Emergence of bluetongue virus serotype 4 in mainland France in 2017

Le virus de la fièvre catarrhale ovine est présent en Europe depuis la fin des années 1990, impliquant différents sérotypes. La présence du sérotype 4 a notamment été plusieurs fois rapportée dans différents pays du bassin méditerranéen ces vingt dernières années, mais n’avait jamais été détectée en France continentale. En novembre 2017, un veau âgé de 15 jours et provenant de Haute Savoie a été détecté positif pour le BTV-4 par RT-PCR en temps réel (rtRT-PCR). Le séquençage du génome a permis de montrer une proche parenté entre cette souche et la souche BTV-4 impliquée dans plusieurs épizooties dans la péninsule balkanique (2013), en Italie (2014) et en Corse (2016 et 2017). Il est probable que le BTV-4 a été introduit en France continentale par l’importation d’animaux corses infectés. En juin 2018, 84 foyers de BTV-4 ont été confirmés en France métropolitaine.Bluetongue virus is present in Europe since the end of the 1990’s involving different serotypes. The presence of serotype 4 has been reported several times and in different countries of the Mediterranean basin in the last 20 years, but had never been reported in mainland France. In November 2017, a 15-days-old calf born in Haute-Savoie was detected rtRT-PCR BTV-4 positive. Whole genome sequencing showed that this strain was closely related to BTV-4 strains involved in a large BT outbreak in the Balkan Peninsula (2013), in Italy (2014) and in Corsica (2016 and 2017). It is likely that BTV-4 has been introduced in mainland France by importation of Corsican infected animals. Currently, 84 BTV-4 outbreaks have been confirmed in mainland France

Genetic evolution of equine influenza virus strains (H3N8) isolated in France from 1967 to 2015 and the implications of several potential pathogenic factors

International audienceEquine influenza virus (EIV) is a major respiratory pathogen of horses despite the availability of equine influenza vaccines. This study aimed to determine genetic evolution of EIV strains in France between 1967 to present. A whole genome comparative analysis was also conducted on recent French strains in order to identify potential factors of pathogenicity. Comparison of French EIV sequences with vaccine and worldwide epidemic strains revealed amino acid substitutions in both haemagglutinin (HA) and neuraminidase, especially within the antigenic sites and/or close to receptor binding sites (HA). Amino acid substitutions were also identified in other genes, mainly the polymerase complex proteins and PB1-F2. Viruses belonging to Eurasian and American lineages have circulated until 2003 and Florida sub-lineage Clade 2 strains predominates since 2005. The last French strain (2015) displayed several specificities in HA suggesting the occurrence of antigenic drift with presence of pathogenic markers in the PA and PB1-F2 genes

Likely introduction date of Schmallenberg virus in two french departments using serological studies in cattle

Monthly serological surveys between August 2011 and April 2012 were performed among cattle population from Manche and Meurthe-et-Moselle departments. First positive results were observed in October 2011 for both departments, with respectively 12,7 and 55,6% SBV serological prevalences. Those rates increased quickly to reach very high levels from the end of 2011. Likely introduction date of SBV in France may be situated in the second half of September or during the first days of October 2011.Une enquête de séroprévalence individuelle vis-à-vis du virus Schmallenberg (SBV) est menée entre les mois d’août 2011 et avril 2012 dans la population bovine des départements de la Manche et de la Meurthe-et-Moselle. Une séropositivité est observée à partir du mois d’octobre 2011 dans les deux départements, avec des prévalences respectives de 12,7 et 55,6%. Ces taux augmentent rapidement les mois suivants pour atteindre des prévalences élevées. Comptetenu de la position géographique de ces départements et des connaissances actuelles sur le SBV, l’introduction présumée du virus en France est située vers la fin septembre-début octobre 2011

Unexpected progression of two arboviral diseases : West Nile fever and bluetongue

This paper describes the spread of two arboviral diseases in Europe, and the control measures implemented by health authorities. Bluetongue, which affects only animals, occurred for the first time in Europe in 1998, and West Nile Fever, which affects horses and humans, re-emerged in 1996. Up until 1998, bluetongue was considered as an exotic disease. In 2006 and 2007, its unexpected explosion in Northern Europe highlighted the emergence and expansion capacities of vector-borne diseases. Surprisingly, the disease became perennial in Europe, rapidly spreading to eight European countries and crossing the English Channel and contaminating several herds in England. Its expansion resulted from vector movements carried over long distances by the wind (100 km), and followed a centrifugal pattern in 2006/2007. By 2008, the bluetongue virus (BTV) was occupying a wider European territory. The only control measure available is vaccination, which has been largely implemented in 2008. West Nile fever is a viral disease transmitted by mosquitoes, whose amplifying hosts are birds, whereas horses and humans are incidental but particularly sensitive hosts. West Nile fever appeared in Europe in the 60’s and 70’s, especially in the Camargue region of France, with sporadic foci. At the end of the 90’s, besides the introduction and expansion of the virus on the American continent, major epidemics affected several hundreds of people in Europe (Romania in 1996 and Russia in 1999). Since then, four distinct episodes of West Nile virus (WNV) circulation, associated with clinical cases in horses, were reported in France: in the Camargue region in 2000 and 2004, in the Var department in 2003 and in the Eastern Pyrenees in 2006. An increase in WNV activity was observed in Europe in 2008, with cases of infection reported in Italy, Romania, Hungary and Austria. An inactivated vaccine (Fort Dodge) has recently received a marketing agreement from the European commission. However, until now, control measures rely exclusively on a reinforced surveillance of neurological conditions in humans and animals (horses and birds generally), and on information of exposed people.Cet article décrit l'extension de deux arboviroses en Europe ainsi que les mesures de lutte mises en oeuvre par les autorités sanitaires. La fièvre catarrhale ovine (FCO), strictement animale, est apparue pour la première fois en Europe en 1998, tandis que la fièvre du Nil occidental, transmissible à l'homme, a ré-émergé en 1996. Jusqu'en 1998, la FCO était considérée comme une maladie exotique. En 2006 et 2007, son explosion inattendue dans le nord de l'Europe a fourni un éclairage nouveau sur les capacités d'émergence et d'extension des maladies vectorielles. De façon surprenante, la maladie s'est installée de façon pérenne en Europe gagnant rapidement huit pays européens et traversant la Manche pour contaminer plusieurs élevages en Angleterre. Son extension résulte du déplacement du vecteur porté par le vent sur de grandes distances (100 km), et a donc été centrifuge en 2006/7. L'année 2008 confirme cette extension et l'installation du virus sur un territoire européen élargi. La seule méthode de lutte est la vaccination mise en oeuvre de façon massive en 2008. La fièvre du Nil occidental, ou West Nile Fever, est une virose transmise par les moustiques dont les hôtes amplificateurs sont les oiseaux, tandis que le cheval et l'homme sont des hôtes accidentels particulièrement sensibles. Elle était apparue en Europe dans les années 1960-1970 et, en particulier, en France métropolitaine dans la région de la Camargue, en des foyers sporadiques. À la fin des années 1990, outre l'introduction et la progression du virus sur le continent américain, des épidémies importantes ont touché plusieurs centaines de personnes en Europe (Roumanie en 1996, Russie en 1999). Puis, quatre épisodes distincts de circulation du virus West Nile (VWN), associés à des cas cliniques chez le cheval, ont été décrits en France: en Camargue, en 2000 et 2004, dans le Var en 2003 et dans les Pyrénées-Orientales en 2006. Un regain de l'activité du virus a été observé en 2008 en Europe, l'Italie, la Roumanie, la Hongrie et l'Autriche ayant rapporté des cas d'infection par le VWN. Un vaccin inactivé (Fort Dodge) a récemment obtenu une AMM européenne. Cependant, jusqu'ici, les méthodes de lutte s'appuient jusqu'ci sur la surveillance renforcée des affections nerveuses chez l'homme et l'animal (chevaux et oiseaux généralement) et sur l'information des personnes exposées

The nonstructural protein NSs of Schmallenberg virus is targeted to the nucleolus and induces nucleolar disorganization

Schmallenberg virus (SBV) was discovered in Germany in late 2011 and then spread rapidly to many European countries. SBV is an orthobunyavirus that causes abortion and congenital abnormalities in ruminants. A virus-encoded nonstructural protein, termed NSs, is a major virulence factor of SBV, and it is known to promote the degradation of Rpb1, a subunit of the RNA polymerase II (Pol II) complex, and therefore hampers global cellular transcription. In this study, we found that NSs is mainly localized in the nucleus of infected cells and specifically appears to target the nucleolus through a nucleolar localization signal (NoLS) localized between residues 33 and 51 of the protein. NSs colocalizes with nucleolar markers such as B23 (nucleophosmin) and fibrillarin. We observed that in SBV-infected cells, B23 undergoes a nucleolus-to-nucleoplasm redistribution, evocative of virus-induced nucleolar disruption. In contrast, the nucleolar pattern of B23 was unchanged upon infection with an SBV recombinant mutant with NSs lacking the NoLS motif (SBVΔNoLS). Interestingly, unlike wild-type SBV, the inhibitory activity of SBVΔNoLS toward RNA Pol II transcription is impaired. Overall, our results suggest that a putative link exists between NSs-induced nucleolar disruption and its inhibitory function on cellular transcription, which consequently precludes the cellular antiviral response and/or induces cell death

Protective efficacy of multivalent replication-abortive vaccine strains in horses against African horse sickness virus challenge.

African horse sickness virus (AHSV) is an orbivirus, a member of the Reoviridae family. Nine different serotypes have been described so far. AHSV is vectored by Culicoides spp. to equids, causing high mortality, particularly in horses, with considerable economic impacts. For development of a safe attenuated vaccine, we previously established an efficient reverse genetics (RG) system to generate Entry Competent Replication-Abortive (ECRA) virus strains, for all nine serotypes and demonstrated the vaccine potential of these strains in type I interferon receptor (IFNAR)-knockout mice. Here, we evaluated the protective efficacies of these ECRA viruses in AHSV natural hosts. One monoserotype (ECRA.A4) vaccine and one multivalent cocktail (ECRA.A1/4/6/8) vaccine were tested in ponies and subsequently challenged with a virulent AHSV4. In contrast to control animals, all vaccinated ponies were protected and did not develop severe clinical symptoms of AHS. Furthermore, the multivalent cocktail vaccinated ponies produced neutralizing antibodies against all serotypes present in the cocktail, and a foal born during the trial was healthy and had no viremia. These results validate the suitability of these ECRA strains as a new generation of vaccines for AHSV

Bluetongue in the north of Europe

Bluetongue is a non-contagious viral disease transmitted by the hematophagous midge Culicoides. Bluetongue causes a generalised and serious infection affecting mainly sheep. Since its reemergence in Europe in 1998, 5 out the 24 serotypes (1, 2, 4, 9 and 16) were isolated in numerous Mediterranean countries. In France, only Corsica has suffered four epizootics involving serotypes 2, 4 and 16. In 2006, the bluetongue virus serotype 8 emerged unexpectedly in Belgium, Germany, the Netherlands, France, and Luxemburg. This bluetongue epizootic was atypical, as it affected cattle as well, a species only very rarely affected by the bluetongue virus, with varying degrees of severity. The characteristics of this epizooty, the diagnostic methods, and the prophylactic measures are described in this article.La fièvre catarrhale ovine, aussi appelée « bluetongue », est une arbovirose transmise par un moucheron hématophage du genre Culicoïdes. Elle se manifeste cliniquement principalement chez les moutons et se traduit par une infection généralisée et grave. Depuis sa réapparition en Europe en 1998, cinq sérotypes (1, 2, 4, 9 et 16) sur les 24 existants ont été recensés dans de nombreux pays du pourtour méditerranéen. En France, seulement la région Corse a subi quatre épizooties impliquant les sérotypes 2, 4 et 16. En 2006, de façon inattendue, la bluetongue (sérotype 8) a émergé en Belgique, Allemagne, Pays bas, France et au Luxembourg. La symptomatologie associée à cette épizootie a de quoi surprendre, puisque les bovins présentent des signes cliniques de gravité variable, alors que classiquement, le virus de la bluetongue ne provoque que très rarement des manifestations cliniques dans cette espèce. Les caractéristiques de cette épizootie, les méthodes de diagnostic et les moyens prophylactiques seront présentés dans cet article