Large multistate outbreak of norovirus gastroenteritis associated with frozen strawberries, Germany, 2012

Abstract

, the largest recorded food-borne outbreak in Germany occurred. Norovirus was identified as the causative agent. We conducted four analytical epidemiological studies, two case-control studies and two surveys (in total 150 cases) in secondary schools in three different federal states. Overall, 390 institutions in five federal states reported nearly 11,000 cases of gastroenteritis. They were predominantly schools and childcare facilities and were supplied almost exclusively by one large catering company. The analytical epidemiological studies consistently identified dishes containing strawberries as the most likely vehicle, with estimated odds ratios ranging from 2.6 to 45.4. The dishes had been prepared in different regional kitchens of the catering company and were served in the schools two days before the peaks of the respective outbreaks. All affected institutions had received strawberries of one lot, imported frozen from China. The outbreak vehicle was identified within a week, which led to a timely recall and prevented more than half of the lot from reaching the consumer. This outbreak exemplifies the risk of large outbreaks in the era of global food trade. It underlines the importance of timely surveillance and epidemiological outbreak investigations for food safety.

Reducing the barriers against analytical epidemiological studies in investigations of local foodborne disease outbreaks in Germany – a starter kit for local health authorities

“…The software tool has already proven useful in a large norovirus outbreak linked to contaminated frozen strawberries [10], for which studies were completed, including analysis, within one day. In addition to FBDO, the tool can be used for the investigation of other outbreaks, e.g.…”

“…In such cases, information on the outbreaks is often not transmitted from the local level via the state health department to the RKI. The fact that a causative agent has not (yet) be identified in a FBDO should not hinder the use of the tool; clinical case definitions may be perfectly adequate alternatives to microbiological confirmation [10,11]. Epidemiologically identifying a suspected vehicle enables better targeted searches for the causative agent in food samples.…”

“…In addition, it may allow estimating the incubation period, which may provide crucial hints at the aetiological agent, thereby informing microbiologic investigation of human cases. Again, the norovirus outbreak linked to frozen strawberries is an excellent example [10].…”

Inactivation of Foodborne Pathogens and Their Surrogates on Fresh and Frozen Strawberries Using Gaseous Ozone

“…During the same period, a total of 20 foodborne outbreaks reported in the United States were traced back to berries (CCDC, 2013). The largest frozen strawberries outbreak happened in Germany in 2012, which resulted in 10,950 illnesses, exemplifying the risk of large outbreaks in the era of global food trade (Bernard et al, 2014). These outbreaks related with frozen berries reveal not only the influences of these products on public health and economic loss, also highlight out the urgent need to identify effective prevention measures that can be used to increase the safety of frozen berries.…”

Interactions between Human Norovirus Surrogates and Acanthamoeba spp

“…In these instances the source of contamination could be environmental. Another more recent outbreak from 2012 related to frozen strawberries imported by Germany from China caused more than 11,000 cases of acute gastroenteritis in German school children (17). Based on various aspects of fresh produce productionexposure to environmental factors such as soil, compost, and water combined with minimal processing-HuNoVs could be introduced into the supply chain through a variety of routes.…”