Numerous wild southern sea otters in California are infected Toxoplasma gondii a parasite, yet the infection is deadly for only a fraction of sea otters, which has long puzzled the scientific community. Research from the University of California, Davis, identifies the parasite’s specific strains that are killing southern sea otters, retracing them to a bobcat and feral domestic cats from close by watersheds.
The study, revealed in the journal Proceedings of the Royal Society B, marks the first time a genetic link has been acertained between the Toxoplasma strains in felid hosts and parasites causing a fatal illness in marine wildlife.
Wild and domestic cats are the one known hosts of Toxoplasma, wherein the parasite forms egg like phases, known as oocysts, of their feces. Shapiro led the preliminary effort to show how oocysts accumulate in kelp forests and are taken up by snails, which are consumed by sea otters.
The study’s outcomes spotlight how infectious agents like Toxoplasma can unfold from cat feces on land to the ocean, leading to detrimental impacts on marine wildlife.
Southern sea otters are among the many most intensely studied marine mammals in California because they’re a threatened species and an remarkable animal for the state. They live inside just some hundred meters of the coastline, allowing for the close observation that enables a wealth of scientific data.
Previous research confirmed that as much as 70 % of stranded southern sea otters had been infected with Toxoplasma, but the infection becomes fatal for only a fraction of them. Many years of detailed investigations by CDFW and UC Davis have confirmed that infection by land-based protozoan parasites such as Toxoplasma and the associated parasite Sarcocystis neurona are common causes of illness and death for southern sea otters.