Scientists have discovered the bacterium Yersinia pestis in the DNA of a 4,000-year-old domesticated sheep from the Bronze Age, located in the settlement of Arkaim in the southern Urals of Russia.[1][2] This is the first case of this pathogen in a non-human host from this time.[1][2] The sheep belonged to the Sintashta culture, known for early horse riding and the raising of cattle, sheep and horses.[1][2] This strain of Y. pestis belonged to the LNBA lineage that spread across Eurasia during the Late Neolithic and Bronze Age, approximately 5000 to 2000 years ago.[2] Genetic analysis showed nearly identical strains in humans and sheep, suggesting transmission from an unknown wild reservoir.[2] Domestic animals such as sheep likely increased human exposure to the pathogen by grazing on large pastures.[2] The study, published in the journal Cell, analyzed the bones and teeth of bronze cattle from the Arkaim site.[1][2]