Two of three mosquito-testing zones in Weld County tested positive for West Nile virus this week, and the county health department is asking residents to take precautions.
The county has three testing zones: one in the Greeley/Evans area, one in the Johnstown/Milliken area and one in the Fort Lupton area, said Eric Aakko, Weld County Department of Public Health and Environment spokesman. Each zone has multiple traps to test mosquitoes, he said.
Aakko said traps set in the more populated areas of the county tested positive for the virus. However, mosquitoes are able to travel long distances and may be present in less populated areas.
“We test in these zones every single year, and we’re seeing positive tests earlier this year,” Aakko said. “It doesn’t necessarily mean it’s going to be a bad West Nile virus season. We can’t predict that at this time. All we can say with certainty is they are showing up earlier than usual.”
The county contracts with Colorado Mosquito Control for mosquito trapping and testing.
In past years, West Nile activity did not begin until July, Aakko said. There are high numbers of floodwater mosquitoes due to the recent mountain runoff and rains, but these mosquitoes do not carry West Nile virus. The Culex mosquito is known to spread West Nile virus and is tested to determine the risk of disease to humans.
Although Aakko said floodwater mosquitoes won’t spread West Nile, it’s possible for Culex mosquitoes to lay eggs in any standing water, including floodwater.
“It’s possible, as temperatures rise, that we may see more of them begin to lay eggs and hatch,” Aakko said.
Some municipalities in Weld County have mosquito control programs that include spraying. These programs reduce the number of mosquitoes but don’t eliminate all of them. Unfortunately, spraying for mosquitoes also kills beneficial insects, such as bees.
Aakko said the county sees a few cases of West Nile virus in humans every year, and if anyone experiences symptoms, they should go see their doctor immediately.
West Nile virus is carried by birds and transmitted by mosquitoes that bite the infected birds. Infected mosquitoes transmit the virus to humans, horses and birds. West Nile virus symptoms may appear three to 14 days after infection.
Initial symptoms include fever, headache, nausea and vomiting, muscle ache and weakness and rash. Symptoms of severe illness include high fever, stupor, disorientation, coma, tremors, muscle weakness, vision loss, paralysis and death.
For more information on West Nile virus and mosquito bite prevention, visit www.weldhealth.org.