Amber encased insects reveal history of malaria

A comprehensive analysis of insect-borne diseases shows that malaria was present in the New World before humans existed and has evolved through birds and monkeys.

Researchers from Oregon State University presented their findings in a recent issue of American Entomologist. They based their study on insect specimens preserved in amber, according to HealthCanal.com.

In addition to malaria, the scientists traced the evolution of several human diseases, including leishmaniasis and trypanosomiasis. The study shows that all three pathogens have existed for at least 100 million years, suggesting that efforts to eradicate such formidable and adaptive foes may be more difficult than previously thought.

“Amber tells us that these diseases have been here for many millions of years, have co-evolved with their hosts and move readily from one species to another,” George Poinar, Jr., a professor of zoology at OSU and a world-renowned expert on the study of fossils encased in amber, said, HealthCanal.com reports. “Malaria is one of the greatest insect-borne killers in human history, and more than one million people a year are still dying from it. But the evolutionary record suggests it can easily change its protein coat in response to vertebrate immune reactions. That’s why it’s always becoming resistant to drugs, and efforts to create vaccines will be very difficult.”

Insect fossils preserved in the semi-precious stone are offering new clues to the ancient history of diseases. The blood-feeding vectors caught in once oozing tree sap reveal different stages of the evolutionary development of the pathogens they carried.

Mosquitoes carrying malaria parasites from the genus Plasmodium, the type that causes illness in humans, existed in the New World at least 15 million years ago, long before the arrival of humans, who are only thought to be about 200,000 years old. At that time, the disease infected various types of birds. From birds, it is thought that malaria transferred to monkeys and then to humans.