Rea Blakey: West Nile spread sparks concern

CNN Medical Correspondent Rea Blakey says year-round mosquitoes in the South threaten older people who winter in the region

ATLANTA, Georgia (CNN) -- West Nile virus is spreading much faster than health experts had expected. CNN Medical Correspondent Rea Blakey looks at what this means and what people can do to lessen their risk of contracting the virus.

Q: How significant is it that the virus has shown up in 10 new states this year?

BLAKEY: Experts at the U.S. Geological Survey say its highly significant. The virus has spread farther and faster than anticipated. The rapid expansion of the virus is a public health concern because in the South, the mosquito transmission season is year-round in some places. Senior citizens are considered a vulnerable population and many seniors migrate the South for the winter. Also, West Nile infects horses and could have a substantial impact on the equine industry.

Q: Why do health officials believe the virus is spreading so rapidly?

BLAKEY: Migratory birds infected by mosquitos carry West Nile virus. According to the U.S. Geological Survey, the spread of the virus during the year 2000 showed a northward movement in the spring and a southward movement in the fall.

Q: How concerned should people be, and who is most at risk?

BLAKEY: The elderly and people with underlying major health problems such as a weakened immune system are at greatest risk of severe complications from West Nile virus. But health experts remind us -- many healthy people can be infected with the virus and only develop a mild headache or mild flu-like symptoms. Just one percent of everyone who becomes infected become clinically ill.

Q: What preventative measures can be taken to keep it from spreading?

BLAKEY: The National Institutes of Health says the Boston company Acambis is working on a human West Nile vaccine that could be tested in humans within a year to 18 months.

Meanwhile, you can reduce the spread of West Nile by taking precautions to prevent mosquito larvae from developing. Drain off all standing water around your home and community. Just a teaspoon of stagnant water can become a breeding ground for thousands of mosquitos. If you have a pool, pond or lake get products from your hardware, home improvement or garden supply store that prevent mosquito larvae from developing.

Wear long sleeves and long pants to protect yourself from mosquito bites. Wear insect repellent containing DEET, applying carefully, as directed. And avoid being outdoors at dusk, when mosquitos are most likely to be feeding.