Nancy Donley, an avid and educated food safety advocate with STOP Foodborne Illness (previously Safe Tables Our Priority), has often said, and I can only paraphrase here, that if you go back far enough in any E. coli outbreak investigation, you will eventually bump into a cow.
I assume she was referring to O157:H7, but many have taken those words to mean ANY E. coli outbreak. The rationale is that even if the food vector were produce or drinking water, the produce or water probably became contaminated by cow manure containing the E. coli pathogen, a reasonably safe conclusion. The contamination could occur through spreading manure as fertilizer, contaminated irrigation water, pathogens spread by furry animals, etc.
But an interesting report regarding the disaster occurring in Germany was just shared with me by one of the leading E. coli experts in the United States. You can read it yourself here, but I warn you that if your computer does not have the translate function, you will have to read German.
The home page for BfR (Bundesinstitut fur Risikobewertung) says “BfR is responsible in Germany for scientific risk assessments in consumer health protection.” The home page also states they are heavily involved in the search for the source of the E. coli O104:H4 that is causing such devastation in Europe.
As we have heard before, the report cited above says that the current strain is probably a recombinant of two pathogenic E. coli types, and that “(B)ased on the strain analysis of the serotype O104:H4, BfR believes that it is likely that the transfer of the pathogen to the affected food could have been caused in the current outbreak event via humans or from humans via the environment.”
The BfR goes on to explain why in very scientific language, but in a very simplified version I will try and explain what I have digested from the BfR report.
STECs (Shiga toxin-producing E. coli) hosts are generally ruminants, cows being the most frequently mentioned. After a DNA sequence analysis carried out in a strain associated with the current outbreak, it was determined that the serovar EHEC O104:H4 has more commonalities with the enteroaggregative E. coli (EaggEC) than with the conventional Shiga toxin-forming E. coli (STEC).
The current pathogen in the limelight has 93% similarity with an EaggEC which has already been characterized. The reservoir for EaggEC is human, not ruminant, as far as the current knowledge states, but the report does state very clearly that “only a few EHEC O104 strains have been found all over the world.”
This EaggEC pathogen type has not been detected so far in animals. So, maybe in this case we will not “eventually bump into a cow” but will bump into a human–or two.
Just maybe we are now back to looking at the two workers at the sprouting establishment (rumored to now be 3) who were sick from the E. coli O104:H4?