Taylor Hermes, an assistant professor of anthropology at the U of A, received a grant of €100,000 (about $105,000 U.S.) from the Max Planck Society in Germany to research the evolution and spread of the plague-causing bacterium Yersinia pestis in Central Asia during the Bronze Age.

Yersinia pestis is well known for causing the Justinian Plague in the sixth century and the Black Death in the 14th century, as the bacterium rapidly spread via fleas and rats in Europe. However, a prominent lineage of Yersinia pestis emerged 5,000 years ago without the genetic architecture for flea transmission. This lineage, known as the Late Neolithic and Bronze Age (LNBA) plague, repeatedly spread throughout Eurasia and caused deadly outbreaks for millennia until its extinction.

By analyzing DNA of Yersinia pestis from the teeth of ancient people and domesticated sheep, Hermes and colleagues at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, have honed in on the world's first horse riders as a major influence behind the spread of the LNBA plague. Their latest research argues that horse riding led to an intensification of pastoralism in the Sintashta Culture of Central Asia (ca. 4,000 years ago). Larger herds contributed to livestock contracting LNBA plague from natural reservoirs of rodents or migratory birds more often, effectively causing livestock to become bridge hosts for human infections. The team's research has appeared in a new preprint.

"It was remarkable to discover a domesticated sheep from the Bronze Age that was infected with LNBA plague. This gave us an important clue for how plague could transmit within pastoralist communities without fleas as vectors," Hermes said.

Hermes's project will support archaeological excavations at Sintashta Culture sites in Kazakhstan to search for more cases of LNBA plague in livestock and people, and to better understand the zoonotic dynamics.

"Previous ancient DNA studies on Yersinia pestis found infections incidentally. This project turns that approach inside out by targeting livestock carriers of LNBA plague to trace disease evolution and human transmission within this Bronze Age epicenter," Hermes explained.

Hermes will lead a Max Planck Partner Group at the U of A that is affiliated with the Department of Archaeogenetics at the Max Planck Institute for Evolutionary Anthropology for five years. This collaboration will create research and training opportunities for U of A students in paleogenomics, archaeology and museum curation. Excavations will begin this summer in Kazakhstan.