A terrifying new strain of flesh-eating bug that kills one in four of those it invasively infects is spreading around the world, evidence suggests.
The group A streptococcus bacteria have caused a sharp rise in skin and throat infections in the UK over the past 17 years. In severe cases, the microbes can cause necrotising fasciitis - the "flesh-eating" condition which destroys body tissue - pneumonia and blood poisoning.
Around a quarter of people who suffer an invasive infection do not survive.