A team of experts believe they have confirmed the first US case of tick-borne disease caused by a particular bacterium. The case involved a 75-year-old man from Alabama who had possibly caught the germ of a solitary tick. Fortunately, the man was successfully treated with antibiotics.
The case was detailed in last month’s edition of Emerging Infectious Diseases, a journal run by the Centers for Disease Control and Prevention. Its authors include scientists from the CDC, as well as doctors and researchers from the University of Alabama at Birmingham and the University of Washington.
According to the report, the 75-year-old Alabama resident first saw doctors at UAB Hospital’s Kirklin Clinic in April 2019. For about a month, he suffered from extreme fatigue accompanied by recurrent bouts of fever, chills, sweating, headache. , and dizziness. The man had not traveled recently, but four weeks before the trouble started, he found a tick feeding on him. Tests later revealed that he had some kind of spirochete bacteria in his blood – a large group of spiral-shaped bacteria, some of which are known to be spread by ticks. Doctors quickly put him on antibiotics.
After the first dose, the man developed a high fever and became stuporous (a condition in which someone becomes almost numb). But he recovered within 24 hours and completed the full treatment without any further issues. Over the following months, all remaining signs of infection also disappeared.
It would take three months to confirm the man’s diagnosis: tick-borne relapsing fever (TBRF). TBRF is known to be caused by several species of Borrelia bacteria, distant cousins of the bacteria responsible for Lyme disease. But when they examined the man’s blood under a microscope and analyzed the genetics of the bacteria, they found none of these known germs; instead, they found Borrelia is a shame bacteria. Given the available evidence, researchers say this is likely the first documented US case of TBRF caused by B. be honored
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B. be honored has an interesting story. It is seen frequently in solitary ticks and was first found to infect humans over two decades ago. The bacterium was originally suspected to be the cause of southern tick-associated rash disease (STARI), a tick-borne disease with symptoms similar to Lyme, including a bulls eye rash, spread by the lone star tick. But further research failed to confirm this link, and to date no one knows what causes STARI.
In this case, however, it is already known that a close relative of B. be honoredcalled Borrelia miyamotoi, can sometimes cause TBRF. Most TBRF infections are caused by different bacteria spread by “soft ticks”, but, if confirmed, B. be honored would be the second TBRF germ known to be spread by hard ticks.
B. be honored may be less able to cause disease than other notorious tick-borne germs, study finds authors. The man in this case was taking immunosuppressants to control his slow-growing lymphoma, which may have contributed to his illness. That said, they also note that B. be honored is difficult to identify using typical laboratory methods, which means doctors may have missed many potential cases so far. Either way, it’s likely we’ll eventually better understand how often it can make people sick.
“In the years to come, increased awareness of the pathogenic potential of B. be honored and the use of molecular diagnostics can give us an approximation of the true burden of human disease caused by this bacterium,” study author and infectious disease specialist Vazquez Guillamet said Special Edition on Infectious Diseases.
In general, tick-borne diseases are should become more common and widespread in the United States as tick populations continue to expand their range in a warmer climate.