Mosquitoes can carry West Nile virus. Image via San Diego County Twitter

A 53-year-old San Diego County resident is the first locally acquired human case of West Nile virus this year, the county Health and Human Services Agency announced Friday.

The La Jolla man was hospitalized but is expected to recover.

There was one West Nile virus case in San Diego County in 2020, three in 2019 and two in 2018.

West Nile virus can be transmitted to people by certain species of native San Diego County mosquitoes that first feed on an infected bird or animal and then a bite a person.

At least 80% of people who become infected with West Nile virus never know it and never suffer any symptoms. About one in five people who are infected develop a fever and other symptoms such as headache, nausea, fatigue, skin rash or swollen glands. About 1 out of 150 infected people will develop serious illness.

County public health and environmental health officials said the best way for people to protect themselves against the virus is to follow the county’s “Prevent, Protect, Report” guidelines.

The guidelines can also help county residents protect themselves from mosquitoes that transit West Nile virus as well as invasive Aedes mosquitoes that can transmit tropical diseases, such as Zika, dengue and chikungunya, if they first bite an infected person and then bite non-infected people.

The county recommends dumping out or removing 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 county’s Vector Control Program, may be used to control mosquito breeding in backyard water sources such as unused swimming pools, ponds, fountains, and horse troughs.

People can protect themselves from mosquito-borne illnesses by wearing long sleeves and pants or using repellent when outdoors. People should use insect repellent that contains DEET, picaridin, oil of lemon eucalyptus or IR3535. They should also make sure screens on windows and doors are in good condition and secured to keep insects out.

Residents should 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 vector@sdcounty.ca.gov.

Residents should also report if they are being bitten by mosquitoes during daylight hours, or if they find mosquitoes that match the description of Aedes mosquitoes.

City News Service contributed to this article.

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