Detection of equine herpesviruses in aborted foetuses by consensus PCR

International audienceThe major role of EHV-1 in equine abortion is widely reported in the literature but the contribution of EHV-2, EHV-3, EHV-4 or EHV-5 remains less well documented. The objective of this study is to evaluate the contribution of these five different EHVs to equine abortion in a variety of biological tissues using a consensus polymerase chain reaction (PCR). The test was validated for specificity and sensitivity in horses before screening specimens from 407 foetuses, stillbirths and premature foals collected over a 2.5-year interval. Positive results obtained with this assay were compared to other EHV type-specific PCR or by sequencing. EHV-1 was identified as the major cause of abortion in French mares (59/407 cases). However, there was evidence to suggest some variation in the potential of EHV-1 strains to induce abortion. Indeed, DNA samples from EHV-2 (in three cases) and EHV-5 (in one case) inferred a role of these viruses in abortion. The presence of viral DNA from EHV-3 or EHV-4 strains was not detected in the specimens studied. The data obtained suggest that the consensus herpesvirus PCR is an efficient screening tool. In association with a specific PCR, the test provides a rapid identification of the type of herpesvirus involved in abortion and is useful for routine diagnostic tests as it allows the identification of herpesviruses other than the EHV-1 strain

Données récentes sur l'implication de l'herpès virus équin de type 1 dans les avortements et les pathologies de forme nerveuses

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Monitoring of equine acute respiratory syndromes in France

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Identification of Pathogenic Leptospira Strains in Tissues of a Premature Foal by Use of Polymerase Chain Reaction Analysis

International audienceStudies were carried out to determine the cause of death in a prematurely born Thoroughbred foal that died 24 hours after birth. Necropsy revealed gross lesions suggestive of septicemia. A commercial Leptospira polymerase chain reaction (PCR) assay designed to specifically amplify the hemolysis-associated protein 1 ( hap1) gene present only in pathogenic Leptospira strains detected the presence of Leptospira DNA in various tissues of the foal. Histologic examination of lung, liver, kidney, and myocardium revealed numerous spirochetes in Warthin–Starry-stained tissue sections. Results of PCR analysis and histologic examination suggested a leptospiral infection in the newborn foal. At the moment of death, the infection coexisted with a streptococcal-associated aspiration bronchopneumonia and postpartum septicemia. These findings indicate that the PCR assay based on the amplification of the hap1 gene represents a useful tool for specific detection of pathogenic leptospira in field samples taken from horses

Further Evidence for in Utero Transmission of Equine Hepacivirus to Foals

International audience(1) Background: Equine hepacivirus (EqHV), also referred to as non-primate hepacivirus (NPHV), infects horses—and dogs in some instances—and is closely related to hepatitis C virus (HCV) that has infected up to 3% of the world’s human population, causing an epidemic of liver cirrhosis and cancer. EqHV also chronically infects the liver of horses, but does not appear to cause serious liver damages. Previous studies have been looking to identify route(s) of EqHV transmission to and between horses. (2) Methods: In this retrospective study, we sought to evaluate the prevalence of vertical transmission taking place in utero with measuring by quantitative RT-PCR the amounts of EqHV genome in samples from 394 dead foals or fetuses, paired with the allantochorion whenever available. (3) Results: Detection of EqHV in three foals most likely resulted from a vertical transmission from the mares to the fetuses, consistent with the in utero transmission hypothesis. In support of this observation, the presence of EqHV genome was found for the first time in two of the allantochorions. (4) Conclusions: As seemingly benign viruses could turn deadly (e.g., Zika flavivirus) and EqHV happens to have infected a significant proportion of the world’s horse herds, EqHV infectious cycle should be further clarified

Hepacivirus and the “new triade” : Further evidence for in utero transmission of equine hepacivirus to foals

International audienceEquine hepacivirus (EqHV), also referred to as non-primate hepacivirus (NPHV), infects horses —and dogs in some instances— and is closely related to hepatitis C virus (HCV) that has infected up to 3 % of the world’s human population, causing an epidemic of liver cirrhosis and cancer. EqHV is also chronically infecting the liver of horses, but does not appear to cause serious liver damages. Recent work often associates two other viruses, Theiler Disease Associated Virus (TDAV) and Pegivirus (EqPV) to this research during hepatic syndrome. If the name of the hepatic triad has emerged in recent years, the recent discovery of a new virus, a potentially involved equine parvovirus, raises new questions. Among these, the mode of transmission of these viruses is an essential issue. Previous studies have been looking to identify route(s) of EqHV transmission to and between horses. In a retrospective study, we sought to evaluate the prevalence of vertical transmission taking place in utero with measuring by quantitative RT-PCR the amounts of EqHV genome in samples from 394 dead foals or fetuses, paired with the allantochorion whenever available. Detection of EqHV in three foals most likely resulted from a vertical transmission from the mares to the fetuses, consistent with the in-utero transmission hypothesis. In support of this observation, the presence of EqHV genome was found for the first time in two of the allantochorions. If the first transmission tracks emerge for EqHV, studies are needed for the "triad" or even the "tetrad"

French 2007 equine viral arteritis outbreak : epidemiological and pathological features

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Description of the first recorded major occurrence of equine viral arteritis in France

International audienceReasons for performing study: The vast majority of equine arteritis virus (EAV) infections are inapparent or relatively mild, but may occasionally cause outbreaks of equine viral arteritis. The event observed in France during the summer of 2007 was the most important seen in the country, with mortality and disruption of economic activity.Objectives: To describe the different stages seen during the outbreak and to show how molecular tools were used for both the detection and management of the crisis.Methods: EAV detection was performed by real-time reverse transcription-polymerase chain reaction (RT-PCR) in blood, nasal swabs, semen or organ samples. Characterisation of EAV strains was performed by sequencing the ORF5 fragment.Results: The outbreak affected 18 premises in 5 counties in western France, which represented the index, 8 primary and 9 secondary premises. Artificial insemination in draught horses was responsible for the virus spread. Eight mortality cases were observed, including one fetus, 5 young foals and 2 mature horses. Forty-three individuals had positive results by real-time RT-PCR. The range of measured cycle threshold (Ct) values varied from 19.8 to 40.4 depending on the biological samples. Phylogenetic analysis revealed that the 33 isolated strains all clustered within the EU-2 subgroup.Conclusions: The mortality rate attests to the virulence of the strain involved in this outbreak. Real-time RT-PCR was used for the first time in order to follow-up an epidemic disease in horses.Potential relevance: The early detection of 3 signals with high Ct values attest the importance of taking low signals into account in field conditions

Surveillance de la grippe équine en France : bilan du réseau RESPE et phylogénie des virus circulants

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