Mosquito patrol is enough to drive an intern buggy
Aspen Times Staff Writer
Lacey Gaechter’s summer job bugs her.
She tromps around in tall grasses next to slimy ponds – perfect bug territory – in search of the culex tarsallis. She hasn’t found any yet and might not discover a single one all summer, but the more fruitless her endeavor, the better.
Gaechter is a summer intern with Aspen’s Environmental Health Department. Her assignment is mosquito patrol.
She’s looking for the sole species of mosquito that is both a carrier of West Nile virus and, possibly, capable of living at this altitude.
Her work is part of a broader effort across Colorado and the country to track the spread of the potentially deadly virus. Once contained in Africa, the virus was first documented in the northeast United States in 1999 and has been moving westward ever since.
The virus made it to Colorado by late last summer, but has not been discovered at higher altitudes, where elevation and colder temperatures may keep the various species blamed for spreading the disease at bay.
“We’re really curious to see what role elevation plays,” said C.J. Oliver, city environmental health specialist and Gaechter’s colleague.
With the reappearance of the virus in Colorado this month – a dead magpie found in Freemont County, southwest of Colorado Springs, tested positive for the disease – state officials have urged Coloradans to take such precautions as using mosquito repellent.
Here in Aspen, though, Gaechter has yet to encounter the first big hatch of mosquitoes of any kind. While her traps have yielded an assortment of insects, the annoying, biting kind have yet to emerge in significant numbers.
Four afternoons per week, she sets two traps near likely mosquito breeding grounds, rotating among sites at the Aspen Center for Environmental Studies, Aspen Highlands, the North Star Nature Preserve and the Marolt Open Space.
The following morning, she returns to see what she has netted over night.
Tuesday morning, next to an algae-choked pond at ACES, Gaechter collected the bugs. The traps are poised over a pan of “the yuckiest water that’s around,” she explained. Insects are drawn to the pan, where a battery-powered fan draws them up a cylinder and into a net that can be removed from the trap.
The nets are placed in a cooler containing dry ice. The carbon dioxide released from the ice kills the insects, she explains guiltily.
“I tell myself they were only going to live a few days anyway,” Gaechter said.
Dumping the collection of dead bugs onto a sheet of white paper, Gaechter plucks out any mosquitoes she finds – there weren’t any in the batch on Tuesday – and puts them under a microscope.
The culex tarsallis is easily identified by a white band around its proboscis – the tube it pokes into a victim’s flesh to draw blood. “It’s a pretty dead giveaway,” she said.
She hasn’t found any of the species yet, but if she does, the insects will be sent to the Colorado Department of Public Health to be tested for the virus.
If the virus is documented in Aspen or Pitkin County, local governments are prepared to have potential mosquito breeding grounds on some city and county open space treated with an environmentally friendly larvicide. Private property owners will be urged to do the same.
Gaechter, an Aspen High School graduate, is serving her third stint as a summer intern for the city’s Environmental Health Department. The 22-year-old will be a senior at the University of Colorado this fall, where she’s majoring in environmental studies.
With hopes of becoming a wildlife biologist, Gaechter figures she’s starting small when it comes to wildlife.
“I do think it actually will be a good experience, as far as identifying species,” she said.
[Janet Urquhart’s e-mail address is firstname.lastname@example.org]
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