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West Nile Virus Season Returns

West Nile Virus Season Returns

With our warm spring weather and showers, the mosquitoes will be appearing and that means the return of West Nile Virus!

In 2006, Fremont County had one confirmed human case of West Nile Virus (WNV) out of 345 human cases statewide. There were seven deaths in Colorado from West Nile Virus last year.

With the onset of mosquito season, it's a good idea to review general information about West Nile Virus and precautions to avoid the disease. West Nile Virus is transmitted by the bite of an infected mosquito with an incubation period of 3-14 days following the bite. People who contract West Nile Virus disease may start to have symptoms as early as 3-4 days after being bitten by an infected mosquito and symptoms include:

  • Serious Symptoms in a Few People. About one in 150 people infected with WNV will develop severe illness. The severe symptoms can include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. These symptoms may last several weeks, and neurological effects may be permanent. Contact your medical provider if you experience any of these severe symptoms.
    Milder Symptoms in Some People.
  • Up to 20 percent of the people who become infected have symptoms such as fever, headache, and body aches, nausea, vomiting, and sometimes swollen lymph glands or a skin rash on the chest, stomach and back. Symptoms can last for as short as a few days, though even healthy people have become sick for several weeks.
  • No Symptoms in Most People. Approximately 80 percent of people (about 4 out of 5) who are infected with WNV will not show any symptoms at all.

Late summer is the time for the greatest mosquito activity in Colorado, but precautions should be taken through the entire WNV season including:

  1. When weather permits, wear long-sleeves, long pants and socks when outdoors. Using insect repellants containing DEET.
  2. Eliminating or limiting the number of places around your home for mosquitoes to breed by getting rid of items that hold water such as standing water in ponds, ditches, clogged rain gutters, flower pots, plant saucers, puddles, buckets, jars and cans.
  3. Also check for items that might hold water including wheelbarrows, tires, hubcaps, toys, garden equipment, pool covers, tarps, plastic sheeting, pipes, drains, boats, canoes, recycling bins and trash.
  4. Keeping mosquitoes outside by having well-fitting screens on both windows and doors.

If you spend time outside and you use products containing DEET, remember that the DEET may have to be reapplied:

  • Repellants containing 25% DEET can protect for up to 5 hours.
  • Repellants containing 20% DEET can protect for up to 4 hours.
  • Repellants containing 6.65% DEET can protect for up to 2 hours.
  • Repellants containing 4.75% DEET can protect for up to 1.5 hours

Products containing DEET above 30% don't provide better protection. Use products containing 10% to 30% DEET on children. According to the American Academy of Pediatrics, products containing DEET at a concentration of 10% appear to be as safe as products with a concentration of 30% when used according to the directions on the product labels. AAP recommends that repellents with DEET should not be used on infants less than 2 months old.

Bti briquettes will be available again this year from the CSU Extension Office, Room LL10, Fremont County Administration Building, 615 Macon, Canon City, CO. A flat of 20 briquettes will cost $15. These briquettes biologically control mosquito larvae and are designed to be placed in standing water to kill larvae for up to 30 days. The Bti briquettes are also available commercially at most local hardware stores and garden centers.

Fremont County and Canon City will continue to monitor mosquitoes under a grant from the Colorado Department of Public Health & Environment in 2007. A sentinel zone will be established and mosquito light traps will be set out within the defined zone with an emphasis on testing in summer to provide early indication of the severity of the WNV season. Mosquitoes will be collected and submitted for testing.

Additional information about WNV is available at the Colorado Department of Public Health & Environment website at www.cdphe.state.co.us and at www.FighttheBiteColorado.com.

FOR FURTHER INFORMATION CONTACT: Sid Darden, Fremont County Environmental Health Officer at 276-7460 or J.R. Phillips at 276-7317.