SAUSALITO — A rescue center in Marin County says California sea lions are coming down with a potentially fatal bacterial infection in near-record numbers.

The Marine Mammal Center in Sausalito says more than 220 sea lions rescued this year have been diagnosed with leptospirosis.

It's the second-largest outbreak recorded by the rescue center.

The center says outbreaks aren't uncommon but the last major one was in 2011. It involved nearly 200 sea lions.

The bacterial infection affects the kidneys and can be lethal if untreated. The Marine Mammal Center says the strain affecting the sea lions has also been seen in pigs, skunks and foxes. It's transmitted through infected urine, either directly or in contaminated water or soil.

It's unclear how the sea lions contracted the infection.