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Since 1999, West Nile virus has emerged as a significant health threat in temperate regions of North America and Europe where it has infected crows, horses and humans. The virus is a mosquito-borne virus, related to St. Louis encephalitis. The virus is usually found in countries bordering the Mediterranean Basin, including, Africa, Europe and Asia.
Typically, West Nile Virus results in disease in only a very small percentage of human beings. The segment of the population most susceptible to the virus are the elderly, very young, and people with compromised immune symptoms. The general symptoms of the virus range from the common cold to fever, rash, headache and meningitis, encephalitis, coma, and death. The fatality rate for infected humans is 10 percent. The disease becomes deadly when it progresses to the encephalitis stage, which causes a deadly swelling of the brain.
The only reports of the virus killing domestic animals have been the horse. However, the disease has proven deadly for many species of birds and game, the most common being the crow. All living creatures become exposed to the virus by a mosquito bite. The virus has been able to travel progressively down the east coast due to the crow population it has infected. While crows carry the disease to different locations, the birds cannot transmit the disease. Research has shown that birds are the principle vertebrate hosts of the virus. Research has also shown that a variety of mosquito species transmit the disease, the most notable species being the Culex and the Aedes. These are the most common breed of mosquitoes. However, the virus is also shown to be transmitted via ticks.
The disease was initially isolated from an adult woman in the West Nile region of Uganda in 1937. The virus became recognized as a cause of severe human meningitis, an inflammation of the spinal cord, and encephalitis. The virus has emerged in Israel, Italy, the Czech Republic, Congo, Algeria, the Middle East and Egypt, but did not emerge in the United States until 1999. The states reporting West Nile cases include, New York, Maryland, Connecticut and New Jersey.
In 1999, there were 62 confirmed cases of West Nile virus in the United States, all of which occurred in the New York City area. These were the first recorded cases of the infection in North America. Right now, it is not known how common the virus is or will become in this country. In Europe, the virus has caused sporadic outbreaks. However, public officials in this country are taking precautions against the possibility of an outbreak, and are urging residents to do the same.
Cases in these states have yielded spaying efforts to contain the mosquito population. In addition, local officials are recommending people take precautions to prevent the mosquito population from thriving. The most common breeding ground for mosquitoes are stagnant pools of water. Thus, public officials are recommending people empty gutters, any buckets in the yard, and bird baths, as well as any other source of stagnant water on their property.
Currently, there is no known cure for the virus. However, the symptoms of the virus can be treated through medical intervention.
Some personal precautions to take against being bitten by mosquitoes include, avoiding shaded areas where mosquitoes may be resting, limiting evening activity when mosquitoes are the most active, wearing protecting clothing like long sleeves, and using insect repellants.
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