A strain of flesh-eating group may affect you in various ways - some of them fatally - and scientists have now discovered how this bacteria exploded into a worldwide epidemic. Only four tiny modifications to group A Streptococcus bacteria caused it to explode into a worldwide epidemic the study said. 'The first two events were the acquisition of two bacterial viruses' said infectious disease pathologist James Musser of the Houston Methodist Research Institute in the US.Bacteria just like humans can get infected by viruses Musser noted. Sometime in the 1980s these viruses infected a single bacterial cell of group A