Borrelia burgdorferi is one of many bacteria that ticks can pass onto humans and the one responsible for Lyme disease. It causes an array of symptoms, which can be anything from fatigue, arthritis, facial palsy and occasionally a bulls-eye rash (erythema migrans, if you want to get technical). We’ve only known about the pathogen since the early 1980’s, but it’s been around for much longer than that...potentially for thousands of years longer. Traces of its effects were even found in Ötzi the Iceman, the 5,300-year old hunter found mummified in the Italian Alps.
But while we’re not sure exactly where and when Borrelia originated, we do know a lot about how the disease works and how it’s spread.