Katharina Alpers

Leptospirosis in Germany, 1962–2003

Epidemiologic trends of human leptospirosis in Germany were investigated by analyzing national surveillance data from 1962 to 2003 and by conducting a questionnaire-based survey from 1997 to 2000. After a steady decrease of leptospirosis incidence from 1962 to 1997, surveillance data indicate an increase in disease incidence to 0.06 per 100,000 (1998–2003). Of 102 laboratory-confirmed cases in humans from 1997 to 2000, 30% were related to occupational exposures. Recreational exposures were reported in 30% (including traveling abroad in 16%), whereas residential exposure accounted for 37% of the cases. Direct contact with animals, mostly rats and dogs, was observed in 31% of the cases. We conclude that recent changes in transmission patterns of leptospirosis, partially caused by an expanding rat population and the resurgence of canine leptospirosis, may facilitate the spread of the disease in temperate countries like Germany. Preventive measures should be adapted to the changing epidemiology of leptospirosis.

Large Q fever outbreak due to sheep farming near residential areas, Germany, 2005

In June 2005 Coxiella burnetii-infected sheep, grazing and lambing on a meadow bordering a residential area, caused a large Q fever outbreak (331 cases) in Germany. Our outbreak investigation provided attack rates (AR) by distance between residence and meadow, sex and age groups. The AR of people living within 50 m of the meadow was 11.8%. It decreased the further the residence was from the meadow, falling to 1.3% at 350-400 m distance (RR 8.7, 95% CI 4.5-17.1). The AR was higher in men (RR 1.4, 95% CI 1.1-1.8). In the 25-64 years age group, the AR was 2.3 times higher compared to other age groups (95% CI 1.7-3.0). The distance-related AR showed a relationship between risk of infection and living close to the meadow. Ongoing urbanization will probably lead to further Q fever outbreaks, hence prevention activities undertaken by animal and public health practitioners should be aligned and strengthened.

Changing Epidemiology of Human Brucellosis, Germany, 1962-2005

This endemic occupational disease has become a foodborne and travel-associated zoonosis primarily affecting Turkish immigrants.

Sorbitol-fermenting enterohaemorrhagic Escherichia coli O157:H- causes another outbreak of haemolytic uraemic syndrome in children.

An outbreak of haemolytic uraemic syndrome (HUS) among children caused by infection with sorbitol-fermenting enterohaemorrhagic Escherichia coli O157:H- (SF EHEC O157:H-) occurred in Germany in 2002. This pathogen has caused several outbreaks so far, yet its reservoir and routes of transmission remain unknown. SF EHEC O157:H- is easily missed as most laboratory protocols target the more common sorbitol non-fermenting strains. We performed active case-finding, extensive exploratory interviews and a case-control study. Clinical and environmental samples were screened for SF EHEC O157:H- and the isolates were subtyped by pulsed-field gel electrophoresis. We identified 38 case-patients in 11 federal states. Four case-patients died during the acute phase (case-fatality ratio 11%). The case-control study could not identify a single vehicle or source. Further studies are necessary to identify the pathogens reservoir(s). Stool samples of patients with HUS should be tested with an adequate microbiological set-up to quickly identify SF EHEC O157:H-.

Salmonella Agona Outbreak from Contaminated Aniseed, Germany

A nationwide outbreak of Salmonella Agona caused by aniseed-containing herbal tea occurred from October 2002 through July 2003 among infants in Germany. Consumers should adhere strictly to brewing instructions, although in exceptional cases this precaution may not be protective, particularly when preparing tea for vulnerable age groups.

Characteristics and risk factors for symptomatic Giardia lamblia infections in Germany

BackgroundIn developed countries, giardiasis is considered a travel related disease. However, routine surveillance data from Germany indicate that >50% of infections were acquired indigenously. We studied the epidemiological characteristics of symptomatic Giardia infections acquired in Germany and abroad, and verified the proportion of cases acquired in Germany in order to investigate risk factors for sporadic autochthonous Giardia infections.MethodsWe identified Giardia cases notified by 41 local health authorities between February 2007 and January 2008 and interviewed them on their clinical symptoms, underlying morbidities, travel abroad and potential risk factors for the disease. We conducted a case-control-study including laboratory-confirmed (microscopy or antigen-test) autochthonous Giardia cases with clinical manifestations (diarrhoea, cramps, bloating) and randomly selected controls from the local population registry matched by county of residence and age-group (0-5, 6-19, ≥20 years). Secondary cases, controls with diarrhoea and persons who had travelled outside Germany in the three weeks prior to disease onset (exposure period) were excluded. We calculated adjusted odds ratios (aOR) with 95% confidence intervals (CI) using conditional logistic regression.ResultsOf 273 interviewed cases, 131 (48%) had not travelled abroad during the defined exposure period. Of these 131, 85 (65%) were male, 68 (54%) were living in communities with >100,000 inhabitants and 107 (83%) were aged 20 years or older. We included 120 cases and 240 controls in the case-control study. Cases were more likely to be male (aOR 2.5 CI 1.4-4.4), immunocompromised (aOR 15.3 CI 1.8-127) and daily consumers of green salad (aOR 2.9 CI 1.2-7.2). Contact with animals (pets/farm animals) and exposure to surface water (swimming/water sports) were not associated with symptomatic disease.ConclusionsA substantial proportion of Giardia lamblia cases in Germany are indigenously acquired. Symptomatic cases are significantly more likely to be immunocompromised than control persons from the general population. Physicians should consider Giardia infections among patients with no recent history of travel abroad, particularly if they have immune deficiencies. Green salads may be an important vehicle of infection. Information campaigns highlighting this food-borne risk should emphasise the risk to persons with immune deficiencies.

Survey and case-control study during epidemics of Puumala virus infection.

In Baden-Wuerttemberg, a federal state in south-west Germany, a large outbreak of 1089 laboratory-confirmed human Puumala virus (PUUV) infections occurred in 2007. We conducted a survey to describe the disease burden and a case-control study to identify risk factors for acquiring PUUV. Case-patients were interviewed about clinical outcome and both case-patients and randomly recruited controls were interviewed about exposure. We calculated matched odds ratios (mOR) using a conditional logistic regression model. Multivariable analysis of 191 matched case-control pairs showed that case-patients were more likely than controls to have seen small rodents/their droppings (mOR 1.9, 95% CI 1.2-3.0), cleaned utility rooms (mOR 1.8, 95% CI 1.0-3.4) and visited forest shelters (mOR 3.9, 95% CI 1.1-14.3). Two thirds of case-patients required hospitalization. During PUUV epidemics rodent control measures and use of protective equipment should be considered in utility rooms and shelters.

Underreporting of Human Alveolar Echinococcosis, Germany

Underreporting of Human Alveolar Echinococcosis, Germany

A large outbreak of influenza B-associated benign acute childhood myositis in Germany, 2007/2008.

Background: Benign acute childhood myositis (BACM) is a rare syndrome associated with various viral infections. Bilateral calve pain may lead to inability to walk. During winter 2007/2008, we investigated a nationwide outbreak of influenza-associated BACM (IA-BACM) to identify etiologic (sub)type, describe the course of disease, and explore how well the syndrome is known among physicians. Methods: We performed retrospective and prospective case finding in all German federal states. Physicians returned patient-based questionnaires containing information about sex, age, disease progression, patient-management, and number of BACM cases treated previously. We compared IA-BACM cases with influenza cases from the German virologic sentinel surveillance system for influenza. Results: We investigated 219 children with IA-BACM. They coincided with the curve of influenza B of the German virologic sentinel surveillance system for influenza. Median age was 7 years, 74% (160/216) of cases were male, median time between the onset of fever and onset of BACM-symptoms was 3 days lasting for a median of 4 days. Almost half of the affected children had presented at hospitals. One case with beginning renal impairment occurred, but the patient recovered completely. Most reporting physicians had not seen BACM-patients previously. Multivariable analysis showed IA-BACMs strong association with influenza B, male sex, and age between 6 and 9 years. Conclusions: Influenza B caused a large BACM outbreak in Germany. Onset of BACM symptoms followed shortly after the onset of influenza symptoms. The course of this disease was almost exclusively mild and self-limiting. Diagnosis of this rare but distinct clinical entity by the alert physician can spare the patient potentially unneeded invasive testing and hospital admission.

Outbreak of hepatitis A in two federal states of Germany: bakery products as vehicle of infection

In April 2004, increased numbers of hepatitis A were noted in six neighbouring districts in Germany. Exploratory interviews showed that patients had consumed bakery products from company X where two employees had been diagnosed with hepatitis A in February. A case-control study of consumption of products of company X was carried out through telephone interviews. Altogether, 64 cases were identified. Fifty-two cases and 112 controls aged >or=16 years were included in the case-control study. In total, 46/52 cases and 37/112 controls had consumed company X products [odds ratio (OR) 15.5, 95% confidence interval (CI) 6.1-39.7]. Of these, 36/46 cases and 16/37 controls had consumed pastries (OR 4.7, 95% CI 1.8-12.3), 25/46 cases and 12/37 controls had consumed filled doughnuts (OR 2.5, 95% CI 1.0-6.1). Sequence analysis of the VP1-2A junction region indicated 100% strain homology between cases and an infected employee of company X. We recommended reinforcement of hygiene precautions, and consideration of a prolongation of compulsory work absence after post-exposure vaccination.