Abstract

During 2010, two epizootics involving diarrhea occurred among California sea lions at the Navy Marine Mammal Program. The first epizootic involved four sea lion pups from Northern California; illness was associated with Salmonella enterica, serovar Newport and a novel strain of Campylobacter jejuni. The quarantine focused on containing Salmonella among affected pups, since this pathogen is not endemic in Navy animals. Clinical and subclinical states of actively shed Salmonella were identified among all pups, and shedding was resolved using strict isolation and antibiotic therapy. One pup was isolated and treated with cefpodoxime at 8 mg/kg PO BID for 17 days and cleared the Salmonella infection. The other three pups were treated with cefpodoxime at the same dose but were housed together for behavioral reasons and did not clear Salmonella infection. Shedding was resolved once strict isolation was instituted in combination with trimethoprim sulfamethoxazole at 25 mg/kg for 28 days. One person interacting with the case animals acquired a Campylobacter infection. Centers for Disease Control and Prevention (CDC) confirmed that the person was infected with a novel C. jejuni isolate indistinguishable from the sea lion isolate. A second epizootic involving diarrhea, with or without laryngeal vesicles, likely affected sea lions, bottlenose dolphins (Tursiops truncatus), animal handlers, and dogs of animal handlers; based upon preliminary diagnostics, potential etiologies of this event include Clostridium, Campylobacter, a novel norovirus, California sea lion astrovirus 2, and a novel picobirnavirus. San Miguel sea lion virus was not found. At the request of the Navy, CDC and local public health officials led the investigation of human illnesses.

Acknowledgements

The authors thank Ms. Risa Daniels, the training staff, and management at the U.S. Navy Marine Mammal Program for their support.