This article was contributed by Creative Reporter - Dr. Stephen Lane

For the last couple of weeks, the West Nile virus seems to be a daily topic in the media. Recent developments suggest that the virus may be spread through donated blood or organs. While these kinds of headlines are certainly alarming, it is important to realize that illness due to West Nile virus is extremely rare. The U.S. Centers for Disease Control and Prevention (CDC) notes, "the chance that any one person is going to become ill from a mosquito bite is low." They point out that most people who become infected don't develop any illness. Here we will focus on the West Nile virus: what it is, how it is spread, the potential human illness that it can cause, how to prevent it, and treatment.

West Nile virus is a virus commonly found in Africa, West Asia and the Middle East. Until 1999, the virus had not been reported in the Western Hemisphere. West Nile virus was first identified in the U.S. in the early summer of 1999. It is not known where the U.S. virus originated, but researchers have found that it most resembles the strains found in the Middle East.

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. Mosquitoes become infected when they feed on birds infected with West Nile virus. The virus then sits in the mosquito's salivary glands. When an infected mosquito bites a human to take in blood, the virus may be injected into humans. Once in the body, it can multiply and possibly cause illness. West Nile virus has also been shown to be transmitted through transplanted organs. Studies are currently being performed to determine whether the virus can also be transmitted by blood transfusion.

Even in areas that are affected by West Nile virus, very few mosquitoes are actually infected. Also, less than 1% of people who get bitten by an infected mosquito will get ill. Thus, the chances of becoming ill from any one mosquito bite are extremely small. Although it is plausible that other insects or ticks could carry the West Nile virus, there is no evidence that this occurs. There is also no evidence that eating infected birds or other animals can transmit the virus.

Most people who are infected with the West Nile virus will not develop any type of illness. Approximately 20% of people who become infected will develop "West Nile fever." This consists of mild symptoms, including fever, headache, and body aches, occasionally with a skin rash on the trunk of the body and swollen lymph glands. These symptoms typically only last for a few days and do not appear to cause any long-term effects. It is thought that if symptoms do appear, they will do so between 3 days and 2 weeks following the bite of an infected mosquito.

It is estimated that 1 in 150 persons infected with the West Nile virus will develop a more severe form of disease. The symptoms of severe infection (West Nile encephalitis or meningitis) include headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, and paralysis. Even in these severe cases, the CDC estimates that between 85 and 97% of patients will survive.

You can reduce your chances of becoming ill from West Nile virus by protecting yourself from mosquito bites. DEET- or permethrin- containing repellents work best at preventing mosquito bites. When possible, it's also advisable to wear long-sleeved clothes and long pants. These measures are especially important during peak mosquito biting times between dusk and dawn. The CDC also recommends limiting the number of places that mosquitoes can lay their eggs. Standing water sources, such as birdbaths, are the most common sources.

If you believe that you have symptoms of West Nile virus, talk with your family doctor immediately. Your doctor will take a history to determine your risk, and may draw a blood sample to test for the virus. Although there is no specific treatment for West Nile virus infection, in severe cases hospitalization may be required. This allows for careful observation and support of complications.