Wednesday, December 22, 2010

Sea Lion Deaths from Leptospirosis

This year in Oregon has seen a striking increase in California sea lion deaths from leptospirosis, a contagious bacterial disease that causes kidney failure and manifests visibly as emaciation and lethargy.  The animals may also be observed drinking water; a highly unusual behavior for marine mammals which normally obtain all needed water from their food. The coastal population of California sea lions has been increasing overall, making mortality rates tricky to determine. Nevertheless, it is certain that far more animals are testing positive for the disease, warranting significant concern from researchers and beach-goers. 
Infected California Sea Lion

Leptospirosis can be transmitted to humans and other animals via direct contact with the urine. Dogs running free on the beach are especially at risk since the disease can also be spread through contact with contaminated sand, soil or vegetation. As a result, Oregon State University marine biologists are recommending that beach visitors maintain at least a 50 foot distance from any beached animal while keeping dogs on a leash.

"On the LEFT in the phtograph is a NORMAL KIDNEY, while on the RIGHT is KIDNEY FROM A SEA LION WITH SEVERE LEPTOSPIROSIS. In infected sea lions, the Leptospira bacteria often concentrate in the kidneys, initally causing the affected kidney to swell and become pale due in part to tissue damage and inflammation. Without treatment the damaged kidneys may eventually shut down. Thus the sea lion loses its ability to produce urine as a means to excrete body wastes and toxins."

If you see dead or sick marine mammals on Oregon beaches you're encouraged to call the Oregon State Police (1-800-452-7888).

For more information:

Jess Swihart
Natural History Exhibit Education Coordinator

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