In 1999-2000, a prospective case-control study of sporadic, domestically acquired campylobacteriosis was conducted in three counties in Norway to identify preventable risk factors and potentially protective factors. A total of 212 cases and 422 population controls matched by age, sex, and geographic area were enrolled. In conditional logistic regression analysis, the following factors were found to be independently associated with an increased risk of Campylobacter infection: drinking undisinfected water, eating at barbecues, eating poultry bought raw, having occupational exposure to animals, and eating undercooked pork. The following factors were independently related to a decreased risk: eating mutton, eating raw fruits or berries, and swimming. Results indicated that infection is more likely to occur as a result of cross-contamination from raw poultry products than because of poultry consumption per se. Drinking undisinfected water, reported by 53% of cases, was a leading risk factor in this study. Drinking water may constitute the common reservoir linking infection in humans and animals, including poultry and wild birds. Insight into the ecology of Campylobacter in freshwater ecosystems may be required to understand the epidemiology of campylobacteriosis. The possibility that certain foods confer protection against campylobacteriosis deserves exploration.

Our results show that breaks and maintenance work in the water distribution systems caused an increased risk of gastrointestinal illness among water recipients. Better data on the occurrence of low-pressure episodes and improved registration of mains breaks and maintenance work on the water distribution network are needed in order to assess the public health burden of contamination of drinking water within the distribution network.

BackgroundOn October 29th 2009 the health authorities in the city of Trondheim, Norway were alerted about a case of Shiga toxin-positive E. coli (STEC) O145 in a child with bloody diarrhoea attending a day-care centre. Symptomatic children in this day-care centre were sampled, thereby identifying three more cases. This initiated an outbreak investigation.MethodsA case was defined as a child attending the day-care centre, in whom eae- and stx1- but not stx2-positive E. coli O145:H28 was diagnosed from a faecal sample, with multilocus variable number of tandem repeat analysis (MLVA) profile identical to the index isolate. All 61 children, a staff of 14 in the day-care centre, and 74 close contacts submitted faecal samples. Staff and parents were interviewed about cases' exposure to foods and animals. Faecal samples from 31 ewes from a sheep herd to which the children were exposed were analyzed for E. coli O145.ResultsSixteen cases were identified, from which nine presented diarrhoea but not haemolytic uremic syndrome (HUS). The attack rate was 0.26, and varied between age groups (0.13-0.40) and between the three day-care centre departments (0.20-0.50), and was significantly higher amongst the youngest children. Median duration of shedding was 20 days (0-71 days). Children were excluded from the day-care centre during shedding, requiring parents to take compassionate leave, estimated to be a minimum total of 406 days for all cases. Atypical enteropathogenic E. coli (aEPEC) were detected among 14 children other than cases. These isolates were genotypically different from the outbreak strain. Children in the day-care centre were exposed to faecal pollution from a sheep herd, but E. coli O145 was not detected in the sheep.ConclusionsWe report an outbreak of stx1- and eae-positive STEC O145:H28 infection with mild symptoms among children in a day-care centre. Extensive sampling showed occurrence of the outbreak strain as well as other STEC and aEPEC strains in the outbreak population. MLVA-typing of the STEC-isolates strongly indicates a common source of infection. The study describes epidemiological aspects and socioeconomic consequences of a non-O157 STEC outbreak, which are less commonly reported than O157 outbreaks.

Purpose – Investigations of food-borne outbreaks are complex and require multidisciplinary collaboration. The purpose of this paper is to help food technologists face this challenge and be competent members of a multidisciplinary team, a study module on the investigation of a “real-life” food-borne outbreak was developed. Design/methodology/approach – The module design was based on the principles of inquiry-based learning with the purpose to motivate and activate students with challenging assignments. The didactic impact of the module was evaluated as a qualitative case study with questionnaires, reflection assignments and interviews of students and lecturers. Findings – A teaching module developed by an external professional taking part in the academic environment provides a learning environment well adapted to the curriculum, as well as bringing first-hand realism and enthusiasm into the classroom. The external lecturer’s dedication to the subject was appreciated by the students. A majority of the students believed that the outbreak investigation simulation play gave a better understanding of how food-borne outbreaks are investigated. A majority of the students 68 per cent (2011) and 82 per cent (2012) believed that what they learned in this module would be useful in a future work situation. Research limitations/implications – There are some limitations to the study, the most important one being the small sample size, and as the classes rarely exceeds 30 students, the use of a control group was not logistically feasible. Originality/value – Teaching food technologists to become knowledgeable professionals in this field will constitute a valuable contribution to the multidisciplinary food-borne outbreak investigation team. In turn, this may increase confidence among the general public in the food industry.

Aims: To investigate whether a sheep flock was the original reservoir of a Shiga toxinproducing Escherichia coli (STEC) O103 strain causing a clinical human case and to compare the two diagnostic methods automated immunomagnetic separation (AIMS) and AIMS-ELISA. Methods and Results: AIMS detected Escherichia coli O103 in 36AE5% of the samples and AIMS-ELISA detected E. coli O103 in 52AE1% of the samples. Polymerase chain reaction detected stx 1 and eae in three of 109 E. coli O103 isolates. Pulsed field gel electrophoresis showed that the sheep and human STEC O103 were characterized by distinctly different profiles. Conclusions: The sheep flock was shown to carry STEC O103, although an association between the sheep flock and the clinical human case could neither be proven nor eliminated. Substantial agreement was found between AIMS and AIMS-ELISA, but AIMS-ELISA was less time consuming and resulted in a higher recovery of E. coli O103. Significance and Impact of the Study: The study shows that sheep may be carriers of STEC that are associated with human disease and that the methods described can be used to increase the sensitivity of STEC detection.

Most of the outbreaks in the ten-year period were linked to public water distribution systems, while almost half were linked to non-disinfected water supplies to individual households. Although most of the outbreaks were small, two extensive outbreaks were also registered in the period, resulting in more than one thousand cases of illness. This underscores the need for good contingency planning and surveillance, so that suspicion of waterborne outbreaks is rapidly notified to the responsible authorities, and the importance of good protection of water sources, as well as proper maintenance of water treatment plants and distribution systems.

On 21 January 2012, the Norwegian Food Safety Authority was informed about gastrointestinal illness among 111 swimming club members, who were staying at a hotel in Trondheim. A hotel dinner on 20 January was their only common meal. Kitchen staff were interviewed, and food leftovers and kitchen environment were sampled. A case was defined as a swimming team member staying at the hotel from 20 to 22 January, who fell ill with diarrhoea, abdominal pain or nausea during this period. A total of 43 cases were identified, with median duration of symptoms of 35 hours. cpe-positive Clostridium perfringens (3.8 x 108 CFU), but not Bacillus cereus, was isolated from beef stew eaten by cases. cpe-negative C. perfringens was detected in a sample from the kitchen floor. SDS-PAGE showed indistinguishable protein profiles among C. perfringens cultures isolated from the beef stew, but slightly different profiles from the culture isolated from the kitchen floor. Cohort analysis showed that eating beef stew and rice was significantly associated with illness. No pathogens were detected in the rice. The temperature control of the stew, but not of the rice, was poor. Our results strongly indicate that cases were infected by Clostridium perfringens in beef stew that had inadequate temperature control during preparation.

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