Toxic tide

Cat litter implicated in sea otter deaths

source: Elin Kelsey,
New Scientist no 2358 August 31 2002
starts p42, 2 pages long

There is concern that sea otters off California may have been infected by pathogen pollution from cat litter. Dozens of otters have fallen sick with a brain infection. Researchers at the University of California, Davis, have found that dead and sick sea otters have a parasite, Toxoplasma gondii, in their brains. The parasite affected 40% of the living otters sampled, and 60% of the dead otters. Southern sea otters are suffering a decline in their population, and are an endangered species.

Toxoplasma is carried by cats, and both cats and humans can be infected, but usually it is infirm and sick individuals which succumb, whereas otters appear to bemore susceptible. The reason for their susceptibility is unclear. They may be vulnerable on account of being a new host, or have a genetic susceptibility, or have suffered massive exposure. Flushable cat litter involves exposing marine animals to faecal waste. The US is also home to some 60 million feral cats, and their faeces can pass through storm drains to rivers, and so to the ocean. Otters living locations where storm drains and streams reach the ocean are more likely to be infected. Otters may also become infected from eating bivalve shellfish, such as clams and oysters. Humans could also be at risk from pathogen pollution.