Investigating a New Threat to Sea Otter Health

SUMMARY: Researchers will study the emergence of Leptospira infections in the endangered southern sea otter as a step to saving this cherished species.

THE PROBLEM: In California, the southern sea otter is an endangered species that has recovered slowly despite many conservation efforts. This is largely due to the impact of diseases that have reduced their population growth, so understanding causes of disease is a vital way to help sea otter populations. Our team recently confirmed a new infection caused by the bacteria Leptospira that can kill sea otters and is currently causing an alarming outbreak in the core of the southern sea otter range. It is an urgent priority to learn more about this disease and the factors that allow it to infect and kill sea otters.

THE PROJECT: The study aims to describe patterns of infection in space and time and identify factors that lead to otter infections. Working with state wildlife scientists, the team will test 1000 banked tissue samples collected from otters that stranded and died over the last 30 years. Test results will be used to track changes in the fraction of infected otters over time and find "hot spot" areas with high risk of infection. The team will also study factors that may increase risk of infection in otters, including rainfall, coastal runoff, or infections in other marine mammals. Identifying these risk factors will help wildlife managers and conservationists understand how the disease gets passed from other animals to southern sea otters. This information is crucial to develop effective strategies to save this iconic species.

POTENTIAL IMPACT: This knowledge will help guide actions to prevent disease, which is essential to help southern sea otter populations recover. Since this disease also affects people, pets, and a broad range of other animal species, the research will also benefit wildlife conservation and human and domestic animal health.