The West Nile virus has officially arrived with mosquitoes testing positive in Mesa and Chandler.
The virus’s presence, confirmed in mosquitoes tested April 21 and 28, is early this year — an indication the state is in for a long season with West Nile, said Michael Fink, an epidemiology specialist for the Arizona Department of Health Services.
"I think it means we have a lot of virus in the area and we’ll see more mosquitoes testing positive," he said. "It’s here and people need to realize it’s not going away."
Public health authorities are urging people to get rid of stagnant water around their homes, which can become breeding grounds for virus-spreading mosquitoes. One of the positive West Nile tests last month came from a backyard swimming pool with a broken pump, a common problem area for mosquito-breeding in the Valley, Fink said.
Mosquitoes pick up West Nile from infected birds that have migrated to the area, then spread the virus when biting animals and humans. Last year, Arizona had 13 reported cases of the West Nile virus in humans, and one death, according to the Centers for Disease Control and Prevention. State officials said the virus killed 28 horses and 250 birds.
Public health experts worry that Arizona could follow Colorado’s experience last year with West Nile, which infected nearly 3,000 people and caused more than 60 deaths. The virus typically has its worst impact the second year it is detected in an area. Colorado had its second year with West Nile in 2003. Arizona is in its second year with the virus this year.
"This is going to be a pivotal year for West Nile virus in Arizona," Fink said. "We’re expecting that we might have something just as serious happen this year."
Most people who become infected with West Nile develop no symptoms. For those who do, one in five people develop flu-like symptoms. One in 150 people develop a serious infection resulting in encephalitis, swelling of the brain, or meningitis, swelling of the membrane covering the brain and spinal cord. Other symptoms of severe infection include paralysis, severe muscle weakness or seizures. Those most at risk include senior citizens and people with compromised immune systems.
Hospitals have begun training staff to recognize signs of the virus in patients, and United Blood Services has started asking prospective donors if they’ve had a fever with a headache, which can be a sign of West Nile, in the week before they give blood.
Last week, state and county officials announced campaigns to eliminate mosquito breeding sources and encourage people to protect themselves from mosquito bites. Also, Gov. Janet Napolitano authorized $100,000 for statewide mosquito abatement efforts.
IN YOUR YARD
• Don’t allow water to stand for more than four days.
• Drain standing water from old tires, bird baths, pet dishes, buckets, cans, cups, outside toys, wheelbarrows, boats and flowerpots.
• Remove any water that collects on pool covers.
• Clear leaves and twigs from eaves, troughs and gutters.
• Fill in low areas in lawns.
• Repair leaky pipes and outside faucets.
• Let your neighbors know about potential mosquito breeding grounds on their property.
TO REDUCE THE CHANCES OF GETTING BITTEN
• Stay indoors from dusk to dawn, when mosquitoes are most active.
• Wear loose-fitting clothing, long sleeves and long pants.
• Apply insect repellent containing DEET to clothing as well as exposed skin.
• Do not use insect repellent on children younger than 2.
• For general information on mosquito-eating fish at no charge, contact Maricopa County Vector Control at (602) 506-0700.
• To report a mosquito complaint, call (602) 506-6616 or go to