West Nile Virus Signs and Prevention

By Samantha-Rae Tuthill, AccuWeather.com Staff Writer
9/10/2012 1:46:23 PM

A record-breaking number of West Nile Virus (Flavivirus) cases have cropped up across the United States this year. With almost 2,000 reported cases and 87 confirmed deaths, the virus' growth is causing concerns.

This past mild winter has played a part in the spread of the virus. Many infected mosquitoes that would have typically died out from the cold Midwestern winters were able to survive longer and continue to transmit the infection. The increased warmth of the outbreak season has also increased the spread. The virus and mosquitoes both develop faster in warmer temperatures. For West Nile Virus, 58 degrees Fahrenheit is the temperature it needs to start developing inside its host. The development rate doubles for every 12 degrees the temperature is increased.

Mosquito larvae was found in water that pooled inside this tree. Photo courtesy of ah zut

Surprisingly, the drought that has affected large portions of the country has also helped the mosquito population thrive. Storm drains that often house mosquitoes have remained more stagnant than usual; rains haven't fallen that would normally wash away mosquito eggs and larvae.

Related: Experts Unsure About Cause of Record-Breaking West Nile Outbreak, Suggest Extreme Weather

The virus is spread primarily through mosquito bites, usually by feeding off of an infected bird and then biting a human or another animal. It can only be spread through blood contact, not casual contact or saliva. Once bitten by an infected mosquito, it takes 3-14 days for symptoms to start to show. However, the majority of those infected (80 percent) will not display symptoms of the infection.

Symptoms that are visible include abdominal pain, vomiting, muscle aches, nausea, headache and fever. Severe symptoms include muscle weakness, stiff neck, confusion and loss of consciousness. About a quarter to a half of West Nile Virus patients will also develop a rash.

The majority of those infected with West Nile Virus are able to recover, though it still has the potential to be fatal. In other extreme cases it can lead to brain swelling, which may also cause permanent brain or muscle damage. Those at risk for a more severe infection include the elderly, pregnant women and those with compromised immune systems.

There is no distinct cure for West Nile Virus infections. Symptoms in mild cases will run their course, from a few days up to a few weeks. Severe cases require hospitalization for intravenous fluids and for help to keep up breathing. Several experiments are being done to develop antiviral medications, but for now there is no cure.

The best way to prevent West Nile Virus infection is to prevent mosquito bites. This is best done by using insect repellants, especially during early night or morning hours, when in the woods or near stagnant water. Wearing light, long-sleeved shirts and pants is also advised. Make sure window and door screens are secure and free of tears or holes big enough for mosquitoes to get in. Eliminate breeding areas for mosquitoes around your house by draining areas that puddle frequently. After rain storms, check for pools of water in objects around your home and dump the water out.

While not always fatal, the virus is still incredibly unpleasant, and not worth the risk. Take the steps to prevent infection and decrease mosquitoes around your home.