When a strain of shiga toxin producing E. coli (VTEC O8:H19) was found in Spanish cucumbers in May 2011 during the Germany-based sprout outbreak that killed 53 – and subsequently proven to not be the outbreak strain – producers and politicians focused on how public health got it wrong, and demands for compensation.

Shouldn’t it have been worrisome that any shiga-toxin producing E. coli was found at retail, in a cucumber?

Researchers in Sweden are now reporting that microsporidia may be an underreported source of foodborne illness after cucumbers were linked to dozens of sick people visiting a hotel in Sweden. Abstract below.

Microsporidia are spore-forming intracellular parasites that infrequently cause disease in immunocompetent persons. This study describes the first report of a foodborne microsporidiosis outbreak which affected persons visiting a hotel in Sweden.

Enterocytozoon bieneusi was identified in stool samples from 7/11 case-patients, all six sequenced samples were genotype C. To confirm that this was not a chance finding, 19 stool samples submitted by healthy persons from a comparable group who did not visit the hotel on that day were tested; all were negative for microsporidia. A retrospective cohort study identified 135 case-patients (attack rate 30%). The median incubation period was 9 days.

Consumption of cheese sandwiches [relative risk (RR) 4·1, 95% confidence interval (CI) 1·4–12·2] and salad (RR 2·1, 95% CI 1·1–4) were associated with illness. Both items contained pre-washed, ready-to-eat cucumber slices.

Microsporidia may be an under-reported cause of gastrointestinal outbreaks; we recommend that microsporidia be explored as potential causative agents in food- and waterborne outbreaks, especially when no other organisms are identified.

Epidemiology and Infection March 2012, 140:519-527

V. Decraene, M. Lebbad, S. Botero-Kleiven, A.-M. Gustavsson and M. Lofdahl