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Researchers Make Progress on West Nile Vaccine

Updated: Friday, September 7 2012, 12:45 PM CDT
(AP) The Oklahoma State Department of Health reported Thursday that two more elderly people have died from the West Nile virus, prompting a warning from Gov. Mary Fallin than residents should take steps to protect themselves.

The latest deaths were reported this week in Oklahoma and Seminole counties, and officials identified them only as people older than 80. The state's other death this year, reported last week in Oklahoma County, was someone older than 75.

Those most at risk are adults over the age of 50 due to their diminishing immune system, said state epidemiologist Dr. Kristy Bradley.

Bradley said the Culex mosquito, which spreads the disease through its bite, is most active in the early morning and early evening hours. Fallin released a statement reminding residents to limit outdoor activities during those times and wear an insect repellant containing DEET.

"This disease has hit Oklahomans hard this year and unfortunately, those who seem to be most at risk are older citizens," Fallin said. "Oklahomans are or will soon be gearing up for night-time outdoor activities like high school football games, athletic practices, lakeside camping, gardening and evening jogs."

Officials also warned that residents should make sure window and door screens are not torn in order to keep the mosquitoes out. Standing water should also be drained or treated with a mosquito larvacide, and to keep gutters free of leaves and other debris.

There have now been 61 cases of the disease in 14 Oklahoma counties with 41 of the cases people 50 or older. Those infected have ranged in age from 12 to 90, the health department said.

Thirty-nine of the 2012 cases have been neuro-invasive, the most severe form, the health department said. Bradley said the neuro-invasive disease cause inflammation of the brain and spinal cord and symptoms include an inability to walk, mental confusion and disorientation. Some victims are unable to speak, may lose vision or hearing or suffer paralysis of their legs or arms.

The health department has projected that, at the current pace, there could be 200 or more cases of West Nile Virus in Oklahoma this year, nearly doubling the previous record of 107 cases in 2007 when eight people died of the disease.

"The Oklahoma State Department of Health is continuing to receive and investigate reports of West Nile disease, so our case numbers will increase," Bradley said.

Bradley said there can be a risk of exposure into early November.

From 2002, when the virus first appeared in Oklahoma, through 2011 there were 326 cases of the disease and 20 deaths.

There is no vaccine to prevent the virus in humans and no drugs to treat it, Bradley said, although there is a vaccine for horses.

Bradley said there have been at least two cases of the virus in horses this year, with one animal euthanized.Researchers Make Progress on West Nile Vaccine