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Many infected by West Nile, CWC research determines
Mar 29, 2012 - By Joshua Scheer, Staff Writer
Central Wyoming College students said their research found that 11 percent to 22 percent of Fremont County's population contracted West Nile virus last year.
"For the last three years, we've had a research program specifically directed at West Nile virus," said CWC assistant professor of biology and microbiology Steve McAllister at a March 21 colloquium on campus in Riverton.
He said the first couple of years were spent getting approvals for doing the data collection, which began last year.
Six student researchers were in attendance at the announcement: Jonathan McFall, Josh Graham, Seth Hosking, Kelli Neimeyer, Rachel Lamb and Rod Printz. More were involved over the years.
Graham began the presentation by talking about the research done on 84 Fremont County residents.
Going into the study, the students hypothesized that a drop in reported human cases of West Nile virus was because more people in the county were immune.
Graham said data compiled by the Centers for Disease Control and Prevention indicate that in 2007 there were 117 reported human cases of West Nile virus in the county. That dropped to two in 2008, four in 2009 and none in 2010.
Graham said that historically, 80 percent of people who contract the disease never show symptoms.
"What we hypothesized was that people didn't know they were getting it," Graham said.
Using the Elisa method -- a way to test blood samples for the virus -- the research team found nine of 84 people tested were positive for the virus.
Therefore, Graham said, their hypothesis was wrong. There was not a large percentage of the population contracting the virus but not showing symptoms. Only a small percentage got the illness.
One attendee asked if there was a higher percentage of people who contracted the disease because they lived by rivers. McAllister said at this point the team is unsure if it could legally release that information.
Hosking then discussed the team's efforts to collect and test mosquitoes for the virus.
Between July 30 and Sept. 3, the team collected mosquitoes from two locations in Riverton and one each in Shoshoni, Arapahoe and Pavillion.
Hosking described how they used lamps to attract mosquitoes. Fans were attached to the lamps that then sucked the insects into a net where they would be trapped. The apparatus would be set from 8 p.m. to 8 a.m.
Of all the mosquitoes trapped, varying by location, 17 percent to 36 percent were culex tarsalis, the species known for carrying the virus. At one in-town location in Riverton, Hosking's home, there were no culex tarsalis found, which he guessed was because of insecticide spraying.
Of the culex tarsalis collected, none tested positive for the virus.
McAllister said he was ready to "start firing people" because he was sure they were wrong.
But he was wrong.
"The results are in conformity with the rest of the state," Hosking said.
McAllister learned other agencies statewide were having difficulty finding mosquitoes carrying the virus.
As the college moves forward with its research, Hosking said researchers would look for a correlation between the prevalence of the virus in mosquitoes and the local crow and blackbird population. The birds serve as a reservoir for the virus and are the source of it for mosquitoes.
The team also plans to refine its mosquito-catching apparatus and collect more environmental data.
Five of the six students are pursuing careers in medical fields. The sixth, McFall, wants to get into entomology. All said they gained something from the experience.
At the end of the presentation, dean for workforce and community education Lynn McAuliffe said she contracted West Nile virus in 2006 and was a member of the 1 percent who had a serious reaction to it.
"Thank you," she said to the researchers. "What you're doing is really important work."