Skip to main content

Whales in San Francisco Bay

Roughly 30 gray whales have been spotted in the Bay this season, many more than is typical. Sadly, there have also been at least 14 deaths this year, which is more than in all of 2024. 

We are investigating to help determine the cause of these deaths. By gaining insights into what is causing these tragedies, we can better understand how to help prevent them.

Learn more
gray whale fluke
northern elephant seal looking up from underwater

Acute Renal Failure and Mortality from Leptospirosis in Rehabilitated Northern Elephant Seals

Isolation of Leptospira from a Phocid: Acute Renal Failure and Mortality from Leptospirosis in Rehabilitated Northern Elephant Seals (Mirounga angustirostris), California, USA
  • Leptospirosis

Abstract

During rehabilitation, acute renal failure due to leptospirosis occurred in eight male northern elephant seals (Mirounga angustirostris) that stranded along the central California coast in 2011. Characteristic histologic lesions including renal tubular degeneration, necrosis, and mineralization, and mild lymphoplasmacytic interstitial nephritis were noted in the six animals examined. Immunohistochemistry, bacterial culture, and PCR were positive in 2/3, 2/3, and 3/4 seals, respectively, and 6/8 had high serum antibody titers to Leptospira interrogans serovar pomona. Pulsed-field gel electrophoresis confirmed one isolate as serovar pomona. Variable number tandem repeat (VNTR) analysis showed both elephant seal isolates were identical to each other but distinct from those isolated from California sea lions (Zalophus californianus). The time from stranding to onset of azotemia was 1 to 38 (median=24) days, suggesting some seals were infected at the rehabilitation facility. Based on temporal and spatial incidence of infection, transmission among elephant seals likely occurred during rehabilitation. Molecular (VNTR) analysis of the two isolates indicates there is a unique L. interrogans serovar pomona genotype in elephant seals, and sea lions were not the source of infection prior to or during rehabilitation. This study confirms the susceptibility of northern elephant seals to leptospirosis, indicates intraspecies transmission during rehabilitation, and reports the first isolation and preliminary characterization of leptospires from elephant seals. 


Delaney, M.A., Colegrove, K.M., Spraker, T.R., Zuerner, R.L., Galloway, R.L., Gulland, F.M.D. 2014. Isolation of Leptospira from a phocid: Acute renal failure and mortality from Leptospirosis in rehabilitated Northern elephant seals (Mirounga angustirostris), California, USA. Journal of Wildlife Diseases, 50(3); 621-627

leptospirosis

Related Publications

Related News