Massachusetts oysters were never associated with Vibrio contamination until last year, when two people fell ill from oysters harvested in waters traditionally believed to be too cold for the bacteria.
An official speaking to the Times attributed the rise of cases to two factors: First, heightened awareness among public health officials might just mean more cases are getting properly diagnosed and reported. Rising ocean and air temperatures, however, were likely factors. Sea-surface temperatures were the highest ever recorded in the region this year, and the region has seen some of the warmest mean air temperatures in recorded history.
Another microbiologist told the Times that there was not enough evidence to assume rising temperatures contributed to recent illnesses.
In 2010, the U.S. Centers for Disease Control released a report finding that while most pathogens associated with foodborne illness had dropped in prevalence since 1996, Vibrio cases had risen by 115 percent.
“Vibrio infections are rare, but often serious, and are caused by eating contaminated seafood or exposing an open wound to seawater,” the report stated. “Continued Vibrio illnesses highlight the lack of implementation of available control measures.”
Vibrio infections are more commonly associated with Gulf coast states, and no national surveillance system for the bacteria until 2007. Between 1988 and 2006, the CDC received reports of roughly 900 Vibrio infections.
Following the two Massachusetts cases from 2011, the officials in the state implemented a Vibrio management plan that requires fishermen to ice or refrigerate their oysters within five hours and keep them out of direct sunlight. Wholesalers have 10 hours to drive the oysters’ internal temperatures to 50 degrees Fahrenheit and maintain that temperature until sale.
This year’s rise in cases — despite the management plan — has driven the state’s health department back to drawing board to reevaluate the plan’s effectiveness. Officials may extend the plan to more fishing communities — it covers nine right now — or limit the time of year oysters can be harvested to the cooler months.
The state health department has inspected 39 wholesale seafood distributors this year to ensure compliance with the management plan, the Times reported.
Symptoms of Vibrio infection may include watery diarrhea, abdominal cramps, fever, nausea and vomiting.
