Publications by authors named "Stéphan Zientara"

140 Publications

The VP3 Protein of Bluetongue Virus Associates with the MAVS Complex and Interferes with the RIG-I-Signaling Pathway.

Viruses 2021 02 2;13(2). Epub 2021 Feb 2.

UMR 1161 Virologie, Laboratory for Animal Health, INRAE, Department of Animal Health, Ecole Nationale Vétérinaire d'Alfort, ANSES, Université Paris-Est, 94700 Maisons-Alfort, France.

Bluetongue virus (BTV), an arbovirus transmitted by biting midges, is a major concern of wild and domestic ruminants. While BTV induces type I interferon (alpha/beta interferon [IFN-α/β]) production in infected cells, several reports have described evasion strategies elaborated by this virus to dampen this intrinsic, innate response. In the present study, we suggest that BTV VP3 is a new viral antagonist of the IFN-β synthesis. Indeed, using split luciferase and coprecipitation assays, we report an interaction between VP3 and both the mitochondrial adapter protein MAVS and the IRF3-kinase IKKε. Overall, this study describes a putative role for the BTV structural protein VP3 in the control of the antiviral response.
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http://dx.doi.org/10.3390/v13020230DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7913109PMC
February 2021

The antibody response induced FMDV vaccines in sheep correlates with early transcriptomic responses in blood.

NPJ Vaccines 2020 Jan 3;5(1). Epub 2020 Jan 3.

Université Paris-Saclay, INRA, VIM, Domaine de Vilvert, 78350, Jouy-en-Josas, France.

Foot and mouth disease (FMD) is a highly contagious viral disease with high economic impact, representing a major threat for cloven-hooved mammals worldwide. Vaccines based on adjuvanted inactivated virus (iFMDV) induce effective protective immunity implicating antibody (Ab) responses. To reduce the biosafety constraints of the manufacturing process, a non-replicative human adenovirus type 5 vector encoding FMDV antigens (Ad5-FMDV) has been developed. Here we compared the immunogenicity of iFMDV and Ad5-FMDV with and without the ISA206VG emulsion-type adjuvant in sheep. Contrasted Ab responses were obtained: iFMDV induced the highest Ab levels, Ad5-FMDV the lowest ones, and ISA206VG increased the Ad5-FMDV-induced Ab responses to protective levels. Each vaccine generated heterogeneous Ab responses, with high and low responders, the latter being considered as obstacles to vaccine effectiveness. A transcriptomic study on total blood responses at 24 h post-vaccination revealed several blood gene module activities correlating with long-term Ab responses. Downmodulation of T cell modules' activities correlated with high responses to iFMDV and to Ad5-FMDV+ISA206VG vaccines as also found in other systems vaccinology studies in humans and sheep. The impact of cell cycle activity depended on the vaccine types, as it positively correlated with higher responses to iFMDV but negatively to non-adjuvanted Ad5-FMDV. Finally an elevated B cell activity at 24 h correlated with high Ab responses to the Ad5-FMDV+ISA206VG vaccine. This study provides insights into the early mechanisms driving the Ab response induced by different vaccine regimens including Ad5 vectors and points to T cell modules as early biomarker candidates of different vaccine-type efficacy across species.
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http://dx.doi.org/10.1038/s41541-019-0151-3DOI Listing
January 2020

Non-discriminatory Exclusion Testing as a Tool for the Early Detection of Foot-and-Mouth Disease Incursions.

Front Vet Sci 2020 19;7:552670. Epub 2020 Nov 19.

Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany.

Endemic circulation of foot-and-mouth disease (FMD) in Africa and Asia poses a continuous risk to countries in Europe, North America, and Oceania which are free from the disease. Introductions of the disease into a free region have dramatic economic impacts, especially if they are not detected at an early stage and controlled rapidly. However, farmers and veterinarians have an obvious disincentive to report clinical signs that are consistent with FMD, due to the severe consequences of raising an official suspicion, such as farm-level quarantine. One way that the risk of late detection can be mitigated is offering non-discriminatory exclusion testing schemes for differential diagnostics, wherein veterinarians can submit samples without the involvement of the competent authority and without sanctions or costs for the farmer. This review considers the benefits and limitations of this approach to improve the early detection of FMD in free countries and gives an overview of the FMD testing schemes currently in use in selected countries in Europe and the Americas as well as in Australia.
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http://dx.doi.org/10.3389/fvets.2020.552670DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7710516PMC
November 2020

Screening of potential antiviral molecules against equid herpesvirus-1 using cellular impedance measurement: Dataset of 2,891 compounds.

Data Brief 2020 Dec 5;33:106492. Epub 2020 Nov 5.

LABÉO Frank Duncombe, 14280 Saint-Contest, France.

Data presented in this article are associated with the research article "Identification of antiviral compounds against equid herpesvirus-1 using real-time cell assay screening: efficacy of decitabine and valganciclovir alone and in combination" [1]. These data correspond to the screening of 2,891 potential antiviral compounds against equid herpesvirus-1 (EHV-1) based on impedance measurements using the xCELLigence® RTCA MP System. This dataset includes compounds from three different libraries: i) 1,199 compounds from the Prestwick® Chemical Library, which contains mostly US Food and Drug Administration approved drugs (Prestwick® Chemical, Illkirch, France); ii) 1,651 compounds from the Centre d'Etudes et de Recherche sur le Médicament de Normandie (CERMN, Caen, France); iii) 41 compounds (called herein in-house antiviral library) selected for their effects against different human viruses. Compounds effective against EHV-1 were selected using the area under normalised curves (AUC) and the time required for the Cell Index to decrease by 50% after virus infection (CIT). The full dataset from the screen is made publicly available for further analyses.
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http://dx.doi.org/10.1016/j.dib.2020.106492DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7689375PMC
December 2020

Molecular characterization of encephalomyocarditis virus strains isolated from an African elephant and rats in a French zoo.

J Vet Diagn Invest 2021 Mar 8;33(2):313-321. Epub 2020 Dec 8.

Animal Health Laboratory, UMR1161 Virology, INRAE, ANSES, ENVA, Paris-Est University, Maisons-Alfort, France.

In November 2013, a fatal encephalomyocarditis virus (EMCV) case in a captive African elephant () 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 () 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.
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http://dx.doi.org/10.1177/1040638720978389DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7953090PMC
March 2021

Editorial: Emerging Arboviruses.

Front Vet Sci 2020 6;7:593872. Epub 2020 Nov 6.

Department of Diagnostic Medicine/Pathobiology and Center of Excellence for Emerging and Zoonotic Animal Diseases, College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States.

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http://dx.doi.org/10.3389/fvets.2020.593872DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7677233PMC
November 2020

Contrasted Epidemiological Patterns of West Nile Virus Lineages 1 and 2 Infections in France from 2015 to 2019.

Pathogens 2020 Oct 30;9(11). Epub 2020 Oct 30.

UMR 1161 Virology, ANSES, INRAE, ENVA, ANSES Animal Health Laboratory, EURL for Equine Diseases, 94704 Maisons-Alfort, France.

Since 2015, annual West Nile virus (WNV) outbreaks of varying intensities have been reported in France. Recent intensification of enzootic WNV circulation was observed in the South of France with most horse cases detected in 2015 ( = 49), 2018 ( = 13), and 2019 ( = 13). A WNV lineage 1 strain was isolated from a horse suffering from West Nile neuro-invasive disease (WNND) during the 2015 episode in the Camargue area. A breaking point in WNV epidemiology was achieved in 2018, when WNV lineage 2 emerged in Southeastern areas. This virus most probably originated from WNV spread from Northern Italy and caused WNND in humans and the death of diurnal raptors. WNV lineage 2 emergence was associated with the most important human WNV epidemics identified so far in France (n = 26, including seven WNND cases and two infections in blood and organ donors). Two other major findings were the detection of WNV in areas with no or limited history of WNV circulation (Alpes-Maritimes in 2018, Corsica in 2018-2019, and Var in 2019) and distinct spatial distribution of human and horse WNV cases. These new data reinforce the necessity to enhance French WNV surveillance to better anticipate future WNV epidemics and epizootics and to improve the safety of blood and organ donations.
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http://dx.doi.org/10.3390/pathogens9110908DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7692118PMC
October 2020

The Genome Segments of Bluetongue Virus Differ in Copy Number in a Host-Specific Manner.

J Virol 2020 12 9;95(1). Epub 2020 Dec 9.

CIRAD, UMR ASTRE, Montpellier, France

Genome segmentation is mainly thought to facilitate reassortment. Here, we show that segmentation can also allow differences in segment abundance in populations of bluetongue virus (BTV). BTV has a genome consisting in 10 segments, and its cycle primarily involves periodic alternation between ruminants and biting midges. We have developed a reverse transcription-quantitative PCR (RT-qPCR) approach to quantify each segment in wild BTV populations sampled in both ruminants and midges during an epizootic. Segment frequencies deviated from equimolarity in all hosts. Interestingly, segment frequencies were reproducible and distinct between ruminants and biting midges. Beyond a putative regulatory role in virus expression, this phenomenon could lead to different evolution rates between segments. The variation in viral gene frequencies remains a largely unexplored aspect of within-host genetics. This phenomenon is often considered to be specific to multipartite viruses. Multipartite viruses have segmented genomes, but in contrast to segmented viruses, their segments are each encapsidated alone in a virion. A main hypothesis explaining the evolution of multipartism is that, compared to segmented viruses, it facilitates the regulation of segment abundancy, and the genes the segments carry, within a host. These differences in gene frequencies could allow for expression regulation. Here, we show that wild populations of a segmented virus, bluetongue virus (BTV), also present unequal segment frequencies. BTV cycles between ruminants and biting midges. As expected from a role in expression regulation, segment frequencies tended to show specific values that differed between ruminants and midges. Our results expand previous knowledge on gene frequency variation and call for studies on its role and conservation beyond multipartite viruses.
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http://dx.doi.org/10.1128/JVI.01834-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7737730PMC
December 2020

Identification of antiviral compounds against equid herpesvirus-1 using real-time cell assay screening: Efficacy of decitabine and valganciclovir alone or in combination.

Antiviral Res 2020 11 11;183:104931. Epub 2020 Sep 11.

LABÉO Frank Duncombe, 14280, Saint-Contest, France; Normandie Univ, Unicaen, BIOTARGEN EA7450, 14280, Saint-Contest, France; Normandie Univ, UNICAEN, ImpedanCELL, 14280, Saint-Contest, France. Electronic address:

Equid herpesvirus-1 infections cause respiratory, neurological and reproductive syndromes. Despite preventive treatments with vaccines, resurgence of EHV-1 infection still constitutes a major threat to equine industry. However, no antiviral compound is available to treat infected horses. In this study, 2891 compounds were screened against EHV-1 using impedance measurement. 22 compounds have been found to be effective in vitro against EHV-1. Valganciclovir, ganciclovir, decitabine, aphidicolin, idoxuridine and pritelivir (BAY 57-1293) are the most effective compounds identified, and their antiviral potency was further assessed on E. Derm, RK13 and EEK cells and against 3 different field strains of EHV-1 (ORF30 2254 A/G/C). We also provide evidences of synergistic interactions between valganciclovir and decitabine in our in vitro antiviral assay as determined by MacSynergy II, isobologramm and Chou-Talalay methods. Finally, we showed that deoxycytidine reverts the antiviral effect of decitabine, thus supporting some competition at the level of nucleoside phosphorylation by deoxycytidine kinase and/or DNA synthesis. Deoxycitidine analogues, like decitabine, is a family of compounds identified for the first time with promising antiviral efficacy against herpesviruses.
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http://dx.doi.org/10.1016/j.antiviral.2020.104931DOI Listing
November 2020

Replication of Equine arteritis virus is efficiently suppressed by purine and pyrimidine biosynthesis inhibitors.

Sci Rep 2020 06 22;10(1):10100. Epub 2020 Jun 22.

Laboratoire de Santé Animale, site de Normandie de l'ANSES, PhEED Unit, 14430, Goustranville, France.

RNA viruses are responsible for a large variety of animal infections. Equine Arteritis Virus (EAV) is a positive single-stranded RNA virus member of the family Arteriviridae from the order Nidovirales like the Coronaviridae. EAV causes respiratory and reproductive diseases in equids. Although two vaccines are available, the vaccination coverage of the equine population is largely insufficient to prevent new EAV outbreaks around the world. In this study, we present a high-throughput in vitro assay suitable for testing candidate antiviral molecules on equine dermal cells infected by EAV. Using this assay, we identified three molecules that impair EAV infection in equine cells: the broad-spectrum antiviral and nucleoside analog ribavirin, and two compounds previously described as inhibitors of dihydroorotate dehydrogenase (DHODH), the fourth enzyme of the pyrimidine biosynthesis pathway. These molecules effectively suppressed cytopathic effects associated to EAV infection, and strongly inhibited viral replication and production of infectious particles. Since ribavirin is already approved in human and small animal, and that several DHODH inhibitors are in advanced clinical trials, our results open new perspectives for the management of EAV outbreaks.
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http://dx.doi.org/10.1038/s41598-020-66944-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7308276PMC
June 2020

First detection and genome sequencing of SARS-CoV-2 in an infected cat in France.

Transbound Emerg Dis 2020 Nov 23;67(6):2324-2328. Epub 2020 Jun 23.

UMR VIROLOGIE, INRAE, Ecole Nationale Vétérinaire d'Alfort, ANSES, Laboratoire de santé animale, Université Paris-Est, Maisons-Alfort, France.

After its first description in Wuhan (China), SARS-CoV-2 the agent of coronavirus disease 2019 (COVID-19) rapidly spread worldwide. Previous studies suggested that pets could be susceptible to SARS-CoV-2. Here, we investigated the putative infection by SARS-CoV-2 in 22 cats and 11 dogs from owners previously infected or suspected of being infected by SARS-CoV-2. For each animal, rectal, nasopharyngeal swabs and serum were taken. Swabs were submitted to RT-qPCR assays targeting 2 genes of SARS-CoV-2. All dogs were tested SARS-CoV-2 negative. One cat was tested positive by RT-qPCR on rectal swab. Nasopharyngeal swabs from this animal were tested negative. This cat showed mild respiratory and digestive signs. Serological analysis confirms the presence of antibodies against the SARS-CoV-2 in both serum samples taken 10 days apart. Genome sequence analysis revealed that the cat SARS-CoV-2 belongs to the phylogenetic clade A2a like most of the French human SARS-CoV-2. This study reports for the first time the natural infection of a cat in France (near Paris) probably through their owners. There is currently no evidence that cats can spread COVID-19 and owners should not abandon their pets or compromise their welfare.
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http://dx.doi.org/10.1111/tbed.13659DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7300955PMC
November 2020

"Frozen evolution" of an RNA virus suggests accidental release as a potential cause of arbovirus re-emergence.

PLoS Biol 2020 04 28;18(4):e3000673. Epub 2020 Apr 28.

MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom.

The mechanisms underlying virus emergence are rarely well understood, making the appearance of outbreaks largely unpredictable. Bluetongue virus serotype 8 (BTV-8), an arthropod-borne virus of ruminants, emerged in livestock in northern Europe in 2006, spreading to most European countries by 2009 and causing losses of billions of euros. Although the outbreak was successfully controlled through vaccination by early 2010, puzzlingly, a closely related BTV-8 strain re-emerged in France in 2015, triggering a second outbreak that is still ongoing. The origin of this virus and the mechanisms underlying its re-emergence are unknown. Here, we performed phylogenetic analyses of 164 whole BTV-8 genomes sampled throughout the two outbreaks. We demonstrate consistent clock-like virus evolution during both epizootics but found negligible evolutionary change between them. We estimate that the ancestor of the second outbreak dates from the height of the first outbreak in 2008. This implies that the virus had not been replicating for multiple years prior to its re-emergence in 2015. Given the absence of any known natural mechanism that could explain BTV-8 persistence over this long period without replication, we hypothesise that the second outbreak could have been initiated by accidental exposure of livestock to frozen material contaminated with virus from approximately 2008. Our work highlights new targets for pathogen surveillance programmes in livestock and illustrates the power of genomic epidemiology to identify pathways of infectious disease emergence.
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http://dx.doi.org/10.1371/journal.pbio.3000673DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7188197PMC
April 2020

Evaluation of a commercial ELISA for detection of epizootic haemorrhagic disease antibodies in domestic and wild ruminant sera.

Transbound Emerg Dis 2020 Nov 14;67(6):2475-2481. Epub 2020 May 14.

Laboratoire de Santé Animale d'Alfort, ANSES, ENVA, INRA, UMR 1161 VIROLOGIE, Université Paris Est, Maisons-Alfort, France.

Bluetongue (BT) and epizootic haemorrhagic disease (EHD) are vector-borne viral diseases affecting domestic and wild ruminants. Both are notifiable under OIE rules. BT and EHD viruses (BTV and EHDV) are closely related Orbiviruses with structural, antigenic and molecular similarities. Both viruses can produce analogous clinical signs in susceptible animals. Serological tests are commonly used for BT and EHD diagnosis and surveillance. Competitive ELISA (c-ELISA) is the most widely used serological test for the specific detection of BTV or EHDV viral protein 7 (VP7) antibodies (Abs). The specificity and sensitivity of the BTV c-ELISA kits available on the market are recognized for the detection of BTV Abs. Concerning EHD, a single commercial EHDV c-ELISA kit (ELISA A kit) commonly used for diagnosis in Europe and Africa was available between 2011 and 2018 but is now no longer on the market. In this study, we evaluated a new commercial c-ELISA to detect ruminant EHDV VP7 Abs in 2,199 serum samples from cattle, sheep, goats, wild deer and zoo animals. The results showed that this ELISA kit is specific and can detect the presence of IgG anti-EHDV VP7 with a very good diagnostic specificity and a satisfactory sensitivity in domestic ruminants, zoo animals and wild deer. Therefore, the evaluated c-ELISA can detect the introduction of EHDV into an area where BTV-seropositive domestic animals are present. The performance of this kit is similar to that of the c-ELISA A kit and can thus be used for diagnosis.
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http://dx.doi.org/10.1111/tbed.13586DOI Listing
November 2020

Experimental infection of calves with seven serotypes of Epizootic Hemorrhagic Disease virus: production and characterization of reference sera.

Vet Ital 2019 Dec 31;55(4):339-346. Epub 2019 Dec 31.

UMR Virologie, INRA, Ecole Nationale Vétérinaire d'Alfort, laboratoire de santé animale d'Alfort, ANSES, Université Paris-Est, 94700 Maisons-Alfort, France.

The aim of this study was to produce reference sera against the seven serotypes of Epizootic hemorrhagic disease virus (EHDV‑1, EHDV‑2, EHDV‑4, EHDV‑5, EHDV‑6, EHDV‑7, and EHDV‑8). In a high containment unit, seven Prim 'Holstein calves were inoculated at day 0 (D0) with the selected strains (1 EHDV serotype per calf ). Blood samples (EDTA and whole blood) were periodically taken from D0 until the end of the experiment (D31). Sera were tested with two commercially available EHDV competitive ELISAs (c‑ELISA). Viral genome was detected from EDTA blood samples using in‑house real‑time RT‑PCR. Sera taken on D31 post infection (pi) were tested and characterized by serum neutralization test (SNT) and virus neutralization test (VNT) (for calibration of reference sera). Viral RNA was first detected at D2 pi in five calves. All infected animals were RT‑PCR positive at D7 pi. Seroconversion was observed between D10 and D23 pi depending on the EHDV serotype. SNT and VNT have allowed to determine the neutralizing antibody titers of each serum and the potential cross‑reactions between serotypes. The two c‑ELISA used in this study showed similar results. The calibrated sera are now available for the serological identification of an EHDV isolated on tissue culture or to be used as positive control in seroneutralization assay.
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http://dx.doi.org/10.12834/VetIt.2104.11179.1DOI Listing
December 2019

The antibody response induced FMDV vaccines in sheep correlates with early transcriptomic responses in blood.

NPJ Vaccines 2020 3;5. Epub 2020 Jan 3.

Université Paris-Saclay, INRA, VIM, Domaine de Vilvert, 78350 Jouy-en-Josas, France.

Foot and mouth disease (FMD) is a highly contagious viral disease with high economic impact, representing a major threat for cloven-hooved mammals worldwide. Vaccines based on adjuvanted inactivated virus (iFMDV) induce effective protective immunity implicating antibody (Ab) responses. To reduce the biosafety constraints of the manufacturing process, a non-replicative human adenovirus type 5 vector encoding FMDV antigens (Ad5-FMDV) has been developed. Here we compared the immunogenicity of iFMDV and Ad5-FMDV with and without the ISA206VG emulsion-type adjuvant in sheep. Contrasted Ab responses were obtained: iFMDV induced the highest Ab levels, Ad5-FMDV the lowest ones, and ISA206VG increased the Ad5-FMDV-induced Ab responses to protective levels. Each vaccine generated heterogeneous Ab responses, with high and low responders, the latter being considered as obstacles to vaccine effectiveness. A transcriptomic study on total blood responses at 24 h post-vaccination revealed several blood gene module activities correlating with long-term Ab responses. Downmodulation of T cell modules' activities correlated with high responses to iFMDV and to Ad5-FMDV+ISA206VG vaccines as also found in other systems vaccinology studies in humans and sheep. The impact of cell cycle activity depended on the vaccine types, as it positively correlated with higher responses to iFMDV but negatively to non-adjuvanted Ad5-FMDV. Finally an elevated B cell activity at 24 h correlated with high Ab responses to the Ad5-FMDV+ISA206VG vaccine. This study provides insights into the early mechanisms driving the Ab response induced by different vaccine regimens including Ad5 vectors and points to T cell modules as early biomarker candidates of different vaccine-type efficacy across species.
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http://dx.doi.org/10.1038/s41541-019-0151-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6941976PMC
January 2020

Clinical cases of Bluetongue serotype 8 in calves in France in the 2018-2019 winter.

Transbound Emerg Dis 2020 May 8;67(3):1401-1405. Epub 2020 Jan 8.

Epidemiology Unit, Laboratory for Animal Health, ANSES, University Paris Est, Maisons-Alfort, France.

Bluetongue virus serotype 8 (BTV-8) caused an epizootic in Europe in 2006/09. Transplacental transmission of BTV-8 was demonstrated leading to abortions, congenital malformations or nervous clinical signs in newborn calves. BTV-8 re-emerged in France in 2015. Although the re-emergent strain is nearly genetically identical to the one that had circulated in 2006/2009, it has caused very few clinical cases. However, from mid-December 2018 to April 2019, cases of calves with congenital malformations or displaying nervous clinical signs occurred in some departments (French administrative unit) in mainland France. Blood samples from these animals were sent to local laboratories, and the positive ones were confirmed at the French Bluetongue reference laboratory (BT-NRL). Out of 580 samples found positive at the local laboratories, 544 were confirmed as RT-PCR BTV-8 positive. The 36 samples found positive in the local laboratories and negative in the BT-NRL were all at the limit of RT-PCR detection. Hundred eighty-eight of the confirmed samples were also tested for the presence of Schmallenberg virus (SBV) and bovine virus diarrhoea virus (BVDV) infection: 4 were found positive for BVDV and none for SBV. The main clinical signs recorded for 244 calves, for which a reporting form was completed by veterinarians, included nervous clinical signs (81%), amaurosis (72%) and decrease/ no suckling reflex (40%). Hydranencephaly and microphthalmia were reported in 19 calves out of 27 in which a necropsy was practiced after death or euthanasia. These results indicate that the re-emergent strain of BTV-8 can cross the transplacental barrier and cause congenital malformations or nervous clinical signs in calves.
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http://dx.doi.org/10.1111/tbed.13466DOI Listing
May 2020

Seroprevalence and molecular characterization of foot-and-mouth disease virus in Chad.

Vet Med Sci 2020 02 16;6(1):114-121. Epub 2019 Dec 16.

Laboratoire de Santé Animale de Maisons-Alfort, UMR Virologie 1161, INRA, École Nationale Vétérinaire d'Alfort, ANSES, Université Paris-Est, Maisons-Alfort, France.

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%.
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http://dx.doi.org/10.1002/vms3.206DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7036305PMC
February 2020

Red deer () Did Not Play the Role of Maintenance Host for Bluetongue Virus in France: The Burden of Proof by Long-Term Wildlife Monitoring and Snapshots.

Viruses 2019 09 27;11(10). Epub 2019 Sep 27.

UMR Virologie, INRA, Ecole Nationale Vétérinaire d'Alfort, laboratoire de santé animale d'Alfort, ANSES, Université Paris-Est, 94700 Maisons-Alfort, France, (C.V.).

Bluetongue virus (BTV) is a -borne pathogen infecting both domestic and wild ruminants. In Europe, the Red Deer () (RD) is considered a potential BTV reservoir, but persistent sylvatic cycle has not yet been demonstrated. In this paper, we explored the dynamics of BTV1 and BTV8 serotypes in the RD in France, and the potential role of that species in the re-emergence of BTV8 in livestock by 2015 (i.e., 5 years after the former last domestic cases). We performed 8 years of longitudinal monitoring (2008-2015) among 15 RD populations and 3065 individuals. We compared communities and feeding habits within domestic and wild animal environments (51,380 samples). diversity (>30 species) varied between them, but bridge-species able to feed on both wild and domestic hosts were abundant in both situations. Despite the presence of competent vectors in natural environments, BTV1 and BTV8 strains never spread in RD along the green corridors out of the domestic outbreak range. Decreasing antibody trends with no PCR results two years after the last domestic outbreak suggests that seropositive young RD were not recently infected but carried maternal antibodies. We conclude that RD did not play a role in spreading or maintaining BTV in France.
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http://dx.doi.org/10.3390/v11100903DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6832957PMC
September 2019

Model of persistent foot-and-mouth disease virus infection in multilayered cells derived from bovine dorsal soft palate.

Transbound Emerg Dis 2020 Jan 29;67(1):133-148. Epub 2019 Aug 29.

Host Pathogen Interaction Group, Section of Ruminant Medicine, Department of Clinical Science, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.

Foot-and-mouth disease virus (FMDV) causes a highly contagious vesicular disease in livestock, with serious consequences for international trade. The virus persists in the nasopharynx of cattle and this slows down the process to obtain an FMDV-free status after an outbreak. To study biological mechanisms, or to identify molecules that can be targeted to diagnose or interfere with persistence, we developed a model of persistent FMDV infection in bovine dorsal soft palate (DSP). Primary DSP cells were isolated after commercial slaughter and were cultured in multilayers at the air-liquid interface. After 5 weeks of culture without further passage, the cells were infected with FMDV strain O/FRA/1/2001. Approximately, 20% of cells still had a polygonal morphology and displayed tight junctions as in stratified squamous epithelia. Subsets of cells expressed cytokeratin and most or all cells expressed vimentin. In contrast to monolayers in medium, multilayers in air demonstrated only a limited cytopathic effect. Integrin α β expression was observed in mono- but not in multilayers. FMDV antigen, FMDV RNA and live virus were detected from day 1 to 28, with peaks at day 1 and 2. The proportion of infected cells was highest at 24 hr (3% and 36% of cells at an MOI of 0.01 and 1, respectively). At day 28 after infection, at a time when animals that still harbour FMDV are considered carriers, FMDV antigen was detected in 0.2%-2.1% of cells, in all layers, and live virus was isolated from supernatants of 6/8 cultures. On the consensus level, the viral genome did not change within the first 24 hr after infection. Only a few minor single nucleotide variants were detected, giving no indication of the presence of a viral quasispecies. The air-liquid interface model of DSP brings new possibilities to investigate FMDV persistence in a controlled manner.
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http://dx.doi.org/10.1111/tbed.13332DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7003861PMC
January 2020

Bluetongue Virus in France: An Illustration of the European and Mediterranean Context since the 2000s.

Viruses 2019 07 23;11(7). Epub 2019 Jul 23.

UMR Virologie, INRA, Ecole Nationale Vétérinaire d'Alfort, laboratoire de santé animale d'Alfort, ANSES, Université Paris-Est, 94700 Maisons-Alfort, France.

Bluetongue (BT) is a non-contagious animal disease transmitted by midges of the genus. The etiological agent is the BT virus (BTV) that induces a variety of clinical signs in wild or domestic ruminants. BT is included in the notifiable diseases list of the World Organization for Animal Health (OIE) due to its health impact on domestic ruminants. A total of 27 BTV serotypes have been described and additional serotypes have recently been identified. Since the 2000s, the distribution of BTV has changed in Europe and in the Mediterranean Basin, with continuous BTV incursions involving various BTV serotypes and strains. These BTV strains, depending on their origin, have emerged and spread through various routes in the Mediterranean Basin and/or in Europe. Consequently, control measures have been put in place in France to eradicate the virus or circumscribe its spread. These measures mainly consist of assessing virus movements and the vaccination of domestic ruminants. Many vaccination campaigns were first carried out in Europe using attenuated vaccines and, in a second period, using exclusively inactivated vaccines. This review focuses on the history of the various BTV strain incursions in France since the 2000s, describing strain characteristics, their origins, and the different routes of spread in Europe and/or in the Mediterranean Basin. The control measures implemented to address this disease are also discussed. Finally, we explain the circumstances leading to the change in the BTV status of France from BTV-free in 2000 to an enzootic status since 2018.
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http://dx.doi.org/10.3390/v11070672DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6669443PMC
July 2019

Novel Function of Bluetongue Virus NS3 Protein in Regulation of the MAPK/ERK Signaling Pathway.

J Virol 2019 08 30;93(16). Epub 2019 Jul 30.

UMR Virologie, INRA, École Nationale Vétérinaire d'Alfort, ANSES, Université Paris-Est, Maisons-Alfort, France

Bluetongue virus (BTV) is an arbovirus transmitted by blood-feeding midges to a wide range of wild and domestic ruminants. In this report, we showed that BTV, through its nonstructural protein NS3 (BTV-NS3), is able to activate the mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) pathway, as assessed by phosphorylation levels of ERK1/2 and the translation initiation factor eukaryotic translation initiation factor 4E (eIF4E). By combining immunoprecipitation of BTV-NS3 and mass spectrometry analysis from both BTV-infected and NS3-transfected cells, we identified the serine/threonine-protein kinase B-Raf (BRAF), a crucial player in the MAPK/ERK pathway, as a new cellular interactor of BTV-NS3. BRAF silencing led to a significant decrease in the MAPK/ERK activation by BTV, supporting a model wherein BTV-NS3 interacts with BRAF to activate this signaling cascade. This positive regulation acts independently of the role of BTV-NS3 in counteracting the induction of the alpha/beta interferon response. Furthermore, the intrinsic ability of BTV-NS3 to bind BRAF and activate the MAPK/ERK pathway is conserved throughout multiple serotypes/strains but appears to be specific to BTV compared to other members of genus. Inhibition of MAPK/ERK pathway with U0126 reduced viral titers, suggesting that BTV manipulates this pathway for its own replication. Altogether, our data provide molecular mechanisms that unravel a new essential function of NS3 during BTV infection. Bluetongue virus (BTV) is responsible of the arthropod-borne disease bluetongue (BT) transmitted to ruminants by blood-feeding midges. In this report, we found that BTV, through its nonstructural protein NS3 (BTV-NS3), interacts with BRAF, a key component of the MAPK/ERK pathway. In response to growth factors, this pathway promotes cell survival and increases protein translation. We showed that BTV-NS3 enhances the MAPK/ERK pathway, and this activation is BRAF dependent. Treatment of MAPK/ERK pathway with the pharmacologic inhibitor U0126 impairs viral replication, suggesting that BTV manipulates this pathway for its own benefit. Our results illustrate, at the molecular level, how a single virulence factor has evolved to target a cellular function to increase its viral replication.
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http://dx.doi.org/10.1128/JVI.00336-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6675888PMC
August 2019

Presence of bluetongue and epizootic hemorrhagic disease viruses in Egypt in 2016 and 2017.

Infect Genet Evol 2019 09 30;73:221-226. Epub 2019 Apr 30.

Université Paris Est, ANSES, ENVA, INRA, UMR 1161 VIROLOGIE, Laboratory for Animal Health, Maisons-Alfort, France. Electronic address:

BTV and EHDV are closely-related orbiviruses that are transmitted between domestic and wild ruminants via the bites of hematophagous midges. Previous studies have reported seropositivity against BTV antibodies in sheep and goats in two Egyptian governorates (Beni Suef and Menoufia). However, no recent data are available on the BTV serotype(s) circulating in Egypt and the likely presence of EHDV has never been explored. This study investigated the presence of BTV and EHDV among cattle which had been found BTV-seropositive by ELISA method. These cattle living in proximity to sheep and goats previously found BTV-seropositive. These cattle displayed no clinical signs of BT but reproductive problems had been reported in herds. A total of 227 cattle blood samples were therefore collected in 2016 and 2017. Ninety-four of the 227 animals tested by a BTV ELISA were positive for BTV antibodies (41.4%). Of these 94 ELISA-positive cattle, only 83 EDTA-blood samples were available and therefore tested for BTV and EHDV genome detection by RT-PCR and sequencing. Of the cattle sampled in 2016, results revealed that two were RT-PCR-positive for BTV and seven for EHDV. Sequencing showed the presence of EHDV-1 and BTV-3 genome sequences. EHDV-1 S2 shared 99.5% homology with an EHDV-1 S2 from a strain isolated in 2016 in Israel. BTV-3 S2 and S8 sequences shared >99.8% nucleotide similarity with the BTV-3 Zarzis S2 and S8 sequences (Tunisian BTV, also detected in 2016). Of the 66 blood samples tested following their collection in 2017, they were all EHDV-negative by RT-qPCR while five were BTV- positive by RT-qPCR. However, attempts to identify the BTV serotype of these five samples were unsuccessful. Only part of BTV S8 was sequenced and it showed 79% nucleotide similarity with S8 of atypical BTV serotypes (particularly with BTV-26 and another BTV serotype strain isolated from a sheep pox vaccine). Overall, these findings demonstrate that both BTV and EHDV were circulating in Egypt in 2016 and 2017.
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http://dx.doi.org/10.1016/j.meegid.2019.04.033DOI Listing
September 2019

Serological evidence of infection with dengue and Zika viruses in horses on French Pacific Islands.

PLoS Negl Trop Dis 2019 02 7;13(2):e0007162. Epub 2019 Feb 7.

UMR 1161 Virology, ANSES, INRA, ENVA, ANSES Animal Health Laboratory, EURL for equine diseases, Maisons-Alfort, France.

New Caledonia and French Polynesia are areas in which arboviruses circulate extensively. A large serological survey among horses from New Caledonia and French Polynesia was carried out to investigate the seroprevalence of flaviviruses in the horse population. Here, 293 equine sera samples were screened for flaviviruses using a competitive enzyme-linked immunosorbent assay (cELISA). The positive sera were then confirmed using a flavivirus-specific microsphere immunoassay (MIA) and seroneutralization tests. This serosurvey showed that 16.6% (27/163) and 30.8% (40/130) of horses were positive for cELISA tests in New Caledonia and French Polynesia, respectively, but the MIA technique, targeting only flaviviruses causing neuro-invasive infections in humans and horses (i.e. West Nile virus [WNV], Japanese encephalitis virus [JEV] and tick-borne encephalitis virus [TBEV]), showed negative results for more than 85% (57/67) of the cELISA-positive animals. Seroneutralization tests with the main flaviviruses circulating in the South Pacific revealed that 6.1% (10/163; confidence interval [95% CI] 3.0%-11.0%) of sera in New Caledonia and 7.7% (10/130; 95% CI 3.8%-13.7%) in French Polynesia were positive for dengue virus serotype 1 (DENV1) and 4.3% (7/163; 95% CI 1.7%-8.6%) in New Caledonia and 15.4% (20/130, 95% CI 9.7%-22.8%) in French Polynesia were found positive for Zika virus (ZIKV). Seroprevalence of the JEV and WNV flaviviruses on the 293 samples from both island groups were comparatively much lower (less than 2%). This seroprevalence study in the horse population shows that horses can be infected with dengue and Zika viruses and that these infections lead to seroconversions in horses. The consequences of these infections in horses and their role in ZIKV and DENV epidemiological cycles are two issues that deserve further investigation.
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http://dx.doi.org/10.1371/journal.pntd.0007162DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6382171PMC
February 2019

Evidence of reduced viremia, pathogenicity and vector competence in a re-emerging European strain of bluetongue virus serotype 8 in sheep.

Transbound Emerg Dis 2019 May 22;66(3):1177-1185. Epub 2019 Feb 22.

The Pirbright Institute, Pirbright, UK.

The outbreak of bluetongue virus (BTV) serotype 8 (BTV-8) during 2006-2009 in Europe was the most costly epidemic of the virus in recorded history. In 2015, a BTV-8 strain re-emerged in France which has continued to circulate since then. To examine anecdotal reports of reduced pathogenicity and transmission efficiency, we investigated the infection kinetics of a 2007 UK BTV-8 strain alongside the re-emerging BTV-8 strain isolated from France in 2017. Two groups of eight BTV-naïve British mule sheep were inoculated with 5.75 log TCID /ml of either BTV-8 strain. BTV RNA was detected by 2 dpi in both groups with peak viraemia occurring between 5-9 dpi. A significantly greater amount of BTV RNA was detected in sheep infected with the 2007 strain (6.0-8.8 log genome copies/ml) than the re-emerging BTV-8 strain (2.9-7.9 log genome copies/ml). All infected sheep developed BTV-specific antibodies by 9 dpi. BTV was isolated from 2 dpi to 12 dpi for 2007 BTV-8-inoculated sheep and from 5 to 10 dpi for sheep inoculated with the remerging BTV-8. In Culicoides sonorensis feeding on the sheep over the period 7-12 dpi, vector competence was significantly higher for the 2007 strain than the re-emerging strain. Both the proportion of animals showing moderate (as opposed to mild or no) clinical disease (6/8 vs. 1/8) and the overall clinical scores (median 5.25 vs. 3) were significantly higher in sheep infected with the 2007 strain, compared to those infected with the re-emerging strain. However, one sheep infected with the re-emerging strain was euthanized at 16 dpi having developed severe lameness. This highlights the potential of the re-emerging BTV-8 to still cause illness in naïve ruminants with concurrent costs to the livestock industry.
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http://dx.doi.org/10.1111/tbed.13131DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6563110PMC
May 2019

Bluetongue and epizootic hemorrhagic disease viruses: recent developments with these globally re-emerging arboviral infections of ruminants.

Curr Opin Virol 2019 02 14;34:56-62. Epub 2019 Jan 14.

Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise, OIE Reference Laboratory for BTV, Teramo, Italy.

Bluetongue (BT) and epizootic hemorrhagic disease (EHD) are globally re-emerging diseases of domestic and wild ruminants, respectively caused by BT virus (BTV) and EHD virus. Both viruses are transmitted by hematophagous midges; however, newly recognized BTV serotypes may be transmitted horizontally without requirement for any biological vector. The global range of these viruses and/or their associated diseases have changed remarkably in recent years, most notably with the invasion of Europe by multiple serotypes of BTV since 1998. Although not zoonoses, the unanticipated emergence of BT and EHD in several different areas of the world provides a uniquely sobering and unambiguous reminder of the potential consequences of climate change on the distribution and severity of vector-borne diseases. Recent experiences with these viruses have also emphasized the need for effective, DIVA-compatible vaccines to combat anticipated future incursions, as existing vaccines have serious inherent deficiencies.
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http://dx.doi.org/10.1016/j.coviro.2018.12.005DOI Listing
February 2019

Proteogenomics Uncovers Critical Elements of Host Response in Bovine Soft Palate Epithelial Cells Following In Vitro Infection with Foot-And-Mouth Disease Virus.

Viruses 2019 01 12;11(1). Epub 2019 Jan 12.

Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, 17493 Greifswald, Germany.

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 naïve 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.
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http://dx.doi.org/10.3390/v11010053DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6356718PMC
January 2019

Epidemiology and genetic diversity of Anaplasma ovis in goats in Corsica, France.

Parasit Vectors 2019 Jan 3;12(1). Epub 2019 Jan 3.

BIOEPAR, INRA, Oniris, 44307, Nantes, France.

Background: Anaplasma ovis is a major cause of small ruminant anaplasmosis, a tick-borne disease mainly affecting small ruminants in tropical and subtropical regions of the world. Due to health and production problems in dairy goat flocks in Corsica, France, and the demonstration of A. ovis infection in some animals, an extensive survey was conducted in the island in spring 2016. The aim of the survey was to determine the prevalence and geographical distribution of A. ovis infections in goats and ticks as well as possible relationships with anaemia and other health indicators. In addition, the genetic diversity of A. ovis was evaluated.

Methods: Blood and faecal samples were collected in 55 clinically healthy flocks (10 goats per flock) for A. ovis qPCR, haematocrit determination, paratuberculosis ELISA seropositivity and gastrointestinal nematode egg excretion quantification. Ticks were collected, identified and processed for A. ovis DNA detection.

Results: A high prevalence of A. ovis DNA detection was found at the individual (52.0%) and flock levels (83.6%) with a within-flock prevalence ranging between 0-100%. Rhipicephalus bursa was the only tick species collected on goats (n = 355) and the detection rate of A. ovis DNA in ticks was 20.3%. Anaplasma ovis DNA prevalence was higher in flocks located at an altitude above 168 m, in goats of Corsican/crossbred breed and in goats > 3 years-old. No relationship was found between A. ovis DNA detection at the individual or flock level and haematocrit, paratuberculosis seropositivity or gastrointestinal parasites. Positive A. ovis goat samples were used for amplification of gltA and msp4 genes for species confirmation and strain identification, respectively. Sequence and phylogenetic analysis of these genes confirmed the detection of A. ovis and allowed identification of six different strains of this pathogen (named Corsica 1-6 (COR1-6). While the msp4 sequence of strain COR1 had 100% identity with strains previously reported, COR2 to 6 were found to be novel strains. The strain COR1 was the most represented, corresponding to 94.6% of the msp4 sequences obtained.

Conclusions: The results showed a relatively high genetic diversity of A. ovis associated with high bacterial prevalence in goats.
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http://dx.doi.org/10.1186/s13071-018-3269-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6318933PMC
January 2019

Evidence of bluetongue and Epizootic Haemorrhagic disease circulation on the island of Mayotte.

Acta Trop 2019 Mar 24;191:24-28. Epub 2018 Dec 24.

ASTRE, Univ Montpellier, CIRAD, INRA, Montpellier, France; CIRAD, UMR ASTRE, Sainte Clotilde, La Réunion, France.

A cross-sectional study was conducted to explore the epidemiological situation in Mayotte regarding two orbiviruses: Bluetongue virus (BTV) and Epizootic Haemorrhagic Disease virus (EHDV). In all, 385 individual asymptomatic cattle were blood-sampled (one EDTA and one serum tube per animal) between February and June 2016. Antibody (ELISA) and genome prevalence (PCR) was assessed. Almost all the selected cattle showed antibodies against both BTV and EHDV, at 99.5% (CI95% [98.00, 100]) and 96.9% (CI95% [94.5, 98.3]), respectively. Most of the cattle acquired antibodies in their first years of age. EHDV and BTV genomes were detected in 25.2% (CI95% [21.1, 29.8]) and 18.2% (CI95% [14.6, 22.4]) of samples, respectively. Coinfection with BTV and EHDV was observed in 9.4% of samples (CI95% [6.8, 12.7]). Cattle under three years old were more frequently reported as positive for genome detection by PCR than older cattle. Five serotypes of BTV and one serotype of EHDV were identified from eight samples: BTV-4, BTV-9, BTV-11, BTV-15, BTV-19 and EHDV-6, of which some were reported in neighbouring areas. BTV and EHDV both circulate in Mayotte and in its surrounding territories.
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http://dx.doi.org/10.1016/j.actatropica.2018.12.037DOI Listing
March 2019

Melarsomine hydrochloride (Cymelarsan) fails to cure horses with Trypanosoma equiperdum OVI parasites in their cerebrospinal fluid.

Vet Parasitol 2018 Dec 9;264:47-51. Epub 2018 Nov 9.

ANSES, Dozulé Laboratory for Equine Diseases, Bacteriology Unit, 14430, Goustranville, France.

The aim of this study was to evaluate the ability of melarsomine hydrochloride (Cymelarsan) to cure horses suffering from a nervous form of dourine, a sexually-transmitted disease caused by Trypanosoma equiperdum. The recently described experimental model for assessing drug efficacy against horse trypanosomosis allowed us to obtain eight horses (Welsh pony mares) infected by T. equiperdum with parasites in their cerebrospinal fluid. The Cymelarsan treatment evaluated consisted of the daily administration of 0.5 mg/kg of Cymelarsan over 7 days. Two control horses remained untreated, three horses received the treatment 36 days p.i. and three horses received the treatment 16 days p.i. Following treatment, we observed parasite clearance in blood, stabilization of rectal temperature and a relative improvement in the mean packed cell volume levels for all treated horses. However, live parasites were later observed again in the CSF of all treated horses. Our results indicate the inability of Cymelarsan to reach Trypanozoon located in the central nervous system of infected horses and thus discourage the use of Cymelarsan to treat animals suffering from a nervous form of dourine.
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http://dx.doi.org/10.1016/j.vetpar.2018.11.005DOI Listing
December 2018

Evaluation of an IGM-specific ELISA for early detection of bluetongue virus infections in domestic ruminants sera.

Transbound Emerg Dis 2019 Jan 23;66(1):537-545. Epub 2018 Nov 23.

Laboratoire de Santé Animale d'Alfort, Université Paris Est, ANSES, ENVA, INRA, UMR 1161 VIROLOGIE, Maisons-Alfort, France.

Competitive-ELISA (c-ELISA) is the most widely used serological test for the detection of Bluetongue virus (BTV) viral protein 7 (VP7) antibodies (Ab). However, these BTV c-ELISAs cannot to distinguish between IgG and IgM. IgM Ab are generated shortly after the primary immune response against an infectious agent, indicating a recent infection or exposure to antigens, such as after vaccination. Because the BTV genome or anti-VP7 Ab can be detected in ruminant blood months after infection, BTV diagnostic tools cannot discriminate between recent and old infections. In this study, we evaluated an IgM-capture ELISA prototype to detect ruminant anti-BTV VP7 IgM on 1,650 serum samples from cattle, sheep, or goats. Animals were BTV-naive, infected, or/and vaccinated with BTV-1, -2, -4, -8, -9, -16, or -27, and we also included 30 sera from cattle infected with the Epizootic haemorrhagic disease virus (EHDV) serotype 6. Results demonstrated that this ELISA kit is specific and can detect the presence of IgM with satisfactory diagnostic specificity and sensitivity from 1 to 5 weeks after BTV infection in domestic ruminants (for goats and cattle; for sheep, at least up to 24 days). The peak of anti-VP7 IgM was reached when the level of infectious viruses and BTV RNA in blood were the highest. The possibility of detecting BTV-RNA in IgM-positive sera allows the amplification and sequencing of the partial RNA segment 2 (encoding the serotype specific to VP2) to determine the causative BTV serotype/strain. Therefore, BTV IgM ELISA can detect the introduction of BTV (or EHDV) in an area with BTV-seropositive domestic animals regardless of their serological BTV status. This approach may also be of particular interest for retrospective epidemiological studies on frozen serum samples.
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http://dx.doi.org/10.1111/tbed.13060DOI Listing
January 2019