Rare strain of parasite that killed 4 otters in California could pose a danger to humans, researchers say

A rare and unusually powerful strain of a parasite commonly found in cat feces has killed four otters off the California coast, a finding researchers described Wednesday as unprecedented and potentially dangerous to humans and other animals.

Karen Shapiro, an associate professor of pathology, microbiology, and immunology at the University of California, Davis, described the preliminary findings in a press release as a “complete surprise” and said the rare strain of the parasite, known as toxoplasma gondiiit had never been seen before in sea otters or any other aquatic mammal or bird.

Shapiro and three co-authors from the university and the California Department of Fish and Wildlife published their research Wednesday in the journal Frontiers in Marine Science..

Melissa Miller-Henson, of the Department of Fish and Wildlife, said in the statement that she has studied toxoplasmosis in sea otters for 25 years and has never seen lesions this severe or a large number of parasites.

“We are reporting our preliminary findings to alert others to this worrisome condition,” he said. “Since toxoplasma can infect any warm-blooded animal, it could also cause disease in animals and humans that share the same environment or food resources, including mussels, clams, oysters, and crabs eaten raw or undercooked.”

Most cases of toxoplasmosis in healthy humans go undetected, though it can cause serious illness in people with compromised immune systems, as well as miscarriages and other health problems in women who contract the parasite shortly before or during pregnancy, according to the Centers. for Disease Control. and Prevention.

It’s unclear how the rare strain of toxoplasma can affect people, according to the statement.

The four southern sea otters studied by the researchers were found between February 2020 and March 2022 in San Luis Obispo and Santa Cruz counties, according to the study. The researchers suggest that the animals may have contracted the parasites from rainwater runoff.

The type of toxoplasma found on their bodies, known as COUG, was first discovered in Canadian cougars in 1995. It’s unclear how the parasite got to California, but the statement describes it as a newcomer.