Play Live Radio
Next Up:
Available On Air Stations
Watch Live


First sign of West Nile virus in mosquitoes found in Los Peñasquitos Lagoon

A mosquito bites a man's arm in this undated photograph.
San Diego County Communications Office
A mosquito bites a man's arm in this undated photograph.

Mosquitoes collected from the north end of Los Peñasquitos Lagoon adjacent to Del Mar and parts of San Diego tested positive for West Nile virus, prompting county environmental health officials Wednesday to remind people to protect themselves from the insects.

County officials said people should continue to follow the county's "Prevent, Protect, Report" guidelines, including finding and dumping out standing water around homes to keep mosquitoes from breeding.

Wednesday's news marks the first sign of the disease in mosquitoes this year. However, there have been no locally contracted human West Nile virus cases reported.


According to the county's office of environmental health, if people who become infected suffer symptoms, they are typically mild, including headache, fever, nausea, fatigue, skin rash or swollen glands. In rare cases, West Nile virus can make people extremely ill and even kill them. In 2015, 44 San Diego County residents tested positive for West Nile virus and six county residents died.

West Nile virus is mainly a bird disease, but it can be transmitted to humans by local mosquitoes if they feed off an infected animal, mainly birds, and then bite people.

Mosquitoes like to live and breed near people, in yards and even inside homes. Some invasive types can potentially transmit diseases not naturally found here including chikungunya, dengue and Zika — but only if they first bite an infected person.

Besides dumping out standing water, the county recommends wearing long sleeves and reporting increased mosquito activity or dead birds to environmental health's Vector Control Program by calling 858-694-2888 or emailing