First Bourbon Virus Case Confirmed in New York, Raising Concerns of Wider Spread

The first case of Bourbon virus has been confirmed in New York, prompting researchers to call for expanded surveillance and testing amid warnings that the rare tick-borne infection may be more widespread than currently known.

Discovered in 2014 and named after Bourbon County, Kansas, where it was first identified, the virus is believed to be transmitted by the lone star tick. There is no vaccine or medicine available to prevent or treat the illness. Symptoms include fever, fatigue, rash, headache, body aches, nausea, and vomiting.

Only six human cases have been reported since the virus was identified, primarily in the central US. The first known patient, diagnosed in Kansas in 2014, died.

According to a Stony Brook Medicine study released last month, Bourbon virus “could soon begin to complicate diagnoses if it becomes more prevalent this summer and in coming years.”

Researchers studied blood samples from 107 patients who developed fever and other symptoms after recent tick bites in Suffolk County between 2019 and 2024 and found that two had antibodies to Bourbon virus.

One of the patients, a 67-year-old Long Island man, developed severe symptoms and was hospitalized after being bitten by lone star ticks in 2021. He was initially treated with doxycycline for suspected Lyme disease, but his fatigue and severe headaches failed to improve. He eventually made a full recovery, but a re-examination of his test results showed an eightfold increase in Bourbon virus antibody levels over one month, confirming the infection.

“There are a lot of lone star ticks in New York and in the Northeast. We have dense populations, and when someone is infected with Bourbon virus, the symptoms are similar to those of other tick-borne infections,” Dr. Luis Marcos, a Stony Brook Medicine professor and director of its Tick-Borne Disease Clinic, said.

“For these reasons, the Bourbon virus is likely more prevalent than we think in our region, and other cases are likely going undiagnosed.”

No commercial diagnostic test is currently available, and suspected samples in New York must be sent to the state Department of Health for specialized analysis. The researchers called for expanded surveillance and testing, arguing that without identifying the cause of an infection, the chances of developing accurate diagnostic tests or effective treatments “are minimal.”

Lone star ticks are aggressive, reddish-brown, blood-feeding arachnids. Adult females are identifiable by a prominent white dot on their backs, while nymphs and adult females most frequently bite humans and spread disease, according to the CDC.

Previously concentrated in the southern US, the species has spread across much of the eastern US and can now be found as far north as Maine. Its bites can transmit ehrlichiosis, Heartland virus disease, and tularemia. It has also been linked to southern tick-associated rash illness and alpha-gal syndrome, an allergy to red meat.