RALEIGH, N.C. (WNCN) — North Carolina health officials say they’re seeing reports of neuroinvasive West Nile Virus activity increasing in the state.

Four neuroinvasive cases of the virus have been reported in several parts of the state so far this year, according to the North Carolina Department of Health and Human Services.

Health officials say this is double the average number of cases reported by the end of August each year, which is two.

They say the numbers are concerning.

“It takes two-to-three weeks from when a mosquito bites a person to when we get a report of a positive neurological case or neuroinvasive case, so we’re always a week or two behind,” says Michael Doyle, North Carolina Public Health Entomologist. “So having that many cases of both by the first part of September, that is concerning.”

He says there are at least 100 more cases of West Nile Virus in the state, but most of these are not serious.

However, officials say neuroinvasive cases of the virus are usually serious enough where people are hospitalized with neurological issues.

The breakdown

NCDHHS tells CBS 17 the four cases were reported in Durham County, Cumberland County, Mecklenburg County and New Hanover County.

The Cumberland County Health Department recently reported its first case of West Nile Virus on Sept. 8.

Why more cases?

Health officials say fall is the time of year when most cases of mosquito-borne illnesses are reported, and active transmission season lasts for another two months.

Doyle says this is because mosquitoes reproduce during the summer, and more mosquitoes means a higher likelihood of finding one infected with West Nile.

He says there are two reasons why we’re seeing more cases this year — more interactions with mosquitoes and more interaction with birds.

The two species pass the virus between each other, then infected mosquitoes could bite humans and pass the virus to them, he explains.

“The dry and wet conditions of this summer have pushed the birds and mosquitoes together around ponds and water bodies, so the birds are more likely to become infected,” says Doyle.

What if I get the virus?

According to a release, the majority of those infected with West Nile Virus usually experience no symptoms.

If they do, the release says it’s typically a mild, flu-like illness, with 20 percent of people developing a fever with other symptoms like headache, body aches, joint paint, vomiting, diarrhea or a rash.

Health officials say only about one percent of infections are serious or neuroinvasive — with encephalitis (inflammation of the brain), meningitis (inflammation of the membranes surrounding the brain and spinal cord) and meningoencephalitis (inflammation of the brain and surrounding tissues). In some cases, they say the neuroinvasive virus could lead to death.

What you can do

Experts are encouraging people to take the following precautions to prevent the mosquito-borne illness:

  • Use mosquito repellent that contains DEET (or equivalent) when outside in areas where mosquitoes might be present.
    • Use caution when applying to children. Click here for repellants that will work for you and your family.
  • Install or repair screens on windows and doors to keep mosquitoes outside. Or keep windows and doors closed and use air conditioning if possible.
  • Reduce mosquito breeding by emptying standing water from flowerpots, gutters, buckets, pool covers, pet water dishes, discarded tires and birdbaths at least once a week.
  • If you think you or a family member might have WNV disease, talk with your health care provider.

“If you have ability to do mosquito suppression around your home, such as removing any type or water containers, that’s always a good action because then you’ll end up with fewer mosquitoes that could potentially spread virus around your home,” Doyle explains.

For more information about preventing mosquito bites, click here.