A devastating ancient plague is believed to have spread around 5,000 years ago, with evidence suggesting it may have originated from domestic sheep. The plague is thought to have affected hunter-gatherers, with ancient dna and remains found in areas such as lake baikal and siberia providing clues about the outbreak. The exact details of the plague's spread are still being uncovered, but it is considered one of the earliest known plague outbreaks, occurring nearly 5,000 years before the black death.