Chile's Other Food-Borne Disease Outbreak

December 27, 2008

While most of the attention is focused on Chile's cheese-related outbreak of Listeria monocytogenes, health investigators are also working to contain another – completely unrelated – outbreak, linked to consumption of raw or undercooked seafood.

In just two weeks, from December 8th to the 21st, Chile's Ministry of Health has received reports of 493 cases of Vibrio parahaemolyticus gastroenteritis – 399 of them in the week of December 15th, alone. Most of the illnesses were clustered in just three regions, Maule (218), Bio Bio (137) and Los Lagos (118).

Vibrio parahaemolyticus is a salt-loving bacterium that grows best in warm ocean waters, such as are found along the coastlines during summer months. The microbe dies off quickly when refrigerated or frozen, and also is killed readily by cooking. It finds its victims among those who enjoy raw or nearly raw shellfish.

Gastroenteritis outbreaks caused by Vibrio parahaemolyticus are an annual summer event Chile, in spite of the Ministry of Health's efforts to educate the public about the hazards of consuming raw shellfish. The pathogen caused nearly 11,000 cases of gastroenteritis in the summer of 2004/05, 3,651 cases in 2005/06, 1,008 in 2006/07 and 3,643 cases in 2007/08.

Fortunately, Vibrio parahaemolyticus infections usually result in a relatively mild gastroenteritis. Of the most recent 493 victims, only two required hospitalization. Symptoms may include diarrhea, abdominal cramps, nausea, vomiting, headache, fever and chills, lasting just a few days.

The pathogen is not unique to Chile. Vibrio parahaemolyticus can be found in warm coastal waters in many parts of the world. It has long been a major cause of gastroenteritis in Japan, where raw and minimally cooked seafood is a dietary mainstay. Coastal regions of the United States also have a history of Vibrio parahaemolyticus outbreaks.

Minimizing the risk of being struck down by Vibrio parahaemolyticus gastroenteritis is simple. All that's needed is to forego raw seafood.