West Nile Virus cases rare but rising in NC after wet summer: What you need to know
As summer ended, incidents of West Nile Virus were trending above average in North Carolina and being reported among residents of the Triangle and Charlotte.
There were 16 reported cases of the disease among North Carolina residents as of mid-September, according to the most recent data provided by the Centers for Disease Control and Prevention.
Historically, the state has averaged fewer than five human disease cases a year, according to CDC data collected since the introduction of West Nile Virus to the U.S. in 1999.
That may be changing, though.
“We’ve had case counts closer to 16 than five the last two years,” said Kelly Haight Connor, spokesperson for the state Department of Health and Human Services, which also monitors the disease.
The virus, most commonly spread by mosquito bites, typically peaks in late summer in the United States, though cases can continue to pop up in the fall, especially if the weather remains wet and warm.
After a notably dry start to the summer, North Carolina was drenched with rain in July and August, assistant state climatologist Corey Davis told The News & Observer.
“The timing and amounts we’ve seen from our rain events over the past few months has led to lots of standing water, which is an ideal breeding ground for mosquitoes and the diseases they transmit,” Davis said.
Several cold fronts stalled across the state for several days in July, soaking the ground ahead of Tropical Storm Debby, which brought several more inches of rain.
“There was nowhere for that excess moisture to go, and it ended up puddling up and in some cases, sticking around for days or weeks after the storm,” Davis said.
The state ended up with is 35th wettest summer on record, notching 10.5% more precipitation than normal, according to the National Oceanic and Atmospheric Administration.
September has continued the pattern, with an unnamed tropical system last week stalling along the coast and dropping a startling amount of rain.
Where WNV has been found in NC
As of Sept. 17, residents of 10 counties in North Carolina have confirmed cases of the disease, the CDC reports:
- Beaufort County: 2 cases
- Buncombe County: 1 case and 3 presumptive blood donors
- Cabarrus County: 1 case
- Cleveland County: 1 case
- Columbus County: 3 cases
- Mecklenburg County: 2 cases and 2 presumptive blood donors
- Orange County: 1 case
- Rutherford County: 1 case
- Wake County: 3 cases and 2 presumptive blood donors
- Wilkes County: 1 case
A presumptive blood donor is someone who had no symptoms at the time of the donation but whose blood later screens positive for the disease.
A Durham County blood donor who was flagged for a possible case last month was found not to have the virus, local health officials said.
Columbus and Forsyth counties have both detected non-human cases of the disease. That’s most commonly among horses, according to DHHS.
Symptoms and risks of West Nile Virus
The U.S. has recorded 659 cases in 43 states so far this year, according to the CDC, though the agency warns that is likely an undercount. That’s because only 20% of people infected with West Nile Virus develop symptoms.
Symptoms can include fever and aches, as well as nausea, diarrhea and skin rash.
“Most people with WNV are infected through the bite of an infected mosquito. It is not spread person-to-person by casual contact,” Haight Connor said.
There is no cure or specific medicine to treat it in humans, though it is rarely serious.
About 1 in 150 people develop severe illness affecting the central nervous system, the CDC reports. That can result in high fever, confusion, convulsions, severe headaches, neck stiffness and paralysis.
In cases where illness progresses to the central nervous system, 1 in 10 die, according to the CDC.
How to avoid West Nile Virus
The best way to avoid West Nile Virus is to avoid mosquito bites, experts say.
- Use insect repellent.
- Wear long sleeves and long pants.
- Dump out standing water where mosquitoes can lay eggs.
- Fix window screens and close doors.
This story was originally published September 23, 2024 at 12:01 PM.
