Tracking Sources of Toxoplasma Infection in California Sea Otters

Investigators determined that Toxoplasma gondii is a major source of mortality for threatened California sea otters; an estimated 17 percent die from brain infections caused by T. gondii. One strain (type X) is extremely common in otters and was also found in wild mussels, which are an otter food source, and three species of land animals residing along the coast. These findings further support the hypothesis that sea otters become infected with this parasite by eating shellfish that become contaminated by cat feces present in freshwater runoff. This research has been critical in guiding management policies for sea otter populations and helped lead to public awareness campaigns on the importance of keeping cats indoors and properly disposing of their waste. In addition, the results helped lead to passage of state legislation that increased legal protection of this species.