North Carolina health officials are warning that West Nile virus is spreading after two deaths were linked to the disease.

The two deaths were adults from central North Carolina, according to the state’s Department of Health and Human Services.

Currently, 2026 is on pace to be the second-highest year on record for West Nile virus cases, after 2024, according to local ABC News affiliate WTVD.

Transmission levels are higher because of warm weather lasting longer, continuing into mid-October.

"As long as the weather stays warm and what I mean by warm is over 50s during the day, then the mosquito that carries it will continue to bite," Michael Doyle, state public health entomologist with NCDHHS, told WTVD.

West Nile virus is the leading cause of mosquito-borne disease in the continental U.S., according to the Centers for Disease Control and Prevention.

Cases usually occur during mosquito season, which starts in the summer and continues through fall, according to the CDC.

Mosquitoes typically become infected with the virus after feeding on infected birds and then spread it to humans and other animals, the federal health agency said.

The majority of patients don't have symptoms, but about one in five will experience symptoms two to six days after being bitten, including fever, headaches, body aches, joint pain, diarrhea, vomiting or a rash.

Most symptoms disappear, but weakness and fatigue may last for weeks or months. No medications are available to treat West Nile. Those with mild illness can often manage symptoms with rest, staying hydrated and taking over-the-counter medications -- such as acetaminophen -- for fever, pain and headaches, according to the CDC.

About one in 150 patients will develop severe disease leading to encephalitis, which is inflammation of the brain, or meningitis, which is inflammation of the membranes that surround the brain and spinal cord -- both of which can lead to death, the CDC says.

Each year, about 2,000 people in the U.S. are diagnosed with West Nile virus, but the CDC says this is likely an underestimate because most people either don't develop symptoms or believe their mild symptoms were caused by another illness.

More than 1,300 people develop severe illness affecting the central nervous system, the CDC says.

There are no licensed vaccines or medications that protect against the virus. The CDC recommends using insect repellent, wearing long-sleeved shirts and pants, treating clothing and gear and taking steps to control mosquitoes. This last step includes putting screens on windows and doors, using air conditioning and emptying out containers with still water.

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