HPA issues report on May Cryptosporidium outbreak

The U.K. Health Protection Agency confirmed the findings of an investigation on Tuesday into an outbreak of the Cryptosporidium parasite affecting approximately 300 people in Scotland and England in May.

The report found there was strong evidence of an association between the infection and pre-cut bagged salad products labelled as ready-to-eat. The outbreak was short lived and the number of cases returned to typical seasonal levels within a month of the first cases being reported. The infections caused mild to moderate illness and no deaths.

"This outbreak was fortunately short lived but it was important to see if we could find the source," Stephen Morton, the regional director of the HPA's Yorkshire and Humber region, said. "Our findings suggest that eating mixed leaf bagged salad was the most likely cause of illness. It is however often difficult to identify the source of short lived outbreaks of this type as by the time that the outbreak can be investigated, the affected food and much of the microbiological evidence may no longer be available."

The HPA conducted an extensive investigation involving interviews of people who became unwell about their shopping habits and food history. The investigation found significant statistical association between infection and the consumption of pre-cut spinach and pre-cut mixed salad leaves from a major supermarket chain.

"We'd like to remind everyone of our usual advice to wash all fruits and vegetables, including salad, before you eat them, unless they are labelled 'ready-to-eat,'" Alison Gleadle, the director of food safety at the Food Standards Agency, said. "It's also important to wash hands thoroughly as well as clean chopping boards, knives and other utensils between preparing raw and ready-to-eat foods to prevent cross contamination."

The Cryptosporidium parasite causes cryptosporidiosis, a disease that results in mild to severe diarrhea. The parasite is transmitted through the consumption of contaminated food or water, swimming in contaminated water or through contact with contaminated food or affected animals.