West Nile Virus: Mosquitoes Spread Disease

It's material worthy of a horror movie: a cloud of vicious bees stinging people or pets to death; swarms of voracious termites reducing houses to dust; people dying from an outbreak of an unknown exotic disease.

These dramatic scenarios are not out of fiction, but actually happened in the United States. New York City's famed Central Park closed in the summer of 2000 because of the discovery of a mosquito carrying the dangerous West Nile Encephalitis virus.

From 1999 through 2001, 149 cases of West Nile virus in humans were reported to the Centers for Disease Control, including 18 deaths.

As of August 12, 2002, state health departments have released information on 135 cases of West Nile virus related human illness this year, including seven deaths. Infected birds have been found in states as far ranging as Louisiana, Vermont, and Georgia. In fact, after five adults died from the disease in Louisiana, the governor declared a state of emergency. The outbreak is blamed on the unusually hot summer.

Named for the West Nile District of Uganda, where it was discovered in 1937, West Nile Encephalitis is one of a host of disturbing illnesses, such as Ebola, hantaviruses, and Lyme disease, to emerge in the past 100 years.

Spread by mosquitoes, the disease usually causes a mild inflammation of the brain, accompanied by fever, headache, body ache, skin rash, and swollen lymph glands. It appeared in North America for the first time in 1999.

The virus mainly kills birds. Officials estimate 10,000 crows died in 1999 in the New York metropolitan area. As feared, it is believed that birds migrating south spread the disease throughout the East Coast and the Gulf of Mexico. In addition, a number of horse deaths in the New York area were also blamed on the disease. The vast majority of people bit by infected mosquitoes develop no symptoms.