Yes, the German E. coli O104:H4 was a pathogen of a high virulence that suddenly emerged, and that might point to an unnatural phenomenon. But might it have been a deliberate act? Or some kind of accident? To be sure, the 2011 outbreak centered on Northern Germany was large, severe, and deadly. Out of the 2,987 confirmed cases not involving hemolytic uremic syndrome (HUS), 18 died. And out of 855 HUS cases, 35 died. Fenugreek sprouts, probably grown from E. coli contaminated seeds imported from Egypt, were blamed in the official investigations for the unusual E. coli O104 outbreak. However, some researchers still put the 2011 outbreak in a special category. They call it an unusual epidemiological event or UEE. “The sudden and unexplainable emerging of a fast increasing number of cases and deaths from bloody diarrhea and HUS might have been caused naturally, accidentally, or intentionally,” a Serbian-German research team writes in the European Journal of Public Health Advance Access for April 15. Vladan Radosavljevic with Serbia’s University of Defense; Ernst-Jürgen Finke, retired senior scientist and microbiologist from Munich; and Goran Belojevic, with University of Belgrade medical faculty, have reopened the mystery surrounding the 2011 outbreak. They use three models to determine if an infectious disease outbreak is accidental, deliberate or natural. Each model is different, but each involves deciding on criteria or indicators and then scoring them. Not surprisingly, the three models produced varying results. The first model indicates the outbreak “was probably a UEE with features of accidental or intentional epidemics.” In the second model, the researches came up with a score that indicates deliberate release is doubtful. The third model showed the outbreak was “probably a natural one,” but the outcome also “mimicked in some epidemiological and microbiological features accidental or deliberate epidemic events.” They say there are six important clues in Model 3 that are positive for deliberate or accidental outcomes. “From the onset of the outbreak, there was confusion about the source and mode of transmission,” the researchers point out. The European Food Safety Agency (EFSA) accepted fenugreek seeds as the source of the E. coli O104 contamination, but the researchers find it puzzling that there have been no similar outbreaks in Egypt caused by the new E. coli strain found in the German epidemic. They also note that sprouts are not usually a very efficient transmission source for enteric pathogens. The researchers bottom line is that it is not possible to rule out accidental or deliberate acts as the cause for the deadly German outbreak. Work on the project was funded by the Serbian Ministry of Education and Science. (To sign up for a free subscription to Food Safety News, click here.)