Harmful algal blooms occur when certain types of algae grow out of control and release toxic substances that damage fish, shellfish, birds, marine mammals and humans. In California, sea lions are the most commonly affected and the problem, scientists say, is getting worse [PDF].
Many sea lions who survive domoic acid poisoning, a product of some algae, develop severe neurological diseases later. Recently team of researchers from Colorado State University and the Marine Mammal Center in Sausalito, Calif., released a study detailing the effects of domoic acid on the brain.
"We found that, even though some animals may have been exposed to domoic acid for a short period of time, when that exposure was gone they still seemed to get worse and had more of these epileptic-like features," says Ron Tjalkens, a professor of toxicology and neuroscience at CSU. "What we found was that ongoing inflammation in the brain seemed to correlate very closely with the decline in function in these animals."
As of now there are no approved drugs to treat domoic acid poisoning and brain inflammation either in humans or in animals. "So the research into even a naturally occurring event like sea lion poisoning can shed interesting mechanistic light on this [illness]," Tjalkens says. "Because if we can understand what are the molecular signals that turn on this inflammation in the brain, well now you have better targets for therapy."