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Avian Influenza Detected at Año Nuevo State Park

A small number of young northern elephant seals at Año Nuevo State Park recently tested positive for H5N1, also known as bird flu. This is the first detection of H5N1 in California’s marine mammal population.

The risk of H5N1 to the public remains very low. We’re sharing guidance on how to protect yourself, your pets and marine mammals – and how you can help.

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California sea lion resting on the pen floor with a young sea lion in the background

Prevalence of Cancer in Stranded California Sea Lions (2005-2015)

Prevalence of urogenital carcinoma in stranded California sea lions (Zalophus californianus) from 2005-2015
  • Cancer

Abstract

Urogenital carcinoma is common in wild California sea lions (Zalophus californianus) along the west coast of the US. From 1979 to 1994, this cancer was observed in 18% (66/370) of necropsied subadult and adult sea lions at The Marine Mammal Center in Sausalito, California. A retrospective review of records from 1 January 2005 to 31 December 2015 was performed to characterize prevalence and characteristics of cancer over this decade. Fourteen percent (263/1917) of necropsied sea lions had cancer, of which 90% (237/263) were urogenital carcinoma. The prevalence of urogenital carcinoma was significantly higher in adults compared to juveniles and subadults. Advanced-stage disease with metastases was identified histologically in 78% (182/232) of cases and was the cause of death in 95% (172/182) of these cases. Metastases were most common in lung and lymph nodes, and hydronephrosis, secondary to ureter obstruction by metastases, was identified in 62% (114/185) of animals with advanced disease. No significant temporal change in prevalence was detected over the decade, and this highly aggressive, fatal cancer remains common in stranded California sea lions. 


Deming, A.C., Colegrove, K.M., Duignan, P.J., Hall, A.J., Wellehan, F.X., Gulland, F.M.D. 2018. Prevalence of urogenital carcinoma in stranded California sea lions (Zalophus californianus) from 2005-2015. Journal of Wildlife Disease (Short Communications). 54(3).

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