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Its Back! West Nile Fever

© Neal Rolfe Chamberlain

Our world is getting smaller every year. People can jet across the globe in less than a day. Not only are people moving but animals go with them. It is believed that sometime in 1999 a bird or mosquito infected with the West Nile Virus (WNV) got into the United States. In the first couple of years it remained in the northeastern part of the United States. People hoped that winter would kill off the infected mosquito population and the primary reservoir, birds, would also be free of the disease by the next summer. This did not happen. Infected mosquitoes survived the winter and now WNV can be found nearly everywhere in the United States. Only 4 states in the continental United States were WNV-free by the end of 2002 (Oregon, Utah, Nevada, Arizona).

You have heard a lot about this disease and probably don't need a big long article telling you all the details of this nasty microbe. However, a local newspaper in my area reported the first case of human West Nile Fever in Missouri for 2003 and I thought a refresher course might not hurt. I also included some links to get you all back up to speed.

WNV was originally found only in certain countries in Africa. It is a virus that can live in and cause disease in over 130 different kinds of birds. It can also infect many different mammals and humans. Fortunately, this virus does not cause serious disease in most of the individuals it infects. It is however pretty nasty to birds. Many birds have serious infections that lead to death. 

This virus is transmitted by mosquitoes. They can transmit the virus from animal to animal, animal to human and human to human. There are other ways (blood transfusions/organ transplant, breastfeeding, pregnant women to fetus) the virus can spread but they are uncommon. Fortunately, humans are less susceptible to serious infections than birds. People who are more like to develop serious life-threatening infections tend to be older. People over the age of 50 are more likely to develop serious symptoms of WNV if they do get sick and should take special care to avoid mosquito bites.

Around 80 percent of those infected will have no symptoms at all. About 20 percent of the people who become infected will have mild symptoms, which include fever, headache, and body aches, nausea, vomiting, and sometimes swollen lymph glands or a skin rash on the chest, stomach and back. These symptoms usually last a few days. 

This virus in some people will attack the brain and the membranes (meninges) that surround the brain. Only 1 in 150 people infected with WNV develop serious

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