About The West Nile Virus
What is West Nile Virus?
West Nile Virus (WNV), also known as West Nile Fever, affects wild birds, horses and humans. Young geese (goslings) are also susceptible to the disease and may show clinical signs when infected. WNV was named after the first human case was identified in the West Nile district of Uganda in 1937. In exceptional cases, WNV can cause meningitis and/or encephalitis resulting in coma or death.
WNV is commonly found in Eastern Europe, Africa, West Asia and the Middle East. Its appearance in North America is recent, beginning in 1999. The disease is believed to be spread by infected migratory birds flying to breeding and wintering grounds.
About The Virus, The Disease, And How It's Spread
West Nile virus is spread by the bite of an infected mosquito, and can infect people, horses, many types of birds, and some other animals.
Most people who become infected with West Nile virus will have either no symptoms or only mild ones. However, on rare occasions, West Nile virus infection can result in severe and sometimes fatal illnesses.
There is no evidence to suggest that West Nile virus can be spread from person to person or from animal to person.
West Nile Virus In Animals
In the United States, there have been cases of WN virus documented in a cat, domestic rabbit, chipmunk, gray squirrel, striped skunk, bats and in numerous horses. For animals which show symptoms these could include any combination of the following: fever, weakness, lack of coordination, muscle spasms, seizures and/or changes in temperament or personality. There have been no documented cases of one animal infecting another animal, or of an animal infecting a human.
Horses infected with WNV show a similar pattern of illness seen in people including CNS signs. Most infected birds do not show symptoms but certain North American bird species (crows, ravens and jays - members of the Corvid family) are particularly susceptible to disease and/or death when infected. Crows appear to be the most susceptible North American species recognized thus far, with large die-offs caused by WNV being reported since 1999.
Weak Or Compromised Immune Systems
Most people bitten by an infected mosquito will show no signs of symptoms, other than flu like symptoms or a rash. People who have a weak or compromised immune system, (2/3 of North Americans are thought to have weak or suppressed immune functioning) are at greater risk of contracting the disease.