What is the primary cause of disorientation and memory loss after eating raw oysters?

The primary cause of disorientation and memory loss after eating raw oysters is indeed amnesic shellfish poisoning. This condition is specifically linked to the consumption of shellfish that have accumulated toxins produced by a type of algae known as diatoms. When ingested, these toxins can affect the brain and lead to severe neurological symptoms, including disorientation, memory loss, headaches, and in some cases, can be life-threatening.

Amnesic shellfish poisoning is distinct from other foodborne illnesses, as it does not stem from bacteria or viruses, but rather from natural toxins that the mollusks absorb from their environment. While foodborne illnesses generally cause gastrointestinal symptoms and allergic reactions are linked to immune responses, they do not typically result in the neurological effects associated with amnesic shellfish poisoning. Gastroenteritis, on the other hand, refers to inflammation of the stomach and intestines, primarily causing symptoms like vomiting and diarrhea, rather than the cognitive effects observed with amnesic shellfish poisoning.