Question

A Nevada resident who had just returned home from a cruise on Prince William Sound in July 2007 was struck by gastrointestinal distress so severe that medical intervention was required. Laboratory tests for this patient indicated the presence of Vibrio parahaemolyticus, a pathogenic bacterium known to cause gastroenteritis. In this case, the patient's illness began 3 days after eating raw oysters from Prince William Sound. Further investigation by the epidemiology section of the Alaska Division of Public Health revealed that a total of 54 people had developed watery diarrhea, along with various other gastrointestinal symptoms, beginning within 2 days of consuming raw oysters collected from Alaskan waters. Stool samples provided by eight patients all contained V. parahaemolyticus. However, the discovery of this bacterium was puzzling because V. parahaemolyticus requires a minimum water temperature of 16.5°C to survive, and the waters of Prince William Sound have historically been colder than that. Inspectors from the U.S. Food and Drug Administration (FDA) investigated disinfection and food-handling practices aboard the cruise ship and obtained food and water samples for laboratory testing. They also assessed the oyster farm that had supplied the suspect oysters. When samples of oysters, water, and sediment were retrieved for analysis, two water samples, one sediment sample, and six oyster samples were culture-positive for V. parahaemolyticus. This incident led to the closure of seven oyster farms in Alaska pending further investigation. In addition, as a result of this case, testing for V. parahaemolyticus is now routine throughout Alaska, and many oyster farmers have developed new practices to reduce the chances of contamination.

What is the likely explanation for the contamination of the oysters in this case?

Select one:

a. The oysters were cooked at the optimum temperature for the bacteria.

b. The vector population was dramatically increased.

c. Changing weather patterns altered the currents of Prince William Sound.

d. Warmer waters allowed the bacteria to expand their natural habitat.

Answer 1

Answer:

What is the likely explanation for the contamination of the oysters in this case? Select one:

• a. The oysters were cooked at the optimum temperature for the bacteria.
• b. The vector population was dramatically increased.
• c. Changing weather patterns altered the currents of Prince William Sound.
• d. Warmer waters allowed the bacteria to expand their natural habitat - Correct Option (Warming ocean waters is suspected to have contributed to this outbreak. Based on a research, it was found that in mid-2004, the water in the area was much warmer (~2°C more) as compared to previous six summers, and the mean temperature also remained above 15.0°C for a longer duration as compared to the preceding years.)