Tackle E.coli ‘super-shedding’ cattle and sheep: Pennington
Pennington, who was the author of two seminal reports into serious E.Coli O157 outbreaks in Scotland in 1996 and one in Wales in 2005, which hospitalised many people and caused a number of deaths, has called for a programme of real-time testing of animals on farms across the nation to determine the full extent of the problem.
Super-shedding cattle and sheep
Super-shedding cattle and sheep contain far higher levels of the pathogen E.Coli O157 in their guts than other animals in herds and flocks. This gets spread to land on which they graze through their faeces and leads to cross contamination with other animals and humans.
Pennington said a strategy of dealing with these high-risk cattle and sheep should be implemented. He said this might include a programme of vaccination against the bacterium combined with hygiene controls, similar to that used to prevent the spread of salmonella infection in poultry flocks. “The problem is, who is going to pay for a vaccine?” he asked.
“I would like to see better systems for detecting these animals in real time,” said Pennington. “The technology is there to do that and then you have to decide what you are going to do with the results of better detection. And maybe the best place might be on the farm … you detect the super-shedders, then take them out. That has not been addressed as quickly as I would like.”
Tiny amount of E.Coli O157 causes infection
Giving the Annual Lecture of the Society of Food Hygiene and Technology (SOFHT) in London on Thursday (November 28), Pennington said: “One of the issues that we have with E.Coli O157 is it is very common in cattle and sheep … But the big problem I see is that a very small number of animals will be what we call super-shedders. They will have in their intestines millions per gram of E.Coli O157 … You only need to eat one E.Coli O157 bug to be potentially infected. So a tiny amount is enough to cause an infection.”
Pennington called for action to “sort out these super-shedders” on farms to stop animals spreading the infection before they are sent for slaughter. “Or, if we sorted them out at the abattoir pre-slaughter, we would essentially get rid of the problem in terms of meat contamination,” said Pennington. “It’s quite reasonable and a rapid solution but hasn’t happened yet.”
The Advisory Committee on the Microbiological Safety and Food (ACMSF), which advises the Food Standards Agency, heard the results of a study conducted by the Scottish Agricultural College into super-shedding cattle in Scotland at its meeting in December 2009.
ACMSF chair, Professor Sarah O’Brien, called for better cross-government working on the management of E.coli O157 as transmission was not solely through food.
O’Brien also said more work was also required on the definition of ‘super-shedder’. The cost effectiveness and benefit of interventions should be investigated and in particular more information on vaccine development was required, she added.
UK has highest E.Coli O157 infections
Pennington went on to explain that the UK had the highest proportion of incidents of E.Coli O157 infection in the world, although its concentration in animals varied around the nation, with the highest density in Scotland and in north east Scotland in particular.
He cited the example of where 20 children had become infected with E.Coli O157 after attending a Millennium scout camp in May 2000 on an agricultural show ground at New Deer in Aberdeenshire. The camp site had previously been used to graze sheep, some of which were subsequently found to be super-shedders. Pennington noted that the boys who became ill, were those who hadn’t washed their hands properly before eating.
