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Mosquitoes test positive for West Nile Virus

FLAGSTAFF, Ariz. - Coconino County Public Health Services District (CCPHSD) officials announced Sept. 22 that mosquitoes found in an area southwest of Flagstaff have tested positive for West Nile virus (WNV). This is the first positive WNV test in Coconino County this year. No human cases have been reported in Coconino County in 2011. Two human case of WNV were reported in 2010 and one case in 2009.

Larvicide treatment of the water pools in the affected area, in addition to cooler night temperatures, has resulted in a reduction of mosquitoes. CCPHSD staff will continue trapping and testing mosquitoes in areas where there is mosquito activity until colder weather returns.

WNV is a mosquito-borne virus that can cause symptoms in humans ranging from mild flu-like symptoms to severe neurological symptoms. However, in most infected people there are no symptoms at all.

Mosquitoes are most active at dusk and dawn, so it is advisable to stay indoors during these times, wear shoes and socks, long pants and a long-sleeved shirt when outdoors, and use mosquito repellent.

According to the Centers for Disease Control and Prevention, products containing these active ingredients typically provide reasonably long-lasting protection: DEET, Picaridin, oil of lemon eucalyptus or PMD - the synthesized version of oil of lemon eucalyptus and IR3535.

Be sure to follow the directions on the label of the repellent. Additional information on repellents is available at Residents are encouraged to remove standing water from areas around their homes when possible. The following suggestions may help reduce or eliminate standing water:

• Dispose of or turn upside down tin cans, plastic containers, ceramic pots or similar water-holding containers.

• Remove all discarded tires from your property. Used tires have become one of the most common mosquito breeding sites in the country.

• Drill holes in the bottoms of all recycling containers that are kept outdoors.

• Make sure roof gutters drain properly, and clean clogged gutters in the spring and fall.

• Turn over plastic wading pools and wheelbarrows when not in use.

• Change the water in birdbaths, pet dishes and flower pots at least twice per week.

• Clean vegetation and debris from the edge of ponds.

• Clean and chlorinate swimming pools, outdoor saunas and hot tubs.

• Drain water from pool and spa covers.

• Use landscaping to eliminate standing water that collects on your property.

These preventive measures should be continued until cold weather returns and mosquito activity diminishes in the fall.

Although the chance of becoming ill due to WNV is small, persons over the age of 50 are at higher risk for serious illness. In mild cases of WNV disease, symptoms including sudden onset of fever, headache, nausea, vomiting, eye pain, muscle pain, and rash, typically occur 3-14 days after the mosquito bite. More severe forms of the illness, including encephalitis and meningitis, are marked by weakness, high fever, stiff neck, headache, confusion, paralysis, and seizures. Very severe illness can be fatal, but less than 1 percent of those infected develop the more severe illness.

There is no specific treatment for WNV other than supportive care, and there is no vaccine available for humans. A WNV vaccination is available for horses. The Coconino County Public Health Services District encourages horse owners to vaccinate their horses.

For more information or to report any concerns, call the Coconino County Public Health Services District at (928) 679 8750 or toll free, 1-877-679-7272.

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