Summer may be gone, but West Nile Virus remains a threat

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  • By Military Health System Communications Office
  • Military Health System
Summer has come to an end, but mosquito-borne illnesses are still a risk. Whether you’re enjoying the outdoors at home or traveling abroad, knowing where West Nile Virus can be found and taking steps to prevent mosquito bites can help reduce your risk.

“We want to keep our service members and their families safe from infection,” said Navy Lt. Cmdr. Alexandra Singer, an internal medicine provider and the chief of Preventive Health for the Defense Health Agency Occupational & Environmental Health Branch. “For West Nile Virus, the best way to reduce your risk of illness is by protecting yourself from mosquito bites.”

West Nile Virus is a mosquito-borne infectious disease that first appeared almost 20 years ago, according to the National Institutes of Health. While most infected people show either no symptoms or mild symptoms, 1 in 150 people will develop a severe illness which can turn fatal if it causes inflammation of the brain or the tissue that surrounds the brain and spinal cord.

The Army Public Health Center said approximately 4 out of 5 people infected with the virus show no symptoms at all, and up to 20 percent develop mild symptoms, such as a fever, headache, and body aches. Severe symptoms include a high fever, neck stiffness, disorientation, tremors, muscle weakness, vision loss, numbness, and paralysis.

“If you become ill with symptoms such as headache, fever, muscle weakness, and disorientation, and you think you may have been exposed to West Nile Virus, the best course of action is to seek medical attention as soon as possible,” Singer warned. Symptoms usually develop three days to two weeks after being bitten by a mosquito, and can last for a few days or several weeks depending on the severity, the Centers for Disease Control and Prevention said.

Singer said mosquito activity peaks from summer to early fall. Although most cases are transmitted by mosquitoes, the virus can also spread through blood transfusions, organ transplants, and from mother to child during pregnancy or breastfeeding, according to the CDC.

“Giving providers as many details as possible about recent whereabouts and possible exposure to mosquitoes can help them decide whether any testing is needed,” said Singer. “If the suspicion of West Nile Virus infection is high, blood is drawn to test for antibodies.” The CDC warns that if running this test within a week of exposure to the virus, results may return as a false negative, requiring repeat testing.

“There continue to be developments in trying to establish some therapeutics as well as vaccine for the West Nile Virus infection,” said Dr. Limone C. Collins Jr., chief of vaccine safety and evaluation for the DHA Immunization Healthcare Branch, adding that research is still in its early stages. “A worldwide effort to mitigate this epidemic has been underway.”

According to the World Health Organization, West Nile Virus is most commonly found in Africa, Europe, the Middle East, North America, and West Asia. The virus first appeared in the United States in 1999 and has since been detected in all 48 contiguous states, as well as the District of Columbia and Puerto Rico, Singer noted.

The Army Public Health Center recommends limiting mosquito contact by applying insect repellent to exposed skin, spraying clothing and supplies with permethrin, making sure windows and doors have screens, and wearing clothes that minimize skin exposure. Emptying containers – such as buckets, wading pools, and bird baths – to get rid of shallow, standing water where mosquito larva thrive can also help reduce risk for infection, said Singer.

“Knowledge is power,” said Singer. “Remaining informed and aware of any infectious disease threats or outbreaks in your environment will go a long way toward helping you reduce your risk of infection.”