Yersinia pseudotuberculosis infection in four free-ranging odontocetes

Yersinia pseudotuberculosis is a zoonotic pathogen that has been recovered from a variety of companion, production, laboratory, wildlife and avian species. The prevalence of this bacterium varies geographically but is generally considered widespread within the terrestrial environment with human exposure principally by ingestion of contaminated food or water. Pseudotuberculosis, due to Y. pseudotuberculosis, is a common cause of mortality in captive exotic birds and mammals and, according to the OIE WAHIS-Wild Interface, is the 8th most frequently reported disease/infection for all wildlife worldwide and the 5th in wild mammals. This report increases the number of recognized species susceptible to pseudotuberculosis and expands the environmental distribution of this bacterium into the marine habitat with four Y. pseudotuberculosis culture-positive cases in three odontocete species, including three from the North Sea and one from the northeastern Pacific Ocean. This case series is the first to report pseudotuberculosis in mammals that reside exclusively in the marine habitat. At present, there is insufficient information on the natural history of Y. pseudotuberculosis and marine mammal infections to infer whether exposure was due to terrestrial contamination of water courses or, alternatively, the bacterium persisting within the marine environment.