Fossilized Ticks in Amber Reveal Lyme Disease is Older Than the Human Race

It turns out that Lyme disease may be far older than we first thought. Although the disease was only recognized about 40 years ago, scientists have discovered 15-million-year-old ticks fossilized in amber that once had the bacteria that causes Lyme disease today.

Lyme disease is a stealthy and often misdiagnosed disease. It can be caused through the bite of a tick, which can transfer bacteria to an individual. Lyme disease can cause problems with joints, the heart and the central nervous system. If recognized early and treated with antibiotics, it can be cured; unfortunately, it's often mistaken for other health conditions.

"Ticks and the bacteria they carry are very opportunistic," said George Poinar, one of the researchers, in a news release. "They are very efficient at maintaining populations of microbes in their tissues, and can infect mammals, birds, reptiles and other animals. In the United States, Europe and Asia, ticks are a more important insect vector of disease than mosquitoes. They can carry bacteria that cause a wide range of diseases, affect many different animal species, and often are not even understood or recognized by doctors."

Yet while Lyme disease was only recognized 40 years ago, it seems as if it's been around far longer-possibly millions of years. Scientists analyzed a series of four ticks from Dominican amber and found a large population of spirochete-like cells that most closely resemble those of present-day Borrelia species. In addition, the researchers found cells that resemble Rickettsia bacteria, the cause of the Rocky Mountain spotted fever and related illnesses.

What's more surprising is that this bacteria occurred long before there were even humans. This means that humans have likely been getting diseases, including Lyme disease, from tick-borne bacteria as long as there have been humans.

The findings reveal a little bit more about the evolution of these bacteria. This, in turn, could help inform future studies about tick-borne diseases.

The findings are published in the journals Historical Biology and Cretaceous Research.