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In Switzerland, just over 700 veterinary medicinal products are authorized. Nevertheless, in practice veterinarians are often confronted with extraordinary situations in which a suitable veterinary medicinal product is not authorized, unavailable or otherwise not applicable. For livestock and horses in particular, this poses a challenge for pharmacotherapy due to food safety regulations. In these cases, the reclassification assistant can be used to determine whether and how a medicinal product containing the appropriate drug can be reclassified and correctly applied in food-producing animals. The users will be guided step by step with selectable options through the online assistant. If the desired reclassification is permitted in the legal framework, information on the withdrawal periods to be observed for the chosen medicinal product will be provided. This online assistant follows an algorithm based on the reclassification cascade and applicable food safety regulations.In der Schweiz sind etwas mehr als 700 Tierarzneimittel zugelassen. Trotzdem stehen die Tierärzte in der Praxis immer wieder vor ausserordentlichen Situationen, in denen ein passendes Tierarzneimittel nicht zugelassen, nicht verfügbar oder aus anderen Gründen nicht anwendbar ist. Für die Pharmakotherapie stellt dies vor allem bei Nutztieren und Pferden auf Grund der gesetzlichen Vorschriften bezüglich Lebensmittelsicherheit eine Herausforderung dar. In diesen Fällen kann mit Hilfe des Umwidmungs-Assistenten geprüft werden, ob ein Präparat mit dem passenden Wirkstoff umgewidmet werden kann und wie dieses Präparat korrekt anzuwenden ist. Die Nutzerinnen und Nutzer werden schrittweise mit wählbaren Optionen durch den Online-Assistenten geführt. Sofern die gewünschte Umwidmung im gesetzlichen Rahmen erlaubt ist, werden Angaben zu den für das Arzneimittel einzuhaltenden Absetzfristen angezeigt. Der Umwidmungs-Assistent folgt dabei einem auf der Umwidmungskaskade und den Bestimmungen der Lebensmittelsicherheit basierenden Algorithmus.En Suisse, un peu plus de 700 médicaments vétérinaires sont autorisés. Néanmoins, dans la pratique, les vétérinaires sont souvent confrontés à des situations extraordinaires dans lesquelles un médicament vétérinaire approprié n’est ni autorisé, ni disponible, ni utilisable pour d’autres raisons. En particulier pour le bétail et les chevaux, cela pose un défi pour la pharmacothérapie en raison de la réglementation sur la sécurité alimentaire. Dans ces cas, l’assistant de reconversion peut être utilisé pour déterminer si et comment un médicament contenant le principe actif approprié peut être reconverti et correctement appliqué. Les utilisateurs seront guidés pas à pas avec des options sélectionnables via l’assistant en ligne. Si la reconversion souhaitée est autorisée dans le cadre légal, des informations sur les délais d’attente à respecter pour le médicament choisi seront fournies. Cet assistant en ligne suit un algorithme basé sur la cascade de reconversion les réglementations applicables en matière de sécurité alimentaire.In Svizzera sono poco più di 700 i medicamenti veterinari omologati. Tuttavia, nella pratica, i veterinari si trovano ripetutamente confrontati a situazioni straordinarie in cui un medicamento veterinario adatto non è omologato, non disponibile o non utilizzabile per altri motivi. Per la farmacoterapia, ciò rappresenta una sfida, soprattutto per gli animali da reddito e i cavalli, a causa delle disposizioni legali in materia di sicurezza delle derrate alimentari. In questi casi, l’assistente al cambiamento di destinazione può essere utilizzato per verificare se un preparato con il principio attivo appropriato può ottenere una nuova destinazione e come questo preparato può essere utilizzato correttamente. Gli utenti vengono guidati passo dopo passo attraverso l’assistente online con opzioni selezionabili. Se il cambiamento di destinazione desiderato è consentito dal quadro giuridico, vengono visualizzate le informazioni sui termini di attesa da rispettare per il medicamento. L’assistente per il cambiamento di destinazione segue un algoritmo basato sulle norme di sicurezza delle derrate alimentari e sulla cascata per il cambiamento di destinazione.

Monitoring programs and guidelines on the use of antibiotics and antibiotic resistance in human and veterinary medicine have been developed worldwide to promote the prudent use of antibiotics in recent years. However, such information on the use of antibiotics in exotic pets is absent. This fact must be taken into account, since the number of exotic pet patients is constantly increasing and the administration of antibiotics is particular challenging due to the diversity of species and the differences in physiology. The present study reports the results of a survey of frequently used antibiotics and the criteria of antibiotic usage in exotic pets (rabbits, rodents, birds and reptiles) among Swiss veterinarians. These data should form the basis for the development of antibiotic usage guidelines in exotic pets. A total of 61 veterinarians returned the questionnaire. The most important decision-making criteria for antibiotic treatment and antibiotic selection were clinical symptoms (55/59, 93% for antibiotic treatment and 40/59, 68% for antibiotic selection), experience (41/59, 69% and 36/59, 61%, respectively) and textbooks (39/59, 66% and 40/59, 68%). The most important decision-making criteria for dosage and duration of therapy were textbooks (59/59, 100%) and experience (31/59, 53%). The use of a microbial culture was used as a decision criterion for both antibiotic treatment and antibiotic selection by 39% of the participants, sensitivity testing was chosen as a decision criterion by 37% for antibiotic treatment and by 46% for antibiotic selection. Fluoroquinolones were used most frequently, 46/56 (82% of the participants) for rabbits, 49/57 (86%) for rodents, 36/37 (97%) for reptiles and 38/46 (83%) for birds. The vast majority of veterinarians (57/58, 98%) would consult a guide for the use of antibiotics. The frequent use of critical antibiotics in exotic pets underscores the need for a guide to the prudent use of antibiotics. The positive influence of such guidelines has already been proven in dogs and cats.Zur Förderung des umsichtigen Umgangs mit Antibiotika wurden in den vergangenen Jahren weltweit Überwachungsprogramme und Leitlinien zum Antibiotikaeinsatz und zur Antibiotikaresistenz in der Human- und Veterinärmedizin entwickelt. Allerdings fehlen solche bislang für exotische Heimtiere, ebenso wie umfassende Informationen zum Antibiotikaeinsatz in der tierärztlichen Praxis. Diesem Umstand ist Rechnung zu tragen, zumal die Zahl der exotischen Heimtierpatienten stetig zunimmt und die Verabreichung von Antibiotika aufgrund der Artenvielfalt und der Unterschiede in der Physiologie eine besondere Herausforderung darstellt. In der vorliegenden Untersuchung wurde eine Umfrage durchgeführt, um einen Überblick über häufig verwendete Antibiotika und die Kriterien für den Antibiotikaeinsatz bei exotischen Heimtieren (Kaninchen, Nager, Vögel und Reptilien) bei Schweizer Tierärzte/-innen zu erhalten. Diese Daten sollen die Grundlage darstellen für die Entwicklung eines Antibiotika-Leitfadens für exotische Heimtiere. Insgesamt 61 Tierärzte/-innen haben den Fragebogen beantwortet. Die wichtigsten Entscheidungskriterien für eine Antibiotikabehandlung und die Antibiotikaauswahl waren Symptomatik (55/59, 93% für Antibiotikabehandlung bzw. 40/59, 68% für Antibiotikaauswahl), Erfahrung (41/59, 69% bzw. 36/59, 61%) und Fachbücher (39/59, 66% bzw. 40/59, 68%). Die wichtigsten Entscheidungskriterien für Dosis und Therapiedauer waren Fachbücher (59/59, 100%) und Erfahrung (31/59, 53%). Die Nutzung einer mikrobiellen Kultur wurde von 39% der Teilnehmenden als Entscheidungskriterium sowohl für die Antibiotikabehandlung als auch für die Antibiotikawahl angegeben und ein Antibiogramm wurde von 37% als Entscheidungskriterium für eine Antibiotikabehandlung und 46% für die Antibiotikawahl gewählt. Es zeigte sich, dass Fluorchinolone am häufigsten eingesetzt werden, und zwar bei 46/56 (82% der Teilnehmenden) für Kaninchen, 49/57 (86%) für Nagetiere, 36/37 (97%) für Reptilien und 38/46 (83%) für Vögel. Die überwiegende Mehrheit der Tierärzte/-innen (57/58, 98%) gaben an, dass sie für den Einsatz von Antibiotika einen Leitfaden konsultieren würden. Die häufige Verwendung von kritischen Antibiotika bei exotischen Heimtieren unterstreicht die Notwendigkeit eines Leitfadens zum umsichtigen Einsatz von Antibiotika. Der positive Einfluss solcher Leitlinien ist für Hunde und Katzen bereits nachgewiesen worden.Pour promouvoir une utilisation prudente des antibiotiques, des programmes de surveillance et des lignes directrices sur l’utilisation des antibiotiques et la résistance aux antibiotiques en médecine humaine et vétérinaire ont été élaborés dans le monde entier ces dernières années. Cependant, il n’existe actuellement aucune information de ce type en ce qui concerne les nouveaux animaux de compagnie ainsi que des informations exhaustives sur l’utilisation d’antibiotiques dans la pratique vétérinaire. Ce fait doit être pris en compte, d’autant plus que le nombre d’nouveaux animaux de compagnie est en constante augmentation dans la patientèle et que l’administration d’antibiotiques est un défi particulier en raison de la diversité des espèces et des différences de physiologie. Dans la présente étude, une enquête a été menée pour avoir un aperçu des antibiotiques fréquemment utilisés et de leurs critères d’utilisation chez les nouveaux animaux de compagnie (lapins, rongeurs, oiseaux et reptiles) auprès de vétérinaires suisses. Ces données sont destinées à servir de base à l’élaboration d’un guide sur les antibiotiques pour les animaux exotiques. Au total 61 vétérinaires ont répondu au questionnaire. Les critères de décision les plus importants pour le traitement antibiotique et la sélection d’un antibiotique étaient les symptômes (55/59, 93% pour le traitement antibiotique et 40/59, 68% pour la sélection de l’antibiotique), l’expérience (41/59, 69% et 36/59, 61%, respectivement) et la littérature spécialisée (39/59, 66% et 40/59, 68%). Les critères de décision les plus importants pour e dosage et la durée du traitement étaient la littérature spécialisée (59/59, 100%) et l’expérience (31/59, 53%). L’utilisation d’une culture bactériologique a été donnée par 39% des participants comme critère de décision à la fois pour le traitement antibiotique et le choix de l’antibiotique et un antibiogramme a été choisi par 37% comme critère de décision pour le traitement antibiotique et 46% pour le choix de l’antibiotique. Il a été constaté que les fluoroquinolones sont utilisées le plus fréquemment, chez 46/56 (82% des participants) pour les lapins, 49/57 (86%) pour les rongeurs, 36/37 (97%) pour les reptiles et 38/46 (83%) pour les oiseaux. La grande majorité des vétérinaires (57/58, 98%) a déclaré qu’ils consulteraient un guide pour l’utilisation des antibiotiques. L’utilisation fréquente d’antibiotiques critiques chez les nouveaux animaux de compagnie souligne la nécessité d’un guide sur l’utilisation prudente des antibiotiques. L’influence positive de ces recommandations a déjà été prouvée pour les chiens et les chats.Al fine di promuovere un uso prudente degli antibiotici, negli ultimi anni sono stati sviluppati in tutto il mondo programmi di sorveglianza e linee guida sull’uso degli antibiotici e sulla resistenza agli antibiotici sia in medicina umana che veterinaria. Tuttavia, non sono ancora disponibili queste informazioni per gli animali da compagnia esotici, nonché informazioni complete sull’uso degli antibiotici nella pratica veterinaria. Perciò questa mancanza va presa in considerazione, soprattutto perché il numero dei pazienti tra gli animali da compagnia esotici è in costante aumento e la somministrazione di antibiotici è una sfida a causa della diversità delle specie e delle differenze nella fisiologia. Nel presente studio, è stato condotto un sondaggio per ottenere una panoramica degli antibiotici usati di frequente e dei criteri per l’uso degli antibiotici negli animali da compagnia esotici (conigli, roditori, uccelli e rettili) da parte dei veterinari svizzeri. Questi dati intendono costituire la base per lo sviluppo di linee guida per gli antibiotici usati negli animali da compagnia esotici. Un totale di 61 veterinari ha risposto al questionario. I criteri decisivi più importanti per la scelta di un trattamento antibiotico e per la selezione degli antibiotici erano i sintomi (55/59, 93% per il trattamento antibiotico e 40/59, 68% per la selezione antibiotica), l’esperienza (41/59, 69% e 36/59, 61%, rispettivamente) e la letteratura specialistica (39/59, 66% e 40/59, 68%). I criteri decisivi più importanti per la dose e la durata della terapia erano la letteratura specialistica (59/59, 100%) e l’esperienza (31/59, 53%). L’uso di una coltura microbica è stato dato dal 39% dei partecipanti come criterio decisivo sia per il trattamento antibiotico che per la scelta dell’antibiotico, e un antibiogramma è stato scelto dal 37% come criterio decisionale per il trattamento antibiotico e dal 46% per la scelta dell’antibiotico. Il risultato del sondaggio ha dato che i fluorochinoloni sono usati più frequentemente, in 46/56 (82% dei partecipanti) per i conigli, 49/57 (86%) per roditori, 36/37 (97%) per i rettili e 38/46 (83%) per gli uccelli. La grande maggioranza dei veterinari (57/58, 98%) ha indicato che consulterebbe delle linee guida per l’uso degli antibiotici. L’uso frequente di antibiotici critici in animali da compagnia esotici sottolinea la necessità di linee guida per un uso prudente degli antibiotici. Le ripercussioni positive di tali linee guida sono già state dimostrate per i cani e i gatti.

The administration of antibiotics in livestock has been criticized for many years, in particular because of an inappropriate use and the appearance of antibiotic residues in the environment, which can promote the emergence and spread of resistant bacteria. However, antibiotics are essential for the successful and sustainable control of bacterial pathogens. With the aim of optimizing the use of antibiotics in food animals and minimizing the prevalence of resistant bacteria, AntibioticScout. ch provides a decision aid for the prudent use of antimicrobial drugs. This approach emphasizes the importance of supportive therapy and the hallmarks of preventive concepts. Procedures to improve animal health and animal welfare in accordance with the principles of good veterinary practice are primary and effective tools to reduce the use of antimicrobial drugs. The necessary reduction in the use of antibiotics must, therefore, be accompanied by appropriate management strategies in animal husbandry. In particular, hygiene, animal welfare and biosecurity measures are crucial to ensure an optimal health status in farm animals.Seit Jahren wird der Einsatz von Antibiotika in der Nutztierhaltung diskutiert, insbesondere wegen unsachgemässer Anwendung sowie der Umweltbelastung mit Antibiotikarückständen, die das Auftreten und die Ausbreitung von Resistenzen fördern. Antibiotika sind jedoch wesentlich für eine erfolgreiche und nachhaltige Bekämpfung bakterieller Krankheitserreger. Mit dem Ziel, den Einsatz von Antibiotika in der Nutztierhaltung zu optimieren und damit die Entwicklung von Resistenzen zu reduzieren, bietet AntibioticScout.ch eine Entscheidungshilfe für den umsichtigen Gebrauch dieser Wirkstoffe („prudent use“). Gleichzeitig wird das Augenmerk auf die unterstützende Therapie und Ansätze zur Prävention gerichtet. Massnahmen zur Verbesserung der Tiergesundheit und des Tierwohls unter Beachtung der Grundsätze der guten veterinärmedizinischen Praxis sind primäre und wirkungsvolle Instrumente zur Reduzierung des Antibiotikaeinsatzes. Diese notwendige Reduktion muss daher mit geeigneten Managementstrategien in der Tierhaltung einhergehen. Insbesondere Hygiene und tiergerechte Haltungsbedingungen sowie die Implementierung von Biosicherheits-Massnahmen sind für die Optimierung der Gesundheit der Nutztierbestände entscheidend.On discute depuis des années de l’usage des antibiotiques dans l’élevage des animaux de rente, en particulier en ce qui concerne leur utilisation incorrecte et la charge environnementale liée à des résidus d’antibiotiques susceptibles de favoriser l’apparition et la propagation de résistances. Toutefois les antibiotiques sont essentiels pour assurer une lutte efficace et durable contre les maladies d’origine bactérienne. Dans le but d’optimiser l’usage des antibiotiques dans l’élevage des animaux de rente et, par conséquence, de réduire le développement de résistances, AntibioticScout.ch propose une aide à la décision pour un usage prudent de ces substances („prudent use“). Parallèlement, on attire l’attention sur les traitements adjuvants et sur les mesures de prévention. Des mesures visant à améliorer la santé et le bien-être des animaux en tenant compte des fondements d’une bonne pratique vétérinaire sont des instruments efficaces pour réduire l’usage des antibiotiques. Cette réduction indispensable doit donc être combinée avec des mesures de gestion adéquates dans les élevages. Ce sont en particulier l’hygiène et les conditions d’élevage correctes ainsi que la mise en place de mesures de biosécurité qui sont décisives pour l’optimisation de la santé des troupeaux.Da anni, l’uso di antibiotici nell’allevamento di animali da reddito viene discusso, in particolare a causa dell’uso improprio e dell’esposizione ambientale dei residui provenienti dagli antibiotici che provocano la comparsa e la diffusione di resistenze. Tuttavia, gli antibiotici sono essenziali per una lotta efficace e duratura contro agenti patogeni batterici. Allo scopo di ottimizzare l’uso di antibiotici nell’allevamento di animali da reddito e quindi di ridurre lo sviluppo di resistenze, Antibiotic Scout.ch offre uno strumento decisionale per un impiego prudente di queste sostanze (“prudent use”). Contemporaneamente, l’attenzione è rivolta alle terapie e ai principi di supporto per la prevenzione. Le misure per migliorare la salute degli animali e il loro benessere nel rispetto dei principi di una buona pratica veterinaria sono gli strumenti primari ed efficaci per ridurre l’uso di antibiotici. Queste riduzioni necessarie devono essere accompagnate da adatte strategie di allevamento. In particolare, l’igiene e le condizioni di tenuta corrette degli animali così come l’implementazione di misure di biosicurezza sono determinanti per ottimizzare la salute degli animali di allevamento.

Antibiotic-resistant bacteria are of increasing importance in human and veterinary medicine. Also, small animal clinics and practices are facing patients carrying antibiotic-resistant bacteria. What risk do these animals pose for animal owners? How can the risk of transmission to humans be reduced? A working group of human and veterinary medicine experts developed a guide for dog or cat owners with pets carrying antibiotic-resistant bacteria. The guide contains background information on the most important antibiotic-resistant bacteria in dogs and cats, namely methicillin-resistant staphylococci and extended spectrum beta-lactamase (ESBL)- and carbapenemase-producing Enterobacteriaceae. Measures are listed to reduce the risk of transmission to humans. This review explains the pathophysiology, occurrence and risk factors of these bacteria in dogs, cats and humans. Recommended measures are outlined.Antibiotikaresistente Keime sind in der Human- und Veterinärmedizin von zunehmender Bedeutung. Auch Kleintierkliniken und -praxen sind mit Patienten konfrontiert, bei denen antibiotikaresistente Keime nachgewiesen wurden. Welches Risiko stellen diese Tiere für die Tierhalter dar? Wie kann das Risiko einer Übertragung auf den Menschen reduziert werden? Durch eine Arbeitsgruppe mit Fachexperten aus Human- und Veterinärmedizin wurde ein Ratgeber für Halter erarbeitet, deren Hunde oder Katzen Träger von antibiotikaresistenten Keimen sind. Der Ratgeber enthält Hintergrundinformationen zu den wichtigsten antibiotikaresistenten Keimen bei Hunden und Katzen, namentlich zu Methicillin-resistenten Staphylokokken und Extended Spek­trum Beta-Lactamase (ESBL)- und Carbapenemase-produzierenden Enterobacteriaceae. Ausserdem werden Massnahmen aufgeführt, die das Risiko einer Übertragung dieser Keime auf den Menschen reduzieren sollen. Der vorliegende Review erläutert die Hintergrundinformationen zu den Eigenschaften der Keime und deren Vorkommen und Risikofaktoren bei Hund, Katze und Mensch, und erläutert die empfohlenen Massnahmen.Les germes résistants aux antibiotiques revêtent une importance croissante en médecine humaine et vétérinaire. Les cliniques et pratiques pour petits animaux sont également confrontées à des patients chez lesquels des germes résistants aux antibiotiques ont été détectés. Quel risque ces animaux présentent-ils pour les propriétaires d’animaux? Comment réduire le risque de transmission à l’homme? Un groupe de travail composé d’experts en médecine humaine et vétérinaire a élaboré un guide pour les propriétaires dont les chiens ou les chats sont porteurs de germes résistants aux antibiotiques. Le guide contient des informations générales sur les germes résistants aux antibiotiques les plus importants chez les chiens et les chats, à savoir les staphylocoques résistants à la méthicilline et les entérobactéries productrices de bêta-lactamases à spectre étendu (BLSE) et de carbapénémases. Des mesures sont également répertoriées pour réduire le risque de transmission de ces germes à l’homme. Cette revue explique les informations de base sur les propriétés des germes et leur occurrence, les facteurs de risque chez les chiens, les chats et les humains, et explique les mesures recommandées.I germi resistenti agli antibiotici sono sempre più importanti nella medicina umana e veterinaria. Anche le cliniche e gli ambulatori per piccoli animali sono confrontati a pazienti in cui sono stati rilevati germi resistenti agli antibiotici. Che rischio comportano questi animali per i proprietari? Come si può ridurre il rischio di trasmissione all’uomo? Un gruppo di lavoro con esperti di medicina umana e veterinaria ha sviluppato una guida per i proprietari i cui cani o gatti sono portatori di germi resistenti agli antibiotici. La guida fornisce informazioni di base sui più importanti germi resistenti agli antibiotici nei cani e nei gatti, vale a dire gli stafilococchi resistenti alla meticillina, la beta-lattamasi a spettro esteso (ESBL) e le Enterobacteriaceae che producono carbapenemasi. Inoltre essa elenca le misure per ridurre il rischio di trasmissione di questi germi all’uomo. Questa revisione fornisce informazioni di base sulle caratteristiche dei germi e sulla loro presenza, sui fattori di rischio nei cani, nei gatti e negli esseri umani, e descrive le misure raccomandate.

Methicillin-resistant Staphylococcus aureus (MRSA) has emerged over the last few decades as a One Health problem with an increasing prevalence in various animal species. The most notable animals are pigs, as asymptomatic carriers, and horses, where there is often an association with infections. The current study looked at the course of MRSA prevalence in Swiss livestock since 2009, with a special focus on pigs, followed by screening of veterinarians and farmers. Livestock isolates were obtained from the Swiss monitoring program and then characterized by spa typing. Concentrating on the year 2017, we analyzed the prevalence of MRSA in Swiss veterinarians and farmers, followed by whole-genome sequencing of selected human and animal strains. The phylogeny was assessed by applying core-genome multilocus sequence typing (MLST) and single-nucleotide polymorphism (SNP) analyses, followed by screening for resistance genes and virulence factors. The prevalence of MRSA in Swiss pigs showed a dramatic increase from 2% in 2009 to 44% in 2017. Isolates typically belonged to clonal complex 398 (CC398), split between spa t011 and t034. The higher prevalence was mainly due to an increase in t011. spa t034 strains from farmers were found to be closely associated with porcine t034 strains. The same could be shown for spa t011 strains from horses and veterinarians. spa t034 strains had a high number of additional resistance genes, and two strains had acquired the immune evasion cluster. However, all but one of the pig spa t011 strains clustered in a separate group. Thus, the increase in pig spa t011 strains does not directly translate to humans. IMPORTANCE MRSA is an important human pathogen; thus, its increasing prevalence in livestock over the last decade has a potentially large impact on public health. Farmers and veterinarians are especially at risk due to their close contact with animals. Our work demonstrates a dramatic increase in MRSA prevalence in Swiss pigs, from 2% in 2009 to 44% in 2017. Whole-genome sequencing allowed us to show a close association between farmer and pig strains as well as veterinarian and horse strains, indicating that the respective animals are a likely source of human colonization. Furthermore, we could demonstrate that pig spa t011 strains cluster separately and are probably less likely to colonize humans than are pig spa t034 strains. This research may provide a basis for a more substantiated risk assessment and preventive measures.

A programme to eradicate bovine viral diarrhoea was launched in Switzerland in 2008 with the aim of eradicating the causal virus. During the first year of the programme, the entire population of 1.6 million cattle were tested for the presence of the virus; in the following three years an additional 1.8 million calves were tested. The complexity of information generated during the eradication programme, together with a tight schedule, made computerised data management a necessity. To organise, coordinate and supervise the programme, extensions were made to the computerised information system ISVet, of the Swiss Veterinary Service, which provides automated documents for both the Veterinary Service and private veterinarians. Specific data are accessible by user groups via the BVD-Web platform, ISVet and the Swiss animal movement database. The functionalities of the structure and the reports needed to control the progress of the programme are described in detail. The authors also discuss the major advantages, disadvantages and pitfalls when planning an eradication programme using a national centralised database over a distributed computer network.

Bovine Spongiform Encephalopathy (BSE) rapidly evolved into an issue of major public concern particularly when, in 1996, evidence was provided that this disease had crossed the species barrier and infected humans in the UK with what has become known as “variant Creutzfeldt Jakob Disease” (vCJD). The aim of this paper is to describe the European Geographical BSE risk assessment (GBR) that was successfully used for assessing the qualitative likelihood that BSE could be present in a country where it was not yet officially recognized. It also discusses how this can lead to risk-based and therefore preventive management of BSE at national and international levels. The basic assumption of the GBR method is that the BSE agent is initially introduced into a country's domestic cattle production system through the importation of contaminated feedstuffs or live cattle. This is referred to as an “external challenge”. The ability of the system to cope with such a challenge is, in turn, referred to as its “stability”: a stable system will not allow the BSE agent to propagate and amplify following its introduction, while an unstable system will. The BSE-status of a country assessed by this system was used by the European Commission as the basis for trade legislation rules for cattle and their products. The GBR was an invaluable tool in evaluating the potential global spread of BSE as it demonstrated how a disease could be transferred through international trade. This was shown to be a critical factor to address in reducing the spread and amplification of BSE throughout the world. Furthermore, GBR resulted in the implementation of additional measures and management activities both to improve surveillance and to prevent transmission within the cattle population.

Since 1987, when bovine spongiform encephalopathy (BSE) emerged as a novel disease in cattle, enormous efforts were undertaken to monitor and control the disease in ruminants worldwide. The driving force was its high economic impact, which resulted from trade restrictions and the loss of consumer confidence in beef products, the latter because BSE turned out to be a fatal zoonosis, causing variant Creutzfeldt—Jakob disease in human beings. The ban on meat and bone meal in livestock feed and the removal of specified risk materials from the food chain were the main measures to successfully prevent infection in cattle and to protect human beings from BSE exposure. However, although BSE is now under control, previously unknown, so-called atypical transmissible spongiform encephalopathies (TSEs) in cattle and small ruminants have been identified by enhanced disease surveillance. This report briefly reviews and summarizes the current level of knowledge on the spectrum of TSEs in cattle and small ruminants and addresses the question of the extent to which such atypical TSEs have an effect on disease surveillance and control strategies.

Adeterministic model of BSE transmission is used to calculate the R0 values for specific years of the BSE epidemics in the United Kingdom (UK), the Netherlands (NL), and Switzerland (CH). In all three countries, theR0 values decreased below 1 after the introduction of a ban on feeding meat and bone meal (MBM) to ruminants around the 1990s. A variety of additional measures against BSE led to further decrease of R0 to about 0.06 in the years around 1998. The calculated R0 values were consistent with the observations made on the surveillance results for UK, but were partially conflicting with the surveillance results for NL and CH. There was evidence for a dependency of the BSE epidemic in NL and CH from an infection source not considered in the deterministic transmission model. Imports of MBM and feed components can be an explanation for this discrepancy, and the importance of imports for these observations is discussed.

Different types of transmissible spongiform encephalopathies (TSEs) affect sheep and goats. In addition to the classical form of scrapie, both species are susceptible to experimental infections with the bovine spongiform encephalopathy (BSE) agent, and in recent years atypical scrapie cases have been reported in sheep from different European countries. Atypical scrapie in sheep is characterized by distinct histopathologic lesions and molecular characteristics of the abnormal scrapie prion protein (PrPsc). Characteristics of atypical scrapie have not yet been described in detail in goats. A goat presenting features of atypical scrapie was identified in Switzerland. Although there was no difference between the molecular characteristics of PrPsc in this animal and those of atypical scrapie in sheep, differences in the distribution of histopathologic lesions and PrPsc deposition were observed. In particular the cerebellar cortex, a major site of PrPsc deposition in atypical scrapie in sheep, was found to be virtually unaffected in this goat. In contrast, severe lesions and PrPsc deposition were detected in more rostral brain structures, such as thalamus and midbrain. Two TSE screening tests and PrPsc immunohistochemistry were either negative or barely positive when applied to cerebellum and obex tissues, the target samples for TSE surveillance in sheep and goats. These findings suggest that such cases may have been missed in the past and could be overlooked in the future if sampling and testing procedures are not adapted. The epidemiological and veterinary public health implications of these atypical cases, however, are not yet known.

The national risk of bovine spongiform encephalopathy (BSE) has not been assessed by many countries, and many countries are conducting little or no BSE surveillance. National measures implemented, including import restrictions, surveillance systems, and sanitary controls, should be based on actual BSE risk. Thus, as a first step, the national BSE status must be determined, particularly through assessment of the national risk. The World Organisation for Animal Health (OIE) provides recommendations for surveillance and risk assessment of BSE, which are considered the international standard by the World Trade Organization (WTO). This document describes the variables for determination of BSE status and gives guidance on specific options and practical considerations for meeting the BSE surveillance and risk assessment recommendations of the OIE.

Switzerland is controlling Transmissible Spongiform Encephalopathies (TSE) in cattle (BSE) and small ruminants (scrapie). Since BSE is potentially transmissible to sheep, goats or pigs through feeding of contaminated meat and bone meal, implementation of an active surveillance programme for TSE in these species is discussed. The aim of this pilot study was to obtain preliminary data on the prevalence ofTSE and other neurological disorders in these populations. For that purpose, a total of 398 perished and 825 slaughtered adult small ruminants and pigs was examined for the presence of neuropathological changes. None of these animals revealed positive for TSE. However, the investigations demonstrated that perished sheep and goats exhibited a higher prevalence of relevant neuropathological changes when compared with slaughtered animals. From these results, it is concluded that perished small ruminants are probably a risk population for TSE and should be considered as target populations for an active surveillance programme.

Cattle born after animal-feed control measures were implemented in 1990 have become BSE cases in Switzerland, indicating sub-optimal effectiveness of these measures. To evaluate these measures, the incidence of BSE cases in Switzerland recorded through clinical case reporting from January 1991 to June 2000 (categorized into age groups and birth cohorts of 6-month duration) was analyzed by Poisson log-linear regression using an age-period-cohort model. The incidence was maximum in the cattle cohort born from October 1989 to March 1990, and dropped to zero in the cohort born from April to September 1991. A second peak was observed in a cohort born from April to September 1994. The first drop of incidence is interpreted as a result of initial implementation of the feed ban in 1990. The second peak might be related to exposure of cattle to feed intended for pigs and poultry.

Bovine spongiform encephalopathy (BSE) was first described in the United Kingdom (UK) in November 1986. After the introduction of an active surveillance system, most countries in Europe have reported BSE cases in the cattle population. This indicates that the use of active surveillance in addition to passive surveillance is important to assess the true BSE status in a country. Scrapie, a transmissible spongiform encephalopathy (TSE) in sheep and goats, has been reported in countries throughout the world with a few notable exceptions. Concern was expressed that BSE could have been introduced into sheep and goats. Currently, distinguishing between scrapie and BSE in small ruminants is only possible through lengthy experiments in mice. Preliminary results of active surveillance, introduced in 2002, show that significant under-reporting occurred. The history of BSE in cattle shows that risk assessments concerning the risk in a given country were often ignored and subsequent risk management decisions were inaccurate, i.e. although the risk was probable, no measures were taken in terms of either animal or human health. Furthermore, the effect of the measures taken was often overestimated and these had to be amended several times. The most important action to prevent new cases of TSEs occurring is by banning the feeding meat-and-bone meal (MBM) to ruminants. Further measures to be considered are the exclusion of specified risk material and carcasses from rendering, the process parameters for rendering of animal waste and the prevention of cross-contamination of feed with MBM. The most important measures to protect the consumer are the ban on specified risk material, such as brain and spinal cord, which may contain particularly high concentrations of the BSE agent, and the ban on mechanically recovered meat. The most important measures taken in Europe and the scientific background thereof are described and discussed.

Scrapie has been known to occur in sheep and goats for over 250 years. Sheep and goats can be experimentally infected orally with BSE, however BSE infection can only be distinguished from scrapie using costly and extensive laboratory procedures. An overview of both the current state of knowledge on Transmissible Spongiform Encephalopathies (TSE) in small ruminants as well as the TSE monitoring and control strategies in place in Switzerland is presented.

Es wird eine Methode vorgestellt, mit der ein moglichst hoher Anteil BSE-infizierter Tiere ante mortem in der Gruppe der krankgeschlachteten Tiere erkannt werden kann, nachdem sie unentdeckt den Filter der klinischen Untersuchung passiert haben. Tierarztlichen und nichttierarztlichen Fleischkontrolleuren wird ein Mittel mit effizientem Kosten-Nutzen-Verhaltnis zur Verfugung gestellt, mit dem sie anlasslich der ante mortem Untersuchung nach infizierten Tiere suchen konnen. In einer Fall-Kontroll-Studie wurden die Symptome von 224 zufallig ausgesuchten, krankgeschlachteten Tieren mit den Symptomen von 26 BSE-positiven Tieren aus der Krankschlachtung verglichen. Zusatzlich wurden die Symptome der krankgeschlachteten BSE-positiven Tiere mit den Symptomen der im gleichen Zeitraum diagnostizierten, positiven BSE-Verdachtsfalle verglichen. Aus der Studie resultiert ein Modell, welches 7 Variablen beinhaltet («Aggressivitat, Zahneknirschen, Glotzaugen, vermindertes Wiederkauen, Festliegen, Ubererregbarkeit und Au...

There are several other diseases besides BSE which belong to the group of transmissible spongiform encephalopathies (TSE). Although most mammals can be experimentally infected with the agent of these diseases, generally only single representatives of the orders Artiodactyla (cloven-hoofed animals), Carnivora (carnivores) and Primates (humans and monkeys) are naturally infected in the field. An overview of the current state of knowledge on TSE in several species like exotic ruminants, deer, mink and cats is presented. Etiological, clinical, anatomic-pathological and epidemiological aspects are described.

Visual evaluation of the occurrence of BAB (born after ban) cases pointed towards spatial clustering. Therefore a statistical analysis of spatial case clustering was conducted using GIS technology. In the initial analysis, all 376 cases (135 BAB, 241 BBB/born before ban) diagnosed through mid of March 2001 were investigated using the spatial scan statistic. Two clusters of BBB cases were identified in the western part of Switzerland, and two clusters of BAB cases in the eastern part. Epidemiological investigations performed within the BAB clusters showed an increased pig density in these cluster regions. Pig density is considered an indicator for the probability of contamination of cattle feed with feed containing meat-and-bone meal that is intended for other species (cross-contamination). In an updated cluster analysis including all cases reported until end of June 2002 (data set B), clusters were identified in the same regions as previously. It was shown that the BAB clusters occurred in different time periods. The small scale differences in cluster size and location are discussed, with an emphasis on the implications for following epidemiological investigations.

Over one-third of the cases of BSE in Switzerland have been born after the feed ban of December 1, 1990. Evidence for the geographical clustering of these cases emerged in two distinct regions. All the 354 BSE cases recorded until June 30, 2000 (set A), and the 376 cases recorded up to May 14, 2001 (set B), were georeferenced to the centres of the communities in which the herds of origin were located, and control populations were georeferenced to the centres of the communities in which these herds were located at the time of the census. The latitudes and longitudes of these centres were used in the statistical analysis of the spatial clustering. The Cuzick-Edwards test and the spatial scan statistics were applied to assess the significance of the clusters, while controlling for the spatial distribution of the underlying cattle population. There was global clustering of the cases born after the ban, and distinct and significant (P

In this report we document the results of several independent studies testing the sensitivity, specificity and reliability of the Prionics Western blotting (PWB) procedure to detect bovine and ovine disease-specific, protease-resistant prion protein (PrP(Sc)). Validation of the technique was obtained by blind analysis of samples from cattle affected with bovine spongiform encephalopathy (BSE), clinically normal animals or cattle with neurological diseases unrelated to BSE. Overall, very high sensitivity, specificity and reliability was observed. It became clear that sampling of the correct brain region and the method used for protein extraction are important factors for correct diagnosis. Furthermore, we tested the usefulness of the PWB technique as an instrument for surveillance purposes. We analyzed animals from a culling scheme as well as older animals from abattoirs to determine the number of subclinical BSE cases detectable by histopathological examination, immunohistochemistry for PrP(Sc) and PWB. In both studies, BSE-affected animals with no overt clinical symptoms were detected. These results demonstrate the usefulness of the PWB procedure in surveillance systems serving as a rapid diagnostic tool to identify animals subclinically infected with BSE.

The first case of bovine spongiform encephalopathy (BSE) in Switzerland was diagnosed in November 1990, although the risk factors identified in the United Kingdom were not all present in Switzerland. At 29 December 1998, a total of 282 BSE cases (all animals born in Switzerland), had been recorded. The number of cases is declining, with fourteen cases diagnosed in 1998 (at 29 December 1998). The measures taken are effective. However, the potential weakness in current activities that allow the disease to exist are being evaluated. Further measures to avoid even minimal risk for human and animal health will be taken if required. Experience gained from the past indicates that it is necessary to review the situation constantly and to inform the public and professionals regularly and in a transparent manner.

A national eradication programme was designed with the aim of achieving total freedom from bovine viral diarrhea virus (BVDV) infection in the Swiss cattle population. The eradication programme consisted of testing every Swiss bovine for antigen, culling virus-positive animals and applying movement restrictions. Starting in 2008, the campaign achieved the goal of reducing the proportion of newborn calves that were virus-positive from 1.8% to under 0.2% within two years (situation in September 2010). Both good data flow between the parties involved as well as speed and efficiency (e.g. concerning the application of tests, movement restrictions and slaughter) are central to the success of the programme. Since the beginning of the programme 2.85 million cattle have been tested for bovine viral diarrhea virus (BVDV). The BVD-prevalence in cattle at the individual and herd levels following the implementation of the eradication programme was assessed. Using data collected during this campaign a risk factor analysis was conducted in order to identify factors associated with the appearance of virus positive newborn calves in herds where BVD had not previously been detected; these risk factors would allow targeting of future surveillance. Herd size, early death rate (i.e. the number of animals that either die before 15 days of age or are stillborn per number of newborns per year), buying in stock, using communal summer grazing, production type, age structure and management strategy were factors associated with the appearance of new cases of infection. Testing of newborn calves for antigen will continue to be conducted until the end of 2011, this is combined with outbreak investigation of newly infected herds (consisting of re-testing dams of virus-positive calves and if necessary all cattle on or that recently left the farm). This process is done to identify infected animals that may have been missed during prior testing (false negatives), it also serves to identify other factors that may be responsible for the introduction of BVDV onto the farm. Since October 2009, testing of calves for antigen combined with outbreak investigation has led to the detection of 55 infected animals that had tested negative (presumably false negative) during previous rounds of testing.

Background After bovine spongiform encephalopathy (BSE) emerged in European cattle livestock in 1986 a fundamental question was whether the agent established also in the small ruminants' population. In Switzerland transmissible spongiform encephalopathies (TSEs) in small ruminants have been monitored since 1990. While in the most recent TSE cases a BSE infection could be excluded, for historical cases techniques to discriminate scrapie from BSE had not been available at the time of diagnosis and thus their status remained unclear. We herein applied state-of-the-art techniques to retrospectively classify these animals and to re-analyze the affected flocks for secondary cases. These results were the basis for models, simulating the course of TSEs over a period of 70 years. The aim was to come to a statistically based overall assessment of the TSE situation in the domestic small ruminant population in Switzerland. Results In sum 16 TSE cases were identified in small ruminants in Switzerland since 1981, of which eight were atypical and six were classical scrapie. In two animals retrospective analysis did not allow any further classification due to the lack of appropriate tissue samples. We found no evidence for an infection with the BSE agent in the cases under investigation. In none of the affected flocks, secondary cases were identified. A Bayesian prevalence calculation resulted in most likely estimates of one case of BSE, five cases of classical scrapie and 21 cases of atypical scrapie per 100'000 small ruminants. According to our models none of the TSEs is considered to cause a broader epidemic in Switzerland. In a closed population, they are rather expected to fade out in the next decades or, in case of a sporadic origin, may remain at a very low level. Conclusions In summary, these data indicate that despite a significant epidemic of BSE in cattle, there is no evidence that BSE established in the small ruminant population in Switzerland. Classical and atypical scrapie both occur at a very low level and are not expected to escalate into an epidemic. In this situation the extent of TSE surveillance in small ruminants requires reevaluation based on cost-benefit analysis.

Recently, screening tests for monitoring the prevalence of transmissible spongiform encephalopathies specifically in sheep and goats became available. Although most countries require comprehensive test validation prior to approval, little is known about their performance under normal operating conditions. Switzerland was one of the first countries to implement 2 of these tests, an enzymelinked immunosorbent assay (ELISA) and a Western blot, in a 1-year active surveillance program. Slaughtered animals ( n = 32,777) were analyzed in either of the 2 tests with immunohistochemistry for confirmation of initial reactive results, and fallen stock samples ( n = 3,193) were subjected to both screening tests and immunohistochemistry in parallel. Initial reactive and false-positive rates were recorded over time. Both tests revealed an excellent diagnostic specificity (> 99.5%). However, initial reactive rates were elevated at the beginning of the program but dropped to levels below 1% with routine and enhanced staff training. Only those in the ELISA increased again in the second half of the program and correlated with the degree of tissue autolysis in the fallen stock samples. It is noteworthy that the Western blot missed 1 of the 3 atypical scrapie cases in the fallen stock, indicating potential differences in the diagnostic sensitivities between the 2 screening tests. However, an estimation of the diagnostic sensitivity for both tests on field samples remained difficult due to the low disease prevalence. Taken together, these results highlight the importance of staff training, sample quality, and interlaboratory comparison trials when such screening tests are implemented in the field.

International audience; The paper describes how the comprehensive surveillance of bovine spongiform encephalopathy (BSE) and studies carried out on these data has enhanced our knowledge of the epidemiology of BSE. Around 7 000 BSE cases were detected through the screening of about 50 million cattle with rapid tests in Europe. It confirmed that the clinical surveillance had a poor capacity to detect cases, and also showed the discrepancy of this passive surveillance efficiency between regions and production types (dairy/beef). Other risk factors for BSE were being in a dairy herd (three times more than beef), having a young age at first calving (for dairy cattle), being autumn-born (dairy and beef), and being in a herd with a very high milk yield. These findings focus the risk on the feeding regimen of calves/heifers. Several epidemiological studies across countries suggest that the feedborne source related to meat and bone meal (MBM) is the only substantiated route of infection -- even after the feed ban --, while it is not possible to exclude maternal transmission or milk replacers as a source of some infections. In most European countries, the average age of the cases is increasing over time and the prevalence decreasing, which reflects the effectiveness of control measures. Consistent results on the trend of the epidemic were obtained using back-calculation modelling, the $R_{0}$ approach and Age-Period-Cohort models. Furthermore, active surveillance also resulted in the finding of atypical cases. These are distinct from previously found BSE and classified in two different forms based on biochemical characteristics; their prevalence is very low (36 cases up to 1st September 2007), affected animals were old and some of them displayed clinical signs. The origin and possibility of natural transmission is unknown.

A deterministic model of BSE transmission is used to calculate the R(0) values for specific years of the BSE epidemics in the United Kingdom (UK), the Netherlands (NL), and Switzerland (CH). In all three countries, the R(0) values decreased below 1 after the introduction of a ban on feeding meat and bone meal (MBM) to ruminants around the 1990s. A variety of additional measures against BSE led to further decrease of R(0) to about 0.06 in the years around 1998. The calculated R(0) values were consistent with the observations made on the surveillance results for UK, but were partially conflicting with the surveillance results for NL and CH. There was evidence for a dependency of the BSE epidemic in NL and CH from an infection source not considered in the deterministic transmission model. Imports of MBM and feed components can be an explanation for this discrepancy, and the importance of imports for these observations is discussed.

This paper describes the prevalence of brain lesions in the Swiss fallen stock population of small ruminants. 3075 whole brains (75% sheep, 25% goats) were collected as part of a year-long active survey of transmissible spongiform encephalopathies (TSEs) in small ruminants conducted by the Swiss authorities between July 2004 and July 2005. All fallen stock brains were systematically examined by histopathology to obtain reliable data on histologically identifiable brain lesions. Lesions were found in an unexpectedly high number of animals (8.1% of all examined brains). A wide spectrum of diseases was detected showing that this approach provides an excellent opportunity to screen for the prevalence of neurological diseases. Encephalitic listeriosis was by far the most frequent cause of CNS lesions in both species and its prevalence was unexpectedly high when compared to notified confirmed cases. In conclusion, the prevalence of listeriosis as estimated by passive surveillance based on the notification of clinical suspects has been underestimated in the past.

The effectiveness of two measures against Bovine Spongiform Encephalopathy (BSE), the compulsory processing of animal by products to meat and bone meal (MBM) at 133 degrees C under 3 bars of pressure for 20 minutes in February 1993 and the exclusion of fallen stock, heads with eyes and spinal cord of cattle older than 30 month from MBM production in April 1996, was evaluated in a process model. The transmission of BSE by calculation of the basic reproduction ratio R0 was modelled. The results were verified by use of a cohort model, based on observed surveillance data. Prior to 1990, before the ban of feeding MBM to ruminants, R0, as calculated in the process model, was above 1, coherent with a slowly progressing BSE epidemic. Since 1991, values of R0 were low at 0.06. The corresponding R0 values derived from the cohort model were higher, the lowest value 0.13 calculated for 1996. Given such low R0 values, the epidemic should have died out. Additionally, no influence of the two measures was obvious at that time given the low level of R0. The discrepancy between the results of the two models is evidence for a dependency of the BSE epidemic from an infection source not considered in the process model. This infection source is most likely importation of feed ingredients and MBM.

International audience; Cross-contamination of cattle feed with meat and bone meal (MBM) allowed in feed for other species is regarded as the current hypothesis for the infection pathway of Bovine Spongiform Encephalopathy (BSE) cases occurring after the implementation of a ban on feeding MBM to cattle. This study was aimed at establishing a spatial relation between BSE cases in Switzerland and the findings of MBM in cattle feed. A cluster analysis and a cohort study were performed. Two hundred sixteen BSE cases born after December 1990 and detected until August 1st 2005, screening data of 504 feed producers between 1996 and 2001 and population data from the Swiss 2001 cattle census were included. The cluster analysis showed feed producer, positive for MBM contaminations in cattle feed, as possible cluster centres for BSE cases. In the cohort study, farms within a radius of 2 and 10 km around positive feed producers showed significantly higher odds to have a BSE case than the control group. The odds ratio and its 95% confidence interval were 2.23 (1.26-3.93) for the 2 km radius and 1.38 (1-1.9) for the 10 km radius. The results provide evidence for a spatial relation between cross-contamination and BSE occurrence. These findings support the hypothesis of cross-contamination to be an important route for BSE transmission after a feed ban.

Although, the bovine spongiform encephalopathy (BSE) risk of most countries in Europe has been assessed and they have implemented both measures to control BSE and extensive surveillance systems, complete and valid data is still not consistently available. Globally, data is largely unavailable. Assessments based on incomplete or invalid information could lead to false conclusions. The BSE risk of countries throughout the world must continue to be assessed, and improvements in collection of surveillance data must be made, both in countries already reporting BSE cases and worldwide, in order to evaluate the global BSE picture and assure that cattle and products can be safely traded.

Bovine spongiform encephalopathy (BSE), a disease of cattle first reported in 1986 in the UK [1], has been found in the cattle populations of most European countries. To date, Japan, Israel and Canada are the only nonEuropean countries where BSE has been reported in indigenous cattle [2]. Given all available evidence, the BSE agent is not transmitted horizontally between cattle; rather it is primarily transmitted through feed. Meat-and-bone meal (MBM) is the main source of infectivity and cattle [3] are usually infected during calf-hood. Although it is likely that the other calves in a herd of a similar age to a BSE case also consumed feed from a contaminated batch of MBM, the incidence of BSE within most herds is very low. The most probable explanation is that exposure to the BSE agent was, on average, very low. Recycling of the BSE agent is likely to have resulted in an increased number of ‘packets’ of infectivity rather than an increase in the average titre of infectivity within a contaminated batch of MBM. As a result, the average within-herd incidence would be unlikely to increase [4] (see also the chapter of Bradley). Several strategies, including those that focus on feed as a source of infection and various culling programmes, have been adopted with the aim of eradicating BSE. Culling strategies vary from culling the affected animal only, to culling all animals within the birth cohort of the BSE case, to culling the entire herd.

The current method used to identify suspect BSE cases is based on reporting cattle displaying clinical signs compatible with BSE. The reporting of such cases is dependent on the ability of farmers and veterinarians to recognise the disease symptoms and on the willingness to report such cases. Furthermore, it depends on the stage of the disease, because early clinical signs of BSE are not always typical.

Disease-specific PrP (PrPSc) is at least part of the infectious particle (prion) causing bovine spongiform encephalopathy (BSE) or scrapie in sheep. Digestion with protease allows a distinction between normal PrP (PrPC) and PrPSc i.e. PrPC is completely digested while PrPSc is cleaved at the N-terminus leading to a fragment of reduced molecular weight (PrP 27–30). Detection of this fragment by Western blotting has been described more than a decade ago for rodent PrP. We have now optimized the technique in order to allow rapid analysis of hundreds of samples per day. Here we report the application of this technique to the analysis of 3000 regularly slaughtered cattle from Swiss abattoirs. For comparison all the animals were subsequently examined by classical methods (i.e. histology and immunohistochemistry). All but one animal were negative for BSE by all methods. The Western blot positive animal was confirmed to be a BSE case and the carcass was removed from the food chain. We conclude that it is feasible to examine slaughtered cattle on a routine basis without causing delays to the meat processing industry.

The objective of this study was to model the expected numbers of cattle incubating bovine spongiform encephalopathy (BSE) and the numbers of clinical cases of BSE in the Swiss cattle population between 1984 encephalopathy (BSE) and the numbers of clinical cases of BSE in the Swiss cattle population between 1984 and 2005. The results were compared with the observed number of clinical BSE cases and with the results of a culling and testing scheme on herdmates of cattle with BSE. The age distribution of the Swiss cattle population, the age-at-death distribution of the first 235 BSE cases and exposure information were used to calculate the expected number of infected cattle in each birth cohort and the resulting numbers of clinical cases and survivors incubating the disease for each year. The model which did not assume any underreporting of cases fitted the observed epidemic curve of clinical cases reasonably well, and predicted that the Swiss BSE epidemic would come to an end between 2003 and 2005. The age of survivors incubating BSE iS increasing. The higher than expected incidence of subclinical cases observed in animals from the culling scheme is most probably the result of the heterogeneous distribution of infected animals and affected herds in the population. The results of the model need to be taken into account when designing surveillance and testing schemes for BSE.

Bovine spongiform encephalopathy (BSE), a subacute degenerative disease affecting the central nervous system of cattle, belongs to a group of related diseases known as the transmissible spongiform encephalopathies (TSEs). They are caused by poorly characterized scrapie-like agents (prions) that produce spongiform changes in the brain (1). Sheep scrapie is thought to be the origin of BSE, which was first diagnosed in the United Kingdom in 1986. The disease was confirmed a few years later in domestic cattle in France, Ireland, Portugal, and Switzerland (2), as well as in cattle exported from the United Kingdom to Denmark, Canada, the Falkland Islands, Germany, Italy, Oman, Portugal, and Ireland. Surveillance of BSE and/or scrapie is carried out in some countries. However, there is no test to detect the disease in live animals and the screening for the disease is rather difficult because it is based on the detection of clinically suspect cases (3). An additional approach to ascertain if BSE risk factors are likely to be present in a country is to conduct a qualitative or quantitative risk assessment. This chapter evaluates qualitatively some of the BSE risk factors in Europe.