West Nile Virus is a disease that is transmitted to humans through the bite of a female mosquito. Nationwide WNV has been confirmed in 43 states, and there are 693 confirmed cases for this calendar year so far. To date, there have been seven confirmed cases in Arizona and one death. Cochise County currently does not have any known activity from WNV.
People typically develop symptoms between three and 14 days after they are bitten by an infected mosquito. Approximately 80 percent of those infected with WNV will not show any symptoms at all. Up to 20 percent of infected people will develop symptoms such as fever, headache and body aches, nausea, vomiting, swollen lymph glands or a rash on the chest, stomach and back.
Symptoms generally last only a few days, although some people can be sick for several weeks. Only about one in 150 people infected with WNV will develop severe illness. Symptoms can include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness, paralysis and even death. These symptoms may last several weeks, and neurological effects may be permanent. Those who are bitten and notice any of these symptoms should see their health care provider immediately.
People over 50 are at higher risk of developing serious symptoms of WNV if they do get sick and should take special care to avoid mosquito bites.
Risk of disease transmittal through medical procedures is low. All donated blood is checked for WNV before being used. The risk of getting WNV through blood transfusions and organ transplants is small and should not prevent those who need surgery from having it. People with concerns should talk to their doctors.
Mosquitoes breed in water and do not pose a risk throughout most of the year here in the Sierra Vista/Fort Huachuca area due to the normally arid weather conditions. The only time that mosquitoes become a concern is during monsoon season due to accumulations of standing water.
Every year during the rainy season, installation personnel take preventative measures to keep mosquito populations at a minimum. All ponds, storm water basins and standing water are treated with larvicide, a pesticide that kill mosquito larva. Treatment takes place shortly after the onset of monsoon rains and continues through the end of September.
The easiest and best way to avoid WNV is to prevent mosquito bites by applying insect repellent to exposed skin or clothing. Generally, the more active ingredient a repellent contains, the longer it can protect users from getting mosquito bites.
Repellents may irritate the eyes and mouth, so avoid applying it to children’s hands. When using an insecticide or insect repellent, be sure to read and follow the manufacturer’s directions for use, as printed on the product. Use insect repellent containing an Environmental Protection Agency-registered active ingredient such as DEET, Picaridin, Oil of Lemon Eucalyptus or IR3535. See the EPA webpage for more information on ingredients at www.epa.gov/pesticides/health/mosquitoes/ai_insectrp.htm.
Spray clothing with repellents containing permethrin or another EPA-registered repellent since mosquitoes may bite through thin clothing. Do not apply repellents containing permethrin directly to exposed skin or under clothing. Other helpful hints include wearing long-sleeved shirts, placing mosquito netting over infant carriers and staying indoors at dawn and dusk.
Help reduce the number of mosquitoes in areas outdoors where people work or play by draining sources of standing water. Some examples include flower pots, buckets or discarded tires. This reduces the number of places where mosquitoes can lay their eggs and breed.
For more information on WNV, contact the Center for Disease Control, go to their webpage, www.cdc.gov/ncidod/dvbid/westnile/index.htm, or contact the Environmental Health Section, Preventive Medicine, Raymond W. Bliss Army Health Center, 533.3959.