Thursday, August 28, 2008

Army Center for Health Promotion and Preventive Medicine

Cases of West Nile virus have been documented in every state except Alaska and Hawaii since it was first seen in the United States in 1999.

It is passed on by the bite of an infected mosquito. There is no evidence to suggest that ticks or other insects have played any role in the cases identified in the United States.

Mosquitoes pick up the virus by feeding on infected birds, which have virus circulating in their bloodstream for a few days. Infected mosquitoes then transmit the virus to the next animal on which they feed.

The virus is not transmitted from person-to-person. For example, you cannot get the virus from touching or kissing a person who has the disease, or from a health care worker who has treated someone with the disease.

Likewise, there is no evidence a person can get WNV from handling either live or dead infected animals, the article stated. However, as a general precaution, people should always wear gloves when handling dead animals, including dead birds, and use double plastic bags when disposing of them.

A person’s chance of becoming seriously ill from any one mosquito bite is extremely small. According to the Centers for Disease Control and Prevention less than 1% of mosquitoes are infected and less than 1% of individuals who are actually bitten by an infected mosquito develop severe symptoms.

Most people who are infected with WNV experience mild flu-like symptoms, which can include fever, headache, and body aches, before fully recovering.

In a small number of cases, particularly among the elderly, the disease is much more serious and causes encephalitis. Encephalitis is an inflammation of the brain. It is marked by rapid onset of severe headache, high fever, stiff neck, disorientation, muscle weakness, paralysis, coma, and occasionally death.

There is no documented evidence that a pregnancy is at risk due to infection with WNV.

Although there is no specific treatment, medication or cure, the symptoms and complications of the disease can be treated. Most people who get this illness recover, and it appears that once a person has been infected with WNV, a natural immunity develops. However, that immunity may decrease over time.

Vitamin B, ultrasonic devices, and ‘bug zappers’ are not effective in preventing mosquito bites.

To reduce the risk of becoming infected with West Nile virus:

•Stay indoors at dawn, dusk, and early evening. This is when mosquitoes are most active.
•Wear long-sleeved shirt, long pants, and socks whenever you are outdoors.
•Wear loose-fitting clothing to prevent mosquito bites through thin fabric.
•Use insect repellents that have been approved by the Environmental
Protection Agency. These include products with a 20 to 35 percent concentration of DEET for use on the skin and products with 0.5 percent concentration of Permethrin for use on clothing.
•Eliminate mosquito-breeding sites by emptying water from birdbaths, old
tires, and other outdoor containers or debris.
•Make sure that door and window screens do not have holes.
(Editor’s note: all photos appeared originally in U.S. Army Center for Health Promotion and Preventive Medicine’s “Just the Facts: Mosquito Control Around the Home.“)