Coconino County officials are encouraging residents to take necessary precautions as a second pool of mosqui­toes has tested positive for the West Nile virus. 
The Coconino County Health and Human Services confirmed the second positive mosquito pool sample taken from the Cheshire area in northwest Flagstaff late last week.

The prior week a mosquito sample from an area south of Lake Mary Road in Flagstaff tested positive as well.  Trish Lees, spokeswoman for the CCHHS said no human cases have been reported in Coconino County since 2010, when two indi­viduals tested positive. 

CCHHS staff has applied a non-toxic larvi­cide treatment to reduce mosquito populations in water pools in the affected areas and in other locations in the County. CCHHS will continue trapping and testing mosquitoes in areas where there is mosquito activity until colder weather returns. Although these are the only areas where mosquitoes have tested positive this year, the virus is endemic and could be present in other areas throughout the county, Lees said. Monica Kriner, of Yavapai County Community Health Services, said of the 40 locations where they have mosquito traps throughout the county, none have tested positive for West Nile virus this year or in 2018. 

“Even though we haven’t had any mosquitoes test positive the last two years, West Nile virus is always a concern,” she said. “That’s why we test for it.” 

According to the most recent statistics from the state, by the end of July only three counties had reported positive mosquito pools for West Nile virus — Maricopa [263], Pinal [39] and Yuma [16]. 
According to a state report, there are over 40 species of mosquitoes in Arizona, but only some mosquitoes spread disease. Understanding the distribution of mosquito species within the state and the location of positive mosquito pools is crucial to implementing appro­priate control efforts. The Centers for Disease Control and Prevention report that insect repel­lent containing DEET, Picaridin, oil of lemon eucalyptus or PMD — the synthesized version of oil of lemon eucalyptus — and IR3535 typi­cally provide reasonably long-lasting protection. 

People are encouraged to take the following precautions to prevent mosquito bites: 

• Mosquitoes that carry West Nile virus are most active at dusk and dawn. Stay indoors during these times or wear shoes and socks, long pants and a long-sleeved shirt when outdoors. 
• Use screens on windows and doors. Repair holes in screens to keep mosquitoes outdoors. 
• Use air conditioning, if available. 
• Stop mosquitoes from laying eggs near your home. Once a week, empty and scrub, turn over, cover or throw out items that hold water, such as tires, buckets, planters, toys, pools, birdbaths, flower­pots or trash containers. 
• People should continue taking preven­tative measures until cold weather returns and mosquito activity dimin­ishes in the fall. 

The CCHHS reported that 80% of those infected with West Nile virus do not develop any symp­toms. Symptoms and signs of the virus include fever, headache, body aches, skin rash and swollen lymph nodes. If people experience symp­toms, they should contact a health care provider. 

There is no specific treatment for West Nile other than supportive care, and there is no vaccine available for humans. A vaccination is avail­able for horses, which is why CCHHS encourages horse owners to discuss vaccinations with their veterinarian. 

For more informa­tion or to report any concerns, call the Coconino County Health and Human Services Environmental Health office at 679-8750 or toll free 1-877-679-7272.