Sticky molecules found in aquatic ecosystems could help to transmit land-based pathogens to marine animals.

Karen Shapiro at the University of California, Davis, and her colleagues added varying levels of a gelatinous compound, alginic acid, to seawater samples containing the parasite Toxoplasma gondii, which is carried by cats. They found that it increased the number of parasites stuck to marine aggregates, and that similarly sticky molecules also allow the parasite to adhere to kelp surfaces. Snails, which graze on kelp, ingested and accumulated the pathogen.

Sea otters are known to eat snails, and this finding could explain why the mammals have been infected with T. gondii.

Proc. R. Soc. B 281, 20141287 (2014)