THE mystery of why cholera outbreaks tend to occur in seasonal cycles may have been solved.
In south Asia, outbreaks of the deadly disease tend to peak after the monsoons and spring rains. None of the proposed explanations, such as blooms of plankton that promote bacterial growth, are satisfactory. Now John Mekalanos of Harvard Medical School in Boston and his colleagues in India and Bangladesh have shown that the cycles of infection could be driven by bacteriophages – viruses that infect bacteria.
The investigators focused on two phages, which respectively infect O1 and O139, the two most dangerous strains of the …
