With the higher moisture level from an above-average spring runoff, Garfield County officials want residents to know mosquitoes are out in force on the Western Slope and to protect themselves.

 “It’s up. It is way up, but I think in some people’s minds it’s insane right now, but a lot of that is because we had such a good year last year,” said Steve Sheaffer, contract manager with Vector Disease Control International.

“In a dry year like last year when there wasn’t that much water fluctuating, it was a significantly more Culex tarsalis,” he said of the mosquito variety that’s the most common carrier of the West Nile virus in Colorado. 

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“This year I think we have been seeing 80 percent or more of Aedes variety mosquitoes, which doesn’t typically vector any diseases,” Sheaffer said. “They are just really aggressive and annoying. I think that is what people are noticing right now.”

“You only need a soda cap full of water to start breeding mosquitoes where ever you are.”— Rachel Kappler, Garfield County Public Health

West Nile virus is a viral infection that occurs most commonly from the bite of an infected mosquito.

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Viral spread

Rachel Kappler, a registered nurse with Garfield County Public Health, said it was first discovered in 1937 in Uganda. By 1950, people in the Middle East started becoming sick. Symptoms include fever and encephalitis, which is an infection around the brain.

The virus was first discovered in the United States in 1999 in New York City.

“As of 2005, it has covered the entire hemisphere from Canada to Argentina,” Kappler said.

“We are trapping throughout Garfield County to monitor the numbers of mosquitoes in the genus Culex, to try and keep track of potential West Nile risk and aid in deciding where to focus our operation,” Sheaffer said.

Sheaffer, who is contracted through Garfield County, has been monitoring and controlling the mosquito population in Garfield County for over a decade now.

With the higher number of mosquitoes, the greater the chances for disease-carrying mosquitoes like the Culex tarsalis to be present.

Steve Anthony, vegetation manager for Garfield County, said the program is an intergovernmental agreement with all the municipalities in the county, made up of six jurisdictions. The agreement is renewed every year.

“The big push for West Nile virus came on the radar screen in 2003,” Anthony said. “Up until last year we did not have a confirmed case of West Nile in the county since 2007.”

Mosquito monitoring

To help monitor and trap the pesky insect, there are 11 points throughout the county and occasional floater traps when high concentrations of mosquitoes are detected, to see what is present in the insect population.

Permanent locations include Battlement Mesa, Parachute, three in Rifle, one each in Silt, at Coal Ridge High School, New Castle, Glenwood Springs, and two in Carbondale. 

Anthony said if a person were to leave one standard-sized coffee tin in their backyard and let it fill with water, it will produce 10,000 mosquitoes over one summer.

Mosquitoes look for dense vegetation during the heat of the day, so any overgrown areas in a homeowner’s yard can provide a good home for mosquitoes.

Sheaffer said that agricultural areas where water stands for more than five days would produce a substantial number of mosquitoes. Retention ponds and flooded areas are breeding grounds for the insects, as well.

“From 2018, 48 out of 50 states reported West Nile virus in their state,” Kappler said.

With 2,544 total cases nationwide in 2018,  there were 137 deaths recorded in the United states. Nebraska, California and North Dakota had the highest rates.

“In Colorado, in 2018 there were 96 cases, resulting in three deaths,” Kappler said. “There was one case in Garfield County last year.”

Since 2002 when public health officials started tracking West Nile cases, Garfield County has seen 16 cases. No deaths in Garfield County have been reported.

“It’s important to know that 94 percent of the cases occur between mid-July to late August. But it technically can occur at anytime of the year,” Kappler said.

Watch for symptoms

Some people are more prone to the disease and the risk factors. People age 64 or older have a higher fatality rate, she said.

Eight out 10 people don’t show symptoms, which begin about two to 14 days after a person has been bitten by a mosquito.

Kappler said the symptoms can last about three to 10 days or longer, and one in five people develop a fever, headache, body aches, joint pain, vomiting, diarrhea and rash.

“Most people spontaneously recover from West Nile virus, but it is possible to have long-lasting fatigue and weakness [several] weeks or months after the infections,” Kappler said.

“The big reason we are concerned about West Nile virus is it can cause encephalitis or meningitis,” she said.

Meningitis is the inflammation of the membranes surrounding the brain and spinal cord.

“One out of 150 people, less than 1 percent, will develop encephalitis or meningitis,” Kappler said.

“If anyone develops signs or symptoms that they think is West Nile virus, they should seek medical treatment form a qualified doctor,” she said.

Kappler said the three best steps of prevention involve who, what and when to select a repellent.

“Who are you protecting, because age is a factor; what are you protecting from; and then we go to when and how long is the potential exposure,” Kappler said.

Peach Valley prime

Anthony said parents need to pay particular attention to the area around Coal Ridge High School.

“There will be football practices or other sports throughout the summer. So we try to have that high on the radar screen,” Anthony said. 

Both Anthony and Sheaffer warn that it is an area that gets some Culex and a fair amount of mosquitoes, because it is middle of Peach Valley surrounded by agriculture activities. 

“We get in and treat as much as we can, but they seem to just love converging by the school for whatever reason,” Sheaffer said.

Anthony advises parents of children that are going to Coal Ridge and are taking part in activities in the summer time to send them off with some type of protection, whether it be DEET repellent or an alternative type. 

If people are interested to see where the hot spots are in the county on a weekly basis, they can go to the website garfield-county.com/vegetation-management.

“We get the counts for each trap, and it’s actually documented every week for location. If they really want to know where the Culex is, they should check it out,” Anthony said.

kmills@swiftcom.com