Vetsuisse Public Health Conference 2018

A prize for the best poster and the best presentation were given this year.

The abstract is available below as a drop down window.

Listeria monocytogenes is an important foodborne pathogen that accounts for serious public health problems as well as significant food safety challenges and economic losses to the food industry. Infections of susceptible individuals results in various life-threatening conditions often associated with high mortality rates. Although most cases are sporadic in nature, occasionally large-scale outbreaks linked to common ready to eat food sources occur. To survive in rapidly changing harsh environmental conditions, L. monocytogenes has evolved various adaptive response mechanisms making its control in food a great challenge. This in turn generates populations that are phenotypically heterogeneous in natural situations. In order to improve the knowledge of mechanisms involved in L. monocytogenes nutrient utilization, stress resistance and virulence, different approaches including the Biolog phenotype microarray assay and whole genome analysis were applied to a set of clinical and food related L. monocytogenes isolates that include strains responsible for some of the food associated listeriosis outbreaks in Switzerland.

The strains were assessed for carbon sources utilization capacity, pH stress resistance and osmo-tolerance. Our analysis revealed that despite having a high synteny in gene organization and content, the strains exhibit significant phenotypic differences in carbon sources metabolism and resistance to osmotic and pH stresses relevant in host and food associated environments. Among the tested strains, strain Lm3163, associated with the 2005 Swiss Tomme cheese listeriosis outbreak utilized the highest number of C-sources whilst strain LL195 associated with the 1983 to 1987 Vacherin Mont’dor cheese outbreak was the most tolerant to osmotic and pH stress. Some substance such as L-norvaline, L-hydroxyproline and urease enhanced L. monocytogenes resistance to acidic stress in a strain dependent manner whilst β-phenylethylamine inhibited strains Lm3136 and Lm3163 tolerance to alkaline stress. Targeted phenotypic analyses confirmed selected PM array phenotypes as well as uncovered phenotypic variation in virulence among the examined strains. Outbreak associated Lineage I serotype 4b strains showed superior zebrafish embryo pathogenicity whilst strain Lm3163 showed the highest cell invasiveness. Genome sequence comparison in the strains uncovered a few subtle genetic differences between the strains, suggesting that differences in gene regulation and expression might be responsible for the bulk of the phenotypic differences detected. The obtained data provide a potential basis for the future design of improved Listeria specific media to enhance routine detection and isolation of this pathogen as well as development of novel methods for its control in food.

The abstract is available below as a drop down window.

Chad is a country placed in the Sahel region of the sub-Saharan African continent and is facing major difficulties providing their rural populations and their animals with adequate health services. This is due to limits in trained staff and lack of medical facilities, long distances for reaching the next medical facility and community member’s reluctance regarding western medicine. Community members in the Sahel region live in close contact with their animals and are thus, under high risk of being infected with transmissible diseases. For the improvement of these populations' health status, by the early detection of transmissible diseases, understanding the most common occurring symptoms is very valuable. Such perceptions can be achieved by observing human and animal symptoms concurrently. As a precursor study, for a later to be established case control study with a One Health approach in Chad, in total 92 interviews were conducted using a KoBoCollect survey. A team of Swiss and Chadian researchers visited camps and villages selected by the randomized cluster sampling. Throughout the interviews, community members were asked about the perceived frequency of given symptoms (cough, diarrhea, skin problems, fever, weight loss, weakness, vertigo, pale mucosa, swollen joints, ulcer, abnormal behavior) that occurred among members of their household and their animals during a past time frame. 41 of the interviews took place in villages and 51 interviews in camps within concentration zones. From the 92 interviews in total, community members counted 1373 household members and 9013 animals, which they took in account when asked for observed symptoms. In humans, fever was reported most frequent (720 cases), whilst among animals, cough was reported most frequent (1912 cases) in the past year. The analysis of the data is being proceeded. Regional, seasonal and species depending differences in the occurrence of symptoms are of interest. Data from the questionnaire on the frequency of occurring symptoms will later serve as a base line for the symptom recordings from the case control study. We would like to present preliminary data from the questionnaire study at the conference.

The conference will consist of five sessions, please consult our programme (PDF, 62 KB) for detailed information:

• Animal Welfare Session
• Epidemiology Session
• Food Safety Session
• Poster Session

The detailed programme of presentations and the keynote speakers are also presented below.

Alex Shaw initially trained as an economist and began work on animal health and livestock economics in the mid-1970s. She started her career in Nigeria and went on to work for the Veterinary Epidemiology and Economics Research Unit (VEERU) at Reading University. Much of her working life has focussed on tsetse and trypanosomiasis problem in Africa. With funding from FAO and the DFID-Animal Health Programme, she and colleagues developed an innovative methodology for mapping the monetary benefits of tsetse control, going on to link these to the costs of different control strategies, so as to map benefit-cost ratios.  Her studies of the tsetse and trypanosomiasis problem in livestock and in people led to her becoming increasingly involved in assessing the dual burdens imposed on human and animal populations by other neglected zoonotic diseases, such as rabies, brucellosis and tuberculosis. She now focuses on both human and animal health economics in a One Health context. She contributed to three European Union Framework 7 research projects on neglected zoonoses in Africa, targeting advocacy, training and notably research into impact through ICONZ (Integrated Control of Neglected Zoonoses). She was also involved in the Ecosystems Services for Poverty Alleviation (ESPA) project, Dynamic Drivers of Disease in Africa Consortium focussing on trypanosomiasis in Zambia. Currently she is working with colleagues at the University of Liverpool on two Gates-funded projects: one on the costs of tsetse control using tiny targets to help eliminate gambiense sleeping sickness, the other the first stages of a project to assess the global burden of animal diseases (GBADs). She works as an independent consultant based in Andover and is an Honorary Fellow of the University of Edinburgh’s Division of Infection and Pathway Medicine.

Abstract

DALYs, dogs and dollars: the economics zoonoses control

The development of the DALY, and the first GBD information published in 1996 ushered in an era in human health economics where it was possible to look at disease on a global scale. The transparency and essential simplicity of the DALY with its combination of YLLs and YLDs based on disability weights applicable across countries has made it a very usable tool.  To the veterinary constituency, the DALY highlighted the desirability of an internationally recognised metric which could be used to advocate for resources to control different diseases.  It was widely felt that the ideal would be to have a YLL/YLD based metric for animals. For companion animals, whose lifespan their owners seek to maximise, this concept works well, as shown in a recent article.  For livestock it becomes much more complex, for example where the objective is to rapidly fatten animals to a target slaughter weight. For wildlife, their much longer lifespans in captivity and differing conservation statuses introduce a similar dilemma.  Overall ranking across species adds further complexity: how to compare, say, rats, cats, dogs, cows and giant pandas? The notion of the zDALY provides an elegant solution. This dual metric uses the notion of time trade-off.  Livestock losses are initially valued in monetary terms and then divided by a measure of per capita income, enabling them to be assimilated with DALYs. Where there are no obvious commercial values, as for wildlife and companion animals, more complex time trade-off or willingness to pay approaches would be needed.

For the decision-maker looking at the costs and benefits of controlling zoonoses there were hitherto three approaches.  First, monetary items (intervention costs, human health costs saved and animal health losses averted) could be amalgamated, leading to a ‘net cost’ which could then be compared to the DALY.  Second, the separable costs method apportions the purely monetary benefits between the human and animal health sectors, and allocates costs in the same proportions.  Third, the DALY could be assigned, purely in the context of this type of analysis, a monetary value of between 1 and 3 years GDP per person (the same values used in WHO’s cost-effectiveness thresholds) and a monetary benefit-cost ratio calculated.  Incorporating the zDALY allows for a much needed fourth option.  It effectively mirrors the benefit-cost analysis approach, yielding identical relative shares for human and animal disease losses.  While they can be critiqued and could be improved, these last two methods provide veterinary and medical decision-makers each with a metric familiar to their own constituencies, producing results which can be used to guide investments in a consistent and context-appropriate manner.

The powerpoint presentation can be downloaded from the menu on the right.

Prof. Stefan Schwarz is managing director of the Institute of Microbiology and Epizootics at the Free University in Berlin. Stages in his carreer were at the Justus Liebig University in Giessen, the TiHo in Hannover, and at the College of Veterinary Medicine der China Agricultural University. Prof. Schwarz has published 436 peer-reviewed papers and 37 books/ book chapters. He has received the "Martin-Lerche-Forschungspreis der Deutschen Veterinärmedizinischen Gesellschaft", the "Preis der Akademie für Tiergesundheit” and the "Nachwuchsförderpreis der Deutschen Veterinärmedizinischen Gesellschaft”. He is a veterinary specialist (Fachtierarzt) for Epidemiology, for Molecular Genetics and Gene Technology, and for Microbiology.

Abstract

“One Health” is the evolution of the earlier used term “One Medicine” which recognizes that humans do not exist in isolation, but are a part of a larger whole, a living ecosystem, and that activities of each member of this ecosystem affect the others. The ‘One Health’ concept recognizes that the health of people is connected to the health of animals and the health of the environment. Interdisciplinary collaborations and communications in all aspects of healthcare of humans, animals and the environment are indispensable. Although the term "One Health" is fairly new, the concept has long been recognized, both nationally and globally. Since the 1800s, scientists have noted the similarities in disease processes among animals and humans, although human and animal medicine were separated until the 20^th century.

Under the ‘One Heath’ umbrella, many different topics can be summarized, one of which is antimicrobial resistance. Antimicrobial agents are used extensively in human medicine, veterinary medicine, but also in aquaculture and horticulture. In all sectors, bacterial resistance to antimicrobial agents occurs and the resistant bacteria as well as their resistance properties are interchanged. Examples will be provided that refer to emerging resistance properties seen recently among bacteria from humans and animals, including transferable resistance to (i) carbapenems, (ii) polymyxins, and (iii) oxazolidinones, all of which are antimicrobial agents listed as ‘critically important’ by the WHO. The examples presented will illustrate that antimicrobial resistant bacteria and their resistance genes have evolved in different sectors and are spread within and between these sectors via different transmission routes.

The powerpoint presentation can be downloaded from the menu on the right.

Ruedi Nager is Senior Lecturer at the Institute of Biodiversity, Animal Health and Comparative Medicine of the University of Glasgow.

I am an animal ecologist interested in how animals cope with the environment in which they live. Doing so I am using a range of techniques from behaviour and physiology. I did my PhD at the Universität Basel between 1989 - 1993 on the influence of local environmental factors on the laying date of Great Tits. I then moved via Groningen and Montpellier to Glasgow in 1996 where I still am today as a Senior Lecturer. I initially come to Glasgow to study the costs of egg laying in gulls.  I am particularly interested how wild birds cope with changes  and novel challenges in their natural environment as well as how captive animals cope their captive environment. My main study species are still tits and gulls in the wild. I have also worked for a few years with captive birds which made me very interested in the welfare issue of captive animals. Today I coordinate a diversity of ecological work on wild birds, mainly seabirds and together with my colleagues Dorothy McKeegan and Dominic McCafferty the thermal imaging work in Glasgow which now includes rodents as well directing a MSc programme in Animal Welfare Science, Ethics and Law. I am also an Editor of the ornithological journal Ibis.

Abstract

Stress is cool: Assessment of physiological state using thermal imaging

Assessment of stress is an important aspect of animal welfare as well as when studying the ecology of wild animals. The physiological stress response is typically assessed using measures of Levels of glucocorticoids from a blood sample. Glucocorticoid measurements however have a number of well-known limitations. We also know that the physiological stress response has a number of measurable effects other than elevated levels of glucocorticoids. One of these well-known effects is the change in core body temperature, which however in itself is an invasive and stressful procedure. Recent developments in thermal imaging technology now provides us with an affordable opportunity to study changes in body temperature of animals. Thermal images however measures the surface temperature rather than the core temperature and first we need to better understand the relationship between these two temperatures. In the following I will discuss results from our studies on assessing acute and chronic stress in both captive laying hens and wild blue tits and highlight opportunities and limitations of the use of thermal imaging for the individual state of animals.

The powerpoint presentation can be downloaded from the menu on the right.