LEPTOSPIROSIS IN CALIFORNIA SEA LIONS (ZALOPHUS-CALIFORNIANUS) STRANDED ALONG THE CENTRAL CALIFORNIA COAST, 1981-1994

Prevalence of leptospirosis was determined in California sea lions (Za lophus californianus) stranded live along the central California (USA) coast between January 1981 and December 1994. Clinical signs of renal disease were seen in 764 (33%) of 2338 animals examined; 545 (71%) of these 764 animals died, with similar gross lesions of nephritis. In s ilver impregnation stains of sections of formalin-fixed kidney, numero us loosely coiled spiral organisms were observed. Leptospira pomona ke nniwicki was cultured from four kidney samples in 1991. Epizootics of leptospirosis occurred in 1984, 1988, 1991, and 1994, and were more co mmon in the autumn, typically affecting juvenile males. In 1991 and 19 94, 47 animals sampled were seronegative, and in 1993 three of 20 anim als sampled had low titers to L. pomona.