Amazing stuff! Concerning too! Are downplaying or ignoring zoonoses?
"For the first time, researchers have genetically identified leprosy-causing bacteria in archaeological animal remains—indicating, in this case, that the disease circulated between red squirrels and humans in medieval England. The evidence came from archaeological sites in the city of Winchester, which during the Middle Ages had both a thriving squirrel fur trade and a hospital for leprosy patients, setting the stage for interspecies transmissions. Some medieval Brits even kept the arboreal rodents as pets.
While some modern red squirrels in England still carry leprosy, there’s no evidence of them passing it to humans, as the disease requires frequent close contact with an infected host. But experts argue that considering the interspecies history of leprosy, rather than focusing solely on human infections, can help us anticipate where and how transmission risk might increase. That approach could apply to other nonhuman carriers, too—such as armadillos, which have been linked to a handful of human cases in the Americas. ..."
From the highlights and abstract:
"Highlights
• Genetic evidence of M. leprae infection in medieval English red squirrels
• Ancient M. leprae squirrel strain related to ancient human strains in the same city
• Results suggest a yet-undetected circulation of M. leprae in medieval animal hosts
• First One Health approach for M. leprae about a medieval animal strain
Summary
Leprosy, one of the oldest recorded diseases in human history, remains prevalent in Asia, Africa, and South America, with over 200,000 cases every year. Although ancient DNA (aDNA) approaches on the major causative agent, Mycobacterium leprae, have elucidated the disease’s evolutionary history, the role of animal hosts and interspecies transmission in the past remains unexplored. Research has uncovered relationships between medieval strains isolated from archaeological human remains and modern animal hosts such as the red squirrel in England. However, the time frame, distribution, and direction of transmissions remains unknown. Here, we studied 25 human and 12 squirrel samples from two archaeological sites in Winchester, a medieval English city well known for its leprosarium and connections to the fur trade. We reconstructed four medieval M. leprae genomes, including one from a red squirrel, at a 2.2-fold average coverage. Our analysis revealed a phylogenetic placement of all strains on branch 3 as well as a close relationship between the squirrel strain and one newly reconstructed medieval human strain. In particular, the medieval squirrel strain is more closely related to some medieval human strains from Winchester than to modern red squirrel strains from England, indicating a yet-undetected circulation of M. leprae in non-human hosts in the Middle Ages. Our study represents the first One Health approach for M. leprae in archaeology, which is centered around a medieval animal host strain, and highlights the future capability of such approaches to understand the disease’s zoonotic past and current potential."
Ancient Mycobacterium leprae genome reveals medieval English red squirrels as animal leprosy host (open access)
Figure 1Location of the leprosarium of St Mary Magdalen and Staple Gardens in Winchester (center circle), within the UK
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