A 4-year study of Northern fur seal (Callorhinus ursinus) leptospirosis in the Bering Sea has shown that in newborn pups Leptospira pomona is associated with a multiple hemorrhage syndrome. Adults may develop an interstitial nephritis and shed organisms in the urine. The herd prevalence, based on microscopic slide agglutination tests, ranged between 7.0% and 15.4% for adult females and 3-4 year old bachelor bulls, whereas nursing pups averaging 4 months of age had a prevalence of 2%. These results are used to conclude that leptospirosis is not acquired primarily on the breeding rookeries but rather is more frequently acquired subsequent to the pups leaving the rookeries, presumably through the food chain during their first pelagic cycle.
Naval Biosciences Laboratory, Naval Supply Center, Oakland, California 94625, USA.
Naval Medical Research Unit #2, Jakarta Detachment APO San Francisco 96356, USA.
National Marine Fisheries Service, Marine Mammal Division, Northwest Fisheries Center, Seattle, Washington 98115, USA.
This report was presented at the 7th Annual Conference of the International Association for Aquatic Animal Medicine, April, 1976, Seattle, Washington 98115, USA, and was supported by the Office of Naval Research, U.S. Navy, under a contract between the Office of Naval Research and the Regents of the University of California and the National Marine Fisheries Service, Marine Mammal Division, Northwest Fisheries Center, Seattle, Washington 98115, USA.