Debilitating maladies, including daily bouts of nausea, diarrhea, fever and headaches, as well as a profound lethargy that limits victims to an hour or two of activity a day, are ailments associated with ciguatera, a neurotoxin found in large reef fish, reports the New York Times.

There is no laboratory test for ciguatera. Diagnosis is based on symptoms and dietary history. The disease results from naturally occurring toxins in marine algae, which move up the food chain and accumulate in large tropical fish, including grouper, snapper, barracuda and amberjack. The larger the fish, the higher the concentration of toxins can be.

Cooking does not remove the poison.

Ciguatera sickness can pass within a few days or weeks or persist for decades. No cure is known. The most common treatment is intravenous mannitol, and experts say the best results come when the drug is given within 24 hours of infection.