GRANTS PASS, Ore. — 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.
George Poinar Jr. bought the amber about 30 years ago in the Dominican Republic while researching the ancient origins of diseases spread by ticks and mosquitoes. Poinar is a professor emeritus of entomology at Oregon State University
He did not see the tick inside until five years ago. When he cracked open the amber, he could see with a powerful microscope that the tick was full of millions of fossilized bacteria.
Poinar writes in the online edition of the journal Historical Biology published April 22 that he could not extract a DNA sample for a positive identification of the fossilized bacteria, but its size and form were similar to the genus Borrelia, which includes the species that causes Lyme disease.