Fish, along with other foods, can become contaminated with bacteria through mishandling. This type of contamination can lead to typical food poisoning symptoms, including vomiting, diarrhoea, muscle aches and headache. These symptoms are the same, regardless of the source of the food poisoning. There are several types of food poisoning, however, that are unique to fish and have distinct symptoms.
Ciguatera Poisoning Symptoms
Humans can experience ciguatera poisoning after eating fish contaminated with ciguatoxin. This toxin is produced by algae common in warm tropical waters and accumulates in fish that feed on algae or in large fish that consume the algae eating fish. The risk to humans is highest when consuming grouper, red snapper and sea bass from waters near Florida and Hawaii during the summer months or during algae blooms called red tides. Cooking does not destroy the toxin. Symptoms appear two to twelve hours after eating a fish that contains the poison. The first signs of ciguatera poisoning include severe diarrhoea, stomach cramps, nauseau and vomiting. These symptoms are followed by headache, low heart rate, hives and itching, reddening of the face and hands and a metallic taste in the mouth. Victims may confuse hot and cold, so a cup of hot coffee seems cold and a cold drink seems hot. The victim may have trouble breathing. Anyone experiencing symptoms of ciguatera poisoning should seek medical attention immediately.
Scombroid Poisoning Symptoms
Scombroid poisoning occurs when humans ingest fish that contain high levels of histamine substances, called scombrotoxin. The toxin is produced by bacteria when the fish is not refrigerated or frozen continuously after its death. The fish may or may not smell spoiled. Cooking does not destroy the toxin. Scombroid poisoning in humans is usually linked to tuna, mahi mahi, albacore and mackerel. Symptoms begin within hours after eating the fish and include a burning sensation around the lips, flushed face and rash, profuse sweating, nauseau, vomiting and headache. Victims also experience headache, heart palpitations and dizziness. The mouth may have a metallic taste. Healthy adults may not require treatment for this type of fish poisoning, as the symptoms do not usually last long.
Puffer Fish Poisoning Symptoms
The organs and skin of the puffer fish or blow fish contain tetrodotoxin, which is more toxic to humans than cyanide. Victims experience numbness around the mouth and difficulty swallowing within minutes of ingesting the toxin. Symptoms progress rapidly to convulsions, tingling in the extremities and paralysis moves upward through the body. The victim goes into respiratory failure generally leading to death. Deaths frequently occur in Asia, where the fish is considered a delicacy. Puffer fish in Florida have also been responsible for poisoning due to saxitoxin. The symptoms of saxitoxin poisoning are similar but also include with muscle weakness, nausea and vomiting.