Alzheimer’s is a form of age-related dementia that affects about 35 million people worldwide and is characterised by a build-up of amyloid plaques – sticky clusters of proteins that disrupt biological processes – in the brain.
The disease is specifically human, but similar conditions have been identified among wild animals, including whales and dolphins, which are long-lived, like ourselves. There is evidence that declines in cognitive function and navigational abilities associated with amyloid plaques can contribute to cetacean strandings.
Some scientists think that the plaques form in response to poisoning by algal blooms at sea, which are known to be increasing in frequency.