County hasn’t had any West Nile cases this season
West Nile Virus seems to have lost its bite in Mesa County as no mosquitoes here have tested positive for the virus this year.
That is a sharp contrast to five years ago when the county was a hotbed of West Nile Virus activity, with 127 confirmed cases and four deaths.
Colorado reported nine human cases of West Nile Virus as of Aug. 14, but none of those cases were on the Western Slope. Delta County reported one case of West Nile Virus found in a mosquito population after an Aug. 6 test.
Because of the slowdown in the number of cases and state budget constraints, testing of mosquitoes by the Colorado Department of Public Health and Environment ceased as of Aug. 14.
Steve DeFeyter, director of environmental health at the Mesa County Health Department, said testing for the virus will continue in Mesa County and Delta County through September. DeFeyter said the counties have some excess testing materials they can use to continue keeping watch.
“It makes sense to do surveillance,” he said. “It doesn’t make sense to overreact if we don’t have the mosquitoes.”
The summer season so far has produced an enormous amount of nuisance mosquitoes, called Aedes Vexans (common mosquitoes.) But the infected Culex mosquitoes have not been found here, according to local health department testing.
One person died in Colorado last year of West Nile Virus, and a total of 71 cases were reported.
There were no cases of West Nile in Mesa County last year. In 2007, Mesa County had 34 cases and one death from West Nile Virus. The county had similar numbers in 2006, with two deaths and 38 cases.
Mosquitoes infected with West Nile Virus tend to increase after mid-July after the blood-sucking insects have laid several rounds of larvae, so it’s possible that the counties of Mesa and Delta could report more populations of infected mosquitoes before the fall, DeFeyter said.
West Nile may be making less of a presence locally because of ramped-up mosquito killing efforts and because many of the birds that carried the disease five years ago are now dead.
“Even though the numbers are down, more mosquitoes are going to be infected later in the season,” DeFeyter said. “People need to be vigilant, but by the first of October the risk will go way down.”