West Nile Virus Serious Health Threat, But Preventable


Monday, the Arizona Department of Health Services confirmed that two squirrels captured in Payson tested positive for West Nile virus, a mosquito-borne disease that was first detected in the United States in 1999 and in Arizona in 2003.

Health officials say that West Nile virus poses a significant safety threat and should be taken seriously, but no one has ever contracted West Nile Virus by normal handling of infected animals. West Nile virus is spread to people by infected mosquitoes. Birds and other animals cannot transmit West Nile virus.

Mosquitoes become infected with West Nile virus when they feed on infected birds. Only certain species of mosquitoes carry the virus. Culex mosquitoes are the main carriers of West Nile virus, and these mosquitoes are common throughout Arizona. Culex mosquitoes tend to bite from dusk to dawn.

On its website, the Arizona Department of Health Services reports that West Nile virus infection has been found in more than 280 bird species. Certain types of birds such as crows, ravens and jays appear to be most susceptible to West Nile virus infection. Horses are also susceptible to West Nile virus infection, but a vaccine is available through veterinarians.

West Nile virus infections affecting the nervous system have also been reported in squirrels, goats, sheep and llamas, but the susceptibility of these animals to West Nile virus is not well known, the health department states. West Nile virus in dogs and cats is rare.

The majority of people and animals infected with West Nile virus have no symptoms or only a mild illness. About 20 percent of infected people will have flu-like symptoms such as fever, headache, body aches, swollen glands and muscle weakness. Symptoms can last for days or weeks. In rare cases, West Nile virus can cause more serious conditions such as encephalitis (an inflammation of the brain) and/or meningitis (an inflammation of the linings of the brain and spinal cord).

West Nile virus is a completely preventable disease, said Arizona Department of Health Services Director Catherine Eden in a press release. People can take two simple steps to protect themselves and prevent infection.

First, eliminate standing water, which allows mosquitoes to breed. Consider the life and reproduction cycles of one mosquito. According to a Houston-based pest control website for Special Chemical Applications, some species complete development from egg to adult in 10 to 14 days. They mate within one to two days after reaching maturity. An average female can have eight to 10 broods, averaging 200 eggs per brood. That means within two weeks, 20 million new mosquitoes are hatched.

These statistics underscore the importance of taking precautionary measures to eliminate mosquito breeding areas.

  • Check for conditions outside the home that may provide potential for mosquito breeding, such as poorly maintained swimming pools, cans, bottles, jars, buckets, old tires, drums and other containers with water.
  • Change water in flower vases, birdbaths, planters and animal watering pans at least twice a week.
  • Repair leaky pipes and outside faucets, and move air conditioner drain hoses.

Second, use mosquito repellent when outside during hours in which mosquitoes are active. Effective and long-lasting repellents, such as those containing the ingredients DEET or picaridin, are best. Wearing long-sleeved clothing when outdoors at night will also help prevent mosquito bites.

For additional information about West Nile virus, the state has established a website, www.westnileaz.com, and a toll-free number, (800) 314-9243.

Commenting has been disabled for this item.