“Somewhere around 15 percent of mosquitoes in East Tennessee now are carryng West Nile virus, which is a scary number,” said Dr. Madison Torrence, medical director of SkyRidge Emergency Center.
While SkyRidge has not had any confirmed cases of West Nile virus, there have been cases of the virus treated at Erlanger Medical Center, Torrence said.
He said he thinks more physicians have seen mild cases of the virus, but have simply written it off as the flu.
In order to confirm a West Nile case, samples have to be sent to the state lab.
Statistics show that about 1 person in every 150 who is bitten by a mosquito carrying the virus actually contracts West Nile. Serious cases are more common in the elderly population, Torrence said.
“Most people will just get a flu-like illness,” Torrence said.
Fewer than 1 percent will have serious neurological problems such as encephalitis (inflammation of the outer brain) or meningitis (inflammation of the covering of the brain and spinal cord).
“The elderly are basically the ones more likely to develop serious neurological issues,” Torrence said.
Once someone has the virus it has to run its course, experts say. An antibiotic or other treatment has not been developed to kill the virus.
Torrence said supportive care is offered. Patients may have difficulty breathing, some to the point of needing a respirator. Others may be temporarily paralyzed and need physical and occupational therapy. The survival rate for the general population is 85 to 90 percent.
In 1 in 12 patients the virus can be a killer, Torrence said.
“(The) brain becomes so swollen from the virus that it becomes fatal,” Torrence said.
Increased rainfall in recent months has increased the mosquito population.
Preventing mosquito bites is important to avoiding these risky diseases.
“Being sure that your yard is free of any standing water ... mosquitoes will flourish in that kind of environment,” Torrence said.
Wearing pants and long sleeves can prevent bites. Insect repellant with 20 to 50 percent Deet is the best to use, Torrence said.
The medical director said it was important to wear the repellant during any outdoor activity.
The first case of West Nile Virus in the United States was documented in the 1990s. The disease came from the Middle East and Africa, according to Torrence, and over the last three years has become more prevalent.