West Nile Virus History

The first case of West Nile virus was detected in 1937 in a Ugandan district called the West Nile; however, studies conducted on the evolution of the organism suggest that the virus emerged approximately 1000 years ago. In 1957, during an outbreak in Israel, the virus was branded as a cause of severe meningoencephalitis in elderly patients. In the 1960’s, the virus was noted in Egypt and France, in horses and humans, and then found to be widespread in Australia, southwest Asia, and southern Europe.

Possibly pandemic
West Nile Virus History In 1999, the Western Hemisphere saw its first outbreak of West Nile virus in the New York City area, including New Jersey and Connecticut. By the end of 2002, all but four states (Oregon, Nevada, Utah, and Arizona) had reported cases of West Nile virus in animals and/or humans. Human cases and fatalities from West Nile virus have risen sharply since 1999, a phenomena which could be linked to increasing rainy springs and hot summers, which present ideal conditions for abundant mosquito breeding.

The Center for Disease Control (CDC) reported that 4,156 Americans were infected by the disease in 2002, and 280 of those cases ended in death. In 2006, it was noted that the expected number of cases was decreasing as the American population was being more and more exposed to the disease. This notion was based on studies done in Egypt and Uganda, where people became fully immune to the illness as they reached adulthood. However, shortly thereafter, the CDC reported that cases of the disease in the U.S. could reach an all-time high in the history of the West Nile virus as the hot weather was conducive to mosquito breeding. In 2006, the total number of West Nile virus cases in the U.S. surpassed the totals of 2004 and 2005. Since 1999, cases of the West Nile virus have been reported in Canada, Mexico, the Caribbean, and Central America.

How did it get here?
The West Nile virus history is a nebulous one. A new mosquito species, the Asian Tiger, is believed to have entered North America approximately 10 years ago. While the exact method of travel is still unknown, it is speculated that some infected mosquitoes travelled in pools of stagnant water in old tires imported from Asia for recycling. Others maintain that the disease could have been spread by infected birds that were blown off their migratory patterns. The virus was picked up by some of our own native species of mosquitoes and transmitted among the population through mosquito bites.

Knowledge is helpful
The long-term effects of West Nile virus distribution in North America are yet to be determined. It is assumed that the virus will eventually, over the next few decades, become integrated into one or more of our North American eco-systems and will persist. At that point in time, the extent of its range will no doubt increase intermittently as certain environmental variables fluctuate, such as weather conditions and migration patterns. The risk of infection is dependent on many factors, and cannot be based solely on geographical regions anymore. The West Nile virus poses a substantial threat to the populace, but being aware of its history, how it spreads, and how to reduce risk of infection is a first step towards individual protection.