Updated

Fossilized bacteria found inside a tick encased in 15 million-year-old amber indicates the bacteria that cause Lyme disease were likely around long before there were humans to get the disease.

George Poinar Jr. is professor emeritus of entomology at Oregon State University. He bought the amber about 30 years ago in the Dominican Republic, while researching the ancient origins of diseases spread by ticks and mosquitoes.

He did not find the tick until five years ago, and when he cracked open the amber, saw the tick was full of millions of fossilized bacteria.

Poinar writes in the latest edition of the journal Historical Biology that the fossilized bacteria are similar in form to the bacteria causing Lyme disease.

The fossil record indicates homo sapiens has been around about 200,000 years.