[Noroviruses, these unknown worldwide epidemic enteropathogens]. / Les norovirus, ces entéro-pathogènes épidémiques mondiaux méconnus.

Discovered in the 1970s, human noroviruses (NoV) are the leading cause of foodborne disease and gastroenteritis outbreaks worldwide. NoV affect people of all ages. In children less than 5 years old, despite rotavirus remains the main enteropathogen responsible for viral gastroenteritis, NoV become the first etiological virus in countries where the rotavirus vaccine was introduced. Treatment of viral gastroenteritis is symptomatic. The key element in front of NoV infection is limiting their transmission. A rapid NoV detection during outbreak is important in the aim to rapidly implement hygiene measures to limit the size of the outbreak. Prevention of NoV infections relies on the use of adequate hand hygiene measures and disinfection of contaminated environmental surfaces. In face of an acute gastroenteritis outbreak, the early NoV identification with rapid laboratory tests or molecular biology methods is needed in the aim to implement as soon as possible hygiene measures to limit the size of the NoV outbreak. Due to antigenically diverse NoV strains and the lack of long term immunity, the development of an effective vaccine is difficult.

Découverts dans les années 1970, les norovirus humains (NoV) sont reconnus comme les principaux agents pathogènes responsables de toxi-infections d'origine alimentaire et d'épidémies de gastro-entérites au niveau mondial. Ils infectent toutes les tranches d'âge. Chez les enfants de moins de 5 ans, bien que le rotavirus reste actuellement la première cause de gastro-entérites virales, force est de constater que les NoV sont en passe d'en devenir la première cause dans les pays où la vaccination contre le rotavirus a été introduite. Le traitement des gastro-entérites virales est symptomatique. L'élément clé face aux infections à NoV est de limiter leur transmission. La prévention des infections à NoV repose principalement sur l'application de mesures d'hygiène des mains adéquates et la désinfection de l'environnement contaminé. Lors des épidémies de gastro-entérites aiguës, l'identification précoce des NoV par des méthodes de laboratoire rapides ou de biologie moléculaire est primordiale afin de mettre en place rapidement les mesures d'hygiène permettant de limiter leur propagation. La diversité antigénique des NoV et le manque d'immunité protectrice à long terme rendent la mise au point de vaccins difficile.

[Norovirus nosocomial outbreak : an hospital experience]. / Epidémie nosocomiale à norovirus : à propos d'une expérience hospitalière.

Human noroviruses (NoV) are the main pathogenic agents worldwide responsible for viral sporadic and epidemic gastroenteritis worldwide. A gastroenteritis outbreak broke out in patients hospitalized in several wards located in two different floors of a hospital in Liege, Belgium. The objective was to determine whether a same NoV strain would be involved in the two different floors, and to explore how this outbreak would have spread from a floor to the other. Stool samples from patients and healthcare workers were collected, as well as data from medical files. NoV detection, quantification and characterization were performed using molecular biology methods. A same NoV strain, from genotype GII.4, was detected in two patients hospitalized on the two different floors. This finding allowed to conclude that a same outbreak spread in the two floors, probably due to movements of common healthcare workers. A rapid NoV detection during outbreak is important in the aim to rapidly implement hygiene measures to limit the size of the outbreak.

Les norovirus humains (NoV) sont reconnus mondialement comme les principaux agents étiologiques de gastro-entérites virales sporadiques et épidémiques au niveau mondial. Une épidémie de gastro-entérites s'est déclarée chez des patients hospitalisés dans plusieurs salles d'un hôpital de la région liégeoise, situées à deux étages différents. L'objectif était de déterminer si une même souche de NoV était impliquée aux deux étages, et d'investiguer la manière dont l'épidémie se serait propagée d'un étage à l'autre. Des prélèvements ont été collectés chez les patients et le personnel soignant. Les dossiers médicaux ont été examinés. La détection, la quantification et la caractérisation des souches de NoV ont été réalisées par des méthodes de biologie moléculaire. Une même souche de NoV, du génotype GII.4, a été mise en évidence chez deux patients hospitalisés aux deux étages différents. Ce résultat indique qu'il s'agit de la même épidémie qui s'est étendue à deux étages, probablement transmise par l'intermédiaire du personnel soignant commun. L'identification précoce des NoV lors des épidémies est primordiale afin de mettre en place rapidement les mesures d'hygiène permettant de limiter leur propagation.

Preparedness activities and research needs in addressing emerging infectious animal and zoonotic diseases.

Emerging infectious animal and zoonotic diseases can inflict significant losses on animal production and public health, and threaten the safety and security of the food system. Threat analysis (forecasting), which monitors the measurable risk indicators of disease emergence, should be in place before the emergence of any threat. Animal and public health authorities develop and regularly re-evaluate disease preparedness, response and recovery plans, based on the 'One Health' principle. These plans should include surveillance, biosecurity measures, communication channels and training for personnel. Scenarios for outbreaks of natural emerging infectious disease or bioterrorist events should be prepared and practised. National and international legislation should be regularly updated to provide a robust legal basis to manage outbreaks. Reference laboratories should have reliable and validated diagnostic tools for rapid, high-throughput testing. Strict biosafety, biocontainment and biosecurity control measures must be implemented in laboratories in order to prevent the accidental or malicious release of pathogens. The pharmaceutical industry should be incentivised to develop vaccines and/or antiviral drugs against disease outbreaks. Conventions between public authorities and the pharmaceutical industry should guarantee adequate stockpiling of the pharmaceuticals needed to control large-scale outbreaks. In the early phase of disease emergence (early warning), veterinarians and stakeholders play an important role in early detection at the farm level. Upon notification, veterinary authorities must take rapid response measures to limit disease spread. National and international short- and medium-term strategic research agendas should be developed, based on a comprehensive gap analysis and horizon scan. This planning will help to guide funding agencies and non-governmental organisations in their quest to support relevant research.

Les maladies animales infectieuses et les zoonoses émergentes ont un coût élevé pour la santé animale et la santé publique, en plus d'entraîner d'importantes pertes de production dans les élevages et de menacer la sécurité des systèmes de production alimentaire. Une analyse des menaces (anticipation), grâce au suivi d'indicateurs mesurables du risque d'émergence des maladies animales, devrait être en place avant que ces menaces n'émergent. Les autorités en charge de la santé animale et de la santé publique développent et réévaluent régulièrement des plans de préparation, de réponse et de récupération vis-à-vis de maladies, sur la base du principe « Une seule santé ¼. Ces plans doivent inclure des mesures de surveillance et de biosécurité, en plus de se doter de moyens de communication et de formation du personnel. Il convient d'élaborer et de mettre en pratique des scénarios d'émergence de maladies infectieuses, que celle-ci soit d'origine naturelle ou d'origine bioterroriste. Les législations nationales et internationales en la matière doivent être actualisées régulièrement afin de fournir un fondement juridique solide à la gestion des émergences. Les laboratoires de référence doivent disposer d'outils diagnostiques fiables et validés permettant la réalisation de tests rapides et à haut débit. Des mesures strictes de contrôle de la biosécurité, du bioconfinement et de la biosûreté doivent être appliquées dans les laboratoires pour prévenir toute libération accidentelle ou malintentionnée d'agents pathogènes. L'industrie pharmaceutique doit être incitée au développement de vaccins et d'antiviraux pour maîtriser les maladies émergentes. Les conventions entre les autorités publiques et l'industrie pharmaceutique doivent permettre de garantir la constitution de stocks suffisants de produits pharmaceutiques pour maîtriser les émergences de grande ampleur. Lors des premières phases d'émergence d'un foyer (alerte précoce), les vétérinaires et autres acteurs de terrain jouent un rôle important dans la détection précoce au niveau des élevages. Dès la notification d'un foyer, les autorités vétérinaires doivent réagir rapidement afin d'en limiter la propagation. Il convient de développer des programmes nationaux et internationaux de recherche stratégique à court et moyen terme, basés sur un examen exhaustif des lacunes et sur une analyse prospective complète. Cette planification contribuera à fournir aux agences de financement et aux organisations non gouvernementales des orientations leur permettant de déterminer quel soutien apporter à la recherche.

Las enfermedades animales infecciosas y las zoonosis emergentes pueden causar pérdidas cuantiosas en los ámbitos de la producción animal y la salud pública, además de amenazar la higiene y la seguridad de los sistemas alimentarios. El análisis (pronóstico) de amenazas, que consiste en seguir de cerca indicadores cuantificables del riesgo de aparición de enfermedades animales, es algo que debería estar implantado antes de que surja toda amenaza. Las autoridades sanitarias y zoosanitarias definen y periódicamente reevalúan planes de preparación, respuesta y recuperación frente a enfermedades, basándose para ello en el principio de «Una sola salud¼. Estos planes deben incluir labores de vigilancia y medidas de seguridad biológica, además de prever cauces de comunicación y actividades de formación del personal. También hay que elaborar y aplicar planes para hipotéticos brotes infecciosos, ya sean de origen natural u obra de bioterroristas. Asimismo, a fin de contar con sólidas bases jurídicas para combatir la aparición de enfermedades, es preciso actualizar periódicamente la legislación nacional e internacional. Los laboratorios de referencia deben contar con herramientas de diagnóstico fiables y validadas que permitan efectuar pruebas rápidas y de alto rendimiento. Es preciso implantar en los laboratorios estrictas medidas de control de la protección, la contención y la seguridad biológicas para evitar toda liberación accidental o malintencionada de patógenos. Hay que incentivar asimismo a la industria farmacéutica para que desarrolle vacunas y fármacos antivirales contra las enfermedades emergentes. Por otra parte, las autoridades públicas deben suscribir con el sector farmacéutico convenios que garanticen la constitución de reservas suficientes de los productos farmacéuticos requeridos para hacer frente a la aparición de brotes de grandes dimensiones. En las primeras fases de la aparición de un foco (alerta rápida), los veterinarios y otros interlocutores cumplen una importante función para detectar con prontitud la patología dentro de las explotaciones. Al recibir notificación, las autoridades veterinarias deben reaccionar con rapidez para poner coto a la propagación de la enfermedad. Por último, a partir de un análisis exhaustivo de las carencias existentes y de un estudio prospectivo completo, es preciso elaborar planes nacionales e internacionales de investigación estratégica a corto y medio plazo. Tal planificación ayudará a orientar a los organismos de financiación y las organizaciones no gubernamentales (ONG) en su labor de apoyo a las investigaciones de interés.

Genetic and evolutionary perspectives on genogroup III, genotype 2 bovine noroviruses.

Bovine noroviruses are enteric pathogens that are detected in stool samples from cattle. Five genogroups are currently described in the genus Norovirus (family Caliciviridae), and within the genogroups, sequences are further divided into genotypes according to genetic homology and phylogenetic relationships. In this study, stool specimens from Belgian cattle were screened by RT-PCR. All of the sequences that were detected were phylogenetically related to genogroup III genotype 2 bovine noroviruses, confirming their higher prevalence in comparison with strains from genotype 1. When other sequences from around the world were introduced, phylogenetic inferences allowed neither the determination of phylogenetic lineages over time nor the deduction of topotypes for genotype 2 bovine noroviruses. Three complete genotype 2 bovine norovirus sequences were also compared genetically (Newbury2/1976 /UK, Dumfries/1994/UK and B309/2003/BE). Interestingly, the genetic divergence of the complete genomes of these three strains was relatively low, but a region of the N-terminal protein encoded by ORF1, the hypervariable region of the capsid gene encoded by ORF2, and a region of the minor structural protein encoded by ORF3 seem to be the most exposed to genetic evolution. Bayesian inference also showed that genetic evolution of genogroup III, genotype 2 bovine noroviruses over a 30-year period seemed to be lower than that already reported for noroviruses from the genotypes 3 and 4 in genogroup II.

Antiviral chemotherapy in veterinary medicine: current applications and perspectives.

The current situation in the use of antiviral drugs in veterinary medicine is characterised by a novel and optimistic approach.Viruses of veterinary importance are still used as animal models in the developmentof human therapeutics, but there is growing interest in many of these viruses in the identification of antiviral molecules for use in both livestock and companion animals. The use of antiviral drugs in livestock animals is envisaged for the treatment or control of disease on a large scale (mass treatment), whereas in companion animals an individual approach is favoured. An overview of the most recent examples of research in the use of antivirals in veterinary medicine is presented, with particular emphasis on their in vivo applications.

Complete genome sequence of a novel bovine norovirus: evidence for slow genetic evolution in genogroup III genotype 2 noroviruses.

A new genogroup III genotype 2 bovine norovirus, B309/2003/BE, was entirely sequenced and genetically compared to the original Newbury2/1976/UK strain and to Dumfries/1994/UK, detected in 1976 and 1994, respectively. Interestingly, except in well-defined coding regions (N-terminal protein, 3A-like protease, hypervariable region of the capsid protein, and C-terminal part of the minor structural protein), very low genetic differences were noted between the entire genomes of these three strains along a 30-year-long period. It allowed some hypotheses of hotspots of genetic evolution through a low genetic evolution background in genotype 2 genogroup III bovine noroviruses.

Original findings associated with two cases of bovine papular stomatitis.

Bovine papular stomatitis virus was isolated from two calves in an animal house with biosafety level 3 confinement. The hypotheses on the origin of the infection, the interesting features of the partial amino acid sequences of the major envelope viral protein, and the importance of diagnostic tools available for animal diseases that are not listed by the World Organization for Animal Health (OIE) are discussed.

Aetiology of Canine Infectious Respiratory Disease Complex and Prevalence of its Pathogens in Europe.

The canine infectious respiratory disease complex (CIRDC) is an endemic worldwide syndrome involving multiple viral and bacterial pathogens. Traditionally, Bordetella bronchiseptica (Bb), canine adenovirus type 2 (CAV-2), canine distemper virus (CDV), canine herpesvirus (CHV) and canine parainfluenza virus (CPiV) were considered the major causative agents. Lately, new pathogens have been implicated in the development of CIRDC, namely canine influenza virus (CIV), canine respiratory coronavirus (CRCoV), canine pneumovirus (CnPnV), Mycoplasma cynos and Streptococcus equi subspecies zooepidemicus. To better understand the role of the different pathogens in the development of CIRDC and their epidemiological relevance in Europe, prevalence data were collected from peer-reviewed publications and summarized. Evidence of exposure to Bb is frequently found in healthy and diseased dogs and client-owned dogs are as likely to be infected as kennelled dogs. Co-infections with viral pathogens are common. The findings confirm that Bb is an important cause of CIRDC in Europe. CAV-2 and CDV recovery rates from healthy and diseased dogs are low and the most likely explanation for this is control through vaccination. Seroconversion to CHV can be demonstrated following CIRDC outbreaks and CHV has been detected in the lower respiratory tract of diseased dogs. There is some evidence that CHV is not a primary cause of CIRDC, but opportunistically re-activates at the time of infection and exacerbates the disease. The currently available data suggest that CIV is, at present, neither a prevalent nor a significant pathogen in Europe. CPiV remains an important pathogen in CIRDC and facilitates co-infection with other viral and bacterial pathogens. CnPnV and CRCoV are important new elements in the aetiology of CIRDC and spread particularly well in multi-dog establishments. M. cynos is common in Europe and is more likely to occur in younger and kennelled dogs. This organism is frequently found together with other CIRDC pathogens and is significantly associated with more severe respiratory signs. S. zooepidemicus infection is not common and appears to be a particular problem in kennels. Protective immunity against respiratory diseases is rarely complete, and generally only a reduction in clinical signs and excretion of pathogen can be achieved through vaccination. However, even vaccines that only reduce and do not prevent infection carry epidemiological advantages. They reduce spread, increase herd immunity and decrease usage of antimicrobials. Recommending vaccination of dogs against pathogens of CIRDC will directly provide epidemiological advantages to the population and the individual dog.

The use of germicidal ultraviolet light, vaporized hydrogen peroxide and dry heat to decontaminate face masks and filtering respirators contaminated with a SARS-CoV-2 surrogate virus.

BACKGROUND: In the context of the ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, the supply of personal protective equipment remains under severe strain. To address this issue, re-use of surgical face masks and filtering facepiece respirators has been recommended; prior decontamination is paramount to their re-use. AIM: We aim to provide information on the effects of three decontamination procedures on porcine respiratory coronavirus (PRCV)-contaminated masks and respirators, presenting a stable model for infectious coronavirus decontamination of these typically single-use-only products. METHODS: Surgical masks and filtering facepiece respirator coupons and straps were inoculated with infectious PRCV and submitted to three decontamination treatments, ultraviolet (UV) irradiation, vaporized H2O2, and dry heat treatment. Viruses were recovered from sample materials and viral titres were measured in swine testicle cells. FINDINGS: UV irradiation, vaporized H2O2 and dry heat reduced infectious PRCV by more than three orders of magnitude on mask and respirator coupons and rendered it undetectable in all decontamination assays. CONCLUSION: This is the first description of stable disinfection of face masks and filtering facepiece respirators contaminated with an infectious SARS-CoV-2 surrogate using UV irradiation, vaporized H2O2 and dry heat treatment. The three methods permit demonstration of a loss of infectivity by more than three orders of magnitude of an infectious coronavirus in line with the United States Food and Drug Administration policy regarding face masks and respirators. It presents advantages of uncomplicated manipulation and utilization in a BSL2 facility, therefore being easily adaptable to other respirator and mask types.

Experimental reproduction of bluetongue virus serotype 8 clinical disease in calves.

Cattle are commonly subclinically infected following natural or experimental infection with bluetongue virus (BTV). The introduction of BTV serotype 8 (BTV-8) in Europe has been characterized by the manifestation of clinical signs in infected cattle. In order to study the pathogenesis of BTV-8 in this host, an animal model able to reproduce the clinical manifestations of the disease is required. In this work, two calves were subcutaneously and intravenously injected with a low passage cell-adapted strain of BTV-8. Both calves showed typical bluetongue clinical signs, including pyrexia, ocular discharge, conjunctivitis, oral mucosal congestion, development of ulcers and necrotic lesions on the lips and tongue, submandibular oedema, coronitis and oedema of the coronet and pastern region. A score was assigned depending on the severity of the lesions and a total clinical score was calculated for each animal daily and at the end of the experiment. Both calves became viraemic 24h post-infection and seroconversion occurred between 7 and 11 days P.I. In this study we present the development of a protocol of infection in calves able to reproduce the severity of the lesions observed with BTV-8 in field conditions.

Animal noroviruses.

Among enteric caliciviruses, noroviruses belong to the genus Norovirus, one of the four accepted genera in the family Caliciviridae. These single-stranded, positive-sense RNA viruses are highly variable both genetically and antigenically. Several animal enteric caliciviruses that are morphologically indistinguishable and genetically closely related to human noroviruses have been identified. The first bovine enteric noroviruses were described in Great Britain and are known as Newbury Agent 2. At least three genetic clusters of porcine noroviruses join together within genogroup II noroviruses. Human noroviruses are the most important cause of acute gastroenteritis illness in people of all ages. In the USA, they are associated with approximately 30-50% of all food-borne outbreaks. Until now, noroviruses have not been associated with gastroenteritis outbreaks in immunocompetent animals. Neither bovine nor porcine noroviruses can replicate in cell culture, although human norovirus can grow in a complex 3D culture system. However, the recently discovered murine noroviruses can replicate in cell culture and are therefore used as model viruses to study human noroviruses. This review focusses on virus classification, virion structure, pathogenesis, epidemiology, immune response and diagnosis of animal noroviruses in comparison with human noroviruses. The classification of animal enteric caliciviruses within the Norovirus genus raises the question of whether transmission from an animal reservoir to humans could occur. Answering this question is important in determining the risk of cross-species infections affecting the epidemiology and evolution of these viruses and so complicating the control of human norovirus infections.

Experimental reactivation of equine herpesvirus-3 following corticosteroid treatment.

State of latency, well known for several herpesviruses, has been proposed for equine herpesvirus-3 (EHV-3) and supported by epidemiological observations. No detailed assessment about reactivation, patterns of excretion and reexcretion has been formally reported. An experimental reactivation study by corticosteroid treatment in previously naturally infected horses was therefore carried out. Two polo mares with clinical and virologically confirmed history of equine coital exanthema were injected with dexamethasone and prednisolone on 3 successive days. Clinical signs, body temperature and clinical samples for virological and serological studies were obtained daily. Mares did not show any systemic clinical signs or hyperthermia. EHV-3 shedding, seroconversion and the presence of a small lesion were observed in one of the mares under study 2 weeks after corticosteroid treatment. The results demonstrate that this virus exhibits a latency-reactivation behaviour similar to that of other alpha herpesviruses. Reactivation of latency may have an important bearing on the appearance of clinical signs in mares and/or stallions during the breeding season without the actual evidence of transfer from mare to stallion or vice versa.

Molecular characterization and virulence of an alphaherpesvirus isolated from a BoHV1 gB-seropositive and gE-seronegative Italian buffalo.

During a serological survey, 157 out of 681 unvaccinated buffaloes resulted seropositive for bovine alphaherpesvirus 1 (BoHV1) glycoprotein B (gB) and seronegative for BoHV1 glycoprotein E (gE). These serological results were generally expected in animals vaccinated with a BoHV1 gE-deleted vaccine but not in unvaccinated animals. Seroneutralization tests on 36 selected sera detected neutralizing antibody titers more than three times higher for BuHV1 than for BoHV1. In order to investigate the virus, one of these buffaloes was injected with dexamethasone, and from nasal and vaginal swabs collected at different time points, a ruminant herpesvirus was isolated, characterized and also detected by PCR. Restriction enzyme analysis, sequencing and phylogenic analysis of gB and gD genes showed that the virus was genetically similar but not identical to BuHV1 strain b6. Intranasal inoculation of the virus in a healthy seronegative buffalo resulted in a mild and transient upper respiratory disease; the virus was isolated from clinical specimens and DNA was detected by PCR in nasal and vaginal swabs up to 9 days after infection. Further investigations should be aimed at sequencing the whole viral genome and at evaluating the host-range of this virus. Specific tests are needed to discriminate infections by different ruminant herpesviruses and to improve eradication programs of infectious bovine rhinotracheitis/infectious pustular vulvovaginitis in cattle.

Highly pathogenic avian influenza H5N1 virus in cats and other carnivores.

The Asian lineage highly pathogenic avian influenza (HPAI) H5N1 virus is a known pathogen of birds. Only recently, the virus has been reported to cause sporadic fatal disease in carnivores, and its zoonotic potential has been dominating the popular media. Attention to felids was drawn by two outbreaks with high mortality in tigers, leopards and other exotic felids in Thailand. Subsequently, domestic cats were found naturally infected and experimentally susceptible to H5N1 virus. A high susceptibility of the dog to H3N8 equine influenza A virus had been reported earlier, and recently also HPAI H5N1 virus has been identified as a canine pathogen. The ferret, hamster and mouse are suitable as experimental animals; importantly, these species are also kept as pets. Experimental intratracheal and oral infection of cats with an HPAI H5N1 virus isolate from a human case resulted in lethal disease; furthermore, cats have been infected by the feeding of infected chickens. Spread of the infection from experimentally infected to in-contact cats has been reported. The epidemiological role of the cat and other pet animal species in transmitting HPAI H5N1 virus to humans needs continuous consideration and attention.

Vaccination guidelines: a bridge between official requirements and the daily use of vaccines.

Vaccination guidelines are non-compulsory recommendations which assist the veterinary practitioner to use vaccines efficiently. They complement the official information contained in the shortened form of the summary of product characteristics that is included in the package insert of the product. The aim of this article is to clarify the role of guidelines and examine how they can improve the use of vaccines in practical conditions. The development of vaccination guidelines is explained. Several issues are discussed: primary vaccination schedule; interference with maternally derived antibodies; duration of immunity; vaccination and ageing. Three guidelines dealing with the vaccination of cats against upper respiratory tract disease are compared, as an example. In conclusion, vaccination guidelines are essential tools to assist veterinarians in good vaccination practices. They fill the gap that exists between the official recommendations included in the regulations and the licensing dossiers and the daily use of the vaccines.

Marker vaccines and the impact of their use on diagnosis and prophylactic measures.

Molecular biology and technical advances in DNA recombination have ushered in a new era in vaccinology. This article examines the recent development of specific marker vaccines and examines the impact of their use on the diagnosis and prevention of major infectious diseases. Gene-deleted vaccines, DIVA strategies (differentiating infected from vaccinated animals) and similar methods have been successfully applied in the control and eradication of Aujeszky's disease, infectious bovine rhinotracheitis, classical swine fever, foot and mouth disease and, recently, avian influenza. The efficacy and performance of existing marker vaccines and their companion diagnostic tools (which should be assesed by an independent body) are discussed, as are the ways in which these tools are deployed by competent authorities. The limits and the advantages of the use of marker vaccines are carefully analysed in the light of practical experiences. Although these vaccines can limit the speed and the extent of virus dissemination and thus reduce the number of animals slaughtered, marker vaccines are no substitute for sanitary measures. Early detection and warning systems and the quick implementation of sanitary measures, including stamping out, remain key issues in the control of highly contagious diseases.

Sanitary control in bovine embryo transfer. How far should we go? A review.

Embryo transfer is a globally executed technique which, when properly done, has both economic and sanitary advantages. International guidelines are available to prevent infection of the embryo with pathogens, both originating from the donor animals as from the environment. This manuscript describes the bacteria, viruses, protozoa, fungi and prions that are of major concern in the context of embryo transfer in cattle. In addition, the actual scientific knowledge on these pathogens is evaluated in terms of the current international and national guidelines and legislation.

[Genetic variation and recombination have profound medical implications]. / La recombinaison, moteur de diversité chez les alphaherpèsvirus, a de profondes implications médicales.

In the family Herpesviridae, the subfamily Alphaherpesvirinae contains numerous pathogenic viruses, i.e. herpes simplex and varicella-zoster viruses. These double-stranded DNA viruses exhibit a complex cycle combining lytic and latent infections. Moreover, both intranuclear replication and a sophisticated DNA replication machinery allow an efficient proof-reading mechanism of correction. A low mutation rate is therefore encountered by these viruses. Recombination can be identified as a key element of the genetic biodiversity of alphaherpesviruses, together with mutations. The experimental data recently obtained in the bovine herpesvirus 1 homologous model support the importance of recombination in alphaherpesvirus evolution and its role in the mechanisms involved by the virus to escape from medical tools of prevention and treatment.

Hepatitis E Virus and Related Viruses in Animals.

Hepatitis E is an acute human liver disease in healthy individuals which may eventually become chronic. It is caused by the hepatitis E virus (HEV) and can have a zoonotic origin. Nearly 57,000 people die yearly from hepatitis E-related conditions. The disease is endemic in both developing and developed countries with distinct epidemiologic profiles. In developing countries, the disease is associated with inadequate water treatment, while in developed countries, transmission is associated with animal contact and the ingestion of raw or uncooked meat, especially liver. All human HEV are grouped into at least four genotypes, while HEV or HEV-related viruses have been identified in an increasing number of domestic and wild animal species. Despite a high genetic diversity, only one single HEV serotype has been described to date for HEV genotypes 1-4. The discovery of new HEV or HEV-related viruses leads to a continuing increase in the number of genotypes. In addition, the genome organization of all these viruses is variable with overlapping open reading frames (ORF) and differences in the location of ORF3. In spite of the role of some domestic and wild animals as reservoir, the origin of HEV and HEV-related viruses in humans and animals is still unclear. This review discusses aspects of the detection, molecular virology, zoonotic transmission and origin of HEV and HEV-related viruses in the context of 'One Health' and establishes a link between the previous and the new taxonomy of this growing virus family.

Belgian Wildlife as Potential Zoonotic Reservoir of Hepatitis E Virus.

Hepatitis E is an acute human liver disease in healthy individuals but may become chronic in immunocompromised patients. It is caused by the hepatitis E virus (HEV) and can have a zoonotic origin, particularly in high-income countries. In this study, 383 sera from wild boars were selected for serology; for virological analyses, 69 sera and 61 livers from young wild boars were used. A total of 189 and 235 sera of, respectively, red deer and roe deer were collected for serological analysis. For virological analyses, 84 and 68 sera and 29 and 27 livers from, respectively, red and roe deer were sampled. An apparent seroprevalence of 34% (95% CI 29.71-39.46) was found in wild boars, of 1% (95% CI 0-2.4) in red deer and 3% (95% CI 0.8-4.2) in roe deer. To assess the ELISA screening prevalence, Western blot (WB) analyses were carried out, a receiver operating characteristic curve analysis was performed and different scenarios with varying ELISA specificities relative to WB were analysed. Seroprevalence remained high whatever the scenario in the wild boar population. In wild boar, 4 of 69 sera and 4 of 61 livers were detected as positive for HEV RNA. All sequences obtained from sera belonged to genotype HEV-3. HEV RNA, belonging to genotype HEV-3, was detected in one of 29 red deer livers. Wild boar can be considered as a host reservoir of the virus in Belgium. However, in contrast to the epidemiological role played by them in other countries, the low prevalence in deer makes these species an unlikely reservoir. This evidence needs further investigation to determine in which situation deer can serve as reservoir. These results also raise the question of the dynamics of HEV infection between wild fauna, domestic pigs and humans.