West Nile Virus is a flavivirus that can cause encephalitis (inflammation of the spinal cord and brain). It has been reported in Africa (first in 1937), Europe, the Middle East, west and central Asia, Oceania (subtype Kunjin), and most recently, North America.

In the summer of 1999, in New York City, the West Nile Virus (WNV) made its first confirmed appearance in the US. Through September of 2000, its presence has been confirmed in Connecticut, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, and the District of Columbia.

Birds, most especially crows are the animals most affected by WNV.  Dead birds are the first warning sign of the virus and should be reported to your local health department.  Mosquitoes spread the virus by feeding on a WNV infected bird, then biting and thereby infecting a horse or human.  Most infected mammals never show any signs of the disease.  WNV infected horses or humans cannot transmit WNV, as they are a dead end host.

Horses infected with WNV may seem depressed, listless, and feverish; more
serious symptoms are poor coordination, stumbling, convulsions, or coma. Infected humans may experience problems ranging from mild flu-like illness to severe neurological symptoms. In a very small percentage of cases, WNV is fatal.  Seven humans and nine horses in the New York City area died of WNV in 1999.  Currently no immunization is available for WNV.
Equinfinity - 11/5/00


Sources of information: 
• Centers for Disease Control and Prevention (CDC)

• Division of Vector-Borne Infectious Disease

• Humanitarian Resource Institute Emerging Infectious Disease Network 
West Nile Encephalitis Reference Library http://www.humanitarian.net/eidnet/wnv  eidnet@humanitarian.net 

• US Department of Agriculture Animal and Plant Health Inspection Service (USDA/APHIS)

• New York City Department of Health Bureau of Communicable Disease