https://www.sciencedaily.com/releases/2020/05/200504155200.htm > An international team of researchers led by the Universities of Bath and Sheffield, investigated the evolution of Campylobacter jejuni, a bacterium carried by cattle which is the leading cause of gastroenteritis in high income countries. > The researchers, publishing in the journal Proceedings of the National Academy of Sciences, studied the genetic evolution of the pathogen and found that cattle-specific strains of the bacterium emerged at the same time as a dramatic rise in cattle numbers in the 20th Century.