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Jul 18

West Nile virus Disease Facts and Prevention Measures

Posted on July 18, 2019 at 12:57 PM by Erika Story

Montrose, COLO.— Montrose County Public Health is encouraging the public to take precautions to prevent West Nile virus during active mosquito months. In 2018, there were 96 human cases of West Nile virus in Colorado, eight of those cases were from Montrose County. Currently, there are no confirmed cases of West Nile virus in Montrose County in 2019.

West Nile is a virus transmitted to humans by the bite of a female mosquito seeking a meal to nourish her eggs. It has been common in Africa, west Asia and the Middle East for decades. It first appeared in New York in 1999 and traveled westward across the U.S. It has been in Colorado since 2002 where mosquito season starts in the late spring and ends in mid-September.

"This has been an unusual year for mosquito activity," said Montrose County Community and Public Health Manger Jim Austin. "The large amount of moisture across the western slope increases the probability that this will be a large year for mosquito growth. Proper prevention can limit and possibly prevent exposure to mosquito-transmitted viruses such as West Nile."

The West Nile virus is carried long distances by infected birds and then spread locally by mosquitoes that bite the birds. Infected mosquitoes can then bite and pass the virus to humans and animals, primarily birds and horses. Even in areas where the virus is circulating, very few mosquitoes are infected and most are simply a nuisance. Even if a mosquito is infected, the chance a person will become severely ill from any single mosquito bite is extremely small. West Nile virus has only been seen in a small number of cases, to be spread through blood transfusions, organ transplants, and from mother to baby during pregnancy or at the time of birth.

Most infected people will not get sick or will have only mild symptoms, but West Nile virus can be fatal due to encephalitis in rare cases. Mild symptoms include fever, headache, body aches, and occasionally include skin rashes and swollen lymph nodes. All residents can be at risk, especially those that work outdoors but people over the age of 50 are especially vulnerable to the severe forms of disease.

Montrose County Health and Human Services would like to remind residents to follow these personal protection measures:

  • Avoid mosquitoes by staying indoors at dawn and dusk when bugs are most active.
  • Wear long-sleeved shirts and long pants while outdoors.
  • Apply insect repellent that contains DEET. Follow directions carefully.
  • Install or repair window and door screens to keep mosquitoes out.
  • Have your horses vaccinated against West Nile Virus.

Mosquitoes lay up to 250 eggs at a time in still water, which hatch in seven to 10 days. The following tips help reduce the number of breeding mosquitoes and reduce the need to use chemical pesticides:

  • Remove standing water in ponds, ditches, clogged rain gutters, flowerpots, plant saucers, puddles, buckets and cans.
  • Check for items that might hold water including wheelbarrows, tires, hubcaps, toys, garden equipment, pool covers, tarps, plastic sheeting, pipes, drains, flat roofs, boats, canoes and trash. Drill drainage holes in tire swings.
  • Completely change water in birdbaths and wading pools weekly.
  • Stock ponds and fountains with fish that eat mosquito larvae.
  • Use mosquito “dunks” in small ponds. Dunks are natural bacteria that kill mosquito larvae but are harmless to other animals, and are available at local hardware or home and garden stores.

Montrose County Health and Human Services has a limited supply of mosquito dunks available free of charge for residents. If you have questions about West Nile Virus or mosquito dunks please contact us at 970-252-5011.

West Nile Courtesy CDPHE


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