes — including Culex mosquitoes native to San Diego and, less effectively, invasive Aedes aegypti mosquitoes — if they feed off an infected animal and then bite people.

If people who become infected suffer symptoms, they are typically mild, including headache, fever, nausea, fatigue, skin rash or swollen glands.

New Mosquito-Borne Illness Worries

Protecting against mosquitoes has become even more important for San Diego County residents recently. In the last four years, three types of day-biting, invasive Aedes mosquitoes have been found in San Diego County. All of these mosquitoes like to live and breed near people, in yards and even inside homes. All of them can potentially transmit diseases not naturally found here.Two of these species can potentially transmit chikungunya, dengue and Zika — but only if they first bite an infected person. In general, that means local invasive Aedes mosquitoes could only transmit those diseases if they found, and bit, San Diego County residents who got the disease while traveling and returned home still infected.

To date, that has not happened in San Diego County or California and no invasive Aedes mosquitoes have tested positive here or in the state for chikungunya, dengue or Zika.

Still, County officials said this week that people should help fight mosquitoes and potential illnesses by following the “Prevent, Protect, Report” guidelines.

Prevent mosquito breeding

Dump out or remove any item inside or outside of homes that can hold water, such as plant saucers, rain gutters, buckets, garbage cans, toys, old tires, and wheelbarrows. Mosquito fish, available for free by contacting the Vector Control Program, may be used to control mosquito breeding in backyard water sources such as unused swimming pools, ponds, fountains and horse troughs.

Protect yourself from mosquito bites

Protect yourself from mosquito-borne illnesses by wearing long sleeves and pants or use repellent when outdoors. Use insect repellent that contains DEET, picaridin, oil of lemon eucalyptus, or IR3535. Make sure screens on windows and doors are in good condition and secured to keep insects out.

Report possible mosquito activity

Report increased mosquito activity, or neglected, green swimming pools and other mosquito-breeding sources, as well as dead birds — dead crows, ravens, jays, hawks and owls — to environmental health’s Vector Control Program by calling (858) 694-2888 or emailing Also report if you are being bitten by mosquitoes during daylight hours, or if you find mosquitoes that match the description of Aedes mosquitoes by contacting the Vector Control Program at (858) 694-2888.

For more information about mosquito-borne illnesses, go to San Diego County’s “Fight the Bite” website.

Here are some tips to help keep your yard from becoming a mosquito breeding ground.

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Mosquitos heavy near Santee Lakes in 2021: County in denial

Having lots of trouble with the County not wanting to institute a mosquito prevention plan for Santee Lakes (which is essentially a sewage treatment plant.) Lots of mosquitos near and at the lake, yet the County says they don't breed there and they won't do a thing. Hard to believe. Never saw mosquitos like this and am tired of being bitten, scores of times over the past month I've been here. Have YOU noticed any mosquitos around Santee Lakes?