Since 1998, sea otters have been dying at an alarming rate from Toxoplasma infections. According to The New York Times, “The Toxoplasma parasite, a single-celled organism, is able to infect a wide variety of warm-blooded animals, but it needs to colonize cats, either wild or domestic, to reproduce sexually. Once infected, a cat can shed millions of Toxoplasma in its feces, which can contaminate the soil and water if the animal relieves itself outdoors. Toxoplasma gondii is the reason doctors recommend thatcertain pregnant women avoid litter-box duty. The parasite can harm fetuses and anyone with a compromised immune system, although most people fight off Toxoplasma with few or no symptoms.”
Toxoplasma infections contribute to the deaths of 8 percent of otters that are found already dead, and is the primary cause of death in 3 percent of the general otter population.
Cats (and other common SoCal species like Bob Kats) who are infected with the parasite will shed millions of them in their feces which can leach into the water table and then spread. to the shallow waters otters like to swim in..
After analyzing DNA data and cross-referencing it with the feline DNA of Bob Cats and feral house cats, scientists had what they needed.