According to a press release from Stanford University, California sea lions develop epilepsy from exposure to a toxin produced by algae called domoic acid. The animals develop seizures which can result in memory loss, tremors, convulsions and even death. The hippocampal region in the brain of the affected sea lions shows similar damage as humans with epilepsy, with losses of about 50 percent of neurons. Dr. Paul Buckmaster, professor of comparative medicine at Stanford was quoted as saying, “We found there was a loss of neurons in specific patterns that closely matched what is found in people. And there is synaptic reorganization — a rewiring of surviving neurons. This also matches what is found in humans with temporal lobe epilepsy.” This form of epilepsy is the most commonly observed in humans and there is currently no cure. It usually starts following a traumatic brain injury, fever or lack of oxygen that causes an initial seizure and later on progresses to epilepsy with periodic seizures.
According to the press release, hundreds of California sea lions have washed ashore every year. The problem is with recent increases in algae blooms small fish that sea lions feed on, such as anchovies, accumulate domoic acid.
The hope is that understanding epilepsy in sea lions may lead to better treatments for sea lions and humans alike. Dr. Buckmaster said, “What we need is an interventional treatment — both in humans and sea lions. You’d give the treatment right after the brain injury, and that would prevent them from developing epilepsy. That’s the dream, but we are not there yet.”