Three species of dolphins that were stranded off the Scotland coast showed indicators of Alzheimer's disease, according to a new study.
Researchers from the universities of Glasgow, St. Andrews, and Edinburgh, and the Moredun Research Institute conducted postmortem studies on 22 odontocetes, which include toothed whales like dolphins and porpoises. Eighteen of the animals are aged specimens.
Three aged specimens—a long-finned pilot whale, a white-beaked dolphin, a bottlenose dolphin—had brain changes or lesions associated with Alzheimer's disease.
Alzheimer's, the most common type of dementia, usually affects people over age 65, with symptoms including memory loss, forgetfulness, confusion, and dramatic mood swings.
While types of brain disorders have been detected in some animals, Alzheimer's in particular was believed to be unique in humans, until the recent discovery published in the peer-reviewed European Journal of Neuroscience on Dec. 13.
Researchers also think that the findings could be the answer to the unexplained phenomenon on why some dolphins and whales get stranded in the coast.
The findings could also support the "sick leader" theory in which a group follows its aged leader to shallow waters, researchers said. Groups of odontocetes get usually stranded on British coasts.
Lead researcher Mark Dagleish, however, said despite their "significant findings," they need to conduct more research to better understand what's happening to the animals.
Dagleish pointed out that it's impossible to confirm whether the brain lesions they found indicate that the animals had been suffering the same cognitive deficits associated with human Alzheimer's. A diagnosis, he said, can only be made while they're alive.
"If these are the only animals that spontaneously develop these lesions, further study may give us some sort of help and insight into what happens in the very early stages of the development of these lesions," Dagleish said. "If we can determine the likely triggers of this, can we work out ways to treat or prevent it?”
"Whether these pathological changes contribute to these animals’ stranding is an interesting and important question for future work," co-researcher Tara Spires-Jones added.