Antibiotic Resistances in Livestock: A Comparative Approach to Identify an Appropriate Regression Model for Count Data

Antimicrobial resistance in livestock is a matter of general concern. To develop hygiene measures and methods for resistance prevention and control, epidemiological studies on a population level are needed to detect factors associated with antimicrobial resistance in livestock holdings. In general, regression models are used to describe these relationships between environmental factors and resistance outcome. Besides the study design, the correlation structures of the different outcomes of antibiotic resistance and structural zero measurements on the resistance outcome as well as on the exposure side are challenges for the epidemiological model building process. The use of appropriate regression models that acknowledge these complexities is essential to assure valid epidemiological interpretations. The aims of this paper are (i) to explain the model building process comparing several competing models for count data (negative binomial model, quasi-Poisson model, zero-inflated model, and hurdle model) and (ii) to compare these models using data from a cross-sectional study on antibiotic resistance in animal husbandry. These goals are essential to evaluate which model is most suitable to identify potential prevention measures. The dataset used as an example in our analyses was generated initially to study the prevalence and associated factors for the appearance of cefotaxime-resistant Escherichia coli in 48 German fattening pig farms. For each farm, the outcome was the count of samples with resistant bacteria. There was almost no overdispersion and only moderate evidence of excess zeros in the data. Our analyses show that it is essential to evaluate regression models in studies analyzing the relationship between environmental factors and antibiotic resistances in livestock. After model comparison based on evaluation of model predictions, Akaike information criterion, and Pearson residuals, here the hurdle model was judged to be the most appropriate model.

Retrospective survey of mcr-1 and mcr-2 in German pig-fattening farms, 2011-2012

In November 2015, the first plasmid-encoded colistin resistance gene, mcr-1, was described in animals and in humans in China. Subsequently, a multitude of further studies was performed and quite recently the global spread of mcr-1 as well as the occurrence of a new gene variant, mcr-2, was reported. To obtain an overview of the occurrence of the colistin resistance genes mcr-1 and mcr-2 in German pig farms, a retrospective study, including 436 boot swab and pooled faecal samples collected from 58 pig-fattening farms throughout Germany, was performed. Whilst mcr-2 was not detected, the presence of mcr-1 was confirmed in 43 Escherichia coli isolates from 15 farms, indicating that the mcr-1 gene was present in 9.9% of the analysed samples and 25.9% of the investigated pig farms. Subsequent characterisation of the isolates showed colistin minimum inhibitory concentrations (MICs) of 4-8 µg/mL, with most isolates being resistant to several antibiotics including cephalosporins and/or fluoroquinolones. Pulsed-field gel electrophoresis (PFGE) showed great heterogeneity among the tested mcr-1-positive isolates. However, further analyses of 15 selected E. coli isolates (one per mcr-1-positive farm) indicated that the colistin resistance genes were predominantly located on IncX4 plasmids, highly similar to a plasmid initially isolated from an E. coli derived from a human patient in Brazil. The results described herein support the already expressed concern for public health and further underline the need for monitoring programmes in veterinary practice as well as in human medicine.

Development of a Database for Study Data in Registration Applications for Veterinary Medicinal Products

<p><strong>Objective:</strong> In the present study, the feasibility of a systematic record of clinical study data from marketing authorisation applications for veterinary medicinal products (VMP) and benefits of the selected approach were investigated.</p><p><strong>Background:</strong> Drug registration dossiers for veterinary medicinal products contain extensive data from drug studies, which are not easily accessible to assessors.</p><p><strong>Evidentiary value:</strong> Fast access to these data including specific search tools could facilitate a meaningful use of the data and allow assessors for comparison of test and studies from different dossiers.</p><p><strong>Methods:</strong> First, pivotal test parameters and their mutual relationships were identified. Second, a data model was developed and implemented in a relational database management system, including a data entry form and various reports for database searches. Compilation of study data in the database was demonstrated using all available clinical studies involving VMPs containing the anthelmintic drug Praziquantel.<br /> By means of descriptive data analysis possibilities of data evaluation including graphical presentation were shown. Suitability of the database to support the performance of meta-analyses was tentatively validated.</p><p><strong>Results:</strong> The data model was designed to cover the specific requirements arising from study data. A total of 308 clinical studies related to 95 VMPs containing Praziquantel (single agent and combination drugs) was selected for prototype testing. The relevant data extracted from these studies were appropriately structured and shown to be basically suitable for descriptive data analyses as well as for meta-analyses.</p><p><strong>Conclusion:</strong> The database-supported collection of study data would provide users with easy access to the continuously increasing pool of scientific information held by competent authorities. It enables specific data analyses. Database design allows expanding the data model to all types of studies and classes of drugs registered in veterinary medicine. The needs for detailed data recording and versatility of the data model must be carefully balanced.</p><p><strong>Application:</strong> The database will be used by regulatory authorities.</p>

Approaches to Teaching Biometry and Epidemiology at Two Veterinary Schools in Germany

In a thematically broad and highly condensed curriculum like veterinary medicine, it is essential to pay close attention to the didactic and methodical approaches used to deliver that content. The course topics ideally should be selected for their relevance but also for the target audience and their previous knowledge. The overall objective is to improve the long-term availability of what has been learned. For this reason, an evaluation among lecturers of German-speaking veterinary schools was carried out in 2012 to consider which topics in biometry and epidemiology they found relevant to other subject areas. Based on this survey, two veterinary schools (Berlin and Hannover) developed a structured approach for the introductory course in biometry and epidemiology. By means of an appropriate choice of topics and the use of adequate teaching methods, the quality of the lecture course could be significantly increased. Appropriately communicated learning objectives as well as a high rate of student activity resulted in increased student satisfaction. A certain degree of standardization of teaching approaches and material resulted in a comparison between the study sites and reduced variability in the content delivered at different schools. Part of this was confirmed by the high consistency in the multiple-choice examination results between the study sites. The results highlight the extent to which didactic and methodical restructuring of teaching affects the learning success and satisfaction of students. It can be of interest for other courses in veterinary medicine, human medicine, and biology.

Simultaneous occurrence of Salmonella enterica, Campylobacter spp. and Yersinia enterocolitica along the pork production chain from farm to meat processing in five conventional fattening pig herds in Lower Saxony

The objectives of this study were to gather data on the occurrence of Salmonella (S.) enterica, Campylobacter spp. and Yersinia (Y.) enterocolitica along the pork production chain and to further analyze detected Salmonella isolates by additionally applying MLVA (multiple-locus variable-number tandem repeat analysis). In total, 336 samples were collected at primary production, slaughter and meat processing from five conventional fattening pig farms and one common slaughterhouse. At farm level, S. enterica, Campylobacter spp. and Y. enterocolitica were detected in 19.4%, 38.9% and 11.1% of pooled fecal samples of fattening pigs. At slaughter, more than two-thirds of examined carcasses, 24% of carcass surfaces samples and about 60% of cecal content samples were positive for at least one of the examined pathogens. An amount of 4% of meat samples were positive for non-human pathogenic Y. enterocolitica. Identical MLVA patterns of Salmonella isolates from farm- and associated slaughterhouse samples demonstrated transmission across both production stages. Other MLVA patterns found at slaughter indicated possible colonization of pigs during transport or lairage and/or cross-contamination during slaughter. Identical MLVA patterns from risk tissues and the nearby carcass surface evidenced a direct contamination of carcasses as well. Overall, our data showed wide distribution ranges for all three examined pathogens within the pig production chain and underline the need for appropriate intervention strategies at pre- and postharvest.

Circulation of clonal populations of fluoroquinolone-resistant CTX-M-15-producing Escherichia coli ST410 in humans and animals in Germany

Multidrug-resistant Escherichia coli encoding CTX-M-type extended-spectrum β-lactamases (ESBLs) are isolated in increasing numbers from humans, companion animals and livestock, raising concern regarding the exchange and spread of isolates in these populations. In this study, whole-genome sequencing of CTX-M-15-producing E. coli isolates recently sampled from humans, companion animals, livestock and farm environments was performed. In total, 26 different sequence types (STs) were detected, of which ST410 was the most frequent and was the only ST present in all populations studied. Five clades (designated A-E) were detected within the ST410 isolates. In particular, isolates of clade B were present in all four populations and had core genomes that differed by less than 70 single nucleotide polymorphisms (SNPs). Isolates of clades B and C were also clonally marked, exhibiting identical chromosomal insertions of blaCTX-M-15 at distinct loci. These data provide strong evidence for the clonal dissemination of specific clades of CTX-M-15-producing E. coli ST410 in human and animal populations.

Participatory epidemiology at the neotropics: study of diseases of backyard livestock and description of hunting patterns in Uaxactún, Maya Reserve Biosphere, Guatemala

Background

The intention of the following study was to describe the interrelationship between villagers, domestic animals and wildlife at the Community Forestry Concession of Uaxactún, Guatemala by means of participatory epidemiological methods. The main focus was generating information regarding different livestock diseases considered important by villagers and their relevance, as well as obtaining knowledge concerning hunting activities and cooking methods to gain a better understanding of the interrelationship of people and animals and the diseases of their animals.

Results

For poultry, an overall prevalence of 41 % of Newcastle disease was found by means of the ELISA test by antibody detection, chicken being the most affected species in the village. No samples were positive to avian influenza with the HI test. No virus was isolated by means of the tracheal or cloaca swabbing of ducks.

For hunting

All species could be hunted by chance at any time of the year. There was a difference in species hunted between seasons, peccaries being more frequently hunted during the dry season and in contrast, deer and wild avian during the rainy season.

For cooking

Villagers did not consume any raw meat. The cooking methods depended on the species. Stewing was the most favoured method for peccaries, wild birds, tepezcuintle and domestic poultry, whereas grilling was preferable for deer, roasting for armadillos and marinating for pork.

Conclusion

According to the generated information, the most important domestic livestock species in the village are chickens and pigs, chickens being the most affected by diseases. No evident health problems on pigs were observed in this study. Hunting was shown as an activity enhanced by poverty and the lack of employment opportunities in the village and was mostly directed at larger species such as deer and peccaries. From the viewpoint of a transmission of zoonoses from animals to humans cooking methods mostly reflected a protective factor as no raw meat was eaten, stews and broths being the most common forms of cooking, involving an exposure of meat to high temperatures. Nonetheless, both agricultural and hunting activities represent a risk factor for the spread of diseases as hunters may act as mechanical vectors for different pathogens within domestic and wild animal populations.

Joint use of Disparate Data for the Surveillance of Zoonoses: A Feasibility Study for a One Health Approach in Germany

Zoonotic diseases concern human and animal populations and are transmitted between both humans and animals. Nevertheless, surveillance data on zoonoses are collected separately for the most part in different databases for either humans or animals. Bearing in mind the concept of One Health, it is assumed that a global view of these data might help to prevent and control zoonotic diseases. In following this approach, we wanted to determine which zoonotic data are routinely collected in Germany and whether these data could be integrated in a useful way to improve surveillance. Therefore, we conducted an inventory of the existing data collections and gathered information on possible One Health surveillance areas in Germany by approaching experts through a scoping survey, personal interviews and during a workshop. In matching the information between the status quo for existing data collections and the possible use cases for One Health surveillance, this study revealed that data integration is currently hindered by missing data, missing pathogen information or a lack of timeliness, depending on the surveillance purpose. Therefore, integrating the existing data would require substantial efforts and changes to adapt the collection procedures for routine databases. Nevertheless, during this study, we observed a need for different stakeholders from the human and animal health sectors to share information to improve the surveillance of zoonoses. Therefore, our findings suggest that before the data sets from different databases are integrated for joint analyses, the surveillance could be improved by the sharing of information and knowledge through a collaboration of stakeholders from different sectors and institutions.

The impact of distance and duration of travel on participation rates and participants' satisfaction: results from a pilot study at one study centre in Pretest 2 of the German National Cohort

OBJECTIVES

In this pilot study within the Pretest 2 phase of the German National Cohort, we aimed to (1) test the hypothesis that distance and duration of travel to a study centre may affect participation rates and participants' satisfaction and (2) to obtain data that would help to select recruitment areas around the study centre Hannover with the greatest projected participation rate for the main study.

SETTING

Mixed urban/suburban environment in Northern Germany with approximately 600,000 inhabitants. 4 recruitment areas with divergent estimated mean distances (range, 7-40 km) and duration of travel to the study centre Hannover were selected.

PARTICIPANTS

1050 men and women (ratio, 1:1), aged 20-69 years, were randomly selected from the population registries of the 4 recruitment areas and invited by mail to participate in the Pretest 2 study programme at the study centre Hannover, covering a variety of questionnaire-based and physical assessments. 166 individuals participated (16%).

INTERVENTIONS

All 166 participants completed a travel questionnaire containing 5 items relating to travel duration and satisfaction, amounting to a participation rate of 100% in the questionnaire-based part of the study.

RESULTS

Participation rates in the Pretest 2 programme at the study centre Hannover by area ranged from 11% (area farthest from the study centre, estimated median distance 38 km) to 18% (nearest area, 2 km). The odds of non-participation were highest in the area farthest from the study centre (adjusted OR 2.06; p=0.01; CI 1.28 to 3.32). Nonetheless, 97% of participants were satisfied with travel duration.

CONCLUSIONS

Increasing distance was associated with a lower participation rate. However, acceptance of duration of travel was high, irrespective of distance or duration. Thus, recruiting in farther away locations may select individuals with a greater frustration tolerance for travel to the study centre, perhaps due to a greater interest in participating in health-oriented studies and thus different health-related behaviour.

Evaluation of a questionnaire to assess selected infectious diseases and their risk factors : findings of a multicenter study

Background/objectives

The risk to die from an infectious disease in Germany has been continuously decreasing over the last century. Since infections are, however, not only causes of death but risk factors for diseases like cardiovascular diseases, it is essential to monitor and analyze their prevalence and frequency, especially in consideration of the increased life expectancy. To gain more knowledge about infectious diseases as risk factors and their implications on the condition and change of the immune status, the German National Cohort (GNC), a population-based prospective cohort study, will recruit 200,000 subjects between 2014 and 2017. In Pretest 1, a feasibility study for the GNC, we evaluated a self-administered and self-report questionnaire on infectious diseases and on the use of health care facilities (hereinafter called “ID Screen”) for feasibility and validity.

Methods

From August–November 2011, 435 participants between the ages of 20–69 completed the ID Screen. All subjects had been recruited via a random sample from the local residents’ registration offices by 4 of the 18 participating study centers. The questionnaire encompasses 77 variables in six sections assessing items such as 12-month prevalence of infections, cumulative prevalence of infectious diseases, visit of health care facilities and vaccination. The feasibility was amongst others evaluated by assessing the completeness and comprehensiveness of the questionnaire. To assess the questionnaires ability to measure “immune status” and “susceptibility to infections”, multivariate analysis was used.

Results

The overall practicability was good and most items were well understood, demonstrated by < 2/33 missing questions per questionnaire and only three variables: vaccination for influenza and pneumococci and infection with chickenpox had a frequency > 5 % of missing values. However, direct comparison of the items 12-month prevalence and lifetime prevalence of nephritis/pyelitis showed poor agreement and thereby poor understanding by 80 % of the participants, illustrating the necessity for a clear, lay person appropriate description of rare diseases to increase comprehensibility. The questionnaire will be used to support the assessment of immune dysfunction and frequency of infection. An analysis of these constructs in an exploratory factor analysis revealed limited applicability due to low interitem correlation (Cronbach’s α < 0.5). This is corroborated by the extraction of more than one factor with a Kaiser–Meyer–Olkin measure of 0.6 instead of a unidimensional latent construct for “immune status”.

Conclusion

All in all, the ID Screen is a good and reliable tool to measure infectious diseases as risk factors and outcome in general, but requires a better translation of infection specific terms into lay person terms. For the assessment of the overall immune status, the tool has strong limitations. Vaccinations status should also rather be assessed based on vaccination certificates than on participants’ recall.

Electronic supplementary material

The online version of this article (doi: 10.1007/s00103-014-2052-y) contains supplementary material, which is available to authorized users.

Recommendation for a Standardised Method of Broth Microdilution Susceptibility Testing for Porcine Bordetella bronchiseptica

The objective was to establish and standardise a broth microdilution susceptibility testing method for porcine Bordetella (B.) bronchiseptica. B. bronchiseptica isolates from different geographical regions and farms were genotyped by macrorestriction analysis and subsequent pulsed-field gel electrophoresis. One reference and one type strain plus two field isolates of B. bronchiseptica were chosen to analyse growth curves in four different media: cation-adjusted Mueller-Hinton broth (CAMHB) with and without 2% lysed horse blood, Brain-Heart-Infusion (BHI), and Caso broth. The growth rate of each test strain in each medium was determined by culture enumeration and the suitability of CAMHB was confirmed by comparative statistical analysis. Thereafter, reference and type strain and eight epidemiologically unrelated field isolates of B. bronchiseptica were used to test the suitability of a broth microdilution susceptibility testing method following CLSI-approved performance standards given in document VET01-A4. Susceptibility tests, using 20 antimicrobial agents, were performed in five replicates, and data were collected after 20 and 24 hours incubation and statistically analysed. Due to the low growth rate of B. bronchiseptica, an incubation time of 24 hours resulted in significantly more homogeneous minimum inhibitory concentrations after five replications compared to a 20-hour incubation. An interlaboratory comparison trial including susceptibility testing of 24 antimicrobial agents revealed a high mean level of reproducibility (97.9%) of the modified method. Hence, in a harmonization for broth microdilution susceptibility testing of B. bronchiseptica, an incubation time of 24 hours in CAMHB medium with an incubation temperature of 35°C and an inoculum concentration of approximately 5 x 10⁵ cfu/ml was proposed.

Occurrence of Clostridium botulinum neurotoxin in chronic disease of dairy cows

Botulism caused by neurotoxins of Clostridium (C.) botulinum is a rare, but serious life-threatening disease in humans and animals. Botulism in livestock is usually caused by the oral uptake of C. botulinum neurotoxins (BoNT) via contaminated feed and is characterized by flaccid paralysis. In the recent past a new syndrome caused by BoNT in dairy cattle was postulated. It was supposed that C. botulinum is able to colonize the lower intestine and may subsequently produce neurotoxin. The continuous resorption of small amounts of these BoNT may then provoke the so called syndrome of "chronic" or "visceral" botulism involving unspecific clinical symptoms, reduced performance of dairy cows and massive animal losses in the affected herd. To test this hypothesis a case-control study was conducted involving 92 affected farms and 47 control farms located in Northern Germany. Fecal samples of 1388 animals were investigated for the presence of BoNT to verify the key requirement of the hypothesis of chronic botulism. BoNT was not detected in any of the fecal samples using the most sensitive standard method for BoNT detection, the mouse bioassay. Therefore, the existence of "chronic" or "visceral" botulism could not be proven.

Cross-sectional study on antibiotic usage in pigs in Germany

To be able to analyze the relationship between the level of resistance and the use of antimicrobials, it is necessary to collect detailed data on antimicrobial usage. For this reason, data on antimicrobial use on 495 pig farms from entire Germany were collected and analyzed. In Germany, each application and dispensing of medicines to food-producing animals is documented in detail obligatorily by the veterinarian. This information was collected retrospectively for the year 2011. The analyses undertook separate examinations on the age groups sow, piglet, weaner and fattening pig; both the route of administration and indication per active ingredient, and active ingredient class, were evaluated. In total, 20,374 kg of antimicrobial substances were used in the study population. Tetracyclines were used in highest amounts, followed by beta-lactams, trimethoprim-sulfonamides and macrolides. Concerning the frequency of using an active substance per animal, polypeptides were most commonly administered. In all age groups, respiratory infections were the main indication for using antimicrobials, followed by intestinal diseases in piglets, weaners and fattening pigs and diseases of reproductive organs in sows. Over a period of 100 days, the median number of treatment days with one antimicrobial substance for piglets was 15 days, for weaners about 6 days, for fattening pigs about 4 days and for sows about 1 day. A multifactorial ANOVA was conducted to investigate which factors are associated with the treatment frequency. The factors "veterinarian" and "age group" were related to the treatment frequency, just as the interaction between "veterinarian" and "farm size" as well as the interaction between "veterinarian" and "age group".

Teaching biostatistics and epidemiology in the veterinary curriculum: what do our fellow lecturers expect?

Given veterinary students' varying mathematical knowledge and interest in statistics, teaching statistical concepts to them is often seen as a challenge. Consequently, there is an ongoing debate among lecturers about the best time to introduce the material into the curriculum, and the best thematic content and conceptual approach to teaching in basic biostatistics classes. During a workshop meeting of epidemiology and biostatistics lecturers of Austrian, German, and Swiss veterinary schools, the question was raised as to whether the topics taught in epidemiology and statistics classes are of sufficient relevance to our lecturing colleagues in other fields of veterinary education (i.e., whether our colleagues have certain expectations as to what the students should know about biostatistics before taking their classes). In 2012, an online survey was compiled and carried out at all eight German-speaking veterinary schools to address this issue. There were 266 respondents out of approximately 800 contacted lecturers from all schools and disciplines. Almost 50% responded that the basic biostatistics class should be taught early on (in the second or third year), while only 26% indicated that basic epidemiology should commence before the third year of the veterinary curriculum. There were clear differences in perceived relevance of the 44 epidemiological and biostatistical topics presented in the survey, assessed on a Likert scale from 0 (no relevance) to 4 (very high relevance). The results provide important information about how to revise the content of epidemiology and biostatistics classes, and the approach could also be used for other courses within the veterinary curriculum with a natural science focus.

Evaluation of invalid vaccine doses in 31 countries of the WHO African Region

We examined (a) the fraction of and extent to which vaccinations were administered earlier than recommended (age-invalid) or with too short intervals between vaccine doses (interval-invalid) in countries of the World Health Organisation (WHO) African Region and (b) individual- and community-level factors associated with invalid vaccinations using multilevel techniques. Data from the Demographic and Health Surveys conducted in the last 10 years in 31 countries were used. Information about childhood vaccinations was based on vaccination records (n=134,442). Invalid vaccinations (diphtheria, tetanus, pertussis [DTP1, DTP3] and measles-containing vaccine (MCV)) were defined using the WHO criteria. The median percentages of invalid DTP1, DTP3 and MCV vaccinations across all countries were 12.1% (interquartile range, 9.4-15.2%), 5.7% (5.0-7.6%), and 15.5% (10.0-18.1%), respectively. Of the invalid DTP1 vaccinations, 7.4% and 5.5% were administered at child's age of less than one and two weeks, respectively. In 12 countries, the proportion of invalid DTP3 vaccinations administered with an interval of less than two weeks before the preceding dose varied between 30% and 50%. In 13 countries, the proportion of MCV doses administered at child's age of less than six months varied between 20% and 45%. Community-level variables explained part of the variation in invalid vaccinations. Invalid vaccinations are common in African countries. Timing of childhood vaccinations should be improved to ensure an optimal protection against vaccine-preventable infections and to avoid unnecessary wastage in these economically deprived countries.

[On the occurence of extended-spectrum- and AmpC-beta-lactamase-producing Escherichia coli in livestock: results of selected European studies]

Extended-spectrum-beta-lactamase (ESBL) and plasmid-encoded cephamycinase (pAmpC) producing Escherichia (E.) coli in livestock farms have recently been matter of growing scientific and public concern. This article summarises selected European studies which focus on the prevalence and risk factors associated with the presence of such resistant E. coli isolates in livestock farms. Due to the different methodologies used in these studies, they cannot be compared directly; nonetheless, the overall prevalence found is very high. The prevalence found in broiler farms was higher than 40% and the individual animal prevalence was ca. 30%. The prevalence was more variable in pigs, with reports of pig farms showing prevalence of 1 to 80% and reports of individual animal prevalence of 15 to 100% In studies on cattle farms the production type as well as the age of animals had an influence on the number of positive samples. The highest prevalence was found with calves after birth and in the first weeks, whereas with older cattle the numbers of positive samples were considerably lower. Samples taken from dairy cows were positive more often after calving than before calving. According to the livestock species different risk factors may be assessed for the occurrence of ESBL/pAmpC-producing E. coli isolates. In some studies an association between the occurrence of ESBL-producing E. coli and factors like the use of antimicrobial agents or management factors, as the duration of the fattening period and the acquisition of animals from different origins, were identified. At the moment, there is a lack of systematic and standardised transnational epidemiological investigations on the occurrence of ESBL/pAmpC-producing E. coli in livestock. To control the further spread of ESBL/pAmpC-producing E. coli and the effectiveness of preventive measures, comprehensive monitoring and surveillance systems with harmonised methods are essential. Modern typing methods, in particular the sequence-based methods, can provide more information to clarify transmission pathways.

[Statistical methods for description of phenotypic susceptibility data]

This paper summarizes statistical methods to describe susceptibility data. A frequent data basis in resistance studies are minimum inhibitory concentrations (MICs), measured for different antimicrobial agents. In the statistical context these (semi) quantitative MIC values are ordinal scaled. Therefore, they should be analysed with statistical tools appropriate for ordinal data. The resistance situation for each antimicrobial agent is often described using frequency distributions of MIC values. Resistance patterns can be described by frequencies of resistance profiles. More detailed insights into appearance and changes of simultaneous resistance against different agents are provided by a systematic analysis of dependency structure in susceptibility data. Furthermore, the calculation of differences between resistance profiles using appropriate distance measures enables the application of common methods of multivariate statistic for description and more complex analysis of susceptibility data. To improve the comparability of study results, it is desirable to present as much information as possible in a uniform way.

[Antibiotic usage and antibiotic sales in Germany in 2011--the situation of drug usage in veterinary medicine]

To appreciate the significance of sales data of antibiotics, data on antibiotic consumption (which were collected for selected food-producing animals within the representative VetCAb pilot study in Germany in 2011) were extrapolated for the total German animal population, and subsequently compared to the antibiotic sales data, which were collected throughout Germany in 2011 for the first time and which were published by the Federal Office of Consumer Protection and Food Safety (BVL). The extrapolation was realized based on the average dosage and the number of treatment units determined in the VetCAb pilot project for each active ingredient and animal species. It was extrapolated that 1302 tons of antimicrobial substances were consumed for treating cattle, pigs and broilers--this amount is accompanied by the amount of 1706 tons sold for all animal species. In Germany, tetracyclines and beta-lactams are the most commonly used and sold antimicrobial drugs. In third place are the potentiated sulfonamide, in fourth and fifth place, macrolides and polypeptides. To describe and evaluate the antibiotic usage for the several food-producing animals, detailed information is needed. Therefore, the number of treatments per active ingredient per animal and per day (treatment unit), and the number of treatment days per active ingredient per animal (treatment frequency) were calculated in the VetCAb project. These values represent scientifically collected orientation values for the treatment frequency of food-producing animal with antimicrobial substances in Germany. For example, a fattening pig is treated at 4.2 days (median) with one active ingredient within its 115-day fattening period. A dairy cow is treated at 3.5 days with one active ingredient within one year. A broiler is treated at 10 days with one active ingredient within its 39-day production period.

Extended-spectrum beta-lactamases (ESBL)/AmpC beta-lactamases-producing Escherichia coli in German fattening pig farms: a longitudinal study

The presence of ESBL/AmpC-producing Enterobacteriaceae in healthy livestock, such as pigs, was frequently reported worldwide in the last years. The development and potential spread of these resistant microorganisms in farm animals is discussed critically. Therefore, the main objectives of this longitudinal study were to determine potential sources and prevalence dynamics of ESBL/AmpC-producing Escherichia coli in seven German ESBL/AmpC-positive conventional fattening pig farms in the course of the fattening period. Samples tested were taken at three different times within one finishing fattening period and included 20 individual faeces samples as well as various samples of the animals' housing environment such as pooled faeces, boot swabs, dust and environmental swabs. In individual faeces average carriage levels of 45%, 29% and 36% at the three sampling times were accompanied by decreasing faecal counts from 2.97 x 10(4) cfu/g at the first to 2.17 x 10(3) cfu/g at the third visit. In the animals' housing environment 47.6% of pooled faeces and boot swab samples respectively and 5.9% of environmental swabs but none of the dust samples were tested positive. Altogether 228 E. coli isolates were analysed by combination disc tests, PCR and partly via sequencing.Thereby, a novel gene bla(TEM-206) was detected. This study shows different detection levels of ESBL/AmpC-producing E. coli amongst the different farms and in the course of the fattening period. Pooled faeces and boot swab samples but not dust samples seem to be appropriate to assess the herd status of pigs with respect to ESBL/AmpC-producing Escherichia coli.

Relevance of Campylobacter to public health--the need for a One Health approach

Campylobacter species belong to the most important foodborne bacteria which cause gastroenteritis in humans in both developed and developing countries. With increasing reporting rates, the public awareness towards Campylobacter infections is growing continuously. This strengthens the necessity to establish intervention measures for prevention and control of thermophilic Campylobacter spp. along the food chain, as in particular poultry and poultry meat represent a major source of human infections. An interdisciplinary One Health approach and a combined effort of all stakeholders are necessary to ultimately reduce the burden of campylobacteriosis cases in humans. Numerous studies point out, however, that at present a complete elimination of Campylobacter in the food chain is not feasible. The present aim should therefore be to establish control measures and intervention strategies to minimize the occurrence of Campylobacter spp. in livestock (e.g. poultry flocks) and to reduce the quantitative Campylobacter burden in animals and foods. To this end, a combination of intervention methods at different stages of the food chain appears most promising. That has to be accompanied by targeted consumer advice and education campaigns to raise the awareness towards Campylobacter infections.

Subgrouping of ESBL-producing Escherichia coli from animal and human sources: an approach to quantify the distribution of ESBL types between different reservoirs

Escherichia (E.) coli producing extended-spectrum beta-lactamases (ESBLs) are an increasing problem for public health. The success of ESBLs may be due to spread of ESBL-producing bacterial clones, transfer of ESBL gene-carrying plasmids or exchange of ESBL encoding genes on mobile elements. This makes it difficult to identify transmission routes and sources for ESBL-producing bacteria. The objectives of this study were to compare the distribution of genotypic and phenotypic properties of E. coli isolates from different animal and human sources collected in studies in the scope of the national research project RESET. ESBL-producing E. coli from two longitudinal and four cross-sectional studies in broiler, swine and cattle farms, a cross-sectional and a case-control study in humans and diagnostic isolates from humans and animals were used. In the RESET consortium, all laboratories followed harmonized methodologies for antimicrobial susceptibility testing, confirmation of the ESBL phenotype, specific PCR assays for the detection of bla(TEM), bla(CTX), and bla(SHV) genes and sequence analysis of the complete ESBL gene as well as a multiplex PCR for the detection of the four major phylogenetic groups of E. coli. Most ESBL genes were found in both, human and non-human populations but quantitative differences for distinct ESBL-types were detectable. The enzymes CTX-M-1 (63.3% of all animal isolates, 29.3% of all human isolates), CTX-M-15 (17.7% vs. 48.0%) and CTX-M-14 (5.3% vs. 8.7%) were the most common ones. More than 70% of the animal isolates and more than 50% of the human isolates contained the broadly distributed ESBL genes bla(CTX-M-1), bla(CTX-M-15), or the combinations bla(SHV-12)+bla(TEM) or bla(CTX-M-1)+bla(TEM). While the majority of animal isolates carried bla(CTX-M-1) (37.5%) or the combination bla(CTX-M-1)+bla(TEM) (25.8%), this was the case for only 16.7% and 12.6%, respectively, of the human isolates. In contrast, 28.2% of the human isolates carried bla(CTX-M-15) compared to 10.8% of the animal isolates. When grouping data by ESBL types and phylogroups bla(CTX-M-1) genes, mostly combined with phylogroup A or B1, were detected frequently in all settings. In contrast, bla(CTX-M-15) genes common in human and animal populations were mainly combined with phylogroup A, but not with the more virulent phylogroup B2 with the exception of companion animals, where a few isolates were detectable. When E. coli subtype definition included ESBL types, phylogenetic grouping and antimicrobial susceptibility data, the proportion of isolates allocated to common clusters was markedly reduced. Nevertheless, relevant proportions of same subtypes were detected in isolates from the human and livestock and companion animal populations included in this study, suggesting exchange of bacteria or bacterial genes between these populations or a common reservoir. In addition, these results clearly showed that there is some similarity between ESBL genes, and bacterial properties in isolates from the different populations. Finally, our current approach provides good insight into common and population-specific clusters, which can be used as a basis for the selection of ESBL-producing isolates from interesting clusters for further detailed characterizations, e.g. by whole genome sequencing.

Zoonotic disease surveillance--inventory of systems integrating human and animal disease information

Although 65% of recent major disease outbreaks throughout the world have a zoonotic origin, there is still a sharp division among the disciplines into the human and animal health sectors. In the last few decades, a global integrative concept, often referred to as 'One Health', has been strongly endorsed. Surveillance and monitoring efforts are major components for effective disease prevention and control. As human health and animal health are inextricably linked, it is assumed that a cross-sectoral data interpretation of zoonotic disease information will improve their prevention, prediction and control. To provide an overview of existing systems throughout the world which integrate information from humans and animals on zoonotic diseases, a literature review was conducted. Twenty projects were identified and described regarding their concepts and realization. They all vary widely depending on their surveillance purpose, their structure and the source of information they use. What they have in common is that they quite often use data which have already been collected for another purpose. Therefore, the challenges of how to make use of such secondary data are of great interest.

Comparison of the phenotypic antimicrobial resistances and spa-types of methicillin-resistant Staphylococcus aureus (MRSA) isolates derived from pigs in conventional and in organic husbandry systems

The purposes of this study were to identify differences in the phenotypic resistance to antimicrobials and in the spa-types between 273 methicillin-resistant Staphylococcus aureus (MRSA) isolates derived from conventional (n = 21) versus organic pig farms (n = 10) located in Germany. The susceptibility of the isolates against 19 antimicrobial agents was tested and then compared between the two different husbandry systems. A statistically significant difference was observed between the MRSA strains isolated on conventional and on organic pig farms for the antimicrobials tilmicosin (61.8% vs. 40.0%; OR: 2.42), clindamycin (63.5% vs. 45.7%; OR: 2.06), gentamicin (14.7% vs. 34.3%; OR: 0.33), apramycin (3.8% vs. 22.9%; OR: 0.13) and enrofloxacin (13.9% vs. 34.3%; OR: 0.31). Finally, the results of the susceptibility testing were analysed in order to determine the resistance pattern per isolate. Among the tested isolates a kind of"basic resistance pattern of MRSA"to penicillin, ampicillin and tetracycline was identified. The predominant spa-types in both groups were t011 and t034. Less frequently detected spa-types were t1430, t1197, t2510, t779, t1451 and t1250.

Feasibility study of veterinary antibiotic consumption in Germany--comparison of ADDs and UDDs by animal production type, antimicrobial class and indication

Background

Within a feasibility study the use of antibiotics in pigs and cattle was determined in 24 veterinary practices in Lower Saxony and on 66 farms in North Rhine-Westphalia in Germany. Focus was laid on the comparison of the Used Daily Doses (UDD) (dose per animal and day prescribed by the veterinarians) with the Defined Animal Daily Doses (ADD) (dose per animal and day calculated by means of recommended dosages and estimated live weights).

Results

For piglets and calves most of the UDD (50% and 46% of nUDD, respectively) were above the ADD (i.e. UDD/ADD-ratio above 1.25). Regarding sows, fattening pigs, dairy and beef cattle, most of the UDDs (49% to 65% of nUDD) were lower than the respective ADD (i.e. UDD/ADD-ratio below 0.8). In pigs, the UDDs of beta-lactams, fluoroquinolones and cephalosporins, and in cattle, those of macrolides and beta-lactams were often below the ADDs. Tetracyclines were frequently used above the recommended dose.

Enteric diseases were more often treated below the recommended dose than respiratory diseases, possibly due to overestimation of the live weight (diarrhea in young animals, respiratory diseases in elder animals) and consequently overestimation of the recommended dose.

Conclusion

Comparisons between UDD and ADD can be used to observe differences between antimicrobials and trends in the usage of antibiotics. But individual treatment comparisons of UDD and ADD must be interpreted carefully, because they may be due to lower live weights than estimated. Correlating such data with data on the occurrence of resistant bacteria in future may help to improve resistance prevention and control.

[Two years BVD ear notch samples diagnostics--results from 16 districts of Lower Saxony]

Since June 1st 2010 all calves in Lower Saxony are tested by ear notch samples for the presence of Bovine Virus Diarrhea (BVD) Virus based on the Lower Saxony BVDV-regulation. Since January 1st 2011 the new German BVDV-act requires an examination of the calves in the first 6 months of their life. In the Institute for Animal Health of LUFA Nord-West 1000-2000 ear notch samples originating from 16 rural districts are tested daily. In the period from June 1st 2010 to May 31st 2012 a total of 524,214 tissue samples were examined by an antigen ERNS ELISA. In case of low positive results the tests were verified by PCR. 2454 ear notch samples (0.47%) were from persistently with BVDV infected calves (PI-calves) coming from 763 farms (10.2% of the participating farms). In the first seven months of the eradication program 0.75% of the tested samples were positive. This number decreased in the year 2011 to 0.52%. In the first 5 months of 2012, only 0.18% of the ear notch samples tested positive.

Epidemiology of influences on the performance in broiler flocks--a field study in Germany

To establish which factors influence performance and bird welfare during a fattening period and to identify those factors to be investigated during routine monitoring of farms by veterinary authorities, a questionnaire-based field study was conducted in districts of Lower Saxony, Germany, with the highest density of broiler chickens. Mortality and BW of farms with different stocking densities (≤33, 33.1-39, and >39 kg/m(2)) were investigated. Analyses of 79 farms with 176 stables and 634 fattening periods revealed that flock mortality and BW appeared to be greatly influenced by weather conditions and litter material. In general, it is an advantage to grow broilers under warm weather conditions. However, the longer the fattening period lasts the more important it becomes that the outside weather conditions are not too warm. Therefore, weather conditions should be considered when determining the length of the fattening period, especially before the background of the growing demands of broilers regarding ventilation, absorption of feces by the litter material, and so on. Apart from the length of the fattening period, the weather conditions determine the choice of the litter material, as well. Under cold-humid weather conditions, it is better to use litter material other than wood shavings. In particular in older buildings it is not possible to provide the required conditions, which results in a lower weight gain the longer the fattening period lasts. The study identified differences in the final BW of flocks, which indicate different (farm) management policies. Regardless of the underlying policy, the performance of a fattening period can be improved by optimizing the farm management according to the prevalent conditions. Future routine monitoring, which should be cost effective regarding personnel and finance, should be generally risk based and consider weather conditions, litter material, the age of the building, and the length of the fattening period.

Campylobacter spp., Yersinia enterocolitica, and Salmonella enterica and their simultaneous occurrence in German fattening pig herds and their environment

Campylobacter spp., Salmonella enterica, and Yersinia enterocolitica are common causes of foodborne infections in humans with pork as a potential source. Monitoring programs at farm level are, to date, only implemented for S. enterica, while epidemiological knowledge of the other two pathogens is still lacking. This study aimed to assess the pathogen load (in the pigs' environment) in fattening pig herds, their simultaneous occurrence, and the occurrence of Campylobacter spp. and Y. enterocolitica in herds in different Salmonella risk categories. In 50 fattening pig herds in northern Germany, four pooled fecal samples and 10 swab samples from the pigs' direct environment (pen walls, nipple drinkers), indirect environment (hallways, drive boards), and flies and rodent droppings were collected from each herd and submitted for cultural examination. Campylobacter spp. were detected in 38.1% of fecal, 32.7% of direct environment, 5.3% of indirect environment, and 4.6% of flies/pests samples collected, and Y. enterocolitica in 17.1, 8.1, 1.2, and 3.1% and S. enterica in 11.2, 7.7, 4.1, and 1.5%, respectively. For Campylobacter spp., Y. enterocolitica, and S. enterica, 80, 48, and 32% of herds were positive, respectively; 22 herds were positive for both Campylobacter spp. and Y. enterocolitica, 12 for Campylobacter spp. and S. enterica, and 7 for Y. enterocolitica and S. enterica. There was no significant association between the pathogens at herd level. Campylobacter spp. and Y. enterocolitica were found more often in samples from the low Salmonella risk category (odds ratio, 0.51; confidence interval, 0.36 to 0.73, and 0.3, 0.17 to 0.57), and this was also the case for Y. enterocolitica at herd level (odds ratio, 0.08; confidence interval, 0.02 to 0.3). This study provides evidence that the pigs' environment should be accounted for when implementing control measures on farms against Campylobacter spp. and Y. enterocolitica. An extrapolation from the current Salmonella monitoring to the other two pathogens does not seem feasible.

[Monitoring of antibiotic consumption in pigs on agricultural farms]

The use of antibiotics in the course of one year (1 September, 2006 until - 31 August, 2007) was evaluated in 23 pig farms housing about 18,000 animals in one district in Northrhine-Westfalia. The veterinary application and dispensary documents (section13TAHAV) as well as respecting farmers' documents (ANTHV) served as data sources. Based on this data the amount of the used free substances, the number of treatment units as well as the therapy frequency were evaluated for each age group. Treatment frequency describes the average number of treatment days with one substance in a certain timeframe for a particular age group With the treatment frequency comparisons of antibiotic use can be made regardless of population size. It was shown in this study that piglets (suckling piglets) received about 6.1 antibiotic units per 100 days, fattening pigs about 4.6 units and sows 0.9 units per 100 days. All in all about 676 kg of free antibiotic substances were applied to the animals, especially tetracyclines (58%), sulfonamides/trimethoprim (16%), macrolides (13%) and beta-lactams (11%). These consumption figures do not reflect, however, the frequency of use in animal therapy. 34.7% of all applications performed in pigs were with makrolides, as opposed to only 25.1% with tetracyclines.This discrepancy in consumption levels when compared to the number of treatment units is due to the different dosages applied. With respect to the largest amount of drugs applied, these were used in the treatment of respiratory infections. But, most of the pigs were treated for skin disease.

[Variables describing the use of antibiotics in food-producing animals]

In order to represent relationships between the use of antibiotics in food-producing animals and the extend of bacteria with resistance characteristics, it is necessary to have access to information about dispensary and consumption of antibiotic drugs. This does not only require suitable detection methods, but also the establishment of figures which adequately describe the use of antibiotics both on the level of the enterprise, respectively veterinarian, as well as in cumulative form. In various countries different calculations for the analysis of data on antibiotic use are applied, therefore the results are not always comparable.The aim of this publication is to provide an overview of the national and international terminology and variables, to give concrete definitions and to identify those variables most suitable for particular objectives. Hereby a contribution to the standardization of evaluations should be made, to enable a comparison of data on use of antibiotics from various sources of information.

[Compilation of antibiotic use in farm animals via veterinary surgeries]

A feasibility study with 20 voluntarily participating veterinary surgeries was carried out in order to test, if the consumption of antibiotics in livestock can be determined systematically. Information about the statutory documents on the application of drugs of the participating surgeries were entered in a central database and analysed systematically. Surgeries that treat only livestock used significantly more antibiotics (number of treatment units per veterinarian) per veterinarian than surgeries that treat also small animals. The comparison of small and large surgeries showed that veterinarians in small surgeries treated fewer pigs and more cattle than their colleagues in large surgeries (number of treatment units per veterinarian). All in all, tetracyclines counted for more than 50% of all substances used (regarding the amount), followed by beta-lactams (25%) and sulfonamides incl. trimethoprim (11%). In poultry, polypeptides and beta-lactams were used most frequently. While cephalosporines were used only in cattle in a noteworthy frequency, fluoroquinolones were applied to poultry in almost 12% of all applications (application of one substance to one animal at one day). In total, it was shown, that harmonized documentation of consumption of antibiotics is feasible, but the relation of antibiotics to the treated population is problematic which has to be considered in the future.The number of applications is more suitable to assess the antibiotic use than the amount in kg, because the latter is dependent of the dosage. The impact of highly dosed substances like e.g. tetracyclines is overestimated by regarding the amount, while substances with low dosages are underestimated.

[Monitoring of antibiotic consumption in cattle on agricultural farms]

47 cattle farms with a total of 6500 cattle in one district of Northrhine-Westfalia took part in a study on the use of antibiotic substances on a voluntary basis. The veterinary application and dispensary documents (section 13 TAHAV) as well as respecting farmers' documents (ANTHV) served as data sources. All consumption data of a one-year-period (1 September, 2006 until 31 August, 2007) were entered into a central database. The amount (free substances in kg) of substances were highest for beta-lactams (48%) followed by sulfonamides inc. trimethoprim (17%) and tetracyclines (11%). All in all about 39 kg free antibiotic substances were applied.The analysis of the treatment frequency showed similar figures: beta-lactams were used in 35% of all cattle treatments, but tetracyclines were used only in 9% of the treatments. The highest number of therapies took place against udder diseases (45% of all free substances applied, 56% of all treatment units). The therapy frequency is the average number of applied treatment units (treatment days and number of substances) per age or production group within a certain time period and population. It corresponds basically to the DDD (Defined Daily Dose) of the Netherlands as well as to the ADD (Defined Animal Daily Dose) of Denmark, although these values cannot be compared directly because of different calculation methods. Within a period of 100 days every dairy calf in the study farms achieved 0.7, every dairy cow 0.9 (including teat sealer = one day) and every fattening cattle 0.01 treatment units averagely.

Case-control study on the risks of BSE infections in Northern Germany

This study was to identify risk factors for bovine spongiform encephalopathy (BSE) by means of individual case-control data. 43 BSE cases in a defined region in Lower Saxony and Schleswig-Holstein were compared with 84 control animals. Purchase of new breeding stock and cross contamination between feed on the farm did not seem to have influence on the BSE incidence in these regions. The results indicate independent risk patterns. Pattern 1: Cows with high milk yield seemed to be at risk on big farms with adjacent pig production and when they were not fed milk replacer. Pattern 2: Milk replacer (esp. from certain producers) is a risk factor for Non-Red Holstein cattle, low yielding cows and farms without pig production. Pattern 3: Red Holstein cattle not being fed milk replacer have a higher BSE risk than other breeds when they have a low milk yield and live on small farms with pig production. This study, like findings in Bavaria, Lower Saxony and Schleswig-Holstein, strengthens the hypothesis that BSE in Germany was caused by a feed mediated ubiquitous exposure to PrP(sc) during a confined time period. Producers, in need of buying animal derived feed components during that time slot, were more likely to spread the PrP(sc) than others. Their increased risk is not necessarily due to an inadequate purchasing policy, but can also be coincidental. The breed Red Holstein is not the risk factor itself but represents the risk from concentrated feed for animals during a susceptible age period (calves). Therefore, the authors suggest a continuous exclusion of animal-derived fat components from milk replacers.

Antibiotic susceptibility of Salmonella, Campylobacter coli, and Campylobacter jejuni isolated from Northern German fattening pigs

This study was conducted to assess the antimicrobial susceptibility rate of Salmonella and Campylobacter spp. isolated from Northern German fattening pigs. From 540 lymph node samples, 16 Salmonella Typhimurium, 1 Salmonella Brandenburg, 37 Campylobacter coli, and 11 Campylobacter jejuni strains were isolated. Antibiotic susceptibility testing was carried out by the broth dilution method. The 14 tested antibiotics for Salmonella were ampicillin, cefotaxime, ceftazidime, chloramphenicol, ciprofloxacin, colistin, florfenicol, gentamicin, kanamycin, nalidixic acid, streptomycin, sulfamethoxazole, tetracycline, and trimethoprim. The eight tested antibiotics for Campylobacter spp. were ampicillin, ampicillin-sulbactam (2:1), ciprofloxacin, erythromycin, gentamicin, nalidixic acid, sulfamethoxazole-trimethoprim (1:19), and tetracycline. In total, 93.7% (n = 16) of Salmonella Typhimurium, 75.7% (n = 37) of C. coli, and 54.5% (n = 11) of C. jejuni isolates were resistant to at least one of the tested antibiotics. Multiresistance to three antibiotics was observed in 75% of Salmonella Typhimurium, 16.2% of C. coli, and 0% of C. jejuni isolates. Pansusceptibility was detected in 6.3% of Salmonella Typhimurium, 24.3% of C. coli, and 45.5% of C. jejuni isolates. Multiresistance is defined as resistance to three or more antibiotics, and pansusceptibility is defined as not having resistance to any antibiotic. Regarding drugs of last resort--cefotaxime, ciprofloxacin, and nalidixic acid--resistance was not common among Salmonella (6.3%). The resistance rate of Campylobacter spp. to last-resort drugs--erythromycin, ciprofloxacin, and nalidixic acid--varied between species. The observed trend was not statistically significant. No C. coli isolates and few C. jejuni isolates (9.1%) were resistant to erythromycin. In contrast to C. jejuni, the C. coli isolates were more likely to be resistant to ciprofloxacin (9.1 and 18.9%, respectively) and nalidixic acid (0 and 13.5%, respectively). The same phenomenon was detected for tetracycline (27.3 and 62.2%, respectively), sulfamethoxazole (9.1 and 43.2%, respectively), and ampicillin (9.1 and 21.6%, respectively).

Putative risk factors for infections with Toggenburg Orbivirus in goat herds in Southern Switzerland (Canton of Ticino)

Toggenburg Orbivirus (TOV), only detected in goats, has been described as a member of the Bluetongue virus (BTV) serogroup. The transmission pathway of the virus seems different from other Bluetongue viruses (BTVs). The objective of this study was to explore risk factors, especially the influence of alpine pasture and the presence of other livestock species, for the presence of TOV infected goats on farms. Between February 2008 and September 2009, blood samples were collected and analyzed for TOV and hereupon a total of 60 goat farm owners (37 TOV-positive and 23 TOV-negative holdings) were interviewed. Additionally, goatlings were tested for TOV by rRT-PCR prior and after alpine pasture in 2009. These goatlings were positive for TOV only after the alpine pasture. The final logistic regression model included: "exposure to goats from other farms" (OR=10.12, p=0.007), "exposure of the goats to red deer" (OR=4.79, p=0.04) and "exposure to sheep from other farms" (OR=0.05, p=0.002). These variables do not implicitly include direct contact, and the findings are only vaguely indicative for a contact-driven transmission. Furthermore, it is likely that they are only associated with, and thus indicative for, an unknown risk factor associated with alpine pasture not measured in the study. The results of this screening study do not indicate iatrogenic transmission pathways as a main transmission mode and stimulate the formulation of hypotheses on the origin, the transmission pathway and other host species for TOV. Especially, the involvement of an insect vector in transmission on alpine pasture and the relevance of vertical transmission are to be clarified.

[Leptospire infections in pigs: epidemiology, diagnostics and worldwide occurrence]

Leptospirosis is a systemic disease affecting humans and animals, and pigs are generally considered the reservoir host species for the serovars Pomona, Bratislava and Tarrasovi. Endemic infections in swine herds generally remain subclinical, as do the vast majority of leptospire infections. However, when a susceptible breeding herd is infected for the first time or its immunity is compromised, considerable losses can occur due to abortion, stillbirths, weakly piglets or infertility. Infections in pigs caused by other serovars tend to occur only incidentally, vary regionally, and depend on other reservoir hosts, primarily rodents. Leptospires persist in porcine kidneys, and the Bratislava serovar, in the genital tract; it is excreted in urine and genital fluids. Leptospirosis is transmitted by direct or indirect contact with an infected animal. Fundamental research on porcine leptospirosis was conducted in the 1970s and 1980s. However, despite subsequent application of the most recent molecular biological methods, the pathogenesis of porcine leptospirosis is still largely unknown, and research results from the last 25 years on its incidence are very heterogeneous, due not only to regional differences but also to differences in the evaluation of diagnostic and population studies. Serological testing of pigs showed serovar prevalences ranging between as much as 16.3% (Pomona) and generally no more than 2.9% (Tarassovi), whereas antibodies against Bratislava were found in as many as 41.8% of pigs tested during the last 20 years, as in previous studies, indicating that this remains the most prevalent serovar.