West Nile Virus

By Jared Ellis, MD
Assistant Professor of Family Medicine,
Associate Residency Director,
University of Alabama Family Medicine Residency Program

Late summer brings excitement about football, and hopes that the weather will soon cool off. However, it brings a risk that some have heard of, but few are familiar with: West Nile Virus (WNV) infection. This infection is rather common, and most cases occur in August and September (see chart below), but the diagnosis is infrequently made. For many, it only gives mild symptoms, but for a few, it can lead to devastating consequences or death. It is important to be familiar with the signs and symptoms of this infection, but even more so on how to prevent it.

WNV is not new, having been first identified in 1937 in the African county of Uganda. It was first diagnosed in 1999 in the US in New York. It has rapidly spread across the country. It is transmitted from mosquitoes that have bitten infected birds and then bite humans. Fortunately, 60-80 % of persons who contract the virus have no symptoms. 20-40 % of infected persons have only mild to moderate nonspecific symptoms, which may include fever, headache, muscle aches, swollen lymph nodes, and loss of appetite. 25-50% of these have a rash on the trunk and arms. See picture:

Studies estimate that in the US, one of every 140 to 250 persons has been infected at some point, few of whom were diagnosed. However, about 1 % of persons who get this infection develop serious neurologic (brain) effects, known as West Nile Neuroinvasive Disease (WNND). Symptoms of WNND include tremor, confusion, severe headache, weakness in one or more limbs, and coma. Of these, between 3-15% die. This is more common in younger children and older persons, and those with significant chronic diseases.

If you are concerned that you may have any form of WNV, see your doctor, and mention your concerns. Blood and other tests can be performed, but take a number of days to return. If symptoms are not severe, it may not be necessary to be tested as there is no specific treatment that cures WNV or WNND.

Awareness and prevention are the keys to avoiding this infection. Avoid mosquito bites! Avoid being outside at dusk or dawn. Wear long sleeves and long pants when outdoors if possible. Use mosquito repellants, whether applied to the body, or placed near you or those that they you can attach to yourself. Drain any standing water in your area to limit mosquito breeding. Communities with higher rates of WNV may choose to spray appropriate insecticides in key areas. All of these things may prove helpful.