California sea lions are dying – now scientists know why

Several sea lions have been found dead and dying along the California coast, with scientists suspecting a bacterial infection.

A dozen dead sea lions were found in Bodega Bay, and 10 more in the city of Fort Bragg. More than 70 sick sea lions were taken to the Marine Mammal Center. Samples from sick lions and dead sea lions showed that the mammals were suffering from leptospirosis.

Bodega Bay resident Megan Robbins told a local newspaper I Press Democrat that the sea usually only gets three dead sea lions a year, but this week alone he saw five. “It’s crazy,” he said. “I’ve never seen anything like it.”

Leptospirosis, a disease caused by the bacteria leptospira and spread through urine and other body fluids, can lead to kidney damage, according to the US Centers for Disease Control and Prevention.

The sick sea lions taken in by the Marine Mammal Center were underweight and had stomach ulcers. They behaved victoriously, and many had their wings on their bodies.

“It’s because they’re in a lot of pain,” said Giancarlo Rulli, a spokesman for the Marine Mammal Center, according to San Francisco news site SFGate.. “When they come ashore like this, it’s a bad sign.”

“Leptospirosis is a bacterial disease that attacks the kidneys and leads to loss of function and eventually death,” Elliott Hazen, an ecologist at the National Oceanic and Atmospheric Administration’s Southwest Fisheries Science Center, said earlier. Newsweek. “Leptospirosis can definitely lead to death from kidney failure.”

The disease can spread between closely related animals, such as the migration of lions to the sea, where they come together to mate, give birth and rest.

“These sea lions feed communally in the ocean but return to land frequently, especially young children and females,” Hazen said. “Whether it’s in colonies or relaxed beaches, they’re often overcrowded and that can lead to higher chances of disease spreading.”

Most of the dead sea lions were too decomposed to test for leptospirosis, but the number of patients with the disease indicated that the dead could die from the condition.

“What we’re seeing are carcasses washing up in the oceans near the sea lion migration,” Sue Pemberton, assistant curator of the California Academy of Sciences, told SFGate. “They would live on a soft rocky shore, and when they died there, a big current would wash them away.”

Leptospirosis can be transmitted to humans if they come into contact with the body fluids of an infected animal, but this is very rare.

“The theory is, yes, it can spread to humans, as they will shed the spirochetes in their urine,” Chris McKnight, a biologist at the University of St Andrews’ Sea Mammal Research Unit, said earlier. Newsweek. “But the chances of a human being exposed to this are very small compared to the urine of other land mammals in North America, as almost all animals are susceptible to lepto.”

He went on to say: “It has turned from sea lions to people three times, I believe, before, all those who were researchers working on sea lions and all developed kidney failure, if my memory serves me correctly. But, as I said, the chances of this being any direct issue to people in the area [are] it’s not too small for anyone.”

Dogs can be at greater risk of contracting the disease if they come close to a sick or dead sea lion or enter an area where sea lions may urinate.

“The most important thing we emphasize is to make sure your dog is on a leash and that both you and your pet maintain a safe distance of about 50 yards,” Rulli said. Vaccination against the disease is available for dogs.

This current outbreak of leptospirosis may last a few months, according to Pemberton, similar to the length of previous outbreaks. The most recent outbreak occurred in 2018, when 300 sea lions were monitored by the Marine Mammal Center.

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