In two counties in Illinois, a pathogen continues its emergence. Researchers have found that Lone Star ticks there are carrying the Heartland virus, which can cause headache, fever, nausea, reduced appetite, diarrhea, and fatigue in those that are infected. An investigation that followed two cases of the infection has been reported in Emerging Infectious Diseases. The cases occurred two months apart in 2018 after people had been camping on private property in Kankakee County, which is south of Chicago in the northeastern part of Illinois. Both individuals had discovered tick bites after camping, and though they were infected and ill, they recovered eventually. Samples from the patients confirmed the presence of Heartland virus, reported the Centers for Diseases Control and Prevention (CDC).
Heartland virus was described as a new human pathogen in 2012. The non-specific symptoms of the infection it causes are shared with many other diseases, noted vector ecologist and study leader Holly Tuten of the Illinois Natural History Survey. Misdiagnoses can occur when patients are being treated, she noted. "Heartland virus won't show up on a standard diagnostic panel for tick-borne bacterial diseases. And with COVID-19 on the collective mind, a tick-borne viral infection could be overlooked, especially in cases where a tick bite was missed."
The Lone Star tick, called Amblyomma americanum, can transmit the Heartland virus to people. There are no vaccines for the disease, many infected people end up in the hospital, and several have died.
According to the CDC, about 50 cases of Heartland virus have been found in eleven states: Arkansas, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Missouri, North Carolina, Oklahoma, and Tennessee.
"Lone Star ticks are very aggressive ambush predators and many people don't realize this," Tuten said. "I've seen Lone Star ticks run across a forest floor to me."
Interviews with the patients enabled the researchers to learn more about where they acquired the infections. The site where they were infected was potentially heavily wooded or in a suburban area where there are some trees.
"A single batch of male Lone Star ticks from each county was found to be positive for the Heartland virus," Tuten said. "Infected Lone Star ticks had been found as far north as Missouri, so we expected to find the infections in ticks from Williamson County in the southern part of Illinois. But finding so many Lone Star ticks in Kankakee County, including some with the virus, really surprised us."
Because the ticks were found a year after the cases were documented, the ticks may have been able to overwinter there, said Tuten.
"We want to alert physicians and public health officials throughout Illinois that there is a fairly new pathogen out there that is a danger to public health," she said. "I don't want people to avoid the woods and parks. I just want them to be aware, so they can take concrete steps to reduce tick encounters and bites."
Learn more about tick bite prevention from the video above.