Vibrio parahaemolyticus is one of several Vibrio species pathogenic to humans. It is a halophilic, gram-negative rod known to cause an acute diarrheal illness in both children and adults of varying severity. Less commonly, it can cause sepsis, wound infections, bacteremia, ear and eye infections, and urinary tract infections. It is most common during summer months when the water temperature is elevated.

Inoculation with this organism occurs after ingestion of infected seafood or exposure to coastal waters. Ingestion of contaminated raw or undercooked shellfish is the most common route of exposure, with raw oysters causing the bulk of gastrointestinal infections.

The most common presentation of V. parahaemolyticus infection is gastroenteritis, which starts 24-72 hours post-ingestion. Diarrhea is initially explosive in nature, watery, occasionally mucoid or bloody, and can be associated with abdominal pain and severe cramping. Diarrhea may be associated with nausea or vomiting. Fever, chills, and headache may be present in a minority of cases. Normally, the disease is self-limiting; however, immunocompromised hosts, children, and elderly patients may require medical care and parenteral rehydration.

A less common presentation is that of a wound infection with or without associated bacteremia or sepsis. The wound will be associated with a history of exposure to salt water, especially in warm climates. These patients should be treated with appropriate local debridement, supportive care, and antibiotics.