A species of ticks, whose bite is known to induce red meat allergy in humans, was found out to carry a newly identified, potentially dangerous virus called Bourbon virus.
The virus was first identified in 2014 in a middle-aged man living in Kansas. He was previously healthy, but later on, complained of having flu-like symptoms and a history of tick bites. The doctors treated him as a case of ehrlichiosis, a tick-borne bacterial infection, due to its similar presentation. But the antibiotics did not affect, and the man continued to deteriorate. After he died, his blood samples were sent to the Centers for Disease Control and Prevention (CDC), and the results showed that it was a completely new virus. It was named Bourbon after the place where the patient had lived.
The second case was in 2017 when a 58-year-old woman from Missouri died of the same rare tick-borne illness caused by the Bourbon virus. The victim, Tamela Wilson, was admitted at a hospital in St. Louis with complaints of fever, fatigue, and red rashes. According to her statement with the doctors, she was working at Meramec State Park when she noticed and removed the ticks from her body. A week later, the symptoms started to show.
Wilson’s blood samples were tested for common tick diseases in Missouri. After the results came back negative, the doctors sent the sample to CDC’s Division of Vector-Borne Diseases for further analysis. Washington University infectious disease specialist Jennie Kwon, together with the CDC, identified Bourbon virus as the suspect. Unfortunately, the patient died after spending three weeks in the hospital.
“We were able to tell the patient and her family that we had identified the cause of her illness, but the unfortunate part is that there was no antiviral treatment available,” said Kwon. “The team did its best to provide supportive care, but unfortunately, she did not survive.”
Scientists still know very little about the virus since its discovery in 2014, as only very few cases were identified, including two patients succumbing to the Bourbon virus infection. Up to this day, researchers are still studying the virus and how to treat the disease.
Bourbon virus is described as taking various forms — sometimes it’s long and filamentous or sphere-shaped surrounded by spiky proteins. Aside from affecting the brain cells of infected humans, it could also attack the white blood cells. Apart from this, the virus seems to reside in ticks. CDC researchers have collected the virus in many ticks in Bourbon County, Kansas, where it was first identified. Specifically, it was in the Lone Star tick where the virus was found, and its bite is known to cause red meat allergy in humans.
However, the agency needs further evidence to conclude that these ticks are the vector of Bourbon virus. The CDC has yet to declare the virus as a cause of tick-borne disease. As of now, there are on-going studies on Lone Star ticks and Bourbon viruses in the laboratory, according to Aaron Brault, a microbiologist from CDC’s Division of Vector-Borne Diseases. He also added that the link between the Bourbon virus and the said species of ticks is now a “strong probability rather than simply a possibility.”
Researchers believe that Bourbon virus is a cousin of the influenza virus. With this, influenza virus researchers, such as Jocco Boon who is a virologist at Washington University, became interested in the case.
Boon and his colleagues tried to test whether drugs against influenza could be used against Bourbon virus. All the other influenza drugs were ineffective except for one.
Favipiravir is a drug that interferes with the proteins needed by the virus to multiply. The researchers conducted an experiment using this drug on infected mice. Those that were injected with placebo, shortly after becoming infected did not survive, while those injected with the drug survived without any signs of being ill.
Unfortunately, the drug is not yet FDA approved in the US, although it is available in Japan, where it was developed.
As of now, there is still no medicine for the treatment of the disease. The best way to avoid being infected is to prevent tick bites by using insect repellents, wearing long sleeves and pants, avoiding bushy and wooded areas, and performing tick checks after outdoor activity.