Thomas Müller

University of Maryland, College Park, CGS, Maryland, United States

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Publications (106)318.55 Total impact

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    ABSTRACT: Rabies is a notoriously underreported and neglected disease of low-income countries. This study aims to estimate the public health and economic burden of rabies circulating in domestic dog populations, globally and on a country-by-country basis, allowing an objective assessment of how much this preventable disease costs endemic countries. We established relationships between rabies mortality and rabies prevention and control measures, which we incorporated into a model framework. We used data derived from extensive literature searches and questionnaires on disease incidence, control interventions and preventative measures within this framework to estimate the disease burden. The burden of rabies impacts on public health sector budgets, local communities and livestock economies, with the highest risk of rabies in the poorest regions of the world. This study estimates that globally canine rabies causes approximately 59,000 (95% Confidence Intervals: 25-159,000) human deaths, over 3.7 million (95% CIs: 1.6-10.4 million) disability-adjusted life years (DALYs) and 8.6 billion USD (95% CIs: 2.9-21.5 billion) economic losses annually. The largest component of the economic burden is due to premature death (55%), followed by direct costs of post-exposure prophylaxis (PEP, 20%) and lost income whilst seeking PEP (15.5%), with only limited costs to the veterinary sector due to dog vaccination (1.5%), and additional costs to communities from livestock losses (6%). This study demonstrates that investment in dog vaccination, the single most effective way of reducing the disease burden, has been inadequate and that the availability and affordability of PEP needs improving. Collaborative investments by medical and veterinary sectors could dramatically reduce the current large, and unnecessary, burden of rabies on affected communities. Improved surveillance is needed to reduce uncertainty in burden estimates and to monitor the impacts of control efforts.
    PLoS Neglected Tropical Diseases 04/2015; DOI:10.1371/journal.pntd.0003709 · 4.49 Impact Factor
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    ABSTRACT: Animal migration is a global phenomenon, but few studies have examined the substantial within- and between-species variation in migration distances. We built a global database of 94 land migrations of large mammalian herbivore populations ranging from 10 to 1638 km. We examined how resource availability, spatial scale of resource variability and body size affect migration distance among populations. Resource availability measured as normalised difference vegetation index had a strong negative effect, predicting a tenfold difference in migration distances between low- and high-resource areas and explaining 23% of the variation in migration distances. We found a weak, positive effect of the spatial scale of resource variability but no effect of body size. Resource-poor environments are known to increase the size of mammalian home ranges and territories. Here, we demonstrate that for migratory populations as well, animals living in resource-poor environments travel farther to fulfil their resource needs. © 2015 John Wiley & Sons Ltd/CNRS.
    Ecology Letters 04/2015; 18(6). DOI:10.1111/ele.12435 · 13.04 Impact Factor
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    ABSTRACT: The Middle East is a culturally and politically diverse region at the gateway between Europe, Africa and Asia. Spatial dynamics of the fatal zoonotic disease rabies among countries of the Middle East and surrounding regions is poorly understood. An improved understanding of virus distribution is necessary to direct control methods. Previous studies have suggested regular trans-boundary movement, but have been unable to infer direction. Here we address these issues, by investigating the evolution of 183 rabies virus isolates collected from over 20 countries between 1972 and 2014. We have undertaken a discrete phylogeographic analysis on a subset of 139 samples to infer where and when movements of rabies have occurred. We provide evidence for four genetically distinct clades with separate origins currently circulating in the Middle East and surrounding countries. Introductions of these viruses have been followed by regular and multidirectional trans-boundary movements in some parts of the region, but relative isolation in others. There is evidence for minimal regular incursion of rabies from Central and Eastern Asia. These data support current initiatives for regional collaboration that are essential for rabies elimination.
    PLoS Neglected Tropical Diseases 03/2015; 9(3):e0003569. DOI:10.1371/journal.pntd.0003569 · 4.49 Impact Factor
  • Ecology 01/2015; 96(5):150128114954005. DOI:10.1890/14-2010.1 · 5.00 Impact Factor
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    ABSTRACT: Due to the implementation of oral rabies vaccination (ORV) programmes, the European Union (EU) is becoming progressively free of red fox (Vulpes vulpes)-mediated rabies. Over the past three decades, the incidence of rabies had decreased substantially and vast areas of Western and Central Europe have been freed from rabies using this method of controlling an infectious disease in wildlife. Since rabies control is a top priority in the EU, the disease is expected to be eliminated from the animal source in the near future. While responsible authorities may consider the mission of eliminating fox rabies from the EU almost accomplished, there are still issues to be dealt with and challenges to be met that have not yet been in the focus of attention, but could jeopardise the ultimate goal. Among them are increasing illegal movements of animals, maintaining funding support for vaccination campaigns, devising alternative vaccine strategies in neighbouring Eastern European countries and the expanding distribution range of several potential rabies reservoir species in Europe.
    The Veterinary Journal 10/2014; 203(1). DOI:10.1016/j.tvjl.2014.10.026 · 2.17 Impact Factor
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    ABSTRACT: Background: Rabies is a neglected zoonotic disease caused by viruses belonging to the genus lyssavirus. In endemic countries of Asia and Africa, where the majority of the estimated 60,000 human rabies deaths occur, it is mainly caused by the classical rabies virus (RABV) transmitted by dogs. Over the last decade new species within the genus lyssavirus have been identified. Meanwhile 15 (proposed or classified) species exist, including Australian bat lyssavirus (ABLV), European bat lyssavirus (EBLV-1 and -2), Duvenhage virus (DUVV), as well as Lagos bat virus (LBV) and Mokola virus (MOKV) and recently identified novel species like Bokeloh bat lyssavirus (BBLV), Ikoma bat lyssavirus (IKOV) or Lleida bat lyssavirus (LLBV). The majority of these lyssavirus species are found in bat reservoirs and some have caused human infection and deaths. Previous work has demonstrated that Purified Chick Embryo Cell Rabies Vaccine (PCECV) not only induces immune responses against classical RABV, but also elicits cross-neutralizing antibodies against ABLV, EBLV-1 and EBLV-2.
    Human Vaccines and Immunotherapeutics 10/2014; 10(10). DOI:10.4161/21645515.2014.972741 · 3.64 Impact Factor
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    ABSTRACT: The European Union has used IPA (Instrument for Pre-Accession) funds to provide technical assistance and supplies for the eradication, monitoring and control of rabies in several pre-Accession countries. As a result, since 2010, multi-annual oral rabies vaccination (ORV) programmes for eliminating fox rabies have been launched in six Western Balkan countries. Here the implementation of the ORV programme in Kosovo, the smallest of the West Balkan countries, is described. Associated challenges under difficult political conditions, potential biases, and the results of rabies surveillance and monitoring of ORV campaigns (bait-uptake and immunisation rates) since 2010 are reported.
    International Journal of Medical Microbiology 10/2014; 304(7). DOI:10.1016/j.ijmm.2014.07.009 · 3.42 Impact Factor
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    ABSTRACT: Large scale vaccination with glycoprotein E (gE)-deleted marker vaccines and the rapid and reliable differentiation of wild-type and marker vaccine strains are important aspects in eradication programs for Suid herpesvirus 1 [SuHV-1, syn. Aujeszky's disease virus (ADV) or pseudorabies virus (PrV)]. Therefore, two multiplex real-time PCR (qPCR) assays for the genetic differentiation of wild-type and gE-deleted vaccine SuHV-1 strains have been developed. In the first multiplex qPCR SuHV-1 gB-gene specific detection was combined with a gE-gene specific assay and an internal control based on heterologous DNA. In the second system, a SuHV-1 UL19 (major capsid protein gene) assay, a different gE-gene specific assay and an internal control based on the beta-actin gene were combined. The gB-gene, UL19 as well as both gE-gene specific assays had an analytical sensitivity of less than 10 genome copies per reaction in the respective multiplex approaches. A series of reference strains including field isolates obtained from domestic and wild animals, and gE-deleted SuHV-1 were reliably detected, while genetically related non-SuHV-1 herpesviruses tested negative. Both newly developed triplex SuHV-1-specific qPCR assays are specific and sensitive methods for the rapid genetic differentiation of wild-type viruses and gE-deleted vaccine strains in a single reaction.
    Journal of Virological Methods 09/2014; 209. DOI:10.1016/j.jviromet.2014.08.022 · 1.88 Impact Factor
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    ABSTRACT: Background/Question/Methods Kernel-density estimation (KDE) is unique in its role as a statistically efficient yet non-parametric method for estimating the probability-density function of independent and identically distributed data. Despite its widespread application to home-range estimation, animal tracking data violates the underlying assumption of independence via the presence of autocorrelation. Here, we rederive the kernel-density estimator from first principles, dropping the assumption of independence, and allowing for the presence of autocorrelation. Our new kernel-density estimator is valid for autocorrelated data, which makes it perfectly suited for movement data. Results/Conclusions We test our method against both real and simulated data using a sample of Mongolian gazelles and their previously identified autocorrelated movement model. For the individual gazelle with the longest span of data, our autocorrelated KDE predicts a home-range area of 350,000 -- 800,000 km2, while the conventional estimate is only 46,000 -- 53,000 km2. These results are consistent with those from simulated data. As the sampling rate increases and data quality improves, the conventional home-range estimate shrinks with tightening confidence intervals.
    99th ESA Annual Convention 2014; 08/2014
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    ABSTRACT: 1. Reproductive asynchrony, a temporal mismatch in reproductive maturation between an individual and potential mates, may contribute to mate-finding failure and Allee effects that influence the establishment and spread of invasive species. Variation in elevation is likely to promote variability in maturation times for species with temperature-dependent development, but it is not known how strongly this influences reproductive asynchrony or the population growth of invasive species.2. We examined whether spatial variation in reproductive asynchrony, due to differences in elevation and local heterogeneity in elevation (hilliness), can explain spatial heterogeneity in the population growth rate of the gypsy moth, Lymantria dispar (L.), along its invasion front in Virginia and West Virginia, USA.3. We used a spatially explicit model of the effects of reproductive asynchrony on mating success to develop predictions of the influences of elevation and elevational heterogeneity on local population growth rates. Population growth rates declined with increased elevation and more modestly with increased elevational heterogeneity. As in earlier work, we found a positive relationship between the population growth rate and the number of introduced egg masses, indicating a demographic Allee effect. At high elevations and high heterogeneity in elevation, the population growth rate was lowest and the density at which the population tended to replace itself (i.e., the Allee threshold) was highest.4. An analysis of 22 years of field data also showed decreases in population growth rates with elevation and heterogeneity in elevation that were largely consistent with the model predictions. 5. These results highlight how topographic characteristics can affect reproductive asynchrony and influence mate-finding Allee effects in an invading non-native insect population. Given the dependence of developmental rates on temperature in poikilotherms, topographic effects on reproductive success could potentially be important to the population dynamics of many organisms.This article is protected by copyright. All rights reserved.
    Journal of Animal Ecology 08/2014; DOI:10.1111/1365-2656.12272 · 4.73 Impact Factor
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    ABSTRACT: 1. Many animals hoard seeds for later consumption and establish seed caches that are often located at sites with specific environmental characteristics. One explanation for the selection of non-random caching locations is the avoidance of pilferage by other animals. Another possible hypothesis is that animals choose locations that hamper the perishability of stored food, allowing the consumption of unspoiled food items over long time periods.2. We examined seed perishability and pilferage-avoidance as potential drivers for caching behaviour of Spotted nutcrackers (Nucifraga caryocatactes) in the Swiss Alps where the birds are specialized on caching seeds of Swiss stone pine (Pinus cembra).3. We used seedling establishment as an inverse measure of seed perishability, as established seedlings cannot longer be consumed by nutcrackers. We recorded the environmental conditions (i.e., canopy openness and soil moisture) of seed caching, seedling establishment and pilferage sites.4. Our results show that sites of seed caching and seedling establishment had opposed micro-environmental conditions. Canopy openness and soil moisture were negatively related to seed caching but positively related to seedling establishment, i.e., nutcrackers cached seeds preferentially at sites where seed perishability was low. We found no effects of environmental factors on cache pilferage, i.e. neither canopy openness nor soil moisture had significant effects on pilferage rates. We thus could not relate caching behaviour to pilferage-avoidance.5. Our study highlights the importance of seed perishability as a mechanism for seed caching behaviour, which should be considered in future studies. Our findings could have important implications for the regeneration of plants whose seeds are dispersed by seed-caching animals, as the potential of seedlings to establish may strongly decrease if animals cache seeds at sites that favour seed perishability rather than seedling establishment.This article is protected by copyright. All rights reserved.
    Journal of Animal Ecology 08/2014; DOI:10.1111/1365-2656.12283 · 4.73 Impact Factor
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    ABSTRACT: Studies on the ranging behaviour of birds often suggest that ranges vary seasonally with larger ranges in the non-breeding compared to the breeding season. However, due to limitations in tracking methods very little is known about the underlying processes driving seasonal differences in ranging behaviour, especially in fragmented, heterogeneous landscapes. Such knowledge is particularly important if movements deliver essential ecosystem functions such as seed dispersal. We contrasted the daily ranging behaviour between the breeding and non-breeding season of a frugivorous bird and demonstrate how larger seasonal ranges in the non-breeding season emerge through switching from a stationary home range behaviour to nomadism. We tracked movements of 29 male trumpeter hornbills Bycanistes bucinator across a fragmented landscape of eastern South Africa during different breeding and non-breeding seasons using high temporal resolution GPS data-loggers. Birds in the breeding seasons showed a typical, stationary home range pattern. In the non-breeding seasons birds, rather than expanding their stationary daily ranges, switched to nomadic movements that were characterized by shifts of the general location of daily ranges to a different area every couple of days. We also found that during the breeding seasons hornbills were mostly located in large continuous forests; birds in the non-breeding seasons frequently used forest patches within the agricultural landscape and residential areas. These seasonal differences in the movement behaviour of trumpeter hornbills may have important consequences for seed dispersal of plant species. Our findings show how seasonal range expansion of frugivorous birds may be driven by fundamental behavioural changes that have important consequences for ecosystem processes.
    Ecography 06/2014; 38(1). DOI:10.1111/ecog.00522 · 4.21 Impact Factor
  • Remote Sensing 06/2014; 6(6):5717-5731. DOI:10.3390/rs6065717 · 2.62 Impact Factor
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    ABSTRACT: Abstract Understanding animal movement is a key challenge in ecology and conservation biology. Relocation data often represent a complex mixture of different movement behaviors, and reliably decomposing this mix into its component parts is an unresolved problem in movement ecology. Traditional approaches, such as composite random walk models, require that the timescales characterizing the movement are all similar to the usually arbitrary data-sampling rate. Movement behaviors such as long-distance searching and fine-scale foraging, however, are often intermixed but operate on vastly different spatial and temporal scales. An approach that integrates the full sweep of movement behaviors across scales is currently lacking. Here we show how the semivariance function (SVF) of a stochastic movement process can both identify multiple movement modes and solve the sampling rate problem. We express a broad range of continuous-space, continuous-time stochastic movement models in terms of their SVFs, connect them to relocation data via variogram regression, and compare them using standard model selection techniques. We illustrate our approach using Mongolian gazelle relocation data and show that gazelle movement is characterized by ballistic foraging movements on a 6-h timescale, fast diffusive searching with a 10-week timescale, and asymptotic diffusion over longer timescales.
    The American Naturalist 05/2014; 183(5):E154-67. DOI:10.1086/675504 · 4.45 Impact Factor
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    ABSTRACT: In Germany, rabies in bats is a notifiable zoonotic disease, which is caused by European bat lyssaviruses type 1 and 2 (EBLV-1 and 2), and the recently discovered new lyssavirus species Bokeloh bat lyssavirus (BBLV). As the understanding of bat rabies in insectivorous bat species is limited, in addition to routine bat rabies diagnosis, an enhanced passive surveillance study, i.e. the retrospective investigation of dead bats that had not been tested for rabies, was initiated in 1998 to study the distribution, abundance and epidemiology of lyssavirus infections in bats from Germany. A total number of 5478 individuals representing 21 bat species within two families were included in this study. The Noctule bat (Nyctalus noctula) and the Common pipistrelle (Pipistrellus pipistrellus) represented the most specimens submitted. Of all investigated bats, 1.17% tested positive for lyssaviruses using the fluorescent antibody test (FAT). The vast majority of positive cases was identified as EBLV-1, predominately associated with the Serotine bat (Eptesicus serotinus). However, rabies cases in other species, i.e. Nathusius' pipistrelle bat (Pipistrellus nathusii), P. pipistrellus and Brown long-eared bat (Plecotus auritus) were also characterized as EBLV-1. In contrast, EBLV-2 was isolated from three Daubenton's bats (Myotis daubentonii). These three cases contribute significantly to the understanding of EBLV-2 infections in Germany as only one case had been reported prior to this study. This enhanced passive surveillance indicated that besides known reservoir species, further bat species are affected by lyssavirus infections. Given the increasing diversity of lyssaviruses and bats as reservoir host species worldwide, lyssavirus positive specimens, i.e. both bat and virus need to be confirmed by molecular techniques.
    PLoS Neglected Tropical Diseases 05/2014; 8(5):e2835. DOI:10.1371/journal.pntd.0002835 · 4.49 Impact Factor
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    ABSTRACT: Animal migration, one of the most fascinating of all behaviors, links ecosystems and has profound ecological consequences over very large scales. Ungulatemigrations are among the most imperiled ecological phenomena in the world
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    Conservation Biology 04/2014; 28(6). DOI:10.1111/cobi.12297 · 4.32 Impact Factor
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    ABSTRACT: The "gold standard" for post-mortem rabies diagnosis is the direct fluorescent antibody test (FAT). However, in the case of ante-mortem non-neural sample material or decomposed tissues, the FAT reaches its limit, and the use of molecular techniques can be advantageous. In this study, we developed and validated a reverse transcription PCR cascade protocol feasible for the classification of samples, even those for which there is no epidemiological background knowledge. This study emphasises on the most relevant European lyssaviruses. In a first step, two independent N- and L-gene based pan-Lyssavirus intercalating dye assays are performed in a double-check application to increase the method's diagnostic safety. For the second step, characterisation of the lyssavirus positive samples via two independent multiplex PCR-systems was performed. Both assays were probe-based, species-specific multiplex PCR-systems for Rabies virus, European bat lyssavirus type 1 and 2 as well as Bokeloh bat lyssavirus. All assays were validated successfully with a comprehensive panel of lyssavirus positive samples, as well as negative material from various host species. This double-check strategy allows for both safe and sensitive screening, detection and characterisation of all lyssavirus species of humans and animals, as well as the rapid identification of currently unknown lyssaviruses in bats in Europe.
    Journal of virological methods 03/2014; 203. DOI:10.1016/j.jviromet.2014.03.014 · 1.88 Impact Factor
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    ABSTRACT: 1.By viewing animal movement paths as realizations of a continuous stochastic process, we introduce a rigorous likelihood method for estimating the statistical parameters of movement processes. This method makes no assumption of a hidden Markov property, places no special emphasis on the sampling rate, is insensitive to irregular sampling and data gaps, can produce reasonable estimates with limited sample sizes, and can be used to assign AIC values to a vast array of qualitatively different models of animal movement at the individual and population levels. 2.To develop our approach, we consider the likelihood of the first two cumulants of stochastic processes, the mean and autocorrelation functions. Together, these measures provide a considerable degree of information regarding searching, foraging, migration, and other aspects of animal movement. As a specific example, we develop the likelihood analyses necessary to contrast performance of animal movement models based on Brownian motion, the Ornstein-Uhlenbeck process, and a generalization of the Ornstein-Uhlenbeck process that includes ballistic bouts. 3.We then show how our framework also provides a new and more accurate approach to home range estimation when compared to estimators that neglect autocorrelation in the movement path. 4.We apply our methods to a dataset on Mongolian gazelles (Procapra gutturosa) to identify the movement behaviors and their associated time and length scales that characterize the movement of each individual. Additionally, we show that gazelle annual ranges are vastly larger than those of other non-migratory ungulates. This article is protected by copyright. All rights reserved.
    Methods in Ecology and Evolution 03/2014; 5(5). DOI:10.1111/2041-210X.12176 · 5.32 Impact Factor
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    ABSTRACT: Quantifying ecosystem functions in spatially explicit ways is important for management decisions in increasingly fragmented landscapes. Between-patch dispersal of seeds by frugivores constitutes a key ecosystem function to ensure connectivity for fleshy-fruited plants. However, to date, methodological hurdles have limited our understanding of dispersal pathways on the landscape scale.We made use of newly available tracking devices and combined movement data of 30 trumpeter hornbills Bycanistes bucinator with gut passage times and high-resolution habitat data in a fragmented forest landscape in South Africa. We identified each potential seed dispersal path and distinguished whether potential seed transport happened to a different forest patch (between-patch dispersal), within the same patch (within-patch dispersal) or into the habitat matrix (failed dispersal). To quantify functional landscape connectivity, we identified all possible between-patch connections and used graph networks to estimate landscape connectivity provided by hornbills.Although potential between-patch dispersal events were rare (on average 7% compared to 20% failed dispersal and 73% within-patch dispersal), hornbills could cover distances of up to 15 km. Hornbills visited over 100 forest patches and connected a habitat network with an extent of about 50 km, which increased the potential functional connectivity of the landscape more than twofold.We identified habitat patches that were critical stepping stones for seed dispersal pathways. Without these stepping stones, the network would likely disintegrate into separated components and lead to isolation of forest fragments.Synthesis and applications. We showed that large frugivorous birds can greatly improve functional connectivity for fleshy-fruited plants across broad scales, linking habitat patches in fragmented forest landscapes. Combining high-resolution movement and landscape data in graph networks allows identifying seed dispersal pathways and critical stepping stones in fragmented landscapes. This approach addresses the general challenge of spatially explicit mapping of ecosystem services and can be widely incorporated in reserve design and landscape-level conservation planning.
    Journal of Applied Ecology 03/2014; 51(3). DOI:10.1111/1365-2664.12247 · 4.75 Impact Factor

Publication Stats

1k Citations
318.55 Total Impact Points

Institutions

  • 2008–2015
    • University of Maryland, College Park
      • Department of Biology
      CGS, Maryland, United States
  • 2005–2015
    • Friedrich Loeffler Institute
      • • Institute of Molecular Biology
      • • Institute of Epidemiology
      Griefswald, Mecklenburg-Vorpommern, Germany
  • 2014
    • University of Chicago
      Chicago, Illinois, United States
    • Biodiversität und Klima - Forschungszentrum
      Frankfurt, Hesse, Germany
  • 2013–2014
    • Loyola University Maryland
      • Department of Biology
      Baltimore, Maryland, United States
    • Goethe-Universität Frankfurt am Main
      Frankfurt, Hesse, Germany
    • Conservation Biology Institute
      Corvallis, Oregon, United States
  • 2012
    • Croatian Veterinary Institute
      • Department of Virology
      Zagrabia, Grad Zagreb, Croatia
    • University of Duisburg-Essen
      Essen, North Rhine-Westphalia, Germany
  • 2010
    • University of Zurich
      • Vetsuisse-Faculty
      Zürich, Zurich, Switzerland
    • MSD Animal Health, Germany
      Schleisheim, Bavaria, Germany