Western NC threatened by rare mosquito-borne disease

The La Crosse virus is a mosquito-borne disease first identified in La Crosse, Wisconsin, in 1960. But three counties in western North Carolina — Swain, Transylvania and Jackson — have the highest incidence rates in the U.S., according to the Centers for Disease Control and Prevention.

“Western North Carolina is particularly affected by this neglected virus,” said Dr. Ross Boyce, an expert on epidemiology and vector-borne disease at the UNC School of Medicine. Boyce is co-leader of the La Crosse virus study, funded by the state of North Carolina through the N.C. Collaboratory.

“Nationally, there’s probably been 60 to 70 cases per year over the past 40 years that we know of,” Boyce said. “It’s shameful because these are kids we’re talking about here. Kids who are often left with long-term disability. And it feels like, we, as a country, should have the knowledge and resources to solve this problem.”

Transmitted by the eastern treehole mosquito, the La Crosse virus is the second-most prevalent mosquito-borne virus in the United States and the most common among children. Adults are often asymptomatic or mildly ill, but children under 18 may have severe, life-altering symptoms, including brain inflammation.

(Submitted photo)

In July 2024, the parents of 5-year-old Granger Horney brought their son to Mission Hospital in Asheville, concerned about a rapid decline in his health and cognition. Tipped off by Granger’s neurological symptoms, doctors removed fluid pressing against his spinal cord, gave him medicine to quell his fever and waited for their diagnosis of the La Crosse virus to be confirmed.

“Within a few hours of getting that fluid removed, he was up sitting there, talking, eating,” said Nikki Horney, Granger’s mother. “It was kind of crazy how fast he bounced back just after that.”

While Granger was recovering, doctors and nurses asked the Horney family if they wanted to take part in an ongoing study about the La Crosse virus. They immediately said yes.

Tracking a neglected disease

The study officially began in the Mission Hospital pediatrics department, where medical professionals performed diagnoses and collected important health data. The research team later confirmed that the types of mosquitoes responsible for Granger’s illness were located around the family’s property.

Boyce then coordinated the next phase of the trial at Chapel Hill. The Horney family traveled three hours east to provide blood samples, giving researchers the chance to isolate and study the antibodies that helped Granger fight the infection.

With more samples from courageous children like Granger, researchers studying the La Crosse virus will have the opportunity to develop new diagnostic tools, disease control methods and potentially vaccines that can reduce the severity of the virus in children.

“Important infectious diseases transmitted by insects often go unrecognized,” said Dr. Myron Cohen, director of the Institute for Global Health and Infectious Diseases at the medical school. “The collaboration between UNC-Chapel Hill and Western Carolina University offers an opportunity to improve our understanding of these diseases in North Carolina, develop prevention and treatment strategies and help patients and their families.”

Granger is healthy and is back at baseball practice in Marion, North Carolina. Parents Cody and Nikki Horney are thankful for the opportunity to contribute to new research and help prevent another parent from experiencing the fear and worry that they went through.

“You know your own kids better than anybody else,” said Cody Horney. “Keep advocating for them when something isn’t right. And use plenty of bug spray.”

Read more about in-person and remote study participation.

Read more about Granger Horney.