More mosquitoes trapped within the greater Yakima area have tested positive for West Nile virus, the Yakima Health District said Thursday afternoon.

The confirmation brings the year-to-date total in the county to eight positive mosquito pools and three positive horses.

"We're seeing a greater number of environmental positives earlier in the mosquito season this year," said Laura Charters, environmental health specialist with the Health District.

She added that the District is getting more complaints about mosquitoes this year. So far, there's been no report of any human cases of West Nile virus, which causes fever, headache, body aches, rash and swollen lymph glands. More serious symptoms are neck stiffness, disorientation, coma, tremors, convulsions, muscle weakness and paralysis.

The latest sampling took place Aug. 6 north of Union Gap.

The first line of defense against West Nile virus is getting rid of any standing water where the bugs breed. Horse owners should vaccinate their animals.