A PARTICULARLY virulent bacterium is responsible for the food poisoning cases taking place on the Continent. It only takes a few bacteria to cause severe illness and even death, according to a food scientist at the Food Safety Authority of Ireland.
“This bacteria is rarely if ever reported,” said the authority’s Dr Wayne Anderson. “It has a very low infectious dose compared to other bugs. Just 10 bacteria is enough to cause infection.”
The bacterium involved is enterohaemorrhagic E.coli and a strain known as O104, he said. Once ingested, it attaches to the wall of the intestine and begins to produce a powerful toxin. This in turn is taken into the bloodstream to cause damage in particular to the kidneys, he said. Some patients have developed kidney failure and have gone on to kidney dialysis.
Laboratories across the Continent have been using genetic fingerprinting technologies to identify the specific strain driving the outbreak, said Prof Patrick Wall, associate professor of public health at University College Dublin. “We now have the capability to virtually bar code the bacteria,” he said yesterday.
About 1,000 people have sought treatment for severe gastro-intestinal illness, with most cases centred in Germany. Only 329 of these, however, have been tested and confirmed as the outbreak strain, E.coli O104, Prof Wall said. And four of the 10 known deaths have been linked to the organism.
It is related to the O157 strain that can also cause severe illness, but O157 particularly threatens children and frail elderly, he said. The O104 strain is mainly affecting healthy adults – and more women than men, he said.
There are two possible sources for the outbreak, both in Spain. No genetic fingerprinting has been completed to confirm either location as source, said Prof Wall.
Contaminated cucumbers are considered the most likely source, but food safety authorities are also looking at tomatoes and peppers.
Dr Anderson detailed three likely methods for it spreading. These include food-handlers involved in picking or packing the produce; contaminated irrigation water tainted with O104; and land contaminated with the organism through use of animal manures.
Proper cleaning of vegetables reduces the risk of infection, but growing produce can also take up the bacteria, making it impossible to get rid of by washing, he said.