Another mosquito tested positive for West Nile virus in an unincorporated area of ​​Bexar County, according to the county’s emergency management office.

The mosquito was found near Highway 90 and Cagnon Road in far western Bexar County. It is the third mosquito to test positive for the virus, which can cause illness and, in rare cases, death in people who are bitten.

Bexar County has stepped up its mosquito control efforts in the region, with county crews using fog machines to spray public paths and parks to eliminate the pests.

“The fogging agent used is environmentally friendly and effective in killing mosquitoes,” said a statement from the Office of Emergency Management (OEM).

The OEM went door-to-door to 843 households in the area to provide prevention information to residents, especially households with young children.

County officials say residents can learn about mosquito-borne diseases, including West Nile virus, at http://www.bexar.org/mosquito.