Molecular Confirmation of Yersinia pestis in 6th century Bavaria

Erasing any lingering doubts about the agent of the Plague of Justinian, a group of German biological anthropologists have shown conclusively that Yersinia pestis caused an epidemic in a 6th century Bavarian cemetery at Aschheim. Harbeck et al (2013) provide a convincing refutation of previous theories about the etiologic agent of the Plague of Justinian.   Returning to the same cemetery where plague was previously reported, two independent labs using the most modern standards to prevent contamination confirmed Yersinia pestis from multiple burials within the cemetery making this the best characterized Early Medieval plague cemetery.

The cemetery, called Aschheim, is in Bavaria outside of Munich. It contains the remains of 438 people with an unusually high number of multiple graves but no disordered mass graves. The 19 multiple burials contained two to five individuals arranged in lines. The cemetery was dated archaeologically to 500-700 AD with remains being carbon dated ranging from 530 to 680, all consistent with the 541 pandemic and its aftermath. Harbeck et al (2013) tested 19 individuals from 12 multiple graves. From these, there were eight positive samples, but only one produced enough aDNA to do some SNP genotyping. Added to the previous paper, this makes 11 positive individuals from this cemetery. Given the tenuous survival of aDNA, 11 positive individuals out of 21 tested in the two combined papers is a very good success rate. This is a cemetery that the F1 antigen test would be interesting since it could be used on the entire cemetery without great cost or labor. More sensitive than aDNA, the antigen test could tell us the percentage of plague deaths in the cemetery.

Individual A120 was screened with several SNPs that mapped it to an early region of the phylogenetic tree in the 0.ANT section. This makes the Plague of Justinian isolate ancestral to the Black Death isolates (yellow boxes below) from East Smithfield. This section whose only point of diversity is 0.ANT1 at node 4. Date predictions for the nodes of diversity in the tree fits with the Plague of Justinian falling in this region.  Modern isolates that  form this region of the phylogenetic tree all come from central Asia (around Tibet), suggesting that like the Black Death, the Plague of Justinian also originated in Asia. Overall, everything fits in well with expectations for the first pandemic.

(Harbeck et al, 2013. Fig. 1)

Reference:

Harbeck M, Seifert L, Hänsch S, Wagner DM, Birdsell D, et al. (2013) Yersinia pestis DNA from Skeletal Remains from the 6th Century AD Reveals Insights into Justinianic Plague. PLoS Pathog 9(5): e1003349. doi:10.1371/journal.ppat.1003349

Wiechmann I, & Grupe G (2005). Detection of Yersinia pestis DNA in two early medieval skeletal finds from Aschheim (Upper Bavaria, 6th century A.D.). American journal of physical anthropology, 126 (1), 48-55 PMID: 15386257

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