Background: This report describes a large international chocolate-associated Salmonella outbreak originating from Germany. Methods: We conducted epidemiologic investigations including a case-control study, and food safety investigations. Salmonella (S.) Oranienburg isolates were subtyped by the use of pulsed-field gel electrophoresis (PFGE). Results: From 1 October 2001 through 24 March 2002, an estimated excess of 439 S. Oranienburg notifications was registered in Germany. Simultaneously, an increase in S. Oranienburg infections was noted in other European countries in the Enter-net surveillance network. In a multistate matched case-control study in Germany, daily consumption of chocolate (matched odds ratio [MOR]: 4.8; 95% confidence interval [CI]: 1.3–26.5), having shopped at a large chain of discount grocery stores (MOR: 4.2; CI: 1.2–23.0), and consumption of chocolate purchased there (MOR: 5.0; CI: 1.1–47.0) were associated with illness. Subsequently, two brands from the same company, one exclusively produced for that chain, tested positive for S. Oranienburg. In two other European countries and in Canada chocolate from company A was ascertained that also contained S. Oranienburg. Isolates from humans and from chocolates had indistinguishable PFGE profiles. No source or point of contamination was identified. Epidemiological identification of chocolate as a vehicle of infections required two months, and was facilitated by proxy measures. Conclusions: Despite the use of improved production technologies, the chocolate industry continues to carry a small risk of manufacturing Salmonella-containing products. Particularly in diffuse outbreak-settings, clear associations with surrogates of exposure should suffice to trigger public health action. Networks such as Enter-net have become invaluable for facilitating rapid and appropriate management of international outbreaks.

The number of asylum seekers arriving in Germany has increased rapidly since 2014 and cases of vaccine-preventable diseases at reception centres were reported. Asylum seekers 12 years and older arriving in Lower Saxony were serologically screened for antibodies against measles, rubella and varicella between November 2014 and October 2015. We calculated the seroprevalence from the screening data by disease, country of origin and age group and compared them to literature-based herd immunity thresholds in order to identify immunisation gaps. In total, 23,647 specimens were included in our study. Although the vast majority of asylum seekers tested positive for antibodies against measles, rubella and varicella, the seroprevalences were not sufficient to ensure herd immunity. The seroprevalences varied substantially between countries of origin and increased with age. Immunisation of asylum seekers against measles, rubella and varicella is needed and the detailed information on seroprevalences among subgroups of asylum seekers can be used for targeted immunisations at reception centres.

Between June and August 2014, 45 cases of leptospirosis were notified among workers on two strawberry farms in North‐West Germany. We describe the characteristics of the outbreak and the actions taken to prevent further cases. The activities of the local, federal and national public health and veterinary authorities included collection of case data, laboratory testing of human specimens and of small mammals trapped on the fields, investigation of weather data, as well as information provided to farmers, field workers, physicians and to the authorities in Poland and Romania. Of the 45 identified cases (median age 22, 60% male), 47% were hospitalized. Characteristic symptoms were fever ≥38.5°C, generalized muscle pain and an increase in renal or liver enzymes. Thirteen cases were laboratory confirmed by serological and/or molecular methods. ELISA tests for Leptospira IgG and IgM‐antibodies were positive in those samples taken >5 days after hospitalization. The probable causative agent was identified as Leptospira kirschneri serovar Grippotyphosa. Leptospira‐specific DNA was found in kidneys of 67% of 64 trapped small mammals and was further identified as Leptospira kirschneri multi locus sequence type 110. During the estimated time period of human infections, the affected region faced warm weather with heavy rainfalls. The results of this investigation are in accordance with the theory of a chain of infection from mice to field workers during warm and humid weather. In 2015, a campaign was initiated to inform physicians, farmers and workers to enhance prevention measures, such as the use of personal protective equipment and early consultation of physicians in case of illness. Since then, no further outbreak occurred.

A birth cohort dedicated to studying infections in early childhood may be assisted by parental recording of symptoms on a daily basis and a collection of biomaterials. We aimed at testing the feasibility of this approach for use in a long-term study focusing on infections in children in Germany. Parents of 1- to 3-year-old children (n = 75) were recruited in nursery schools. They were asked to complete a symptom diary on a daily basis and to take monthly and symptom-triggered nasal swabs and stool samples from their child over the study period of three months. Feasibility was measured by means of the return proportions of symptom diaries and bio samples; acceptance was assessed by a questionnaire delivered to participants at the end of the study. The majority of the participants filled in the symptom diary during the three months study for 75 or more days (77.3 %), and provided the monthly nasal swabs (62.7 %) and stool samples (65.3 %). The time needed for the tasks was acceptable for most participants (symptom diary: 92.3 %, nasal swabs: 98.5 %, stool samples: 100.0 %). In 64.3 % of the symptom-triggered nasal swabs, respiratory viruses were found compared to 55.5 % in throat swabs taken by health-care professionals within the “ARE surveillance Lower Saxony”, a special project by the Governmental Institute of Public Health of Lower Saxony to investigate causal pathogens for acute respiratory infections in children. The parental assessment of symptoms and collection of biomaterials in a birth cohort dedicated to studying infections appears feasible in a middle class German population. The success of the study will depend on the ability to maintain these activities over a long time period.

In 2001, two residents of a nursing home in Lower Saxony, Germany, were diagnosed with acute hepatitis B virus (HBV) infection. A systematic contact investigation of 188 residents yielded 19 confirmed or probable cases of acute or recent HBV infection and three persistent asymptomatic HBsAg carriers. Sequence analysis revealed that one carrier had high viraemia (10⁹ genomes/ml), HBV genotype A2, and the same S gene and/or X gene sequence as 16 acutely infected persons. An unmatched case-control study was conducted with the 17 cases that had sequence identity together with 26 controls. The strongest association was found for treatment by a particular general practitioner (GP) (OR>11, P<0·001) and blood sampling for glucose monitoring on a particular day by the GP's staff (OR 13·6, P<0·001, adjusted OR 8·5, P=0·017). Control measures were implemented. Serological controls after 6 and 18 months revealed that the outbreak was brought under control.