lunes, 23 de septiembre de 2013
Emerging pathogens: Vibrio cases in oysters expected to continue increasing
Vibrio doesn’t harm the oysters in any way; it appears to be a symbiotic relationship.
With a nearly 50-percent mortality rate, Vibrio vulnificus is the most deadly foodborne pathogen in the world and instances of infection in the U.S., however rare, are rapidly rising.
Fifteen years ago, there were 21 confirmed cases of Vibrio vulnificus and V. parahaemolitycus infections in the U.S. Last year, there were 193.
While infections from either of the pathogens are still rare compared with, say, Salmonella and Campylobacter, the incidence rate grew faster than any of the other five microbes tracked in the Centers for Disease Control’s 2012 Food Safety Progress Report. The Vibrio vulnificus strain is responsible for 95 percent of seafood-related illness fatalities in the U.S., according to a 2013 study. Another strain, Vibrio parahaemolitycus is milder, causing diarrhea, nausea, fever and chills, according to CDC.
Several studies have linked Vibrio’s quick growth rate with rising ocean temperatures, a critical condition favorable to the saltwater-based bacterium. Instances of Vibrio have started showing up in colder places where they were largely unheard-of before.
Most notably, they’ve been [seeing cases] in places like the Baltic and Germany. While those cases usually involved Vibrio entering humans through wounds while they were swimming, a 2009 article shows that about 93 percent of Vibrio cases in the U.S. manifest themselves in people who have consumed raw or undercooked oysters. Vibrio can also come from other undercooked seafood.
Several post-harvest processing methods exist, which have varying degrees of success at killing Vibrio, but they have several drawbacks. One of these is the largest barriers is cost.