UC Davis Scientists Establish Deadly Pathogen Link In Dying Sea Otters and Feral Cats
DAVIS (CBS13) — A UC Davis study found many wild southern sea otters in California are infected with Toxoplasma gondii, a parasite killing only a fraction of the sea otters carrying it and of which can be traced back to felid hosts in nearby watersheds — namely bobcats and domestic cats.
UC Davis scientists say this is the first time a genetic link has been clearly established between the Toxoplasma strains found in dying marine wildlife and felid hosts.
According to the study, wild and domestic cats are the only known hosts of the parasite which forms oocysts, or egglike stages, in their feces.
The study, which characterized Toxoplasma strains for more than 100 stranded souther sea otters examined between 1998 and 2015, builds upon decades of research that began when scientists were called upon in the late 1990s when the parasite caused several sea otter deaths along California's coast.
Toxoplasma strains were compared in pathology data found in sea otters and nearby felids to identify connections between the pathogen and its hosts.
Scientists say southern sea otters are intensely studied because they are a threatened species. The study lists several ways to help reduce the spreading of the strain. They are:
- Keep cats inside and disposing of cat feces in a bag in the trash. Outdoor cats feeding on rodents and birds are likely to get infected due to the parasite being a common presence in those animals. Oocysts in feces get washed into waterways via rainfall. The study says stormwater runoff has been identified as a key source of Toxoplasma exposure in sea otters.
- Preserving and restoring wetlands and natural areas can reduce contamination and minimize pathogens entering the water via runoff.
Prior research has shown that up to 70 percent of stranded southern sea otters were infected with Toxoplasma, although the infection is only deadly for a fraction of the bunch, according to researchers.