The West Nile virus can be passed to humans by mosquitoes and typically first presents itself as a mild viral illness, said Dr. Art Leis, a neurologist at the Methodist Rehabilitation Hospital in Jackson.

Leis estimated that he has studied 50-60 cases of West Nile virus, as many as anyone in the country.

And you may have had it without realizing it, he said.

&8220;Only one in 100 actually are hospitalized or develop encephalitis or poliomyelitis,&8221; he said.

Encephalitis is the result of the virus attacking the brain; poliomyelitis is an attack on the spinal cord and shows the same symptoms as polio.

Typically the young and old, those with weaker immune systems, are at risk for the more serious attacks.

Leis said West Nile virus has been reported from coast to coast and is &8220;here to stay.&8221;

That doesn&8217;t mean you have to catch it, however. Avoiding mosquito breeding grounds like stagnant water, keeping arms and legs covered &8212; especially around dusk and dawn &8212; and using insect repellant with DEET are all good ways to protect yourself.

There is no cure for the virus but the body usually eradicates it fairly quickly, Leis said. It&8217;s the long-term damage done in its short stay that he and others around the country are trying to figure out.

The difficulty in studying the virus comes in actually conducting studies. The only way to detect the virus is by doing blood work. This blood work is done in two stages. By the time a positive test comes back, if the patient is doing poorly, the doctors are busy trying to save the patient, not enrolling him in a study.

Because the virus gains different amounts of traction in different people, each person shows different symptoms.