Human excrement is the source of a bacterium that causes a devastating disease in Caribbean elkhorn coral.

Kathryn Patterson Sutherland at Rollins College in Winter Park, Florida, and her team exposed healthy Acropora palmata coral in the lab to the PDR60 strain of the bacterium Serratia marcescens, collected from human wastewater. The coral showed signs of white pox disease, which is characterized by white lesions, in as little as four days.

Poor-quality wastewater disposal in the Caribbean and Florida Keys allows leakage into sea water. The authors say that their work is the first example of reverse zoonosis, whereby disease-causing microbes move from humans to marine invertebrates.

PLoS One 6, e23468 (2011)