Search

Since the outbreak of bluetongue in Northern Europe in 2006, numerous outbreaks involving several serotypes have been observed. Since 2008, compulsory or voluntary vaccination campaigns with inactivated vaccines have been carried out to eradicate these serotypes. In France, serotypes 8 and 4 have been enzootic since 2017, and currently, the majority of vaccinations take place in the context of animal movements, to comply with the regulations of the importing countries. Several vaccine manufacturers have developed inactivated vaccines against serotypes 4 and 8 (mono or bivalent). In this study, we investigated and compared the serological responses to a booster vaccination with two different bivalent inactivated vaccines (BTVPUR suspension injectable® 4 + 8, Boehringer Ingelheim or SYVAZUL ® BTV 4 + 8, Biové) following a primary vaccination with BTVPUR® 4 + 8 in the previous year. The results show that using an alternative vaccine for booster vaccination is at least as effective as using the homologous vaccine. Indeed, the antibody response against BTV-8 is higher in the case of a heterologous vaccination and identical for BTV-4. This information could allow more flexibility in the choice of vaccines used for booster vaccination, particularly in cases where homologous vaccines are in short supply or unavailable. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. Disease epidemics can be man-made: Molecular clocks and genomic data for an economically important livestock virus reveal that a current European outbreak may have been caused by accidental release, rather than natural transmission. [ABSTRACT FROM AUTHOR]

Summary: 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 log10TCID50/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 log10 genome copies/ml) than the re‐emerging BTV‐8 strain (2.9–7.9 log10 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. [ABSTRACT FROM AUTHOR]

Since the unexpected emergence of BTV-8 in Northern Europe and the incursion of BTV-8 and 1 in France in 2006-2007, molecular diagnosis has considerably evolved. Several real-time RT- PCR (rt RT- PCR) methods have been developed and published, and are currently being used in many countries across Europe for BTV detection and typing. In France, the national reference laboratory ( NRL) for orbiviruses develops and validates 'ready-to-use' kits with private companies for viral RNA detection. The regional laboratories network that was set up to deal with a heavy demand for analyses has used these available kits. From 2007, ring tests were organized to monitor the performance of the French laboratories. This study presents the results of 63 regional laboratories in the ring trial organized in 2016. Blood samples were sent to the laboratories. Participants were asked to use the rt RT- PCR methods in place in their laboratory, for detection of all BTV serotypes and specifically BTV-8. The French regional laboratories are able to detect and genotype BTV in affected animals. Despite the use of several methods (i.e. RNA extraction and different commercial rt RT- PCRs), the network is homogeneous. The ring trial demonstrated that the French regional veterinary laboratories have reliable and robust BTV diagnostic tools for BTV genome detection. [ABSTRACT FROM AUTHOR]

Background The Schmallenberg virus (SBV) emerged in Europe in 2011 and caused a widespread epidemic in ruminants. In France, SBV emergence was monitored through a national multi-stakeholder surveillance and investigation system. Based on the monitoring data collected from January 2012 to August 2013, we describe the spread of SBV in France during two seasons of dissemination (vector seasons 2011 and 2012) and we provide a large-scale assessment of the impact of this new disease in ruminants. Results SBV impact in infected herds was primarily due to the birth of stillborns or deformed foetuses and neonates. Congenital SBV morbidity level was on average moderate, although higher in sheep than in other ruminant species. On average, 8% of lambs, 3% of calves and 2% of kids born in SBV-infected herds showed typical congenital SBV deformities. In addition, in infected herds, farmers reported retrospectively a lower prolificacy during the vector season, suggesting a potential impact of acute SBV infection during mating and early stages of gestation. Conclusions Due to the lack of available control and prevention measures, SBV spread quickly in the naive ruminant population. France continues to monitor for SBV, and updated information is made available online on a regular basis [http://www.plateforme-esa.fr/]. Outbreaks of congenital SBV are expected to occur sporadically from now on, but further epidemics may also occur if immunity at population level declines. [ABSTRACT FROM AUTHOR]

Bluetongue virus (BTV) is a Culicoides-borne pathogen infecting both domestic and wild ruminants. In Europe, the Red Deer (Cervus elaphus) (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 Culicoides communities and feeding habits within domestic and wild animal environments (51,380 samples). Culicoides 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. [ABSTRACT FROM AUTHOR]

Bluetongue (BT) is a non-contagious animal disease transmitted by midges of the Culicoides 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. [ABSTRACT FROM AUTHOR]

• First introduction of EHDV-8 in France followed by EHD outbreaks in cattle. • Emergence of a new BTV-8 strain in France responsible of severe BT outbreaks. • Successful viral genome sequencing from blood samples using Nanopore technology. • Risk of co-circulation of various BTV genotypes and viral reassortment. Bluetongue (BT) and Epizootic Hemorrhagic Disease (EHD) are two notifiable animal diseases transmitted to ruminants by small hematophagous midges belonging to the Culicoides genus. The etiological agents, Bluetongue virus (BTV) and Epizootic hemorrhagic disease virus (EHDV), are both members of the Sedoreoviridae family and Orbivirus genus, which include double-stranded (ds) RNA segmented genomes (10 segments). By the end of the summer 2023, first's outbreaks of EHD were reported from the south west of France, concurrently with unexpectedly severe BT cases in Central France and Corsica. Within a few weeks, numerous BT and EHD outbreaks were recorded with significant sanitary and economic impact on cattle and sheep farms (no sanitary impact of EHD for sheep). Using a customized SISPA approach and the nanopore sequencing technology we successfully recovered genomic sequences from viral isolates and blood samples from infected animals from EHD and BT outbreaks. Three different viruses were responsible for these outbreaks: EHDV-8, BTV-8 and BTV-4. The EHDV-8 strain detected in France corresponded to the strain circulating in Tunisia, Sardinia and Spain since 2021 and 2022. A new BTV-8 strain of unknown origin, clearly different from the enzootic strain circulating in France since 2015, was responsible of the BT outbreaks in domestic ruminants in 2023 on both mainland France and Corsica. A second BTV, BTV-4, also involved in BT outbreaks in Corsica, corresponded to a BTV-4 strain occasionally detected on Corsica island since 2016, suggesting either a new introduction of this strain or a silent circulation on the field. The exceptional nature of orbivirus epizootics in France in 2023, including new introduction, emergence or incursions, raises numerous questions regarding BTV and EHDV dynamics and epidemiology and stresses out the need to identify factors involved in these emergences. [ABSTRACT FROM AUTHOR]

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.

Schmallenberg virus infection is emerging in European domestic and wild ruminants. We investigated the serologic status of 9 red deer populations to describe virus spread from September 2010 through March 2012 among wildlife in France. Deer in 7 populations exhibited seropositivity, with an average seroprevalence of 20%.

Bluetongue (BT) and/or BT viruses (BTV) have been identified in the Mediterranean basin and the Balkans each year from 1998 to 2002 and in particular BTV serotype 2 in the French Island of Corsica (2000 and 2001). In response to these virus incursions, the French Veterinary Authorities carried out epidemiological studies that included virological, serological and entomological analysis, and two vaccination campaigns performed in the winter of 2000/2001 and the winter and spring of 2001 and 2002. Rapid and reliable serotype differentiation is essential at the start of an outbreak to allow an early selection of vaccine to control the spread of the virus. Thus, molecular tools, that complement conventional methods, have been developed for early detection of infection, determination of the serotype, and differentiation between natural infection and vaccination. Serological results showed that the first vaccination campaign during the winter of 2000/2001 did not provide full protection for all sheep and during the summer of 2001, 335 sheep flocks in Corsica were again infected by BTV 2 (7-fold more that in 2000). Entomological studies have demonstrated that the only proven vector of the disease, Culicoides imicola, was present in the island in 2000 and that it has successfully established itself in Corsica. The safety and immunogenicity of the commercial South African vaccine were studied. Fourteen sheep were vaccinated and then observed for clinical signs. Blood, sera, spleen and lymph nodes were collected and analyzed, and the results confirmed the safety and potency of using this vaccine to protect sheep from clinical disease. As a result, an intensive vaccination campaign was performed during winter and spring 2001/2002. No cases of BT had been observed by the end of summer 2002, indicating that the vaccination campaign has been successful in protecting sheep from infection.