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Foot-and-mouth disease (FMD) is one of the most contagious viral animal diseases. It is an old disease which still poses a permanent threat of re-emergence for free zones. Foot-and-Mouth Disease Virus (FMDV), a Picornavirus belonging to genus Aphthovirus affects domestic and wild artiodactyls. FMD has a considerable socio-economic impact on agricultural production and trade in endemic regions, but also when incursions occur into FMD free areas, as in Europe in 2001. FMDV is historically one of the most studied viruses. Due to its high genetic and antigenic variability, the absence of cross-immunity between its seven serotypes, its ability to survive in the environment, its high contagiousness, its wide range of hosts and its particular biology, FMDV remains of major interest in animal health and the subject of many research projects. This review presents different aspects of FMDV infection, ranging from basic biology to diagnosis, surveillance and control.La fièvre aphteuse (FA) est l'une des maladies virales animales les plus contagieuses. Bien que très ancienne, la FA reste toujours d'actualité et représente une menace permanente de réémergence pour les pays indemnes. Le virus de la FA ou FMDV (pour foot-and-mouth disease virus), de la famille Picornaviridae, genre Aphthovirus, affecte les artiodactyles domestiques comme sauvages (principalement bovins, ovins, caprins, porcins, camélidés et cervidés). La fièvre aphteuse a un impact socio-économique considérable sur la production et le commerce agricoles en zone d'enzootie mais également en cas d'incursion dans une zone précédemment indemne comme ce fut le cas en 2001 en Europe. Le virus de la FA est historiquement l'un des virus les plus étudiés. Par sa grande variabilité génétique et antigénique, l'absence d'immunité croisée entre ses sept sérotypes, sa capacité de survie dans l'environnement, sa grande contagiosité, son large spectre d'hôtes ainsi que sa biologie particulière, ce virus reste d'intérêt majeur en santé animale et l'objet de nombreux travaux de recherche. Cette revue vise à présenter différents aspects de l'infection par le virus de la fièvre aphteuse et ses problématiques actuelles, de la biologie fondamentale au diagnostic en passant par la surveillance et les moyens de lutte.

Foot-and-mouth disease (FMD) affects the livestock industry and socioeconomic sustainability of many African countries. The success of FMD control programs in Africa depends largely on understanding the dynamics of FMD virus (FMDV) spread. In light of the recent outbreaks of FMD that affected the North-Western African countries in 2018 and 2019, we investigated the evolutionary phylodynamics of the causative serotype O viral strains all belonging to the East-Africa 3 topotype (O/EA-3). We analyzed a total of 489 sequences encoding the FMDV VP1 genome region generated from samples collected from 25 African and Western Asian countries between 1974 and 2019. Using Bayesian evolutionary models on genomic and epidemiological data, we inferred the routes of introduction and migration of the FMDV O/EA-3 topotype at the inter-regional scale. We inferred a mean substitution rate of 6.64 × 10

The circulation of Bluetongue (BT) and Epizootic Hemorrhagic Disease (EHD) in the Middle East has already been reported following serological analyses carried out since the 1980s, mostly on wild ruminants. Thus, an EHD virus (EHDV) strain was isolated in Bahrain in 1983 (serotype 6), and more recently, BT virus (BTV) serotypes 1, 4, 8 and 16 have been isolated in Oman. To our knowledge, no genomic sequence of these different BTV strains have been published. These same BTV or EHDV serotypes have circulated and, for some of them, are still circulating in the Mediterranean basin and/or in Europe. In this study, we used samples from domestic ruminant herds collected in Oman in 2020 and 2021 for suspected foot-and-mouth disease (FMD) to investigate the presence of BTV and EHDV in these herds. Sera and whole blood from goats, sheep and cattle were tested for the presence of viral genomes (by PCR) and antibodies (by ELISA). We were able to confirm the presence of 5 BTV serotypes (1, 4, 8, 10 and 16) and the circulation of EHDV in this territory in 2020 and 2021. The isolation of a BTV-8 strain allowed us to sequence its entire genome and to compare it with another BTV-8 strain isolated in Mayotte and with homologous BTV sequences available on GenBank.

Eradication of foot-and-mouth disease in France Foot-and-mouth disease (FMD) is a highly contagious viral disease that affects domestic and wild artiodactyls (mainly cattle, sheep, goats, pigs, camelids and deer). Before the 1980s, Europe, and in particular France, regularly experienced FMD epizootics with a very high number of outbreaks. A compulsory vaccination policy has been implemented at European level. Thus, every year, the French population of domestic cattle (about 20 million animals) was vaccinated. In 1991, due to the lack of detection of the circulating virus, vaccination was stopped. Since that date, France has become a country free from foot-and-mouth disease. The fight against this disease is a good example of the efficacy of vaccination to eradicate Foot-and-mouth disease virus."Éradication de la fièvre aphteuse en France La fièvre aphteuse est une maladie animale virale très contagieuse qui touche les artiodactyles domestiques et sauvages (principalement les bovins, ovins, caprins, porcins, camélidés et cervidés). Avant les années 1980, l’Europe et en particulier la France connaissait des épizooties régulières avec un nombre annuel très élevé de foyers. Une politique de vaccination obligatoire a été mise en oeuvre à l’échelon européen. Ainsi, tous les ans, la population française de bovins domestiques (environ 20 millions d’animaux) était vaccinée. En 1991, compte tenu de l’absence de détection de virus circulant, la vaccination fut arrêtée. Depuis cette date, la France a un statut de pays indemne de fièvre aphteuse (à l’exception d’une introduction ponctuelle en 2001 d’un virus provenant d’Angleterre). Cette lutte contre cette infection virale est donc un exemple indiscutable de réussite d’éradication de ce virus en France par l’utilisation de la vaccination."

Foot-and-mouth disease (FMD) is a highly contagious animal disease caused by an RNA virus subdivided into seven serotypes that are unevenly distributed in Asia, Africa, and South America. Despite the challenges of controlling FMD, since 1996 there have been only two outbreaks attributed to serotype C, in Brazil and in Kenya, in 2004. This article describes the historical distribution and origins of serotype C and its disappearance. The serotype was first described in Europe in the 1920s, where it mainly affected pigs and cattle but as a less common cause of outbreaks than serotypes O and A. No serotype C outbreaks have been reported in Europe since vaccination stopped in 1990. FMD virus is presumed to have been introduced into South America from Europe in the nineteenth century, although whether serotype C evolved there or in Europe is not known. As in Europe, this serotype was less widely distributed and caused fewer outbreaks than serotypes O and A. Since 1994, serotype C had not been reported from South America until four small outbreaks were detected in the Amazon region in 2004. Elsewhere, serotype C was introduced to Asia, in the 1950s to the 1970s, persisting and evolving for several decades in the Indian subcontinent and for eighteen years in the Philippines. Serotype C virus also circulated in East Africa between 1957 and 2004. Many serotype C viruses from European and Kenyan outbreaks were closely related to vaccine strains, including the most recently recovered Kenyan isolate from 2004. International surveillance has not confirmed any serotype C cases, worldwide, for over 15 years, despite more than 2,000 clinical submissions per year to reference laboratories. Serology provides limited evidence for absence of this serotype, as unequivocal interpretation is hampered by incomplete intra-serotype specificity of immunoassays and the continued use of this serotype in vaccines. It is recommended to continue strengthening surveillance in regions of FMD endemicity, to stop vaccination against serotype C and to reduce working with the virus in laboratories, since inadvertent escape of virus during such activities is now the biggest risk for its reappearance in the field.

The World Organisation for Animal Health (OIE) Manual of Diagnostic Tests and Vaccines for Terrestrial Animals describes a diverse array of assays that can be used to detect, characterise and monitor the presence of infectious agents of farmed livestock. These methods have been developed in different laboratories, at different times, and often include tests or kits provided by the commercial sector. Reference panels are essential tools that can be used during assay development and in validation exercises to compare the performance of these varied (and sometimes competing) diagnostic technologies. World Organisation for Animal Health Reference Laboratories already provide approved international standard reagents to help calibrate diagnostic tests for a range of diseases, but there remain important gaps in their availability for comparative purposes and the calibration of test results across different laboratories. Using foot and mouth disease (FMD) as an example, this review highlights four specific areas where new reference reagents are required. These are to: reduce bias in estimates of the diagnostic sensitivity and inter-serotypic specificity of tests used to detect diverse strains of FMD virus (FMDV), provide bio-safe positive controls for new point-of-care test formats that can be deployed outside high containment, harmonise FMDV antigens for post-vaccination serology, and address inter-laboratory differences in serological assays used to measure virus-specific FMD antibody responses. Since there are often limited resources to prepare and distribute these materials, sustainable progress in this arena will only be achievable if there is consensus and coordination of these activities among OIE Reference Laboratories.

In November 2013, a fatal encephalomyocarditis virus (EMCV) case in a captive African elephant ( Loxodonta africana) occurred at the Réserve Africaine de Sigean, a zoo in the south of France. Here we report the molecular characterization of the EMCV strains isolated from samples collected from the dead elephant and from 3 rats ( Rattus rattus) captured in the zoo at the same time. The EMCV infection was confirmed by reverse-transcription real-time PCR (RT-rtPCR) and genome sequencing. Complete genome sequencing and sequence alignment indicated that the elephant’s EMCV strain was 98.1–99.9% identical to the rat EMCV isolates at the nucleotide sequence level. Phylogenetic analysis of the ORF, P1, VP1, and 3D sequences revealed that the elephant and rat strains clustered into lineage A of the EMCV 1 group. To our knowledge, molecular characterization of EMCV in France and Europe has not been reported previously in a captive elephant. The full genome analyses of EMCV isolated from an elephant and rats in the same outbreak emphasizes the role of rodents in EMCV introduction and circulation in zoos.

This study aimed at determining the seroprevalence of foot‐and‐mouth disease (FMD) in domestic ruminants and at characterizing the virus strains circulating in four areas of Chad (East Batha, West Batha, Wadi Fira and West Ennedi). The study was carried out between October and November 2016. A total of 1,520 sera samples (928 cattle, 216 goats, 254 sheep and 122 dromedaries) were collected randomly for FMD serological analyses. Nine epithelial tissue samples were also collected from cattle showing clinical signs, for FMDV isolation and characterization. Serological results showed an overall NSP seroprevalence of 40% (375/928) in cattle in our sample (95% CrI [19–63]). However, seroprevalences of 84% (27/32), 78% (35/45) and 84% (21/25) were estimated in cattle over 5 years of age in East Batha, West Batha and Wadi Fira, respectively. In cattle under 1 year of age, 67% (18/27) seroprevalence was estimated in Wadi Fira, 64% (14/22) in East Batha and 59% (13/22) in West Batha. It was found that the high seroprevalences have been obtained in areas where pastures are shared by several different herds but also in farms where two to three species (bovine, caprine and ovine) are raised together. ELISA PrioCHECK®FMDV types O and A and in‐house solid phase competition ELISA serotyping results showed that the four O, A, SAT1 and SAT2 serotypes have circulated in Chad in 2016. However, the type SAT2 dominated with an overall seroprevalence of 43% (29/67) and was present in the four areas investigated. The phylogenetic analyses of the VP1 coding sequence allowed determining the serotype SAT2 topotype VII, close to viral strains found in Cameroon in 2015 with a similarity of 98.60%., FMD virus serotyping results showed that four O, A, SAT1 and SAT2 serotypes circulated in Chad in 2015. Phylogenetic analyses of the coding sequence VP1 allowed to determine the serotype SAT2 topotype VII, close to the viral strains found in Cameroon in 2015 with a similarity of 98.60%.

Foot-and-mouth disease (FMD) is the most devastating disease of cloven-hoofed livestock, with a crippling economic burden in endemic areas and immense costs associated with outbreaks in free countries. Foot-and-mouth disease virus (FMDV), a picornavirus, will spread rapidly in na&iuml, ve populations, reaching morbidity rates of up to 100% in cattle. Even after recovery, over 50% of cattle remain subclinically infected and infectious virus can be recovered from the nasopharynx. The pathogen and host factors that contribute to FMDV persistence are currently not understood. Using for the first time primary bovine soft palate multilayers in combination with proteogenomics, we analyzed the transcriptional responses during acute and persistent FMDV infection. During the acute phase viral RNA and protein was detectable in large quantities and in response hundreds of interferon-stimulated genes (ISG) were overexpressed, mediating antiviral activity and apoptosis. Although the number of pro-apoptotic ISGs and the extent of their regulation decreased during persistence, some ISGs with antiviral activity were still highly expressed at that stage. This indicates a long-lasting but ultimately ineffective stimulation of ISGs during FMDV persistence. Furthermore, downregulation of relevant genes suggests an interference with the extracellular matrix that may contribute to the skewed virus-host equilibrium in soft palate epithelial cells.

Foot-and-mouth disease (FMD) is a highly contagious disease of livestock affecting animal production and trade throughout Asia and Africa. Understanding FMD virus (FMDV) global movements and evolution can help to reconstruct the disease spread between endemic regions and predict the risks of incursion into FMD-free countries. Global expansion of a single FMDV lineage is rare but can result in severe economic consequences. Using extensive sequence data we have reconstructed the global space-time transmission history of the O/ME-SA/Ind-2001 lineage (which normally circulates in the Indian sub-continent) providing evidence of at least 15 independent escapes during 2013–2017 that have led to outbreaks in North Africa, the Middle East, Southeast Asia, the Far East and the FMD-free islands of Mauritius. We demonstrated that sequence heterogeneity of this emerging FMDV lineage is accommodated within two co-evolving divergent sublineages and that recombination by exchange of capsid-coding sequences can impact upon the reconstructed evolutionary histories. Thus, we recommend that only sequences encoding the outer capsid proteins should be used for broad-scale phylogeographical reconstruction. These data emphasise the importance of the Indian subcontinent as a source of FMDV that can spread across large distances and illustrates the impact of FMDV genome recombination on FMDV molecular epidemiology.

International audience; Vaccination is a key element in the control of foot-and-mouth disease (FMD). The majority of the antigenic sites that induce protective immune responses are localized on the FMD virus (FMDV) capsid that is formed by four virus-encoded structural proteins, VP1 to VP4. In the present study, recombinant canine adenovirus type 2 (CAV2)-based FMD vaccines, Cav-Pl/3C R degrees and Cav-VP1 R degrees, respectively expressing the structural P1 precursor protein along with the non-structural 3C protein or expressing the structural VP1 protein of the FMDV strain O/FRA/1/2001, were evaluated as novel vaccines against FMD. A strong humoral immune response was elicited in guinea pigs (GP) following immunization with Cav-P1/3C R, while administration of Cav-VP1 R degrees did not induce a satisfying antibody response in GP or mice. GP were then used as an experimental model for the determination of the protection afforded by the Cav/P1 R degrees vaccine against challenge with the FMDV strain O-1 Manisa/Turkey/1969. The Cav-P1/3C R vaccine protected GP from generalized FMD to a similar extent as a high potency double-oil emulsion O-1 Manisa vaccine. The results of the present study show that CAV2-based vector vaccines can express immunogenic FMDV antigens and offer protection against generalized FMD in GP. This suggest that Cav-P1 R FMDV vaccine may protect natural host species from FMD. In combination with an appropriate diagnostic test, the Cav-P1 R degrees FMDV vaccine may also serve as a marker vaccine to differentiate vaccinated from infected animals.

In addition to acute infection and disease, foot-and-mouth disease virus (FMDV) can cause persistent infection in ruminants. Such "carrier" animals represent a potential risk for FMDV transmission to susceptible animals. However, the mechanisms and the factors that determine FMDV persistence remain unknown. We describe here the establishment of FMDV type O persistent infection in a bovine epithelial cell line (Madin-Darby bovine kidney; MDBK). Preliminary experiments to assess the permissivity of MDBK cells to FMDV O infection revealed an unusual pattern of infection: after the initial phase of acute cell lysis, new monolayers formed within 48-72 h post-infection. We found that some cells survived cytolytic infection and subsequently regrew, thereby demonstrating that this bovine cell line can be persistently infected with FMDV type O. Further evidence that MDBK cells were persistently infected with FMDV includes: (i) detection of viral RNA in cells as well as in cell culture supernatants, (ii) detection of viral antigens in the cells by immunofluorescence analysis, and (iii) production of infectious viral particles for up to 36 cell passages. Furthermore, preliminary sequence analysis of persistent virus revealed a single nucleotide substitution within the VP1 coding region, resulting in the V50A amino acid substitution. This bovine model of FMDV persistence holds promise for the investigation of the viral and cellular molecular determinants that promote FMDV persistence.

A 21-year-old male African elephant ( Loxodonta africana) died suddenly with no previous medical history. Grossly, there were severe multifocal epicardial and endocardial hemorrhages of the atria and ventricles, hydropericardium, multifocal pleural hemorrhages, and severe pulmonary congestion and edema. Histologically, there was fibrinoid vasculitis and thrombosis in the heart and lung and myocardial necrosis. Citrobacter freundii was isolated in abundance in pure culture from liver and heart samples. Low levels of multiples types of elephant endotheliotropic herpesvirus (EEHV-6, EEHV-2B, and EEHV-3A) were detected in spleen samples, but not in heart samples. The levels of EEHV DNA found were much lower than those usually associated with acute EEHV hemorrhagic disease, and many other genomic loci that would normally be found in such cases were evidently below the level of detection. Therefore, these findings are unlikely to indicate lethal EEHV disease. Polymerase chain reaction for encephalomyocarditis virus (EMCV) and toxicology for oleander ( Nerium oleander) were negative. Stress, resulting from recent transport, and antimicrobial therapy may have contributed to the death of this animal.

A fatal case of encephalomyocarditis virus (EMCV) involving an African elephant (Loxodonta africana) occurred in November 2013 at the Reserve Africaine de Sigean, France. An adult female was found dead without any preliminary symptoms. Gross pathologic changes consisted of petechiae and hemorrhages on mucosae and internal organs, abundant transudate in the abdominal and pericardial cavities, and myocarditis. Histopathologic examination showed extensive degeneration and necrosis of ventricular cardiomyocytes with concurrent lymphoplasmocytic and eosinophilic infiltrate. An EMCV was isolated from several organs and considered the causative agent of the myocarditis. The same strain of virus was also isolated in rodents captured on zoo premises and considered to be the reservoir of the virus. To the authors' knowledge, this is the first EMCV case in a captive African elephant in Europe.

During 2000–2013, 4 genotypes of bluetongue virus (BTV) were detected in Corsica, France. At the end of 2013, a compulsory BTV-1 vaccination campaign was initiated among domestic ruminants; biological samples from goats were tested as part of a corresponding monitoring program. A BTV strain with nucleotide sequences suggestive of a novel serotype was detected.

Emergence and re-emergence of two major diseases in France (bluetongue) and in Mauritius (foot-and-mouth). The emergence of Bluetongue (BT) in continental France (caused by virus of serotype 8 (BTV-8) in 2006 and virus of serotype 1 (BTV-1) in 2007) was a total surprise. End of 2012, six years after the introduction of BT, France was declared free from this disease. However, at the end of August 2015, the BTV-8 made its reappearance in the center of France. In 2016, our laboratory re-isolated this virus. In Corsica, a virus of serotype 4 was identified on 1st December 2016 from sheep samples. On another hand, in 2016, we identified a virus of Foot-and-Mouth disease serotype O in Mauritius. This presentation will describe the conditions of the detection of these viruses as well as the results of phylogenetic analyzes., L’émergence en France continentale de la fièvre catarrhale ovine (FCO) causée en 2006 par le virus de sérotype 8 (BTV-8) puis en 2007, par le virus de sérotype 1 (BTV-1) a constitué une surprise totale. Fin 2012, six ans après l’introduction de la FCO, la France a été déclarée indemne de cette maladie. Pourtant, fin août 2015, le BTV-8 a fait sa réapparition dans le centre de la France. En 2016 notre laboratoire a isolé à nouveau ce virus. En Corse, un virus de sérotype 4 (BTV-4) fut identifié le 1er décembre 2016 à partir de prélèvements de moutons. D’autre part, en 2016, nous avons identifié un virus de la fièvre aphteuse de sérotype O à Maurice. Cette présentation décrira les conditions de détection de ces virus ainsi que les résultats des analyses phylogénétiques., Zientara Stéphan, Sailleau Corinne, Bréard Emmanuel, Vitour Damien, Viarouge Cyril, Belbis Guillaume, Gorna Kamila, Relmy Anthony, Romey Aurore, Blaise-Boisseau Sandra, Cardinale Éric, Bakkali Kassimi Labib. Émergence et ré-émergence de deux dangers sanitaires de catégorie 1 en France (FCO) et à Maurice (FA). In: Bulletin de l'Académie Vétérinaire de France tome 170 n°1, 2017. pp. 66-69.

International audience; Background: Orf or contagious ecthyma is a zoonotic viral infection with a potential serious health threat for the small ruminants industry as well as humans. It is currently emerging in new territories.Results: Eight suspected clinical cases of pustular dermatitis in goats occurred in the rural area of Tebe, in south-eastern Gabon, in January 2013. The orf virus (ORFV) was detected by high-throughput sequencing on sera, buccal swabs and scab pool samples. It was confirmed in six out of eight sick goats by using specific PCR targeting the major envelope protein (B2L) and the orf virus interferon resistance (VIR) genes. Phylogenetic analysis revealed that the Gabonese strain and South Korean strains evolved from a common ancestor, suggesting an Asian origin of the ORFV’ Gabonese strain.Conclusions: This study provides the molecular detection of the ORFV strain involved in the cases of pustular dermatitis in goats and highlights its circulation in Gabon

Bluetongue virus (BTV) and epizootic haemorrhagic disease virus (EHDV) in deer have already been isolated in Reunion Island and have caused more or less severe clinical signs in cattle (EHDV) or in sheep (BTV), as observed in 2003. In January 2009, cattle in Reunion Island showed clinical signs suggesting infection by one or the other of these arboviral diseases. A study was set up to determine the etiology of the disease. Analysis by reverse transcriptase-polymerase chain reaction (RT-PCR) performed on blood samples from 116 cattle from different districts of the island detected the presence of the EHDV genome in 106 samples and, in 5 of them, the simultaneous occurrence of BTV and EHDV. One strain of EHDV (7 isolates) and one of BTV were isolated in embryonated eggs and a BHK-21 cell culture. Group and subgroup primer-pairs were designed on the segment 2 sequences available in GenBank to identify and type the EHDV strains. Phylogenetic analysis of the genomic segment 2 (encoding the VP2 serotype-specific protein) of the isolates confirmed the serotypes of these two orbiviruses as BTV-2 and EHDV-6 and allowed them to be compared with previously isolated strains.

A full-length cDNA clone of an Encephalomyocarditis virus (EMCV) strain (2887A) isolated from aborted swine fetus was constructed and sequenced. Sequence comparison showed more than 99% nucleotide and amino acid sequence identity with two other EMCV strains, EMCV-PV21 and -R. However, the 2887A genomic sequence showed only about 84% nucleotide identity and 96% amino acid identity with EMCV-B, -D and -PV2 variants. RNA synthesized by in vitro transcription of this cDNA clone was infectious upon transfection of BHK21 cells, as shown by cytopathic effects and identification by neutralization test, and by propagation of the virus released into the culture media. The transcript RNA led to the production of infectious particles despite the presence of two nongenomic nucleotide residues at the 5' end, the short poly(C) tract (C(10)TCTC(3)TC(10)), the short poly(A) tail (7A), and the presence of six nongenomic nucleotides at the 3' end. The rescued virus was also found to be highly pathogenic for mice by intra-peritoneal inoculation producing a fatal disease indistinguishable from that of wild-type virus. An important finding concerning the molecular basis of infectivity was that the in vitro synthesized EMCV RNA transcript is infectious, although it contains a very short poly(A). The availability of the infectious cDNA clone of the reproductive failure strain of EMCV should prove to be useful for studying the molecular basis of the pathogenicity of EMCV in pig.

International audience; The encephalomyocarditis virus (EMCV) is a small non-enveloped single- strand RNA virus, the causative agent of not only myocarditis and encephalitis, but also neurological diseases, reproductive disorders and diabetes in many mammalian species. EMCV pathogenesis appears to be viral strain-and host-specific, and a better understanding of EMCV virulence factors is increasingly required. Indeed, EMCV is often used as a model for diabetes and viral myocarditis, and is also widely used in immunology as a double-stranded RNA stimulus in the study of Toll-like as well as cytosolic receptors. However, EMCV virulence and properties have often been neglected. Moreover, EMCV is able to infect humans albeit with a low morbidity. Progress on xenografts, such as pig heart transplantation in humans, has raised safety concerns that need to be explored. In this review we will highlight the biology of EMCV and all known and potential virulence factors.

Encephalomyocarditis virus (EMCV) can infect a wide range of vertebrate species including swine and non-human primates, but few data are available for humans. We therefore wanted to gain further insight into the mechanisms involved in EMCV infection of human cells. For this purpose, we analyzed the permissiveness of primary human cardiomyocytes towards two strains of EMCV; a pig myocardial strain (B279/95) and a rat strain (1086C). In this study, we show that both strains productively infect primary human cardiomyocytes and induce complete cytolysis. Binding and infection inhibition experiments indicated that attachment and infection are independent of sialic acid and heparan sulfate for B279/95 and dependent for 1086C. Sequence comparison between the two strains and three-dimensional analysis of the capsid revealed that six of the seven variable residues are surface-exposed, suggesting a role for these amino acids in binding. Moreover, analysis of variants isolated from the 1086C strain revealed the importance of lysine 231 of VP1 in the attachment of EMCV to cell-surface sialic acid residues. Together, these results show a potential for EMCV strains to use at least two different binding possibilities to initiate infection and provide new insights into the mechanisms involved in primary human cell recognition by EMCV.

The encephalomyocarditis virus (EMCV), a Picornaviridae virus, has a wide host spectrum and can cause various diseases. EMCV virulence factors, however, are as yet ill defined. Here, we demonstrate that the EMCV 2A protein is essential for the pathogenesis of EMCV. Infection of mice with the B279/95 strain of EMCV resulted in acute fatal disease, while the clone C9, derived by serial in vitro passage of the B279/95 strain, was avirulent. C9 harbored a large deletion in the gene encoding the 2A protein. This deletion was incorporated into the cDNA of a pathogenic EMCV1.26 strain. The new virus, EMCV1.26Δ2A, was capable of replicating in vitro , albeit more slowly than EMCV1.26. Only mice inoculated with EMCV1.26 triggered death within a few days. Mice infected with EMCV1.26Δ2A did not exhibit clinical signs, and histopathological analyses showed no damage in the central nervous system, unlike EMCV1.26-infected mice. In vitro , EMCV1.26Δ2A presented a defect in viral particle release correlating with prolonged cell viability. Unlike EMCV1.26, which induced cytopathic cell death, EMCV1.26Δ2A induced apoptosis via caspase 3 activation. This strongly suggests that the 2A protein is required for inhibition of apoptosis during EMCV infection. All together, our data indicate that the EMCV 2A protein is important for the virus in counteracting host defenses, since Δ2A viruses were no longer pathogenic and were unable to inhibit apoptosis in vitro .

Accumulating evidence suggests that hepatitis E virus (HEV) infection is an emerging disease in regions where HEV is nonendemic. In France, the prevalence of anti-HEV antibodies in the general population has never been studied. Using blood donors' samples, we have found a prevalence of 3.20%, which is similar to that of other industrialized countries.

Since its introduction into northern Europe in 2006, bluetongue has become a major threat to animal health. While the efficacy of commercial vaccines has been clearly demonstrated in livestock, little is known regarding the effect of maternal immunity on vaccinal efficacy. Here, we have investigated the duration and amplitude of colostral antibody-induced immunity in calves born to dams vaccinated against bluetongue virus serotype 8 (BTV-8) and the extent of colostral antibody-induced interference of vaccination in these calves. Twenty-two calf-cow pairs were included in this survey. The median age at which calves became seronegative for BTV was 84 and 112 days as assayed by seroneutralisation test (SNT) and VP7 BTV competitive ELISA (cELISA), respectively. At the mean age of 118 days, 13/22 calves were immunized with inactivated BTV-8 vaccine. In most calves vaccination elicited a weak immune response, with seroconversion in only 3/13 calves. The amplitude of the humoral response to vaccination was inversely proportional to the maternal antibody level prior to vaccination. Thus, the lack of response was attributed to the persistence of virus-specific colostral antibodies that interfered with the induction of the immune response. These data suggest that the recommended age for vaccination of calves born to vaccinated dams needs to be adjusted in order to optimize vaccinal efficacy.

International audience; The incidence of developing cancer should increase with the body mass, yet is not the case, a conundrum referred to as Peto's paradox. Elephants have a lower incidence of cancer suggesting that these animals have probably evolved different ways to protect themselves against the disease. The paradox is worth revisiting with the realization that most mammals encode an endogenous APOBEC3 cytidine deaminase capable of mutating single stranded DNA. Indeed, the mutagenic activity of some APOBEC3 enzymes has been shown to introduce somatic mutations into genomic DNA. These enzymes are now recognized as causal agent responsible for the accumulation of CG-> TA transitions and DNA breaks leading to chromosomal rearrangements in human cancer genomes. Here, we identified an elephant A3Z1 gene, related to human APOBEC3A and showed that it could efficiently deaminate cytidine, 5-methylcytidine and produce DNA breaks leading to massive apoptosis, similar to other mammalian APOBEC3A enzymes where body mass varies by up to four orders of magnitude. Consequently, it could be considered that eAZ1 might contribute to cancer in elephants in a manner similar to their proposed role in humans. If so, eAZ1 might be particularly well regulated to counter Peto's paradox. The APOBEC3 (A3) locus is bounded by two conserved genes, chromobox 6 and 7 (CBX6 and CBX7) in most pla-cental mammals and encodes a family of cytidine deaminases capable of converting cytidine residues to uridine in single strand DNA (ssDNA). The mutagenic activity of these enzymes is involved with the restriction of retro-viruses and DNA viruses, as well as endogenous retroelements and retrotransposons through hypermutation of viral DNA in a process called editing 1. The A3 repertoire is extremely variable among mammals, the locus being shaped through extensive gene duplications and functionalization in the context of a virus-host arms race. A3 enzymes are made up of three related, but distinct zinc-finger domains referred to as Z1, Z2 and Z3 2-4 presumably already present in the genome of the ancestor of placental mammals 5. The last few years has seen the identification of two human endogenous A3 cytidine deaminases, APOBEC3A (A3A) and APOBEC3B (A3B) capable of introducing multiple mutations in chromosomal DNA 6-9. These findings are grounded by the analysis of many cancer genomes, revealing far more mutations and rearrangements than hitherto imagined, where CG-> TA transitions appears to be the dominant mutations 10-13. Human A3A is composed of a single Z1 domain, while A3B is composed of a double Z2Z1 domain, although only the C terminal Z1 domain being catalytically functional 6. A3A and A3B enzymes are both localized in the nucleus and can edit cytidine residues to uridine in ssDNA during transcription and replication, following DNA repair, and leave TpC to TpT signature mutations that show up in cancer genomes 6,8,9. Both enzymes can mutate 5-methylcytidine (5MeC) to thymidine leaving another distinct signature in cancer genomes 6,14-16. Although A3A and A3B are accepted as intrinsic mutators of cellular chromosomal DNA, analyzed in several cancer types 8,11,17 , debate still persists regarding the contribution of each enzyme in the accumulation of mutations paving the way for oncogenesis. While, it has been described that A3A and A3B could be enzymat-ically active in different cancers 18 , A3A is the more active of the two enzymes and as a consequence, only A3A can produce double stranded breaks (DSBs), at least in an experimental setting 6,7,19. Editing frequencies of >0.5 can be found which is why the phenomenon is referred to as hyperediting or hypermutation 9. Accumulation of substitutions localized in the A3B C-terminal domain attenuated the activity of the enzyme compared to A3A 6 .

Foot-and-mouth-disease (FMD) is a highly contagious disease that affects domestic and wild artiodactyles. It is endemic in Chad. However, there is very little research on FMD, as the prevalence and risk factors associated with the disease and all circulating serotypes are not well known. My thesis aims to contribute to a better understanding of the epidemiology of this disease, to determine areas at risk, to estimate seroprevalence in three major breeding regions (Batha, Wadi Fira and West Ennedi) and to carry out an initial molecular characterization of the serotypes of the FMDV circulating in Chad.A literature review was carried out to collect data on animal mobility and the current epidemiological situation of FMD in Chad and neighbouring countries. The objective of this work was to establish a risk map based on the occurrence of the disease in relation to animal movements. The results were used to estimate the risk of introduction and spread of FMD and to represent areas at risk using the new risk mapping approach. Thus, 12/347 Chadian communes located at the borders have a "very high" risk of introduction of the FMDV. For the risk of spread, 54 and 78 communes were characterized by a "very high" and "high" risk respectively.In addition, a cross-sectional survey was conducted between October and 2016 to determine the seroprevalence of the disease in domestic ruminants and characterize circulating viral strains. A total of 1520 sera samples (928 cattle, 216 goats, 254 sheep and 122 dromedaries) were collected for serological analysis and nine epithelial tissues from cattle showing clinical signs for virological analysis. Serological results showed an overall seroprevalence of 40% and seroprevalences of 84%, 78% and 84% in cattle over 5 years of age in East Batha, West Batha and Wadi Fira respectively. Among cattle under one year of age, seroprevalence was estimated at 67% in Wadi Fira, 64% in East Batha and 59% in West Batha. In small ruminants over 5 years of age, seroprevalence of 63%, 45%, 34% and 10% have been estimated respectively in West Batha, East Batha, Wadi Fira and West Ennedi. In small ruminants under one year of age, seroprevalence has been estimated at Wadi Fira (50%), East Batha (32%), West Batha (18%), and Ennedi West (11%). Serotyping results from sera of animals less than one year old showed that serotypes O, A, SAT1 and SAT2 circulated in 2015 in Chad. However, serotype SAT2 dominated with an overall seroprevalence of 43.3% and was present in all areas studied. It is followed by serotypes O (29.9%) present in West Batha and Wadi Fira, A (22.4%) present in East Batha and West Batha and SAT1 (4.5%) present only in Wadi Fira. Virological analyses have made it possible to characterize the serotype SAT2 of the FMDV. Phylogenetic analyses of the coding sequence for the VP1 protein made it possible to determine the SAT2 topotype VII serotype, close to the viral strains found in Cameroon in 2015 with a similarity of 98.60%.In conclusion, the serological results confirm that the disease is endemic. Furthermore, the results of molecular characterization prove the cross-border nature of the disease through uncontrolled movements of animals. All these results show that it is important for Chadian veterinary services and researchers to continue research on the molecular epidemiology of FMD throughout the country in order to characterize all serotypes circulating and then develop and implement a surveillance protocol and a risk-based control plan.; La fièvre aphteuse (FA) est une maladie hautement contagieuse qui touche les artiodactyles domestiques et sauvages. Elle est endémique au Tchad. Cependant, il y a très peu de recherches sur la FA, car la séroprévalence et les facteurs de risque associés à la maladie et tous les sérotypes circulants ne sont pas bien connus. Les travaux de ma thèse visent à contribuer à une meilleure compréhension de l'épidémiologie de cette maladie, à déterminer les zones à risque, à estimer la séroprévalence dans trois grandes régions d’élevage (Batha, Wadi Fira et Ennedi Ouest) et à réaliser une première caractérisation moléculaire des sérotypes du virus de la FA circulant au Tchad.Une revue bibliographique a été effectuée pour collecter des données sur la mobilité animale et la situation épidémiologique actuelle de la FA au Tchad et dans les pays voisins. L’objectif de ce travail était d’établir une cartographie du risque basée sur l’occurrence de la maladie en relation avec les mouvements des animaux. Les résultats ont permis d’estimer le risque d’introduction et de propagation de la fièvre aphteuse et de représenter les zones à risque grâce à la nouvelle approche de cartographie du risque. Ainsi, 12/347 communes tchadiennes, situées aux frontières ont un risque « très élevé » d'introduction du virus de la FA aphteuse. Pour le risque de propagation, 54 et 78 communes étaient caractérisées respectivement par un risque « très élevé » et « élevé ».Par ailleurs, une enquête transversale a été menée entre octobre et nombre 2016 pour déterminer la séroprévalence de la maladie chez les ruminants domestiques et caractériser les souches virales qui circulent. Au total, 1520 échantillons de sérums (928 bovins, 216 caprins, 254 ovins et 122 dromadaires) ont été prélevés pour les analyses sérologiques et 9 tissus épithéliaux chez les bovins présentant des signes cliniques pour les analyses virologiques. Les résultats sérologiques ont montré une séroprévalence globale de 40% et des séroprévalences de 84%, 78% et 84% chez les bovins de plus de 5 ans respectivement au Batha Est, Batha Ouest et Wadi Fira. Chez les bovins de moins d'un an, la séroprévalence était estimée à 67 % au Wadi Fira, à 64 % au Batha Est et à 59 % au Batha Ouest. Chez les petits ruminants de plus de 5 ans, des séroprévalences de 63%, 45%, 34% et 10% ont été estimées respectivement au Batha Ouest, Batha Est, Wadi Fira et Ennedi Ouest. Chez les petits ruminants de moins d'un an, des séroprévalences ont été estimées : Wadi Fira (50 %), Batha Est (32 %), Batha Ouest (18 %), et Ennedi Ouest (11 %). Les résultats du sérotypage à partir des sérums d’animaux âgés de moins d’un an ont montré que les sérotypes O, A, SAT1 et SAT2 ont circulé en 2015 au Tchad. Cependant, le sérotype SAT2 dominait avec une séroprévalence globale de 43,3 % et il était présent dans toutes les zones étudiées. Il est suivi des sérotypes O (29,9%) présent aux Batha Ouest et Wadi Fira, A (22,4%) présent aux Batha Est et Batha Ouest et SAT1 (4,5%) présent seulement à Wadi Fira. Les analyses virologiques ont permis de caractériser le sérotype SAT2 du virus de la FA. Les analyses phylogénétiques de la séquence codante pour la protéine VP1 ont permis de déterminer le sérotype SAT2 topotype VII, proche des souches virales trouvées au Cameroun en 2015 avec une similarité de 98,60%.En conclusion, les résultats sérologiques confirment le caractère endémique de la maladie. En outre, les résultats de la caractérisation moléculaire prouvent le caractère transfrontalier de la maladie ceci par le biais de mouvements incontrôlés d'animaux. L’ensemble de ces résultats montrent qu’il est important que les services vétérinaires tchadiens et les chercheurs poursuivent les recherches sur l’épidémiologie moléculaire de la FA sur l’ensemble du territoire pour caractériser tous les sérotypes qui circulent, puis élaborer et mettre en place un protocole de surveillance et un plan de lutte basée sur les risques.