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West Nile Virus Prevention

Submitted by: 
Campus Health Service and Risk Management & Safety

Most people in Arizona are aware of the presence since 2003 of West Nile Virus (WNV) in the mosquito population in our state.  Arizona will continue to see human cases of this viral infection each season now that WNV is endemic in our state. This memo provides some basic information about this virus and its prevention, as well as preventive measures being employed by the UA.

West Nile Virus (WNV) is a mosquito borne virus that is present from May through October during peak mosquito season.  In 2008 there were 111 human WNV cases reported in Arizona (up from the 97 cases in 2007) and 17 cases in Pima County (up from 15 cases in 2007).  There is no treatment for this illness except supportive care. The virus causes no illness (80%) to mild to moderate illness (20%) in the vast majority of humans who are infected. Mild symptoms include:  headache, fever, diarrhea, nausea, vomiting, skin rash, backache, muscle aches, lack of appetite and swollen lymph nodes.  A very small number of infected humans (<1%) may develop a severe or life threatening illness with possible permanent neurological effects.  Signs and symptoms of severe disease include:  high fever, severe headache, stiff neck, disorientation or confusion, stupor or coma, tremors or muscle jerking, lack of coordination, convulsions, pain, and partial paralysis or sudden weakness. 

Although the chance of severe illness is rare, it’s certainly worth preventing.  A survey conducted by MEZCOPH MPH student Shannon Rock found that the effects of WNV can be long-term:  "Interviews revealed that 78% of cases did not feel completely recovered one year post-diagnosis.  Their symptoms included muscle weakness, extreme fatigue and muscle aches, pains and cramps.  Over 50% of people said they felt more confused, lost their concentration more, and experienced a loss of memory more often than before their diagnosis with West Nile Virus."

Infection with WNV can be prevented by eliminating standing water where mosquitoes breed and by preventing mosquito bites.  Insect repellent use and skin-covering clothing are especially important between dusk and dawn when the main type of WNV-carrying mosquito in Arizona is active (Culex quinquefasciatus). 

The following websites are sources of good information regarding WNV:

The University is an active partner with the Pima County Health Department’s “FIGHT THE BITE” efforts, with Entomology researchers conducting basic research, adult mosquito surveillance and community intervention, such as the Midtown Mosquito Project:  http://www.tucsonbotanical.org/mosquito.html.  Public health students work directly with the Pima County Health Department. Campus Health places educational messages in the Arizona Daily Wildcat and around the campus and makes insect repellant available at their pharmacy.  Facilities Management Grounds & Labor regularly inspects outdoor areas and applies a safe mosquito larvicide to known areas of standing water on a weekly basis during warm months.  Custodians routinely flush indoor drains where mosquitoes could breed.  Risk Management and Safety investigates mosquito related complaints and coordinates responses with other campus units such as Facilities Management. 

UA Building Managers and occupants have an important role to play as well by taking the following actions:

Indoors:

  • Flush all sinks & floor drains in your work area twice a week from May – Nov. In labs don’t forget each and every small cup sink in workbenches & fume hoods. Assign this task for all labs and shared equipment rooms. Do not assume somebody else will do it!
  • Do not put ½ full soda cans, bottles in trash or recycling bins.  Pour liquids into sink first.
  • Put a lid on garbage cans (mosquitoes like to hide in dark cave like spots – wet or dry)        

Outdoors:

  • Look for areas where water stands more than a day or two (rain drains, sumps)
  • Check window screens, doors screens and door sweeps are in good repair
  • From dusk to dawn wear long sleeves & pants
  • Provide insect repellent containing either DEET, picaridin or oil of lemon eucalyptus to your employees that work outdoors

References:   

Mayo Clinic Signs & Symptoms
http://www.mayoclinic.com/health/west-nile-virus/DS00438/DSECTION=2

Pima County Health Department West Nile Virus Hotlines
(520) 243-7797 (human & horse cases)
(520) 243-7999 (mosquito complaints or dead bird reports)