Battling bubonic plague
© Alamy
Sweeping across the world in the 1300s, the bubonic plague, or ‘black death’, claimed the lives of 30 to 50 per cent of the global population. The disease is caused by a bacterium called Yersinia pestis (blue). In this scanning electron micrograph image, Yersinia pestis has been imaged clinging to the spines of a rat flea.