A fourth San Diego County resident has tested positive for West Nile virus this summer, prompting renewed warnings from public health officials about mosquito prevention, according to NBC 7 San Diego.

NBC 7, citing county health officials, reported that no local deaths have been reported this year. One recent case required several days of hospitalization, another involved mild symptoms, two were detected through blood-donation screening and one was acquired locally.

County officials urged residents to remove standing water from plant saucers, rain barrels, buckets, garbage cans, toys, old tires and wheelbarrows. The county's Vector Control Program also offers free mosquito fish for stagnant water sites where they can help control mosquito breeding.

For Santee households, the practical takeaway is simple: after irrigation, pool splash-out or any summer cleanup, check yards and patios for water that sits long enough to attract mosquitoes. NBC 7 reported that the county is also using helicopter larvicide drops in areas of standing water around the region this week.

West Nile virus is primarily a bird disease but can spread to people when mosquitoes bite infected birds and then bite humans. Mosquito activity or breeding sources can be reported to the county Vector Control Program at 858-694-2888 or vector@sdcounty.ca.gov.