Leptospirosis in Endangered Island Foxes and California Sea Lions: Outbreak Prediction and Prevention in a Changing World

Leptospirosis, the disease caused by pathogenic bacteria of the genus Leptospira, is a major health burden for humans and animals worldwide and a recognized risk for military personnel. Leptospira has circulated for decades in California sea lions (CSL: Zalophus californianus), and an outbreak of a near-identical strain was recently discovered in endangered island foxes (Urocyon littoralis) on Santa Rosa Island (SRI), California. This raised concerns about risks to island fox subspecies on three nearby Department of Defense islands. This project studied the ecology of Leptospira in these two species of concern, and built models to analyze how non-stationary conditions affect disease incidence and impacts. Our objectives were: (1) to identify the source of the current Leptospira outbreak on SRI, (2) to understand the drivers of Leptospira dynamics in CSL and build a model to make short- and long-term predictions, and (3) to study the ecology of Leptospira in island foxes and build a model to project its future impacts on SRI and assess management strategies under changing conditions.