A bacteria that can sicken dogs, horses, wildlife and people is showing up in sea lions on beaches in Clatsop, Tillamook and Lincoln counties and elsewhere along the Oregon Coast. In addition, a deceased sea lion found near Westport, Washington is being tested for the disease, an indication the problem may extend into waters farther north.
At least eight cases of leptospirosis have been confirmed by Oregon State University’s Diagnostic Laboratory since the outbreak began in late September.
The disease shows up sporadically in marine mammals and was last seen in Oregon in 2010. That was a significant outbreak and coincided with a time of warmer waters and changes in the food supply in California that pushed both healthy and sick sea lions north to Oregon in search of prey, said Julia Burco, a veterinarian with the Oregon Department of Fish and Wildlife.
“So far with this outbreak, it looks like we’re having lower numbers than in 2010,” Burco said, adding that the disease, when it does occur in sea lions, usually peaks in the fall.
OSU also conducts testing of marine mammals found along the south Washington coast and is waiting on lab results for a sea lion from Westport that showed signs of having leptospirosis, according to Washington Department of Fish and Wildlife biologist Dyanna Lambourn. Other sea lions in Washington waters also have been seen that were abnormally skinny and exhibiting lepto-like symptoms, she said. Like Burco, Lambourn said this is the time of year when the disease is most likely to be present.
In Astoria, sea lions congregate on docks at the Port of Astoria’s East Mooring Basin. Marina Manager Janice Burk received a report of a dead sea lion there on Wednesday, but said it isn’t clear why the animal died. She notified fish and wildlife and expects they will run tests on the sea lion to see if leptospirosis was a factor.
Leptospirosis occurs worldwide and can spread when animals come into contact with an infected animal’s urine or bodily fluids. The disease can cause weakness, fever and muscle pain, and lead to kidney failure. Young sea lions, with their lower immune systems, are more susceptible.
The Oregon Department of Fish and Wildlife says the risk of transmission to people is slight, but dogs are more at risk if they approach stranded sea lions on the beach or come into contact with body fluid from sick or dead sea lions.
Sick sea lions may be dehydrated, their eyes sunken in their heads, and will generally appear less lively and alert.
“Pets should be kept away from sea lions as leptospirosis can cause severe disease,” said Emilio DeBess, state public health veterinarian with the Oregon Health Authority, in a statement.
An immunization is available from veterinarians, who urge prompt veterinary care for animals that suddenly loose their appetites and become lethargic after a visit to the beach. The vaccine isn’t totally effective, as there are several strains of the bacteria.
The disease, though it can be fatal, doesn’t seem to devastate sea lion populations, Burco said.
“It’s really something that happens and they move on,” she said. “Their populations can deal with this.”
Federal and state laws protect sea lions. It is illegal to harass, disturb, touch or feed marine mammals. People who discover a sick sea lion or other marine mammals on the beach should stay 50 feet away and report them to the Oregon State Police, which shares these reports with the Oregon Marine Mammal Stranding Network.