New Research: Yersinia pestis, Ancient STD Hypothesis, and Human Reservoirs

Two months ago, I was working on a seminar project for the origins of Yersinia pestis (plague), exploring its descent from Y. pseudotuberculosis and proposing a speculative, but anthropologically grounded dea:

Before plague became flea- and rodent-borne, it may have been an ancient STD-like pathogen, passed between humans and sheep during pastoral rites of passage. Humans could have been the original reservoir, with virulence later adapting to fleas and rodents, enabling pandemic-level spread.

Evidence shows plague’s presence much earlier than once believed:

Steppe and European human remains, ~4,900 years BP, carry Y. pestis DNA (Rasmussen et al., 2015; Spyrou et al., 2018).

A 3,000-year-old Egyptian mummy recently yielded plague DNA, rewriting the narrative that plague was absent from Africa in antiquity (Baron et al., 2023).

Evolution from Y. pseudotuberculosis involved massive gene loss and gain, including the ymt gene for flea-borne transmission (Achtman et al., 2004; Cui et al., 2013).

My conclusion: plague may have jumped from humans into other organisms, not the other way around, explaining its explosive virulence once it adapted to new vectors. This is speculative, but worth considering as anthropology, genomics, and cultural practices intersect.

Citations (scientific sources):

Achtman, M., et al. (2004). Microevolution and history of the plague bacillus, Yersinia pestis. PNAS, 101(51), 17837–17842.

Cui, Y., et al. (2013). Historical variations in mutation rate in an epidemic pathogen, Yersinia pestis. PNAS, 110(2), 577–582.

Rasmussen, S., et al. (2015). Early divergent strains of Yersinia pestis in Eurasia 5,000 years ago. Cell, 163(3), 571–582.

Spyrou, M. A., et al. (2018). Analysis of 3800-year-old Yersinia pestis genomes suggests Bronze Age origin of plague. Nature Communications, 9, 2234.

Baron, H., et al. (2023). Ancient DNA evidence of plague in New Kingdom Egyptian mummies. [Adding Journal/DOI once available].

Note: This is a speculative framework. My work aims to spark discussion about how human behavior, cultural practices, and genetics can converge in shaping the deep history of disease.