Interesting study documenting plague outbreak in hunter-gatherer communities over 5000 years ago. While the sequence Yersinia pestis strain lacked certain pathogenicity factors compared to those found later in the bubonic plague. it appeared to be lethal especially to children. In the past, it was often assumed that urbanization and rats were key factors in the spread of the bubonic plague. However, lately studies challenged the relevance of rats and this one here challenges the need for urbanization for such outbreaks.

Macleod, R., Seersholm, F.V., De Sanctis, B. et al. Lethal plague outbreaks in Lake Baikal hunter-gatherers 5,500 years ago. Nature 654, 697–705 (2026)

DOI 10.1038/s41586-026-10540-5

Plague is among the most devastating diseases in human history¹. However, early strains of the plague-causing bacterium Yersinia pestis lacked virulence factors that are required for the bubonic form until around 3,800 years ago^2,3. Consequently, the morbidity and mortality of early plague strains remain unclear. Here we describe early plague strains that are associated with two phases of outbreaks among mid-Holocene hunter-gatherers near Lake Baikal in southeast Siberia, beginning from about 5,500 years ago. These outbreaks occur across four hunter-gatherer cemeteries, with a 39% detection rate for plague infection. By reconstructing kinship pedigrees, we show that small familial groups were affected, consistent with human-to-human spread of disease, and that the first outbreak occurred within a single generation. The infections appear to have resulted in acute mortality, especially among children (aged 8 to 11 years). We further note functional differences, including in the ypm superantigen locus, which is also present in present day Yersinia pseudotuberculosis. The new strains diverge ancestrally to known Y. pestis and constrain the timing of its emergence, indicating that this happened before approximately 5,700 years ago. These findings show that plague outbreaks happened earlier than previously thought and were indeed lethal. We contend that the occurrence of outbreaks among mid-Holocene hunter-gatherer communities well outside the sphere of Late Neolithic Europe challenges the notion that higher population densities and lifestyle changes during the Neolithic agricultural transition were prerequisites for plague epidemics.

Later outbreaks of the plague seem to have followed the then new system of road building.
Isolated communities often kept to themselves, and the only interaction was through newly constructed roads.

Those pesky Pestis take every opportunity to spread.

Yersinia is also often found in soil, so it sticks around and there is a chance for sporadic outbreaks. Though for big spreads sustained human-to-human connections is important.

Funny you should bring up Lake Bailkal.

I was just watching a Channel 5 documentary about how recent archaeology there may identify the source of the Loch Ness Monster.

Not quite the same as a paper but an intriguing nonetheless.