Nov. 2, 2017 — A California sea lion was found dead on Heceta Beach in early November, with a probable cause of death being leptospirosis.
“I have some results, but not a full set of results,” said Jim Rice, Stranding Coordinator for the Oregon Marine Mammal Stranding Network. “For leptospirosis to be definitive, I need more testing to be done. I’m relatively certain that the animal did succumb to leptospirosis, as all the other signs indicate that it did. I’m missing a piece where I would declare that it was absolutely what it died from.”
Leptospirosis is a bacterium that can lead to kidney failure, fever, weakness and muscle pain in sea lions. It is spread primarily through urine or other body fluids.
The sea lion came ashore on Nov. 9, dying that day. It was discovered the next day by a local resident, who contacted Rice for removal.
The sea lion was a California breed, which is different from the Stellar sea lions that populate Sea Lion Caves.
California Sea Lions are prevalent up and down the coast, and while the Stellar and California populations sometimes overlap, the two breeds generally stay within their own groups.
No Stellar sea lions have been reported with the disease.
“There are a lot of California sea lions that have succumbed to it in the region,” Rice said. “I don’t think it’s necessarily a concern that the Stellar sea lions are going to suddenly get sick with it. It’s been in the California sea lion population for decades. It’s nothing new. It’s just a recurring disease process that happens every few years.”
The general window for the outbreaks is between September and December, and Rice has seen a decline in reported cases in the past two weeks.
“We haven’t had nearly as many reports than we have had in the previous eight to 10 weeks,” Rice said. “Part of that might be the weather is getting rainier on the beaches, and there may be animals that aren’t being reported because people aren’t seeing them.
“But I also suspect that as time goes on, this disease process does run its course. And those animals that have become ill will pass. And those that are able to fight it off will most likely be able to make it through the season.”
For those concerned about the disease spreading to pets, Rice encouraged vaccinations.
“I’ve talked to my own veterinarian about it and others, and they support vaccinations for dogs,” he said. “I’ve had my own dog vaccinated. I think it’s a good idea in general.”
But the best way to prevent the spread of leptospirosis to pets is to just stay away from the sea lions all together.
“If you see a sea lion on the beach, just use common sense,” Rice said. “Just keep your dog on a leash and away from the lions. These animals can spread other diseases as well. Leptospirosis is just one thing that they potentially have, just like all wildlife. You wouldn’t want your dog playing with a raccoon.”
The disease is spread through direct contact of urine or other bodily fluids.
“Unless a dog gets up close to an alive, dead or affected sea lion and ingests some of its urine, it’s not likely to get infected,” Rice said.
Not only is it safer to stay away from the sea lions to prevent disease, Rice believed, it’s better for the sea lions as well.
“When you see a sea lion on the beach, if it’s alive, it’s often there because it wants to get out of the water and get some rest,” Rice said. “Its body is telling it to take some time away from the water. And we need to respect that. We need to give them a chance to recover their strength when they get on shore. And if people are constantly coming up to them and approaching them, it’s just going to stress them out and make their job just that more difficult.”
Anyone who observes a sick sea lion should stay at least 50 feet away from the animal and call Oregon State police dispatchers at 1-800-452-7888.