Study: Lone Star Tick Is Bringing Another Infection Concern

Tick-borne diseases are common throughout the United States, and most cases are treated effectively. A rare diagnosed tick-borne infection, the Bourbon virus, transmitted though the common lone star tick, could soon begin to complicate diagnoses if it becomes more prevalent this summer and in coming years.

So says a team of researchers led by Stony Brook Medicine. They confirmed the first Bourbon virus case in New York State, on Long Island, in a paper published in the American Journal of Tropical Medicine and Hygiene.

The Bourbon virus was discovered in 2014 and named for Bourbon County, Kansas, the area where the virus was first identified. There are no vaccines to prevent or medicine to treat the illness, which remains rare but mostly in regions in the central part of the U.S. Symptoms of the virus include fever, fatigue, rash, headache, body aches and nausea.

The lone star tick acts as a vector to several bacterial and viral illnesses including ehrlichiosis, tularemia, and Alpha-Gal Syndrome, the condition that causes the immune system to produce allergic antibodies leading to a meat allergy. When someone who presents with symptoms common to these conditions and has been bitten by a lone star tick a diagnosis results. But if someone has a rare infection via the lone star tick, such as the Bourbon virus, the diagnosis and treatment is more difficult because there is currently no exact commercial test to confirm this viral infection.

"There are a lot of lone start ticks in New York and in the Northeast, we have dense populations, and when someone is infected with Bourbon virus symptoms they are similar to other tick-born infections," said Luis Marcos, MD, lead author and professor in the Departments of Medicine and Microbiology and Immunology at the Renaissance School of Medicine (RSOM) at Stony Brook University, and director of the Tick-borne Disease Clinic. "For these reasons, the Bourbon virus is likely more prevalent than we think in our region and other cases are likely not being diagnosed."

The Bourbon virus remains a rare infection, and because of this many clinicians may be unfamiliar with it, thus increasing the possibility of misdiagnosis. And because there is no commercial test for the virus any samples in New York are sent to the NYS Department of Health for analysis.

Marcos and colleagues identified the first tick-borne Bourbon virus case in April 2026. The finding was based on the published study of 107 individuals presenting with fever and other tick-borne illness symptoms between 2019 and 2024. Blood samples were collected from patients and sent to the NYS Department of Health. Two cases had neutralizing antibodies for the Bourbon virus. One of these patients had a four-fold rise in antibody titers of the Bourbon virus, which according to the researchers indicates an acute or recent infection of this virus.

"This one case certainly was the Bourbon virus, and over a one-month period antibody titers increased eight-fold. The patient had showed some very severe symptoms and was hospitalized," Marcos said.

He added that early symptoms can be very similar to Lyme disease, and this patient initially was diagnosed as having Lyme disease but received the standard doxycycline and had no improvement in symptoms, which included fatigue and severe headaches.

A 2014 case of the Bourbon virus in Kansas caused by a tick bite resulted in a patient death. In 2026, it caused another fatal case.

Marcos and co-authors stress that for clinicians the results from their study "highlight the need for expanded viral surveillance, clinical testing and assay development to improve clinical decision-making and inform tick-borne disease epidemiology and vector management."

He added, "Without identifying the cause of an infection, the chances of developing accurate diagnostic tests or effective treatments are minimal. That is why it is so important to first understand the true impact of the virus in high-risk areas."