County health officials reported Thursday one new human case of West Nile virus in the San Diego region, while the number of dead birds testing positive continues to swell.
The number of confirmed and probable human cases is up to 31, five of whom have died, according to the county. Another 10 cases are pending confirmation by state laboratory testing.
County Vector Control collected 18 dead birds with the mosquito-born virus in the past week, sending the total for the year to 321. That's more than the 41 found last year, and the most since 563 were discovered in 2008.
Statewide this year, 517 people have tested positive for West Nile virus and 28 people have died, county health officials said.
About 80 percent of people with West Nile virus 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.
The best protection is to empty out areas of standing water where mosquitoes breed — especially after a recent rainfall, stay indoors at dusk and dawn when the insects are most active, and wear long sleeves and pants or use repellent when outdoors.
County officials also urged residents to contact the vector control agency when they find dead birds or green swimming pools, by calling (858) 694- 2888 or emailing vector@sdcounty.ca.gov.
