Rowland: Slim chance of getting West Nile virus

Rhonda Rowland discusses West Nile virus

Rhonda Rowland is a medical correspondent for the health news unit at CNN.

Q: Why is there such a scare that West Nile virus could infect humans?

Rhonda Rowland: Well West Nile virus can infect humans, but what's important to know is that the chance of being bitten is low -- of 100 people infected, only one percent will experience symptoms and of that one percent, only 10 percent will have severe illness. It's important to keep in mind that even though the virus has been detected in 14 states and the District of Columbia, people have only been infected with severe illness in New York, New Jersey, and most likely Florida. The Florida case is a presumptive case -- the Florida Department of Health has confirmed it but the Centers for Disease Control is doing an additional test to give it final confirmation. Health officials don't want people to panic. Even though this has been detected all along the eastern seaboard, only 74 people have become ill in the last two and a half years.

Q: Why do officials test birds to determine if the virus is in their state?

Rowland: Researchers have told me that birds are the natural hosts for West Nile virus and if they see dead birds or dead horses in an area and there's no other explanation, they will test for West Nile. Infected mosquitos transmit the virus to humans, so the dead birds or animals are the best indication of West Nile activity in a given area.

Q: What is the difference between West Nile virus and encephalitis? Is one more deadly than the other?

Rowland: Viral encephalitis can have several different causes. Encephalitis means inflammation of the brain. So West Nile can cause a type of encephalitis, but West Nile seems to have some distinct characteristics. Doctors say that neuropathies are more common, muscle weakness and a type of paralysis. And that's what doctors look for in making the diagnosis.

Q: Where did West Nile virus come from?

Rowland: It was first identified in 1937 in Uganda's West Nile district. It was first identified in 1999 in the U.S. in New York City. Researchers are not sure how it got to the United States. There are a lot of different theories but there is no proof. Among the theories is perhaps there was an imported bird brought in, but no one knows for sure. In other parts of the world, West Nile virus is very common.

Q: Who is most at risk for getting this virus? Is it deadly?

Rowland: Those over age of 50 with weakened immune systems and it seems diabetes is also a risk factor. In these particular patients, if they have encephalitis, researchers are telling doctors to test for West Nile virus because it could be a possibility. There have only been nine deaths so your chances of surviving this are very good. There's no specific West Nile cure or treatment; doctors put the severely ill people in the intensive care unit and they give them good medical care, they say.

Q: How can people prevent acquiring West Nile virus?

Rowland: Avoid spending a lot of time outdoors during dusk and dawn if you are in an area where West Nile has been identified. If you have to go out, wear long sleeves and long pants and a mosquito repellent with Deet. You should practice mosquito control measures around your house -- get rid of any standing water, in bird baths and gutters and things like that. The CDC has all 50 states on alert, they all have plans in place to track West Nile so that if it crops up in an area it's not unexpected.