|
by Thomas Locke, MD, MPH, Clallam County Health Officer
West Nile Virus (WNV) is named for the West Nile district of Uganda where it was first discovered in 1937. It belongs to a family of viruses that can cause illness in humans, horses, birds, and other "vertebrate" animals. In the past decade, WNV has been expanding to Europe, Asia, and the South Pacific. In 1999 the virus made its first appearance in North America, causing an outbreak that resulted in 62 know cases and 7 deaths in New York City. Since this time, the virus has been spreading relentlessly across the United States. As of September 16, 2002, 1,460 cases of the illness have been reported for the year including 66 fatalities. The virus has been detected in 42 different states. The first case of WNV infection in Washington was diagnosed in August of this year in a traveler who appears to have acquired the infection in Louisiana.
Bird species, especially "corvids" (ravens, crows, jays, and magpies) are the principal target of this infection. Humans and horses are also at risk for developing serious illness. Mosquitoes serve as the "vector" which transmits the viral infection from one animal to another. Human to human transmission, or direct transmission from an infected animal to a human appears to be very rare and require extreme circumstances such as organ transplantation. Most people who develop WNV infection experience only mild, flu-like symptoms lasting several days. A small percentage of WNV infections will, however, progress to a life-threatening brain infection (‘encephalitis"). Muscle pain and weakness are also predominate symptoms in WNV infection with residual weakness persisting for over a year in up to 50% of cases. People over the age of 50 are at increased risk for the serious complications of WNV infection.
The progression of WNV across the United States is unstoppable. If the infection fails to make its unwelcome arrival to Washington state this year, it is almost certain it will become established by 2003. What can we do to protect ourselves and our families? As with most viral infections, PREVENTION is the name of the game. Prevention of WNV starts with educating ourselves about the infection and its symptoms. Preventing mosquito bites is a very effective way to avoid infections spread by these annoying insects. Helpful tips are available at the Web Sites listed below. And finally, it is important to realize that WNV is but one of many global infectious disease threats we must confront. Advances in transportation, international trade, and leisure travel have made virtually every corner of the world accessible in less than a days time. Disease-causing microorganisms have also become global travelers. In the final analysis, it is only a strong, effective public health system that stands between each of us and the disturbing array of microbes that can rob us of our health and, sometimes, our lives.
Links:
Clallam County´s West Nile Virus web page
Washington State West Nile Virus web page
Centers for Disease Control West Nile Virus web page |
|
