West Nile virus remains active in the region and across the state, and residents should keep taking steps to protect themselves against mosquitoes, San Diego County health officials said Friday.
Six confirmed or probable human West Nile cases have been identified since the middle of November in the county, bringing this year's total to 41, including five fatalities, according to the Department of Environmental Health.
Testing results are pending for three more human cases.
More than 700 people have tested positive for the mosquito-borne virus across California this year and 39 have died, the highest single-year total since the disease first was found in the state a dozen years ago.
San Diego County officials said they've discovered West Nile this year in 362 dead birds, 49 batches of mosquitoes, 12 chickens and a horse. The number of dead birds with the virus is the most since 563 were discovered in 2008.
Since the disease remains active, San Diegans were encouraged to continue to protect themselves against it.
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.
About 80 percent of people with West Nile 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 the vector control agency when they find dead birds or green swimming pools, by calling (858) 694- 2888 or emailing vector@sdcounty.ca.gov.
