Potential Environmental Contamination Ensues as Rare Parasitic Strain of Toxoplasmosis Detected in California Sea Otters

Sea otters in California are dying from a particularly virulent strain of toxoplasmosis, which may one day threaten both human and animal public health.

New Parasitic Strain, Four Sea Otters

This deadly condition is caused by a rare strain of the Toxoplasma gondii, a microscopic parasite that has so far been found in four stranded otters.

Even though toxoplasmosis in sea otters is common and can even be fatal, the authors emphasized that this particular strain seems particularly vicious and can quickly take the lives of healthy adult animals.

The researchers believe that this strain of Toxoplasma is a recent arrival because it has never been found on the coast of California before.

They expressed concern about possible contamination of the environment as well as the marine food chain as a result, stating that such conditions could be hazardous to the public's health. But no infections in humans have been documented thus far.

Devinn Sinnott from the University of California said that for two main reasons, the discovery of this deadly strain of Toxoplasma in California coasts is alarming. Sinnott is the study co-author.

According to EurekAlert!, the four sea otters involved in the study, which washed up on shore between 2020 and 2022, all displayed "steatitis," which is a severe inflammation of body fat.

Potential Environmental Contamination

Sinnott explained that these issues include the potential effects on a threatened species' population health as well as the parasite's capacity to have an impact on the health of other animals who are prone to Toxoplasma infection.

Because they live close to the coast and can be exposed to the parasite's eggs through storm runoff and by consuming marine invertebrates that have the parasites, the authors noted that sea otters are particularly susceptible to Toxoplasma infection.

However, the occurrence of severe steatitis in sea otters with toxoplasmosis is a very unusual finding, the researchers noted.

According to the study, DNA testing revealed that all four stranded otters carried the uncommon strain of Toxoplasma known as COUG. Mountain lions in Canada were where this strain was first discovered in 1995.

The COUG genotype was never before described in sea otters, anywhere along the California coast, or in any other aquatic mammal or bird, according to Karen Shapiro, a graduate of the UC Davis School of Veterinary Medicine. Shapiro is the senior author of the study.

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Rainfall and Toxoplasma Eggs

According to the study, all four of the otters were exposed to Toxoplasma eggs through storm runoff because they all became stranded during times of heavy coastal rainfall. Three of the tested otters were adult females in San Luis Obispo County, about 16 miles apart from one another, and one was a young male who had become stranded in Santa Cruz County.

The corresponding author Melissa Miller from the California Department of Fish and Wildlife expressed concern that Toxoplasma could potentially cause disease in both animals and people who share the same environment or food sources because it can infect any warm-blooded animal. Such foods include raw or undercooked mussels, clams, oysters, and crabs.

Miller stated that others must be aware of the team's findings, quickly identify cases, and take precautions to avoid infection because this parasite can infect both humans and other animals.

She continued by advising people to exercise extra caution if they notice inflamed systemic fat in sea otters as well as other marine wildlife, The Hill reports.

The study by Sinnott, Miller, Shapiro, and several colleagues was recently published in the journal Frontiers in Marine Science.