INFECTIOUS GASTROENTERITIS FROM FOOD POISONING

1. Staphylococcal. Severe scenario of vomiting, cramps and diarrhea caused by staphylococcal enteretoxin found in contaminated food. It happens in outbreaks when people with skin infections (furuncles, etc.) handle food and contaminate it, and after doing so, leave the food at ambient temperature. The most common foods are custard, custard pies, milk, treated meat and fish. The incubation period (without symptoms) ranges from 2 to 8 hours after the ingestion of the food with enterotoxin. The disorder is brief, with a recovery time of 3-6 hours. In very young children, the elderly or the chronically ill, the disorder can be more serious due to the unbalance of liquids and salts. Intravenous compensation of liquids will produce a spectacular improvement.

2. From Clostridium perfringens. Severe scenario of vomiting and diarrhea caused by the ingestion of food contaminated by the enterotoxin from the microbe Clostridium perfringens. Contaminated meat has caused many outbreaks. The cases are usually mild. Treatment includes liquids compensation, and in serious cases, penicillin.

3. Traveler’s diarrhea. This term is used for sporadic cases of infectious gastroenteritis that affects travelers and tourists. The most frequent cause is the development (away from home, in contact with other water and food) of an aggressive strain of the Escherichia coli bacteria, normally located in the intestine. It can also be caused by an intestine virus (for example, the so called Norwalk agent). The scenario presents nausea and vomiting, cramps and diarrhea. The disorder is usually brief and mild. Treatment includes liquids and salts compensation; antibiotics are not advised. The safest prevention of Traveler’s diarrhea is to be cautious with food and beverages, leaning towards a diet of well cooked or canned food.

4. Salmonellosis. There are 2.200 serotypes of these bacteria. The majority of strains produce gastroenteritis from food ingestion origin. Usual Salmonella sources are eggs and their derivative products, unboiled milk and fowl. Symptoms appear from 12 to 48 hours after ingestion, with nausea, cramps and liquid diarrhea. Usually, the disorder is mild and stays for 1 to 4 days. Treatment includes liquids and salts compensation; antibiotics are not advised because they prolong the microbes excretion. Typhoid Fever is a much more serious type of salmonellosis with treatment and prognosis different to those from common Salmonella gastroenteritis.

POISONING FROM MUSHROOMS

The possibility of mushrooms intoxication is unpredictable and can vary even within the same species, in different times of their seasonal growth and in the way they’re cooked. The most frequent scenarios are the following:

Muscarinic Intoxication. It can be caused by Amanita muscaria, and to several Inocybe species. Symptoms appear within a few minutes and 2 hours after ingestion. These can be watery eyes, increased salivation, sweat, small pupils, cramps, diarrhea, vomiting, vertigo, confusion and coma. Death can result in a few hours, but complete recovery after the adequate treatment can happen in 24 hours.

Phalloidin Intoxication. Caused by Amanita phalloides and akin species. Intoxication appears within 6 and 24 hours after ingestion and digestive symptoms are similar to the above mentioned, but they ultimately affect the kidneys (urination is made impossible) and the liver (jaundice, or yellow tint). Frequently, death can happen in 5 to 8 days.
Obviously, the easiest way to prevent mushrooms intoxication is to avoid ingestion of all those mushrooms that are not perfectly identified as edible.

INTOXICATIONS FROM FISH

1. Allergy. Some people, especially children with atopy (family or personal predisposition to allergy) can develop symptoms of itching, rashes, nausea, vomiting, diarrhea and/or difficulty in breathing, after eating fish (tolerated by their family). This may be caused by allergy to the fish protein, which usually is resistant to heat and digestion. People allergic to fish usually develop asthma (difficulty in breathing, cough, wheezing) after inhaling the smoke from fried fish.

2. Scombroidosis or histamine intoxication. It is the most frequent intoxication from fish in the world. It is produced by bacteria decomposition after the fish is caught, which produces high concentrations of histamine (from the histidine aminoacid degradation) in the fish. The most common cause is the failure to refrigerate the fish at an early time. Histamine usually produces an immediate reaction, identical to the allergic reaction, with redness in the face, conjunctival injection, itching, rashes, nausea, vomiting, diarrhea and/or difficulty in breathing. There is usually a spontaneous recovery in less than 24 hours. Scombroidosis can be produced by scombroid fish (mackerel or scomber, tuna, striped tuna or albacore), or non scombroid fish, like sword fish. This histamine intoxication is usually mistaken as an allergic reaction.

3. Ciguatera. Ciguatera poisoning can be produced after the ingestion of any of the more than 400 species of fish found in tropical coral reefs, and happens frequently in Florida, India and the Pacific Ocean, where a plankton micro organism (a dinoflagellate) produces ciguatoxin, which is ingested and deposited in the sea creature. Bigger and older fish are more toxic.
The taste of fish remains unaltered and no freezing or cooking method is known that can prevent poisoning. Symptoms appear from one to several hours after ingestion. The characteristic scenario lasts around 8 days, and it includes:

Cramps, diarrhea, nausea and vomiting.
Headaches, muscle and joints pains.
Generalized itching.
Sensitive phenomena: Inversion of heat and cold feelings, face pain, feeling of losing teeth, burning or tingling feelings in extremities, etc. They can be felt repeatedly for months after the poisoning.

4. Anisakiasis or anisakidosis. Acute infestation of the digestive tract by the Anisakis Simplex nematode, which larvae are present in great amount in fish (up to 80% of fish from some fisheries). It happens more frequently in countries where fish is eaten raw (sushi or sashimi in Japan, smoked or marinated fish, etc.), and cooking and freezing are the preventive measures.

However, a small number of patients show allergy to the Anisakis antigens, and can suffer of symptoms similar to those of allergy to fish, after ingesting dead or alive Anisakis, apparently without the need of a previous infestation. Allergy to Anisakis cannot be avoided by cooking or freezing, since antigens are resistant to them

SEAFOOD INTOXICATIONS (CRUSTACEANS AND MOLLUSKS)

1. Allergy. Some persons afflicted with atopy (family and/or personal predisposition to allergy) can develop symptoms of itching, rashes, nausea and vomiting, diarrhea and/or difficulty in breathing after the ingestion or crustaceans and/or mollusks (tolerated by others). This may be due to allergy to the animal proteins (tropomyosin in the case of crustaceans), which are usually resistant to heat and digestion. People allergic to seafood also usually develop asthma (difficulty in breathing, cough, wheezing) after inhaling smoke from cooking or grilling seafood.

2. Gastroenteritis from infected seafood is, by far, the most common seafood poisoning, after ingesting mussels, clams, oysters, cockles, scallops or crustaceans, infected with Salmonella typhi, enterotoxic and invasive Escherichia coli, Norwalk virus, or different species of vibrio bacteria (Vibrio cholerae, V. parahaemolyticus, V. vulnificus). The vibrio bacteria affect mainly oysters and crustaceans. Appropriate refrigeration and cooking largely prevent these intoxications. The Hepatitis virus can be transmitted in clams; outbreaks have been linked to the ingestion of steamed clams, a mild cooking method not strong enough to inactivate the virus.

3. Paralytic Intoxication from sea mollusks. A very serious intoxication that occurs in summer outbreaks at some seashores (mainly the Pacific coast and the USA East coast), when mussels, clams, oysters and scallops ingest a toxic dinoflagellate (“red tide”) that produces a neurotoxin (saxitoxin) that is resistant to cooking. Symptoms appear from 5 to 30 minutes after ingestion: tingling sensation around the mouth, followed by nausea and vomiting, abdominal spasms, muscular weakness and paralysis. The diaphragm paralysis can cause death when breathing is made impossible.

4. Chemical Intoxications from contaminants. All the toxic chemicals (heavy elements like mercury, cadmium, arsenic, plumb, inorganic insecticides, etc.) that mollusks and crustaceans ingest are concentrated in their flesh. This would affect in a selective way the shellfish caught in highly polluted zones, but in any case, the amount of flesh needed to be ingested to provoke intoxication symptoms, would have to be considerable.