Stefan O. Brockmann

Pathogens and symbionts in ticks: prevalence of Anaplasma phagocytophilum (Ehrlichia sp.), Wolbachia sp., Rickettsia sp., and Babesia sp. in Southern Germany

Tick-transmitted diseases like tick-borne encephalitis and Lyme borreliosis have been well known in Germany for decades. Ongoing research now gives an additional focus to a broad range of other bacteria and parasites in ticks like Anaplasma phagocytophilum, former Ehrlichia sp., Rickettsia sp. and Babesia sp. Knowledge about the prevalence of these infectious agents in ticks is an important prerequisite for risk assessment of human diseases. Therefore nymphs and adult Ixodes ricinus ticks were collected and examined for Anaplasma phagocytophilum (n = 5424 ticks), Rickettsia sp. (n = 1187), and Babesia sp. (n = 3113). For the detection of Anaplasma phagocytophilum, DNA from the 16S rDNA gene was amplified by nested PCR and hybridized with a DIG-labeled oligonucleotide probe. The examination of Rickettsia sp. was performed by single PCR. A partial sequence of the citrate synthase gene was amplified. As a target for the detection of Babesia sp., DNA from the 18S rDNA gene was amplified, also by single PCR. All positive PCR products were sequenced to control specificity. Anaplasma phagocytophilum was detected by PCR in n = 103 (1.9%) out of 5,424 examined ticks from 11 investigation areas. However, not all positive PCR products hybridized using DIG-labeled oligonucleotide probe. Thus, the result of sequencing indicated that only 1.0% (n = 54) belonged to Anaplasma phagocytophilum and nearly half of these PCR products (0.9%) were identified as Wolbachia sp. Rickettsia sp. in Ixodes ricinus ticks from 3 areas were found in n = 105 (8.9%) out of 1,187 ticks examined (range from 13.3% to 5.6%). Sequencing showed Rickettsia helvetica exclusively. In about 2.6% of Rickettsia-positive ticks, double infection with Anaplasma phagocytophilum was found. Babesia sp. was detected in n= 31 (1.0%) out of 3,113 ticks examined, which originated from 4 different areas. By sequencing, n = 28 (90.0%) were identified as Babesia divergens. Three of all Babesia-positive ticks were identified as harboring Babesia microti. The detection of Anaplasma phagocytophilum, Rickettsia sp. and Babesia sp. demonstrates their possible role as a source of human infection in Germany.

Overweight, physical activity, tobacco and alcohol consumption in a cross-sectional random sample of German adults

BackgroundThere is a current paucity of data on the health behaviour of non-selected populations in Central Europe. Data on health behaviour were collected as part of the EMIL study which investigated the prevalence of infection with Echinococcus multilocularis and other medical conditions in an urban German population.MethodsParticipating in the present study were 2,187 adults (1,138 females [52.0%]; 1,049 males [48.0%], age: 18–65 years) taken from a sample of 4,000 persons randomly chosen from an urban population. Data on health behaviour like physical activity, tobacco and alcohol consumption were obtained by means of a questionnaire, documentation of anthropometric data, abdominal ultrasound and blood specimens for assessment of chemical parameters.ResultsThe overall rate of participation was 62.8%. Of these, 50.3% of the adults were overweight or obese. The proportion of active tobacco smokers stood at 30.1%. Of those surveyed 38.9% did not participate in any physical activity. Less than 2 hours of leisure time physical activity per week was associated with female sex, higher BMI (Body Mass Index), smoking and no alcohol consumption. Participants consumed on average 12 grams of alcohol per day. Total cholesterol was in 62.0% (>5.2 mmol/l) and triglycerides were elevated in 20.5% (≥ 2.3 mmol/l) of subjects studied. Hepatic steatosis was identified in 27.4% of subjects and showed an association with male sex, higher BMI, higher age, higher total blood cholesterol, lower HDL, higher triglycerides and higher ALT.ConclusionThis random sample of German urban adults was characterised by a high prevalence of overweight and obesity. This and the pattern of alcohol consumption, smoking and physical activity can be considered to put this group at high risk for associated morbidity and underscore the urgent need for preventive measures aimed at reducing the significantly increased health risk.

Foci of tick-borne diseases in Southwest Germany

Presently known tick-borne diseases in Germany include Lyme borreliosis, tick-borne encephalitis (TBE-virus, western subtype), Q-fever, babesiosis and presumably ehrlichiosis. Blood samples of 4,368 forestry workers in the State of Baden-Wuerttemberg (B-W), southwestern Germany, were tested for the presence of antibodies against Borrelia burgdorferi sensu lato, TBE-virus and Ehrlichia spp. (genogroup E. phagocytophila). Furthermore 12,327 ticks (Ixodes ricinus) collected in various areas of B-W were analysed by PCR and genotyping for the prevalence of pathogen RNA and DNA. The human seroprevalence rates of antibodies to B. burgdorferi sensu lato ranged from 18% to 52%, for TBE-virus from 0% to 43% and for Ehrlichia spp. from 5% to 16% in various counties of the State. The foci of B. burgdorferi and TBE-virus as indicated by antibody prevalence in humans are only partly overlapping with each other. The highest rates of TBE-virus antibodies are in concordance with available clinical data. However antibody prevalence up to 27% in areas with no reports of clinical cases was found, suggesting that TBE occurs throughout the State of B-W. The prevalence of Ehrlichia spp. antibodies suggests that ehrlichiosis plays a role as a tick-borne disease in Germany, but as long as no clinical data are available, this will remain unclear. Investigations of ticks for TBE-virus (n = 9,189) by nested PCR showed prevalence rates from 0% to 2.3% and for Ehrlichia spp. (n = 1,963) from 2.6% to 3.1%. Examination of ticks (n = 3,138) for the presence of B. burgdorferi sensu lato DNA was performed by PCR and revealed prevalence rates from 13.9% up to 24%. Furthermore 1,106 samples positive for B. burgdorferi sensu lato were used for genotyping. B. afzelii DNA was found in 407 ticks (36.8%), followed by B. garinii (21.9%), B. valaisiana (13.7%), and B. burgdorferi sensu stricto (9.9%). Double infection was found in 6.4% and triple infection in 0.8% of the ticks. 10.5% of the positive samples could not be classified. Prevention of tick-borne diseases has to focus on behavioural intervention to reduce individual tick exposure by proper behaviour in the environment, as a large-scale control of the tick population seems impossible and thus reduction of Lyme borreliosis and TBE through tick control is unlikely. Vaccination against TBE-virus should not only be recommended for high endemic areas but also for persons with a high individual risk.

Large listeriosis outbreak linked to cheese made from pasteurized milk, Germany, 2006-2007.

A commercial cheese (acid curd) made from pasteurized milk caused a large listeriosis outbreak in Germany from October 2006 through February 2007. The Listeria monocytogenes outbreak strain was identified in humans and in cheese samples from a patients home and from the production plant. During the outbreak period, 189 patients were affected, which was 97% above the mean case number for the respective time period of the years 2002 to 2005. Of patients with available detailed information on cheese consumption (n=47), 70% reported to have consumed the incriminated cheese product. Recent European food safety alerts due to Listeria-contaminated cheeses more often concerned products made from pasteurized or heat-treated milk than from raw milk. The findings should be considered in prevention guidelines addressing vulnerable populations.

The influenza pandemic preparedness planning tool InfluSim

BackgroundPlanning public health responses against pandemic influenza relies on predictive models by which the impact of different intervention strategies can be evaluated. Research has to date rather focused on producing predictions for certain localities or under specific conditions, than on designing a publicly available planning tool which can be applied by public health administrations. Here, we provide such a tool which is reproducible by an explicitly formulated structure and designed to operate with an optimal combination of the competing requirements of precision, realism and generality.ResultsInfluSim is a deterministic compartment model based on a system of over 1,000 differential equations which extend the classic SEIR model by clinical and demographic parameters relevant for pandemic preparedness planning. It allows for producing time courses and cumulative numbers of influenza cases, outpatient visits, applied antiviral treatment doses, hospitalizations, deaths and work days lost due to sickness, all of which may be associated with economic aspects. The software is programmed in Java, operates platform independent and can be executed on regular desktop computers.ConclusionInfluSim is an online available software http://www.influsim.info which efficiently assists public health planners in designing optimal interventions against pandemic influenza. It can reproduce the infection dynamics of pandemic influenza like complex computer simulations while offering at the same time reproducibility, higher computational performance and better operability.

Molecular Epidemiology of Norovirus in Outbreaks of Gastroenteritis in Southwest Germany from 2001 to 2004

ABSTRACT The identification and molecular epidemiology of norovirus in outbreaks of gastroenteritis were studied during a 3-year period in Germany. Specimens (n = 316) from 159 nonbacterial gastroenteritis outbreaks from March 2001 to June 2004 were analyzed for the presence of noroviruses by reverse transcriptase PCR. Outbreaks were most frequent in elderly peoples homes and care centers (43%), followed by hospitals (24%). Molecular analyses of strains from 148 outbreaks showed that there were up to 12 genotypes involved in the outbreaks. Genogroup II noroviruses were responsible for 95% of the outbreaks. Cocirculation of more than one strain in the same outbreak and cocirculation of genogroup I and II strains in the same place were observed. Genogroup II4 (Grimsby-like) was the most prevalent strain, accounting for 48% and 67% of the outbreaks in 2002 and 2003, respectively. The genogroup IIb (Castell/Suria) genotype was observed in all the years of the study. Epidemiological and molecular data indicated that there was a major shift of the predominant strain that coincided with the appearance of a new variant of genogroup II4 in 2002. By the application of reverse transcriptase PCR, this study has demonstrated the importance and dynamism of noroviruses in Germany.

Outbreak of leptospirosis among triathlon participants in Germany, 2006

BackgroundIn August 2006, a case of leptospirosis occurred in an athlete after a triathlon held around Heidelberg and in the Neckar river. In order to study a possible outbreak and to determine risk factors for infection an epidemiological investigation was performed.MethodsParticipants of the triathlon were contacted by e-mail and were asked to fill out a standardized questionnaire. In addition, they were asked to supply a serum sample for laboratory diagnosis of leptospirosis. A confirmed case patient was defined as a clinical case (i.e. fever and at least one additional symptom suggestive for leptospirosis) with at least two of the following tests positive: ELISA IgM, latex agglutination testing, or microscopic agglutination testing. Rainfall and temperature records were obtained.ResultsA total of 142 of 507 triathletes were contacted; among these, five confirmed leptospirosis cases were found. Open wounds were identified as the only significant risk factor for illness (p = 0.02). Heavy rains that preceded the swimming event likely increased leptospiral contamination of the Neckar River.DiscussionThis is the first outbreak of leptospirosis related to a competitive sports event in Germany. Among people with contact to freshwater, the risk of contracting leptospirosis should be considered by health care providers also in temperate countries, particularly in the summer after heavy rains.

Influenza pandemic intervention planning using InfluSim: pharmaceutical and non- pharmaceutical interventions

BackgroundInfluenza pandemic preparedness plans are currently developed and refined on national and international levels. Much attention has been given to the administration of antiviral drugs, but contact reduction can also be an effective part of mitigation strategies and has the advantage to be not limited per se. The effectiveness of these interventions depends on various factors which must be explored by sensitivity analyses, based on mathematical models.MethodsWe use the freely available planning tool InfluSim to investigate how pharmaceutical and non-pharmaceutical interventions can mitigate an influenza pandemic. In particular, we examine how intervention schedules, restricted stockpiles and contact reduction (social distancing measures and isolation of cases) determine the course of a pandemic wave and the success of interventions.ResultsA timely application of antiviral drugs combined with a quick implementation of contact reduction measures is required to substantially protract the peak of the epidemic and reduce its height. Delays in the initiation of antiviral treatment (e.g. because of parsimonious use of a limited stockpile) result in much more pessimistic outcomes and can even lead to the paradoxical effect that the stockpile is depleted earlier compared to early distribution of antiviral drugs.ConclusionPharmaceutical and non-pharmaceutical measures should not be used exclusively. The protraction of the pandemic wave is essential to win time while waiting for vaccine development and production. However, it is the height of the peak of an epidemic which can easily overtax general practitioners, hospitals or even whole public health systems, causing bottlenecks in basic and emergency medical care.

Polio emergence in Syria and Israel endangers Europe

WHO has confi rmed an outbreak of at least ten cases of polio in Syria, where vaccination coverage has dramatically decreased during the civil war. Furthermore, wild-type poliovirus 1 (WPV1) has been isolated from sewage and faeces from asymptomatic carriers in Israel since February, 2013. Tourists and travellers could bring the infection to other countries. Precautions during the Hajj in Saudi Arabia in October, 2013, ensured that visitors from regions with known polio transmission were vaccinated, but Syria was not on the list. Moreover, hundreds of thousands of people are fl eeing Syria and seek refuge in neighbouring countries and Europe. Because only one in 200 unvaccinated individuals infected with WPV1 will develop acute fl accid paralysis (case/ infection ratio C=0·005), infected individuals can spread the virus unrecognised. Inactivated polio vaccine, which is used throughout Europe, only partly prevents vaccinees from infection, but it reduces transmission and is highly eff ective in prevention of acute fl accid paralysis, and thus further reduces the ratio of acute fl accid paralysis to infection. In regions with low vaccination coverage (eg, Bosnia and Herzegovina [87%] or Ukraine [74%]), particularly those with low coverage of inactivated polio vaccine (eg, Austria [83%]), herd immunity might be insufficient to prevent sustained transmission. Assuming a borderline effective reproduction number R of 1·1, we expect to see C(R–1)/(R–1) cases of acute flaccid paralysis within n transmission generations. It might take more than 30 generations of 10 days—nearly 1 year of silent transmission—before one acute fl accid paralysis case is identifi ed and an outbreak is detected, although hundreds of individuals would carry the infection. Vaccinating only Syrian refugees—as has been recommended by the European Centre for Disease Prevention and Control—must be judged as insufficient; more comprehensive measures should be taken into consideration. Oral polio vaccination provides high protection against acquisition and spreading of the infection, but this vaccine was discontinued in Europe because of rare cases of vaccination-related acute flaccid paralysis. Only some of the European Union member states still allow its use and none has a stockpile of oral polio vaccines. Routine screening of sewage for poliovirus has not been done in most European countries, but this intensified surveillance measure should be considered for settlements with large numbers of Syrian refugees.

Detection and characterization of sapoviruses in outbreaks of gastroenteritis in southwest Germany.

BACKGROUND Sapovirus (SV) has been reported from many countries as one of the major causes of gastroenteritis in infants, but its importance for a broader age range is not well appreciated. While previous studies in our regional laboratory and other parts of Germany have identified Norovirus (NV) as a major cause of gastroenteritis in Germany, the prevalence of SV has not been recorded. OBJECTIVES To investigate the prevalence of SV in outbreaks of gastroenteritis in Baden-Württemberg, Germany. STUDY DESIGN Stool specimens from 34 outbreaks of gastroenteritis collected in Baden-Württemberg, Germany in 2002 and 2003, which tested negative for other enteric pathogens were tested for SV by RT-PCR. Positive samples were sequenced and typed using phylogenetic analysis. RESULTS SV was identified in two of 157 (1.3%) specimens. These two viruses belonged to different genotypes of SV and had a nucleotide similarity of only 57%. CONCLUSIONS SV circulates within the study area, but is not an important cause of gastroenteritis in the area.