West Nile Virus has made its first appearance of 2007 in Arizona, and state and local health officials are encouraging residents to take precautions against the disease.

Mosquito samples collected April 26 by health officials near Clarkdale in Yavapai County tested positive for West Nile virus at the Arizona State Health Laboratory. These are the first mosquito samples to test positive this year. No human cases have been reported.

West Nile Virus made its first appearance last year in late June.

“Mosquitoes are breeding earlier this year because of warm weather and recent rains,” said Craig Levy, head of the Arizona Department of Health Service’s Vector-Borne and Zoonotic Diseases section. “While we can’t predict how severe the West Nile season will be this year, Arizonans should begin taking steps to protect themselves against mosquito bites.

“West Nile is just as serious this year as it was in previous years; it will still cause serious illness and probably even deaths,” Levy said.

Since its first arrival in Arizona in 2003, more than 650 residents have been infected with the disease. Thirty-five deaths have been attributed to West Nile in the state, including 11 last year.

“Be prepared,” Levy urged. “Use insect repellent, and wear protective clothing, especially between dusk and dawn and in areas where mosquitoes are active. One of the most important things we can do is to be sure we are not raising mosquitoes in our pools, ponds and birdbaths.”

The state has established a web site, www.westnileaz.com, and a toll-free number, 1-800-314-9243, (Metro Phoenix: 602-364-4500), to provide additional information.

West Nile Virus is transmitted to humans and animals through mosquito bites. Mosquitoes become infected when they feed on infected birds.

The best way to protect yourself from mosquito-borne illness is to reduce the number of mosquitoes around your home and neighborhood and to take personal precautions to avoid mosquito bites, such as:

• Eliminate standing water where mosquitoes can breed. Check for items outside the home that collect water, such as cans, bottles, jars, buckets, old tires, drums and other containers.
• 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 frequently.
• Avoid being bitten by mosquitoes when going outside at night by using insect repellent.
• Wear lightweight clothing that covers the arms and legs during dawn or dusk, or in areas where mosquitoes are active.