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Wilderness: Shellfish Poisoning, Gastrointestinal

Shellfish Poisoning Overview

Shellfish poisoning is caused by eating shellfish contaminated with bacteria or, more commonly, viruses. Contaminated shellfish include shrimp, crabs, clams, oysters, dried fish, and salted raw fish. Contaminated fish may have a tainted odor or taste.

Shellfish Poisoning Symptoms

Symptoms of shellfish poisoning begin 4-48 hours after eating and include nausea, vomiting, diarrhea, abdominal pain, and cramps.
A person who has blood in the stool and a fever may have a bacterial infection (from Vibrio parahaemolyticus bacteria).

Shellfish Poisoning Treatment

Vomiting should be induced if the person is awake and alert and has eaten the shellfish or fish within the last 3 hours.
The person should stay well-hydrated.
- The person should be encouraged to drink frequent sips of clear fluids.
- IV fluids may be necessary if nausea and vomiting cannot be controlled.
No specific cure is available.
Antibiotics do not shorten the illness caused by Vibrio bacteria.
Drugs used to control diarrhea, vomiting, and stomach cramps should not be used except for bismuth (Pepto-Bismol). These drugs are referred to as antimotility drugs since they decrease stomach and intestine motion. Antimotility drugs other than bismuth preparations can worsen or lengthen the illness because the infectious agent is not expelled from the body as rapidly.

When to Seek Medical Care

Seek medical treatment as soon as possible.
Seek medical treatment immediately if the person is unable to tolerate oral fluids, if fever is present, or if other concerning symptoms develop.