VALLEY CENTER (CNS) - San Diego County environmental health officials Wednesday reported the first local discovery of the year of West Nile virus -- in a dead red-tailed hawk in Valley Center.
The potentially fatal disease is carried by mosquitoes, which transmit the illness to people by feeding on infected birds and then biting humans.
Mosquitoes rarely bite in cooler weather -- 50 degrees Fahrenheit or lower -- but county officials expressed concern that temperatures have edged up in recent weeks. They're also worried that heavy winter rains have provided the insects with more places to breed.
In 2016, 22 county residents tested positive for the disease and two died. That's half the number of human cases and one-third of the death toll of the prior year.
County vector control teams also found 266 dead birds that tested positive for the virus last year, as well as 99 batches of mosquitoes, nine sentinel chickens and one horse.
Statewide, 436 Californians tested positive for West Nile virus in 2016 and 19 people died.
The best protection against WNV is to empty out areas of standing water where mosquitoes breed; stay indoors at dusk and dawn when the insects are most active; and wear long sleeves and pants or use repellent when outdoors.
About 80 percent of people with WNV don't get symptoms, while the remainder will have headaches, fever, nausea, fatigue, a skin rash or swollen glands.
An estimated one in 150 cases are life-threatening, with the risk going up for patients over age 50, according to the county Health and Human Services Agency.
County officials also urged residents to contact vector control when they find dead birds or green swimming pools, by calling (858) 694-2888 or emailing email@example.com.