First Confirmed Bourbon Virus Case in New York Highlights Diagnostic Challenges of Emerging Tickborne Disease
Key Insights
A Long Island man was confirmed as New York's first Bourbon virus (search) case after initially being misdiagnosed with Lyme disease (search) and failing to respond to doxycycline treatment.
The case emerged from a Stony Brook University study screening 107 tick-bite patients in Suffolk County between 2019 and 2024, which also found evidence of Heartland virus (search).
Bourbon virus (search), first identified in 2014 in Kansas, has no specific treatment or vaccine, and diagnosis requires specialized testing through state health departments.
A tick bite in a Long Island backyard has led to New York State's first confirmed case of Bourbon virus (search), a rare tickborne disease that many clinicians may fail to recognize. The case, published in The American Journal of Tropical Medicine and Hygiene in May 2026, underscores the diagnostic challenges posed by emerging tickborne pathogens that closely mimic more common illnesses like Lyme disease (search).
The patient, Michael Larkin, contracted the virus in 2021. Within five days, he developed debilitating symptoms including an extreme headache, severe night sweats, and a spiking fever, prompting emergency medical care. Initial blood tests revealed elevated liver enzymes and dangerously low platelet counts, yet standard testing for Lyme disease (search) returned negative. Despite undergoing a spinal tap and receiving intravenous antibiotics, Larkin was discharged without a definitive diagnosis.
A Diagnostic Puzzle Resolved Through Surveillance
Larkin's case was ultimately solved through his participation in a continuous tick-bite research initiative at Stony Brook University, led by infectious disease specialist Luis Marcos, MD, MPH, an associate professor of medicine at the Renaissance School of Medicine. Over five years, Marcos collected approximately 100 blood samples from hospitalized patients presenting with unexplained fevers, recent tick bites, and low platelet counts.
These samples were recently examined by the New York State Department of Health, which officially confirmed Larkin's Bourbon virus (search) infection. "This one case certainly was the Bourbon virus, and over a one-month period antibody titers increased eightfold," Marcos said. "The patient showed some very severe symptoms and was hospitalized."
The finding emerged from a broader study of 107 people in Suffolk County, New York, who developed fever and other symptoms following a tick bite between 2019 and 2024. Blood samples were screened for three tickborne viruses: Powassan, Heartland, and Bourbon. Two of the 107 patients had antibodies indicating a Bourbon virus (search) infection, and one had antibodies for Heartland virus (search). No one tested positive for Powassan virus. A fourfold rise in antibody levels in two patients pointed to recent or active infection, researchers noted.
An Emerging Pathogen with Expanding Range
Bourbon virus (search), which belongs to the Thogotovirus group, was first identified in 2014 after the death of a resident of Bourbon County, Kansas, who became ill following tick exposure. According to the CDC (search), the virus was named after the county where the first known patient was diagnosed. Since then, a limited number of cases have been identified in several states, primarily in the Midwest and South.
Researchers believe the lone star tick (Amblyomma americanum) is the primary vector responsible for transmission. A 2023 study published in Emerging Infectious Diseases detected Bourbon virus (search) in field-collected lone star ticks in Missouri, strengthening this connection. A 2024 CDC (search) investigation also found evidence of human Bourbon virus infections in North Carolina, expanding the known geographic footprint and suggesting infections may be underdiagnosed.
Dr. Suraj Saggar, chief of Infectious Disease at Holy Name Medical Center in Teaneck, New Jersey, noted that climate change is facilitating the spread of tickborne diseases. "Areas that historically experienced longer, colder winters or significant snow cover are now more hospitable to ticks," Saggar said. "As temperatures rise and precipitation patterns change, ticks are able to spread northward and thrive in new ecosystems."
Clinical Presentation and Management Challenges
The disease often presents with symptoms resembling many other tickborne illnesses, making diagnosis challenging. According to the CDC (search), patients may develop fever, fatigue, headache, muscle aches, nausea, vomiting, and rash. Laboratory findings commonly include low white blood cell counts and low platelet counts. Unlike bacterial tickborne infections such as ehrlichiosis, patients infected with Bourbon virus (search) typically do not improve with doxycycline, a common first-line treatment.
Marcos noted that early Bourbon virus (search) symptoms closely resemble those of Lyme disease (search), which likely explains the initial misdiagnosis in Larkin's case. Because there is no commercial test available to confirm a Bourbon virus infection, samples from suspected cases in New York must be sent to the state health department for specialized testing.
There is currently no specific treatment for Bourbon virus (search) disease. The CDC (search) states that clinical management is supportive, and patients with severe illness may require hospitalization and intensive supportive care while clinicians manage complications.
Implications for Clinical Practice and Public Health
For healthcare professionals, awareness is critical. Patients presenting with unexplained fever, fatigue, cytopenias, and a history of tick exposure may warrant consideration of Bourbon virus (search), particularly when routine testing is negative and symptoms fail to improve with standard antibiotic therapy.
For the public, prevention remains the best defense. The CDC (search) recommends avoiding tick bites by using EPA-registered insect repellents, wearing long sleeves and pants when outdoors, performing thorough tick checks after outdoor activities, and showering soon after spending time in wooded or grassy areas. Saggar additionally recommended wearing light-colored clothing and tucking pants into socks when hiking, as ticks are drawn to darker colors. "In some cases, healthcare providers may prescribe doxycycline as post-exposure prophylaxis if a tick is believed to have been attached for 48 to 72 hours," he added.
As tick populations continue to expand throughout much of the United States, emerging pathogens like Bourbon virus (search) serve as a reminder that new infectious disease threats continue to emerge alongside familiar ones. The name may sound amusing, but for patients, clinicians, and public health officials alike, increased awareness may be one of the most important tools available until better diagnostics, treatments, and surveillance systems are developed.