What to know about Heartland virus, a new tick-borne disease spreading through the Midwest and southern US
- Heartland virus disease is a relatively new tick-borne illness that was discovered in 2009.
- The virus is spread by the lone star tick in the American South and Midwest.
In 2009, Dr. Scott Folk treated two patients in western Missouri who had fallen ill after getting bitten by ticks.
Most tick-borne diseases, from Lyme disease to Rocky Mountain spotted fever, share similar flu-like symptoms at their onset. The patients in Missouri experienced chills, fever, and headaches, Folk explained in a radio interview with NPR affiliate KCUR.
The doctor thought they had ehrlichiosis, a bacterial infection that is spread by a common tick species in the area. But the patients didn't get better after taking antibiotics, and lab testing revealed that they had a previously unseen viral infection.
The new virus was named Heartland virus, after Heartland Regional Medical Center, where the patients were diagnosed. In the 13 years since its discovery, more than 50 cases of Heartland virus disease have been identified in people living in the southern and midwestern US.
Not much is known about the virus compared with other tick-borne diseases, but doctors and scientists working in the region are collecting ticks to learn more.
"This is not a pathogen that is going to take over the world, so there's no reason to panic at this point," said Gonzalo Vazquez-Prokopec, an associate professor who heads a team studying vector-borne diseases at Emory University. "We as scientists are trying to do what we couldn't do with COVID, which is know as much as we can about the virus before it becomes a problem."
The lone star tick can spread the Heartland virus, among other diseases
Cases of Heartland virus disease have been reported in Arkansas, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Missouri, North Carolina, Oklahoma, and Tennessee, according to data from the Centers for Disease Control and Prevention.
The virus spreads via the bite of the lone star tick, a species widely distributed throughout the eastern US, according to the CDC. The tick is most common in the southeastern states, but it has spread westward and as far north as Canada as temperatures have warmed, Vazquez-Prokopec told Insider.
The lone star tick, identifiable by a single white dot on the back of adult female ticks, is also known to spread other viruses and bacteria that cause more common infections, such as ehrlichiosis. Unlike blacklegged ticks, this species does not carry the bacteria that causes Lyme disease.
Only one case of Heartland virus disease has been identified in Georgia, where Vazquez-Prokopec works, to date — diagnosed posthumously in a Georgia resident who died of an unknown disease in 2005. In that county, researchers at Emory's Prokopec Laboratory recently collected nearly 10,000 ticks. About one in every 2,000 lone star ticks collected carried the virus.
Symptoms include fevers and muscle pain
The first Heartland virus patients identified in Missouri were hospitalized with high fevers, diarrhea, muscle pains, and low counts of white blood cells and platelets.
Other symptoms of Heartland virus disease include fatigue, decreased appetite, headache, and nausea, according to the CDC. Because the illness presents similarly to many tick-borne diseases and other viral infections, the only way to diagnose it is to see a healthcare provider who can order a test.
Infectious disease experts said the actual burden of illness is likely much higher than the CDC's official count of 50. In northwestern Missouri, researchers estimated that between 1% and 4% of the population had antibodies proving they were exposed to Heartland virus, based on donor blood testing done in 2013. At the time, only two cases of the illness had been confirmed in humans.
"That's why we know that the 50 cases is an underestimate, because we're not capturing the whole spectrum of illness," Vazquez-Prokopec told Insider. "People might be sick and not go to the doctor, or they might be going to the doctor and not being tested for the virus."
Regardless of the threat posed by Heartland virus, people should take precautions to avoid ticks when they go outside during the spring, summer, and fall, he added.