Health experts in New York have confirmed the state's first known case of Bourbon virus, a rare tick-borne illness that currently has no cure. The confirmation comes with a warning that the virus could be more prevalent in the region and potentially going undiagnosed.
Bourbon virus can cause fever, fatigue, rash, and pain. In severe cases, it can significantly lower white blood cell counts, compromising the immune system, and reduce platelets, increasing the risk of dangerous bleeding. While often resulting in mild symptoms, the virus has proven fatal in at least two known instances, according to health officials.
The New York case involves Michael Larkin, a 67-year-old Long Island resident. Larkin was bitten by two lone star ticks while doing yard work at his home in Suffolk County in 2021. Although he removed the ticks shortly after, he began experiencing a fever and severe headache days later.
Initially treated with antibiotics for suspected Lyme disease, Larkin's condition continued to worsen. He described debilitating fatigue that left him unable to leave his couch and eventually led to a five-day hospital stay. "I just kept feeling worse and worse," Larkin told CBS News. "I demanded my wife take me to the hospital because that's how bad it was."
After a year-long diagnostic process, doctors at Stony Brook University identified the illness as Bourbon virus in April 2026. The diagnosis was confirmed through an antibody trial published in the American Journal of Tropical Medicine and Hygiene, which analyzed blood samples from 107 patients with tick-borne illness symptoms.
Dr. Luis Marcos, director of the Tick-borne Disease Clinic at Stony Brook University, stated that Larkin "had shown some very severe symptoms and was hospitalized." He noted that Larkin's antibody titers increased eight-fold over a month, confirming the Bourbon virus infection.
The Bourbon virus was first identified in Bourbon County, Kansas, in 2014. Prior to the New York case, known infections were primarily concentrated in the Midwestern United States, including Missouri, Kansas, and Oklahoma. Health authorities believe fatal cases occurred in 2014 and again in 2026, though specific details about these have not been widely released.
Researchers and health officials are concerned about the potential underdiagnosis of Bourbon virus, especially in areas with large populations of lone star ticks, such as New York and the broader Northeast. "There are a lot of lone star ticks in New York and in the Northeast," Marcos explained. "We have dense populations, and when someone is infected with Bourbon virus symptoms they are similar to other tick-borne infections."
This similarity to other tick-borne illnesses, combined with the lack of a commercially available test, makes diagnosis challenging. In New York, suspected samples must be sent to the state Department of Health for analysis.
"Without identifying the cause of an infection, the chances of developing accurate diagnostic tests or effective treatments are minimal," Marcos and his co-authors emphasized in their study. They called for "expanded viral surveillance, clinical testing and assay development" to better understand the virus's impact and improve clinical decision-making and vector management.
Larkin now takes precautions, such as using permethrin-treated clothing, to protect himself from ticks when working outdoors. Health experts recommend individuals in tick-prone areas be aware of potential symptoms and seek medical attention if they experience illness after a tick bite.