POPLAR BLUFF, Mo. -- Mosquitoes that tested positive for the West Nile virus have been found in Poplar Bluff, according to the Butler County Health Department.
Officials said that even though cooler temperatures have moved into the area, residents should still be cautious.
Mosquitoes will be present as long as it is warm enough to reach the 60s, said environmental public health specialist Chris Grider.
"They are still out there, though not in near the same numbers," he said.
The vial of mosquitoes that tested positive was found in mid-October in a trap set as part of the 2011 Arbovirus Mosquito Surveillance Program. The trap was in a zone south of Highway 53 and northeast of U.S. 67.
The health department conducts the testing annually as part of a service contract from the Missouri Department of Health and Senior Services.
"These were found in one of the final weeks of testing," Grider said. "This is a 13-week program."
While the county did not find West Nile-positive mosquitoes in 2010, Grider said it is not unusual for the Butler County to have at least one vial returned positive during the year.
The health department said residents should reduce the amount of standing water present on their properties to eliminate breeding grounds for mosquitoes. Residents should also protect their homes with proper window and door screens.
Most people infected with West Nile virus do not experience any symptoms. About 20 percent of infected people have symptoms such as fever, headache, tiredness and body aches. In rare instances the virus can cause meningitis or encephalitis.
Poplar Bluff, MO