Health beat: Prevent mosquito bites and West Nile virus disease

Mosquito bites can be more than just itchy and annoying. They can cause people to get sick. The most effective way to avoid West Nile virus disease is to prevent mosquito bites. Be aware of the West Nile virus activity in the area and take action to protect yourself and your family.

Know the facts

Almost 40,000 people in the U.S. have been reported with West Nile virus disease since 1999, and of those more than 17,000 have been seriously ill and more than 1,600 have died. Many more cases of illness are not reported to the Centers for Disease Control and Prevention.

Know the risk

Anyone living in an area where West Nile virus is present in mosquitoes can get infected. West Nile virus has been detected in all lower 48 states -- but not in Hawaii or Alaska. Outbreaks have occurred every summer since 1999. Though anyone can get infected with West Nile virus, there are people at higher risk for severe disease. People older than 50 are at higher risk for encephalitis. The reasons one person becomes severely ill and another doesn't aren't entirely known.

Where is West Nile virus a problem?

Some states had greater concentrations of cases of severe disease than others in 2013. This can change each year. Visit tinyurl.com/phuat4v to see a map of severe cases in 2013 in the United States. Some areas of the U.S. are affected by other viruses such as La Crosse, eastern equine encephalitis, St. Louis encephalitis, Powassan or dengue viruses.

Insect repellents

No one is safe from West Nile virus, but there are steps people can take to help prevent West Nile virus infection.

* Apply insect repellent on exposed skin and clothing when going outdoors. Use an Environmental Protection Agency-registered insect repellent. Permethrin sprayed on clothing provides protection through several washes. Don't spray repellent on skin under clothing and don't use permethrin on skin.

* Cover up. Wear long sleeve shirts and long pants and socks while outdoors to prevent mosquito bites.

* Avoid mosquitoes. The mosquitoes that spread West Nile virus bite between dusk and dawn. Limit the amount of time spent outdoors during these hours. If outside, be sure to wear repellent and protective clothing.

* Support local community mosquito control programs. Mosquito control activities are most often handled at the local level, such as through county or city government. The type of mosquito control methods used by a program depends on the time of year, the type of mosquitoes to be controlled and the habitats where the mosquitoes live. Methods can include eliminating mosquito larval habitats, applying insecticides to kill mosquito larvae or spraying insecticides from trucks or aircraft to kill adult mosquitoes. Your local mosquito control program can provide information about the type of products being used in an area. Check with the local health department for more information.

What insect repellent should be used?

The CDC recommends a variety of safe and effective repellents. There are those that can protect for a short while in a backyard or a long while in the woods.

Look for these active ingredients recommended by the CDC and the Environmental Protection Agency:

* DEET

* picaridin

* IR3535

* plant-based oil of lemon eucalyptus

Pick a favorite insect repellent and use it whenever going outside.

All contain an EPA-registered active ingredient and have been evaluated for efficacy and safety. The EPA has a listing of every registered repellent brand in the U.S. There are safe and effective repellents for every budget, age and preference.

Know the symptoms of West Nile infection

* No symptoms in most people. Most people (70 percent to 80 percent) who become infected with West Nile virus do not develop any symptoms.

* Fever in some people. About 1 in 5 people who are infected will develop a fever with other symptoms such as headache, body aches, joint pains, vomiting, diarrhea or rash. Most people with this type of West Nile virus disease recover completely, but fatigue and weakness can last for weeks or months.

* Severe symptoms in a few people. Less than 1 percent of people who are infected will develop a serious neurological illness such as encephalitis or meningitis (inflammation of the brain or surrounding tissues). The symptoms of neurological illness can include headache, high fever, neck stiffness, disorientation, coma, tremors, seizures or paralysis.

Health Beat is a weekly spotlight on a wide range of health issues. The information contained here was provided by the Centers for Disease Control and Prevention. View the CDC features online at cdc.gov/features.