KANNAPOLIS — The N.C. State Laboratory of Public Health identified West Nile virus (WNV) in mosquitoes collected by Cabarrus Health Alliance Environmental Health staff on Oct. 11. Samples were collected in multiple locations throughout the county, and testing was completed Oct. 18. 

The type of mosquitoes collected are responsible for circulating West Nile virus in the wild bird population and transmitting it to humans. Cabarrus Health Alliance Environmental Health staff monitors known West Nile virus mosquito vectors to identify West Nile virus activity throughout the summer and fall transmission season.

Cabarrus Health Alliance Environmental Health Public Information Officer April Sloop shared that mosquito vectors are those that “transmit pathogens to humans and other animals, making them important carriers of disease. When a mosquito bites an infected host, it can pick up viruses, bacteria or parasites” and these pathogens can then be passed on to another host through future bites.

The presence of positive mosquitoes indicates that the risk of West Nile virus remains into the fall months, it was noted in a release.

Mosquito populations start to decline in our region when temperatures drop, usually when nighttime temperatures consistently fall below 50 degrees, said Sloop. They thrive in temperatures between 70 and 85 degrees, and therefore mosquito activity typically peaks in warmer months.

Cabarrus Health Alliance shared in a release a reminder for people to take precautions against mosquito bites following these recent reports of West Nile virus in mosquitoes. Individuals should take steps to minimize their exposure to mosquitoes during outside activities the remainder of the fall season, especially during dusk and dawn.

Tips to help eliminate mosquito breeding and reduce the risk of mosquito-borne disease are as follows:

• Use the tip and toss method after every rainfall. Tip out water in flower pots, planters, children’s toys, wading pools, buckets and any containers that can hold water, even a small amount, including saucers under flower pots.
• When possible, drain any standing water on your property such as puddles and ditches that hold water for more than four days after rain.
• In containers that cannot be drained or dumped, treat with a product to kill the larvae. Samples of the product can be picked up for free at Cabarrus Health Alliance, 300 Mooresville Road, Kannapolis, Monday through Friday from 8 a.m.-5 p.m.
• Store out-of-service or unmounted tires under cover to prevent the collection of any water.
• Change the water in bird baths and pet bowls at least twice a week.
• Keep gutters clean and in good repair, and repair leaky outdoor faucets.
• Make sure rain barrels have tight-fitting screens or lids.
• Use screened windows and doors, and make sure screens fit tightly and are not torn.
• Use insect repellent containing DEET when outdoors, which also repels ticks. Remember to always follow product directions.
• Wear long sleeves and pants at dusk and dawn, when mosquitoes are most active, or stay indoors during these hours.

Standing water is necessary for mosquitoes to complete their life cycle, Sloop shared.

While humid areas may not directly breed them, she noted that “they can create conditions that support their presence. It’s unlikely, but shaded areas near bodies of water can harbor mosquitoes, particularly during the early morning and evening hours.”

The release shared that young, elderly and immunocompromised populations are at greatest risk of West Nile virus illness. There are usually no symptoms in most people who become infected with West Nile virus. About one in five people who are infected will develop a fever with other symptoms such as headache, body aches, joint pains, vomiting, diarrhea or rash. Most people infected with West Nile virus disease recover completely, but fatigue and weakness can last for weeks or months.

As noted on the U.S. Centers for Disease Control and Prevention’s website, https://www.cdc.gov/west-nile-virus/hcp/clinical-signs/index.html, the incubation period for WNV disease is typically two to six days but ranges from two to 14 days and can be several weeks in immunocompromised people. An estimated 70-80 percent of human WNV infections are subclinical or asymptomatic. Most symptomatic persons experience an acute systemic febrile illness that often includes headache, weakness, myalgia, or arthralgia; gastrointestinal symptoms and a transient maculopapular rash also are commonly reported. 

Less than one percent of people who are infected will develop a serious neurologic illness such as encephalitis or meningitis, inflammation of the brain or surrounding tissues. The symptoms of neurologic illness can include headache, high fever, neck stiffness, disorientation, coma, tremors, seizures, paralysis and death.

There is no specific treatment for West Nile virus disease, as shared on the CDC site, https://www.cdc.gov/west-nile-virus/hcp/treatment-prevention/index.html. Clinical management is supportive. Patients with severe meningeal symptoms often require pain control for headaches and antiemetic therapy and rehydration for associated nausea and vomiting.

While there is no vaccine for West Nile virus in people, the release said vaccines are available to prevent West Nile virus in horses. If you are a horse owner, consult your veterinarian regarding proper protective vaccines for your horses and change the water in water troughs at least twice a week to discourage mosquito breeding.

For more information regarding mosquitoes or mosquito control activities in your area, contact Cabarrus Health Alliance at 704-920-1207 or go to https://www.cabarrushealth.org/176/Mosquito-Prevention.