West Nile virus detected in Columbia-area mosquitoes; DHEC urges residents to prevent mosquito bites

September 7, 2016
The S.C. Department of Health and Environmental Control (DHEC), Richland County and the City of Columbia announced today that a sample of mosquitoes trapped in the Shandon area has tested positive for West Nile virus.
“It is not uncommon for us to identify mosquitoes carrying the virus in our state,” said Chris Evans, Ph.D. and DHEC’s staff entomologist. “This identification is a reminder of the importance of preventing mosquito bites. It’s the most important step you can take to prevent the spread of illness from mosquitoes to humans.”
“Most people infected with West Nile virus have no symptoms,” said Linda Bell, M.D. and state epidemiologist. “The risk of serious illness is low as less than one percent of people infected develop a potentially fatal inflammation of the brain, known as encephalitis.”
Bell said about one in five people infected becomes ill within two to 14 days with symptoms that may include fever, headache, joint pain, muscle pain, and occasionally nausea and vomiting, or symptoms of the more severe form of illness with headache, high fever, neck stiffness, disorientation, coma, seizures, or paralysis.
“If you have concerns about the virus or develop symptoms, you should contact your health care provider,” Bell said.
As previously reported by DHEC, South Carolina has identified multiple cases of West Nile infection in people so far this year, including two in Richland County.
DHEC was notified Sept. 6 of the virus-positive mosquitoes taken from the Shandon/Five Points area of the city, which has many homes and an active business district and nightlife.
“The mosquito that carries this virus is usually active at night, but can also be active at dusk and dawn and in shady areas during the day,” Evans said. “As the state’s public health agency, we partner with cities and counties across the state to help trap and identify mosquitoes carrying diseases that can be spread to humans.
“The virus actually starts with a bird,” he said. “It spreads when a mosquito bites a bird that has the virus in their blood. The mosquito then can spread the virus to other birds, animals or people, when it bites during feeding.”
“We have sprayed areas around Shandon, Rosewood, Five Points and the Vista in our efforts to control these mosquitoes,” said Tammy Brewer, director of Richland County Vector Control. “Our trucks conduct spraying during nighttime hours when these mosquito species are most active. The insecticide that we use is very effective, and was selected because it should have a quick knockdown.”
DHEC recommends residents pay attention to the most effective ways to prevent mosquito-borne illnesses:
  • Apply insect repellent containing DEET, picaridin, oil of lemon eucalyptus, or IR 3535 according to label instructions. Repellents help keep mosquitoes from biting.
  • Wear clothing that reduces the risk of skin exposure.
  • Exposure to mosquitoes is most common at night and during the early morning. Some species bite during the day, especially in wooded or other shaded areas. Avoid exposure during these times and in these areas.
  • Make sure that your doors and windows have tight-fitting screens to keep out mosquitoes.
  • Eliminate all sources of standing water on your property, including flowerpots, gutters, buckets, pool covers, birdbaths, old car tires, rain gutters and pet bowls.
Officials emphasize the public plays a vital role in controlling the spread of all mosquito-borne diseases.
“Mosquito control workers can’t do it alone,” Brewer said. “We need citizens to help.”
Dead birds can help DHEC and local partners track West Nile virus. Residents can report the finding of dead birds to DHEC. Learn how here. DHEC is currently accepting submission of birds through Nov. 30, 2016.

For more information about preventing mosquito bites and the spread of West Nile virus and other mosquito-borne illnesses, go to www.scdhec.gov/mosquitoes. Learn more about West Nile virus at www.scdhec.gov/westnile.