Transmission of Toxoplasma: clues from the study of sea otters as sentinels of Toxoplasma gondii flow into the marine environment

This synthesis used southern sea otters as sentinels to trace how the cat-derived parasite Toxoplasma gondii moves from land into the sea. The authors integrated parasitology, oceanography and epidemiology to argue that oocysts shed by felids wash into coastal waters, are concentrated by invertebrate prey, and infect otters and other marine mammals, sometimes fatally. They also discussed unusual atypical (Type X) strains found in otters, hinting at wild felid involvement. By framing the otter as an indicator of land-sea pathogen pollution, the paper crystallized the concept of environmental transmission of a felid parasite at ecosystem scale. It shaped subsequent research on Toxoplasma in marine systems and remains a key reference for the role of cats in coastal wildlife disease.