Ordinarily, when we think of prehistoric items that have been preserved in amber, things like insects come to mind. Recently, however, scientists from Oregon State University uncovered something that's a lot closer to home for us humans. Within a piece of amber found in the Dominican Republic, they discovered what are claimed to be the first fossilized red blood cells from a mammal – likely a monkey.

Also within the 20 to 30 million year-old amber was a blood-engorged tick. Two small holes on its back indicate that it had been picked off of an animal while feeding upon it – this is typical grooming behaviour of monkeys, which were present in the area at the time.

The tick was then dropped into tree resin, where some of the blood that it had sucked oozed out of the two holes and into the resin. That resin hardened into amber over the years, near-perfectly preserving the mammalian red blood cells.

Not only were the tick and the blood present in the amber, but so were parasites that had been infecting the blood cells. The pathogens belonged to the Babesiidae family, members of which today can cause a disease in humans known as babesiosis – it resembles malaria, and can be fatal.

These are the only known fossils of the parasite.

"The life forms we find in amber can reveal so much about the history and evolution of diseases we still struggle with today," says lead scientist Prof. George Poinar, Jr. "This parasite, for instance, was clearly around millions of years before humans, and appears to have evolved alongside primates, among other hosts."

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