Ireland is in the midst of one of its largest E. coli O157 outbreaks ever, with hundreds having been infected, according to a food safety expert.

Alan Reilly, former chief executive of the Food Safety Authority of Ireland, told Food Safety News he wants to draw the attention of the public and government to the problem so something will be done about it.

“You have to ask why (the increase) is happening? The natural habitat for E. coli O157 is the gut of cattle and how is it getting from the gut of the cattle into humans? I don’t think you need to be a rocket scientist to come to a conclusion that somehow it is being recycled in the environment and is ending up in the human population,” he said.

“In Ireland, traditionally most cases would be person-to-person contact in crèches (child care centers) and kindergartens essentially associated with hygiene. It would be down to environmental contamination where people would pick it up in the environment and water wells. This spike now in summer is something different.”

HPSC and European stats
The latest figures from the Health Protection Surveillance Centre (HPSC) show there have been 751 cases of illness due to verotoxigenic E. coli (VTEC) since the start of 2018 until mid-August – an increase of 215 from the same period last year. There were 839 VTEC notifications in 2016 with a notification rate of 17.6 cases per 100,000 population compared to 540 cases in 2012.

The European Union report on trends and sources of zoonoses and foodborne outbreaks in 2016 by the European Food Safety Authority and European Centre for Disease Prevention and Control shows confirmed VTEC cases in 2011 in Ireland were 275, 412 in 2012, 564 in 2013, 572 in 2014, 598 in 2015 and 737 in 2016.

The report says from 2012 through 2016, there were six countries that reported significantly increasing trends — Finland, France, Ireland, Malta, Romania and Spain. The highest country‐specific notification rate in 2016 was in Ireland at 15.6 cases per 100,000 population.

For 2010 through 2014, the highest country-specific increases in notification rates were in Ireland with 90 percent and the Netherlands with 188 percent. The ECDC said these rises could be explained by a change in the laboratory methods used for diagnosis as analysis is now able to detect bacteria in asymptomatic carriers.

Role of produce in large European VTEC outbreaks
Reilly, an adjunct professor at the Institute of Food and Health at the University College Dublin, said Ireland has other VTEC strains such as E. coli O26 and O111, but the current outbreak is the O157 strain.

“There are other types of E. coli that seem to be of growing importance after starting off with O157. You saw O104 in Germany in 2011 and there is an outbreak going on in Sweden at the moment,” he said.

“What does seem to be happening is we are getting larger outbreaks in Europe associated with VTEC. We had the example in Finland and an outbreak in the UK, now we have Sweden with around 100 linked cases and Ireland with something in the region of 200. So there does seem to be something happening here with respect to the spread of this bug and it’s not happening through meat.”

Reilly said although initial cases were linked to meat, fresh produce is now a common vehicle of infection.

“The first cases we saw go back to 1982, you had Jack in the Box in 1993 (in the U.S.) and a number of other cases have been associated with burgers. But the case in Japan in 1996 where you had thousands of kids sick to do with radish sprouts, and then fenugreek seeds in Germany,” he said.

“So you are looking at fresh produce playing more of a role in the larger outbreaks. If it is burgers you can fairly quickly tie it down to food premises or outlet and get on top of it, but with this type of an outbreak where you don’t know what the source is it is more difficult to track and trace.

“If you have it in something like lettuce, you are not going to cook the lettuce. Washing will remove surface contamination but there have been reports of E. coli entering the vascular system of leafy greens. Washing is not a 100 percent guarantee but you will probably remove about 90 percent of contamination.

“Europe is seeing larger outbreaks and it is associated with the environmental contamination. There was a big outbreak this year in the United States associated with romaine lettuce from watering the lettuce with canal water that was contaminated. If you put all of that experience together you can say there is something serious happening here and we need to get on top of it.”

More cases or better detection?
There have been no reports of a similar foodborne outbreak in other European countries or recalls from the Irish food safety agency, so the food or foods behind the current outbreak in Ireland have not been identified, said Reilly.

The Health Service Executive warned in July of a sharp rise of E. coli infections in the country with 96 VTEC cases reported over 10 days. Some of the increase could be because the country has effective labs that are detecting it more, said Reilly.

“If you look at the EFSA zoonoses report there is a caveat that says it is not really possible to compare data from country to country because of different testing methods and capacities. You have to be aware you are not comparing like for like, but if you look at the trends over the last number of years, the incidence in Ireland is going up. Is that because we are better at detecting it? In this case where you have people sick and in hospital, that is not better at detecting it, we have the sick people,” he said.

“For VTEC you are looking at anything as low as 10 cells per gram (as an infectious dose), for Salmonella you (need) up around 10⁵ organisms. The virulent strains of EHEC can be nasty … and really virulent cases can give rise to hemolytic uremic syndrome (HUS) that can lead to kidney failure. Thankfully the strain we have in Ireland at the moment is fairly benign if you could call it that. It is not highly virulent so it has not affected people in the same way as in Germany.”

The Health Protection Surveillance Centre report shows salmonellosis cases are down 94 to 186. Campylobacter infection is up 256 to 2,086 cases this year through mid-August.

Reilly said there tend to be peaks for VTEC and Campylobacter infections in the summer months.

“We have Campylobacter in poultry and people have to be a lot more aware that they are buying raw food that may contain pathogenic organisms and they have to handle it accordingly in terms of chopping boards, hygiene around the kitchen and washing hands. We are doing a lot to try and reduce the occurrence of contamination in raw poultry but we are not there yet,” Reilly said.

Collaboration is key
Reilly said there is a One Health program for antimicrobial resistance and there needs to be a similar approach to the whole of agriculture.

“We need to understand that what we do in the environment is going to affect cattle and then humans. Environment, agriculture and human health — those three should be linked very closely together. The policies we have for the environment should be aware of the impact on the agriculture system and the agriculture system must be aware of what happens to food for the consumers. The inter-dependency of those three groupings is key to developing a strategy to reducing this type of outbreak,” he said.

“You need policies when you are spreading slurry (manure mixtures) on the land to ensure you are not spreading harmful pathogens and that you are out there measuring the impact of spreading slurry to see what is happening to VTEC. We know it survives in the environment for some time.

“That type of knowledge means you cannot irrigate fresh produce with contaminated water if you do you are likely to impact on human health. If you were treating this slurry before we put it on the land, you are going to get rid of VTEC and increase the fertilizer value of the slurries. There are solutions to the problem but we are going to have to invest first.

“It is having this awareness and having everybody in the different sectors aware of the impact. It is for the government to put policies in place to bring all those different sectors together and say look, we have a common problem, we cannot work in silos, we have to work together.”

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