Sea Otters Killed by Unusual Parasite Strain; Rare Form of Toxoplasma Infection May Pose Threat to Marine Animals and Perhaps Humans

Four sea otters that were stranded in California died from an unusually severe form of toxoplasmosis, according to a study from the California Department of Fish and Wildlife and the University of California, Davis. The disease is caused by the microscopic parasite Toxoplasma gondii COUG. Scientists warn that this rare strain, never previously reported in aquatic animals, could pose a health threat to other marine wildlife and humans. The preliminary findings, published on March 22, 2023 in Frontiers in Marine Science, note that toxoplasmosis is common in sea otters and can be fatal. This unusual strain appears to be especially virulent and capable of rapidly killing healthy adult otters. The open-access article is titled “Newly Detected, Virulent Toxoplasma gondii COUG Strain Causing Fatal Steatitis and Toxoplasmosis in Southern Sea Otters (Enhydra lutris nereis).” The rare strain of Toxoplasma hasn’t been detected on the California coast before so is likely to be a recent arrival. Scientists are concerned that if it contaminates the environment and the marine food chain, it could pose a public health risk. At present, no infections with the strain have been reported in humans.