Governments readying for West Nile |

Governments readying for West Nile

Eben Harrell

On the eve of the summer “mosquito season,” Pitkin County and Aspen City officials are preparing to combat West Nile virus.

Both the city and the county will hire a West Nile specialist in the coming weeks and both governments have laid out plans to monitor and prevent the disease.

A larvicide program – the destruction of mosquitoes in their infant state – has also been approved at the discretion of government officials.

Human cases of West Nile virus, which can also infect birds, dogs and horses, have increased exponentially in Colorado over the past two years. In 2001 there were no reported cases. In 2002, there were 14 human cases reported. In 2003 there were 2,274 reported cases – the most in any single state.

West Nile virus only produces symptoms in 20 percent of infected people. Only one in 150 patients with symptoms becomes seriously ill. In rare cases, West Nile can cause meningitis and encephalitis, two extremely dangerous forms of brain inflammation. Last year, 55 people in the state died from such complications.

There were no human cases of West Nile in Pitkin County last year, although a bird near Basalt and a man in Carbondale were found to be infected.

Still, health officials from both Aspen and Pitkin County say they will remain vigilant, routinely collecting mosquitoes and testing dead birds. Due to their susceptibility to the disease, birds are often the first sign of an impending outbreak.

Both the city and county will have certain “triggers” that will start up a larvicide program. The county will begin the larvicide if more than 100 of the species of mosquito that carries the virus is found in a hatch.

The city’s triggers are more sensitive, according to Aspen City Environmental Health Specialist CJ Oliver

“We’re going to start a larvicide program if we have any sign that West Nile might be approaching Aspen,” he said.

Both governments say they are prepared to administer the spraying of chemicals over adult mosquito sites in a worst-case scenario.

Unlike larvicide, which uses a naturally occurring bacteria to destroy mosquito hatches, sprays targeting adults are chemical based.

Officials say education will be the linchpin of their prevention program. Officials will be speaking to individual landowners to encourage private larvicide programs. And representatives will be on hand at major events, such as Aspen’s Saturday market and the Snowmass rodeo, to educate and in some cases hand out insect repellent.

Among the prevention recommendations is the use of insect repellent with at least a 30 percent DEET content for adults and 10 percent for children. DEET is a chemical ingredient shown to be the most effective insect repellent. If used correctly, health officials say the chemical poses no health risks.

Long sleeves should be worn at dawn and dusk when mosquitoes like to feed. Dead birds should be reported to local health authorities. And residents should try to avoid the buildup of stagnant water pools that can provide hatcheries for the insect by routinely emptying outdoor pots, wheelbarrows and other containers where rainwater collects.

Eben Harrell’s e-mail address is