A disease which has devastated one type of Caribbean coral, Elkhorn coral, has been traced back to bacteria found in human faeces. On some reefs, 95% of Elkhorn corals, which used to be the commonest coral in the Caribbean, have been wiped out by the condition, called white pox that shows itself as white spots on the coral, which spread and kill the coral, destroying the living tissue. On average, the disease spreads at a rate of 2.5 square centimetres of coral a day.

The problem is particularly bad in the Florida Keys, where human waste is treated in septic fields rather than extensively treated to kill bacteria.  It is thought to be the first time that a human gut bacterium has been linked to coral disease.