Experts have been warning us for years about the dangers of tick bites; they’re the primary cause of Lyme disease, a terrible infectious disease characterized by cognitive impairments, arthritis, and flu-like symptoms that can linger even after treatment. But a new tick-borne disease to emerge recently has given Americans more of a reason to avoid ticks, as it has killed the man who first developed it.

It’s called Bourbon virus, and was named after Bourbon County, Kansas, where the man who became ill with the disease lived. According to a report from the Centers for Disease Control and Prevention (CDC), the man, who was previously healthy in his 50s, sought medical attention after a series of tick bites and symptoms like fatigue and fever. However, he quickly developed thrombocytopenia and leukopenia, which are an absence of blood platelets — used to clot blood and prevent internal bleeding — and white blood cells, respectively. Within 11 days, his organs had failed, and he died of cardiac arrest.

This chain of events occurred despite the man undergoing antibiotic treatment. Moreover, he underwent a battery of tests for tick-borne viruses, which came back negative. Unsure of what was happening to him, doctors sent a blood sample to the CDC’s headquarters, where more sophisticated testing could determine what the cause of the man’s illness was. There, they found it belonged to a family of viruses known as thogotoviruses, which can be found all over the world.

Speaking to USA Today, J. Erin Staples, a medical epidemiologist at the CDC, said the virus was especially mysterious, as thogotoviruses typically cause symptoms similar to meningitis, which include inflammation of the protective membranes covering the brain or spinal cord, or encephalitis — inflammation of the brain. They also don’t affect blood cells in the way Bourbon virus did; though other tick-borne diseases like Heartland virus can.

CDC officials are unsure about where the virus came from, but Staples speculated the virus may have always been there, albeit with less severe symptoms. In other words, the man may have just experienced complications from a less severe form of the illness; one that hadn’t previously caused someone to seek medical attention. Or, the virus could have changed or evolved to become more dangerous, she said.

“As diagnostic techniques have improved and surveillance of unexplained illnesses have increased, it is not surprising to find novel pathogens,” Amesh Adalja, senior associate at the Center for Health Security of the University of Pittsburgh Medical Center, told USA Today. "It will be important to determine how widespread the Bourbon virus is in both ticks, insects, animals and humans and to grasp the spectrum of illness it is capable of causing. The fact that a novel virus was discovered underscores the need for perpetual vigilance, in all locales, with respect to emerging infectious diseases. It is only by leaving no stone unturned when investigating unexplained illnesses that humans can best prepare for microbial threats."