Unusual parasite strain kills 4 southern sea otters

Four sea otters stranded in California died of unusually severe toxoplasmosis, according to a study by the California Department of Fish and Wildlife and the University of California, Davis.This disease is caused by microscopic parasites toxoplasma gondiia rare stock of toxoplasma It has never been detected off the coast of California.

Preliminary findings published in the journal Frontiers of marine scienceNote that toxoplasmosis likely arrived recently on the California coast, is common in sea otters, and can be fatal. It appears to be able to kill large adult sea otters rapidly. According to a news release from the University of California, Davis, there are currently no reported human infections with this strain.

“Because this parasite can infect humans and other animals, we want others to be aware of our findings, recognize cases immediately if they do come across them, and take steps to prevent transmission. We want you to take precautions,” said Melissa Miller of the California Department of Fish and Wildlife, author of the findings report (release). “If we observe inflammation of whole-body fat deposits in sea otters or other marine organisms, we recommend taking extra precautions.”

Common Parasites, Rare Results

T Gondi It is a common parasite that hosts feral and domestic cats and is excreted in the faeces.Although healthy people rarely experience symptoms, toxoplasmosis can cause miscarriages and neurological disorders.Sea otters are particularly vulnerable toxoplasma They live near shorelines where they can be exposed to parasite eggs in stormwater runoff, and they eat marine invertebrates that can collect parasites, thus leading to infection.

The four sea otters reported in the reported study were stranded between 2020 and 2022. All had steatorritis, a condition involving severe inflammation of body fat.

“The emergence of this deadly type toxoplasma The California coast is of concern for two main reasons. First, because of its potential population health impact on endangered species, and second, because this parasite may also affect the health of other susceptible animals. . toxoplasma .

Microscopic examination of confirmed tissue toxoplasma as the cause of death for all four otters. Numerous parasites were observed throughout the body, with the exception of the brain, one of the major organs in sea otters with deadly toxoplasmosis.

DNA testing identified a rare strain toxoplasma Called COUG in all four cases. The strain was first discovered in Canadian mountain lions in 1995 during surveillance after a nearby human outbreak. toxoplasma The person responsible for the outbreak was not reported. According to Karen Shapiro, senior author of the study at the UC Davis School of Veterinary Medicine, it was surprising to find her COUG in sea otters. “The COUG genotype has never been described in sea otters, anywhere in California’s coastal environment, or in any other aquatic mammal or bird,” Shapiro said in a release.

Sea otters are under threat

All four sea otters ran aground during periods of heavy coastal rainfall. toxoplasma Eggs from storm spills. His three of these otters were stuck close to each other, but it’s unclear if they all got infected in the same spot. It is also unknown how this unusual strain affects humans and other animals.

“Studied toxoplasma In 25 years of sea otter infections, I’ve never seen lesions and parasite counts this severe,” Miller added. “We are reporting our preliminary findings to warn others about this concerning condition. toxoplasma Can infect warm-blooded animals as well as cause disease in animals and humans that share the same environment or food resources that are consumed raw or undercooked, such as mussels, clams, oysters and crabs There is also a possibility.

The researchers noted that with increased surveillance, the COUG strain could be identified in other animals. “We still have a lot to learn,” says Sinnott. “Large-scale studies are needed to understand the potential impact of COUG infection. toxoplasma The strain on sea otter populations, how sea otters are geographically dispersed, how sea otters are introduced into the ocean, and other animals that may be affected.

reference

A sea otter killed by an unusual parasite strain. news release. UC Davis. March 23, 2023. Accessed March 24, 2023. https://www.ucdavis.edu/health/news/sea-otters-killed-unusual-parasite-strain