“The skeleton of the young boy (~6 years old) showed signs of disease consistent with bacterial septic arthritis, a progressive destruction of joints, probably caused by a prolonged and untreated Hib infection, which could have led to physical impairment and in the case of an additional meningeal infection also neurological impairment,” said Guellil, the Research Fellow of Ancient DNA.
The analysis of the Hib genomes allowed for the first evolutionary insights into this major human pathogen and the origin of its b-capsule, which plays a major role in the virulence of the pathogen and is key to the current Hib vaccine.
It also confirmed the presence of the pathogen with a similar clinical phenotype observed in the 20th century as early as the 6th century CE.
The genome itself has a distinct virulence profile from current Hib genomes and places in the now ostensibly no longer circulating serotype b phylogroup. The findings are published in Genome Biology.
The additional recovery of a partial plague genome from the child also highlights how the plague was affecting sub-adult populations during the historical pandemics.
Thanks to widespread vaccination programs, once common and potentially fatal Hib infections are now very rare.