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Dr. Chris Kreuder Johnson

Christine Kreuder Johnson has been studying sea otters’ causes of death since 1998. She worked with the team that discovered that otters were dying mostly from infectious diseases and identified the risk factors associated with the prevalent causes of death. This work helped establish sea otters as a sentinel species for monitoring the near-shore health of marine ecosystems.

She also did an epidemiologic study of a recently identified common cause of sea otter death, cardiomyopathy, or chronic disease of the heart muscle. It showed that inflammation of the heart muscle results when the heart is injured by an infection caused by a parasite (Sarcocystis neurona) or poisoning from domoic acid, a toxin that algae produce in large quantities during algal blooms.

Her current work focuses on figuring exactly how sea otters are exposed to parasites. “It's quite a mystery how they’re being exposed to some parasites and it's critical that we trace disease in sea otters to its source,” she says. For example, one of otters’ favorite foods is shellfish, which filter the water for their food. They accumulate domoic acid from the algae, and can retain the toxin for six months or longer. Investigators are implanting radio tags in sea otters, and then following and monitoring them to see if their choice of food, their use of their habitat and their movements determine how they’re exposed to parasites and toxic blooms.

Assistant Professor of Ecosystem Health and Epidemiology
School of Veterinary Medicine, UC Davis


 

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