Less West Nile virus detected this year

There was less West Nile Virus this year in Tennessee compared to 2008, and unusually cool weather in July and August is probably the reason, according to a state health expert.

“We’ve not had a very hot summer, compared to previous years,’’ said Dr. Abelardo Moncayo, an epidemiologist with the Tennessee Department of Health. “That’s important to mosquito development and also to development of the virus.’’

Moncayo explained that mosquitos, which spread the virus that causes the disease, spawn more vigorously in hot weather. Higher temperatures also aid replication of the virus itself, he said.

August is usually the peak month for West Nile.

Moncayo said the best indicator is tracking tests done on pools of mosquitoes, explaining that there could be late reporting of human cases of the disease.
The mosquito testing has just ended and Moncayo reports a significant drop. In 2008, 14.6 percent of the samples tested came back positive for West Nile, compared with 11.7 percent this summer.