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International audience; Equid alpha-herpesviruses (EHV) are responsible for different diseases in equine population. EHV-1 causes respiratory diseases, abortions and nervous disorders, EHV-4 causes respiratory diseases and sporadic abortion, while EHV-3 is responsible of equine coital exanthema. In view of the lack of efficacy of vaccines against EHV-1 and EHV-4 and in the absence of vaccines against EHV-3, the use of antiviral treatment is of great interest. In this study, we documented the interest of the Real-Time Cell Analysis (RTCA) technology to monitor the cytopathic effects induced by these viruses on equine dermal cells, and established the efficacy of this method to evaluate the antiviral effect of aciclovir (ACV) and ganciclovir (GCV). In addition, the RTCA technology has also been found appropriate for the high-throughput screening of small molecules against EHV, allowing the identification of spironolactone as a novel antiviral against EHV.

Stallions are natural reservoirs of equine arteritis virus (EAV) in their semen, representing a potential source of outbreaks. The carrier-state is testosterone-dependent, and clears spontaneously in 4 to 40% stallions. Reduction of testosterone secretion may be obtained with the anti-GnRH vaccine Equity. In this report, 16 naturally infected stallions excreting EAV in their semen were vaccinated twice with the vaccine EquityTM and monitored irregularly under field conditions for EAV viral load in their semen and plasmatic testosterone concentration. The results are indicated in months (M) after the first vaccine injection. Testosterone concentrations decreased from 1.7 to 0.2 ng/mL (P, Pastusi su prirodni rezervoar uzročnika virusnog arteritisa konja (EAV), koji se izlučuje u sjemenu, te su zbog toga i potencijalni izvor pojave bolesti. Status prenositelja je ovisan o testosteronu i spontano nestaje u 4 do 40 % pastuha. Izlučivanje testosterona moglo bi se smanjiti anti-GnRH cijepljenjem. U ovom je istraživanju 16 prirodno inficiranih pastuha, koji su izlučivali EAV u sjemenu, cijepljeno dva puta cjepivom EquityTM te je u nepravilnim razmacima i u terenskim uvjetima praćena količina virusa u sjemenu i koncentracija testosterona u plazmi. Rezultati su prikazani prema mjesecima (M) poslije prvog cijepljenja. Koncentracija testosterona smanjena je s 1,7 na 0,2 ng/mL (P < 0,002) poslije tri mjeseca. Poslije pet mjeseci količina virusa smanjena je s 3,2 × 109 na 1,1 × 106 RNA kopija/mL sjemena (P < 0,001). Jedan je pastuh uginuo 7 mjeseci nakon prvog cijepljenja. Od trećeg do desetog mjeseca, 12 od 15 pastuha prestalo je izlučivati virus u sjemenu. Od petog do desetog mjeseca, 9 od 15 pastuha imalo je koncentraciju testosterona u plazmi ≥ 0,5 ng/mL, a njih šestero pokazalo je trajno nisku koncentraciju testosterona (≤ 0,3 ng/mL). Od 14 pastuha, od kojih se očekivao oporavak reproduktivne aktivnosti u sljedećoj sezoni rasploda (< M 12), 8 je bilo negativno na EAV i dalo ždrijebe, a 6 nije bilo za rasplod (4 zbog reproduktivne deficijencije i 2 jer su bili pozitivni na EAV). Svi su pastusi bili negativni na EAV poslije 22 mjeseca, s tim da je jedan pastuh nakon 15 mjesci treći put cijepljen. Ovi rezultati pokazuju da bi anti-GnRH cijepljenje moglo pomoći u eradikaciji EAV-a u pastuha, bez osobita utjecaja na reproduktivnu sposobnost većine njih, osim što je u nekih smanjeno izlučivanje testosterone dulje potrajalo.

International audience; Like hepatitis C virus (HCV) in humans, the newly identified equine hepacivirus (NPHV) displays a predominating liver tropism that may evolve into chronic infections. The genomes of the two viruses share several organizational and functional features and are phylogenetically closest amongst the Hepacivirus genus. A limited amount of data is available regarding the spread of hepacivirus infections in horses. In this study, we asked whether in a more representative sample the prevalence and distribution of NPHV infections in France would resemble that reported so far in other countries. A total of 1033 horses sera from stud farms throughout France were analysed by qRT-PCR to determine the prevalence of ongoing NPHV infections and viral loads; in positive samples, partial sequences of NPHV’s genome (50UTR, NS3 and NS5B genes) were determined. Serum concentrations of biliary acids, glutamate dehydrogenase (GLDH) and L-gamma-glutamyl transferase (c-GT) were measured for most horses. We detected NPHV infections in 6.2% of the horses, a prevalence that reached 8.3% in thoroughbreds and was significantly higher than in other breeds. The presence of circulating virus was neither significantly associated with biological disturbances nor with clinical hepatic impairment. Our phylogenetic analysis was based on both neighbour- joining and maximum-likelihood approaches. Its result shows that, like almost everywhere else in the world so far, two major groups of NPHV strains infect French domestic horses. Based on genetic distances, we propose a classification into two separate NPHV subtypes. Viral loads in the serum of horses infected by the main subtype were, in average, four times higher than in those infected by the second subtype. We hypothesize that amino acid substitutions in the palm domain of NS5B between NPHV subtypes could underlie viral phenotypes that explain this result.

International audience

Summary Reason for performing this study Equine influenza virus (EIV) is considered the most economically important equine respiratory pathogen worldwide. The H3N8 subtype, responsible for all outbreaks of equine influenza globally, evolves perpetually. Mutations in the genome of these viruses have the potential to modify their antigenic properties and recognition by pre-existing antibodies. Objectives The aim of this study was to determine the genetic evolution of EIV strains in France and to compare it with the evolution of strains isolated globally. Analysis of the sequence data was performed to investigate any possible links between the outbreaks. Study design Retrospective genetic analysis study of archived material. Methods Analyses were performed on the HA1 domain of haemagglutinin H3 of EIV isolated in a previous study carried out from November 2005 to October 2010. The nucleic acid sequence of 41 strains was analysed and translated. The French viruses were compared with 59 Clade 1 strains and 83 Clade 2 strains. Strains were aligned chronologically and on the basis of their geographical origin. Results The 16 Clade 1 strains are all derived from the outbreak that started in the Grosbois training yard in 2009. The virus genome appears to have been stable during the outbreak. The 25 Clade 2 strains were isolated over the 5-year period during which several mutations had emerged. Some strains incorporate a sporadic mutation, and others a mutation that may occur several times but does not persist. However, all strains are gradually moving towards definitive mutations. Conclusion This study demonstrated that EIVs have evolved in France during this period in a similar manner to EIVs globally. The data lend support to the current World Animal Health Organisation recommendation that the vaccines contain a representative of both Clade 1 and Clade 2 of the Florida sublineage. The Summary is available in Chinese – see Supporting information.

International audience; Equid gammaherpesviruses-2 and -5 are involved in respiratory problems, with potential clinical man-ifestations such as nasal discharge, pharyngitis and swollen lymph nodes. These viruses are sometimesassociated with a poor-performance syndrome, which may result in a significant and negative economicimpact for the horse industry. The aim of the present study was to develop and validate quantitative PCRmethods for the detection and quantitation of EHV-2 and EHV-5 in equine respiratory fluids. Two dis-tinct tests were characterised: (a) for the qPCR alone and (b) for the whole method (extraction and qPCR)according to the standard model AFNOR XP U47-600-2 (viz., specificity, quantifiable sensibility, linearity,accuracy, range of application, trueness, precision, repeatability and precision of reproducibility). EHV-2and EHV-5 detection were performed on nasal swabs collected from 172 horses, all of which exhibitedclinical signs of respiratory disease. The data revealed a high rate of EHV-2/EHV-5 co-detection that wascorrelated significantly with age. Viral load of EHV-2 was significantly higher in young horses whereasviral load of EHV-5 was not significantly different with age.

Summary Reasons for performing the study The Reseau d'Epidemio-Surveillance en Pathologie Equine (RESPE, the French epidemiological network for equine diseases) is a network for epidemio-surveillance of major equine diseases based around sentry veterinarians in France. Objective The aim of this study was to evaluate the contribution of RESPE to efficient surveillance of equine influenza virus (EIV) in France. Study design Retrospective cross-sectional study. Methods From November 2005 to October 2010, epidemiological and phylogenetic studies were performed on 1426 nasopharyngeal swabs received at the Frank Duncombe Laboratory. Detection was performed by real-time reverse transcription polymerase chain reaction using original primers and probes designed in the matrix protein gene. Phylogenetic analysis was carried out on the HA1 part of haemagglutinin gene amplified from 47 positive-testing samples. Epidemiological information was provided with the majority of samples submitted through RESPE. Results Of the 920 samples submitted by RESPE-associated veterinarians, 121 (13.1%) from 42 premises were positive for EIV, compared to 26 (5.1%) of the 607 samples received from non-RESPE associated veterinarians. The most extensive outbreak was observed between February and May 2009, affecting 70 horses on 23 premises, 15 of which were managed by RESPE-associated veterinarians. All strains belonged to the American lineage, Florida sublineage, Clade 1 and Clade 2. Clade 1 was identified only during the Grosbois episode. Conclusion RESPE improved detection of EIV in France, enabled characterisation of the virus strains, yielded valuable information relating to the epidemiology of the disease and identified vaccine breakdown. Potential relevance Implementation of a similar surveillance network in other countries may reduce the economic losses associated with outbreaks of EIV. The Summary is available in Chinese - see Supporting information.

The aim of the present study was to describe the prevalence of Nicoletella semolina in equine airways and its relationships with cytological evaluation of tracheal wash (TW). Samples were collected in the framework of routine bacteriological diagnostics of equine TW between May 2010 and June 2011. N semolina has been isolated, along with either common pathogens or contaminants, from 19 (1.8%) of the 1,054 TW samples. Median TW neutrophil counts (87.0%) in specimens from N semolina-positive horses were significantly different from those from N semolina-“negative” horses (52.0%). The data presented in this report may suggest considering such bacteria in horses clinically suffering from airway inflammation.

published online; International audience; Persons' identification in TV broadcast is one of the main tools to index this type of videos. The classical way is to use biometric face and speaker models, but, to cover a decent number of persons, costly annotations are needed. Over the recent years, several works have proposed to use other sources of names for identifying people, such as pronounced names and written names. The main idea is to form face/speaker clusters based on their similarities and to propagate these names onto clusters.In this paper, we propose a method to take advantage of written names during the diarization process, in order to both name clusters and prevent the fusion of two clusters named differently. First, we extract written names with the LOOV tool; these names are associated to their co-occurring speaker turns / face tracks. Simultaneously, we build a multi-modal matrix of distances between speaker turns and face tracks. Then agglomerative clustering is performed on this matrix with the constraint to avoid merging clusters associated to different names. We also integrate the prediction of few biometric models (anchors, some journalists) to directly identify speaker turns / face tracks before the clustering process.Our approach was evaluated on the REPERE corpus and reached an F-measure of 68.2% for speaker identification and 60.2% for face identification. Adding few biometric models improves results and leads to 82.4% and 65.6% for speaker and face identity respectively. By comparison, a mono-modal, supervised person identification system with 706 speaker models trained on matching development data and additional TV and radio data provides 67.8% F-measure, while 908 face models provide only 30.5% F-measure.

International audience; In virology, different conventional methods are commonly used for virus titration and infectivity studies. Most of them are based on direct examination of viral cytopathic effect, which is time consuming, tedious and requires an endpoint reading. The RTCA xCELLigence system (ACEA Biosciences) has been developed to follow cellular events and their dynamics in real time using a micro-electrical biosensor technology. The aim of this study was to evaluate the feasibility of using this biosensor technology to measure the effect of different equid herpesviruses on equine dermal cell cultures, with or without antiviral acyclovir treatment. Cells were infected with EHV-1 (VR700), EHV-4 (VR2230), EHV-2 (VR701) or EHV-3 (VR352). The viral effects were monitored by 3 different methods: impedance measurements (RTCA), cytopathic effects recording (microscopy) and viral load quantification (qPCR). The RTCA technology showed a dose dependent drop of the cellular index induced by specific impedance variations measured during growth of each virus tested. These results correlated with the cytopathic effect induced by the different herpesvirus species, as well as viral loads measured by qPCR. For example, after 3 days of incubation with EHV-1, RTCA results showed an increase of the cellular index from 0% (infection without antiviral) to 45% and 100% in presence of Acyclovir (10μl/mL and 100 μg/mL, respectively). These results are correlated with the decreased of viral load measured in the presence of Acyclovir: 1010 genome copies/mL with EHV-1 only, 106 copies/mL with EHV-1 + Acyclovir 10 μg/ mL and 105 copies/mL with EHV-1 + Acyclovir 100 μg/ mL. In conclusion, the cellular impedance monitoring system is a new real-time method to monitor cell growth and viral proliferation in cell cultures. This technology is well adapted for high-throughput screening of antiviral molecules. In fact, the xCELLigence system enables continuous impedance measurement and quantification of cell adhesion, proliferation, cell death and detachment during viral infection.

International audience; Hepatitis C virus (HCV) is one of the main causes of end stage liver diseases (cirrhosis and hepatocellular carcinoma) in humans. In vivo studies have been hampered by a lack of access to relevant animal models. Until recently, the genus Hepacivirus was comprised of seven HCV genotypes, plus GBV-B that infects New World monkeys. Within the past few years, new hepaciviruses were identified in dogs and horses (also called canine/equine or non-primate hepaciviruses), in Old World monkeys (Colobus guereza), as well as in rodents (Myodes glareolus and Rhabdomys pumilio) and bats. Yet, the data available regarding newly identified hepacivirus infections is still limited, including in horses. So far, few studies have reported PCR positive horses in different countries (USA, Scotland, Germany, Japan, Brazil and Hungary). The aim of our study was to determine the prevalence of active hepacivirus infections in horses. A RT-qPCR adapted from the test described by Burbello et al. was developed according to the AFNOR norm U47-600-2. We detected 69 positive horses out of 1229 screened with this assay (5,6%). Positive horse samples originated from all parts of France. The number of viral genomes circulating in the blood of hepacivirus-infected horses ranged from 1.15 x 104 to 2.8 x 109 copies/mL, with two third of the results above a threshold of 4.26 x 107 copies/mL. There was no evidence of concomitant hepatic inflammation in the sera, as tested by the levels of gamma-glutamyl transferase and glutamate deshydrogenase. A one-year follow-up study in 7 horses from the same stud farm showed that, from the time of detection, infection persisted up to 18 months. A phylogenetic analysis was performed based on the nucleotide sequences of the 5’-untranslated region of the genome, as well as of the genes encoding the nonstructural proteins 3 and 5B. The result of this analysis suggests that all positive horses identified in France are infected with equine hepacivirus variants distinct from those previously reported. The present study demonstrates for the first time the presence of a significant proportion of ongoing equine hepacivirus infections in the horse herds in France. Determining the consequences of persistent hepacivirus infections in horses warrants further investigation.

Previous studies investigating the potential involvement of viruses in airway inflammation were based either on serological tests or on PCR from nasal swabs only. The objectives of this study were to determine the incidence of welland less-characterised viruses in the equine airways, and their association with clinical signs. In a 2-year prospective longitudinal study, nasal swabs (NS) and tracheal washes (TW) were collected monthly on 52 Standardbred racehorses at training (581 samples). Equine aand g-herpesviruses, equine rhinitis virus-A and -B, equine adenovirus-A, and equine influenza virus were investigated by qPCR. Any positive sample was subcategorised as non-quantifiable (>LOD and LOQ). Clinical signs (nasal discharge, coughing), and tracheal mucus score were simultaneously recorded. In TW, respective monthly incidences were 27.9% (EHV-5), 24.8% (EHV-2), 7.1% (ERBV), 3.8% (EHV-4), 1.9% (EAdV1) and 0.2% (EHV-1, ERAV). EIV has not been detected in any sample. Molecular detection of EHV-2 and ERBV in TW were significantly associated with coughing (OR 3.1; 95% CI 1.4-7.1; P1⁄40.01 and OR 5.3; 95% CI 2.1-14.0; P

During the summer of 2007, an outbreak of equine viral arteritis (EVA) occurred in Normandy (France). After investigation, a link was suggested between an EAV carrier stallion (A) and the index premise of the outbreak. The full-length nucleotide sequence analysis of a study reference strain (F27) isolated from the lung of a foal revealed a 12,710 nucleotides EAV genome with unique molecular hallmarks in the 5′UTR leader sequence and the ORF1a sequence encoding the non-structural protein 2. The evolution of the viral population in the persistently infected Stallion A was then studied by cloning ORFs 3 and 5 of the EAV genome from four sequential semen samples which were collected between 2000 and 2007. Molecular analysis of the clones confirmed the likely implication of Stallion A in the origin of this outbreak through the yearly emergence of new variants genetically similar to the F27 strain.

Summary Reasons for performing study: Surfactant protein D (SP-D), mainly synthesised by alveolar type II cells and nonciliated bronchiolar cells, is one important component of innate pulmonary immunity. In man, circulating concentrations of SP-D are routinely used as biomarkers for pulmonary injury. To date, serum SP-D levels have only been investigated in horses in an experimental model of bacterial airway infection. Objectives: To compare serum SP-D concentrations at rest and after exercise in horses with and without inflammatory airway disease (IAD). Methods: Venous blood samples were collected from 42 Standardbred racehorses at rest and 60 min after performing a standardised treadmill exercise test. Tracheal wash and bronchoalveolar lavage fluid (BALF) samples were collected after exercise. Based on BALF cytology, 22 horses were defined as IAD-affected and 20 classified as controls. Serum SP-D concentrations were assessed using a commercially available ELISA kit and statistically compared between groups of horses and sampling times. Results: Serum concentrations of SP-D in IAD-affected horses were significantly higher than those of control horses, both at rest and after exercise. Within the IAD-affected group, no significant correlation was found between serum SP-D concentrations and BALF cytology. Within each group of horses (IAD and control), no significant influence of exercise was found on serum SP-D levels. Conclusions: This is the first study determining serum SP-D concentrations in a noninfectious, naturally occurring form of lower airway inflammation in horses. The results highlight that IAD is associated with a detectable, though moderate, increase of circulating SP-D levels. Potential relevance: Serum concentration of surfactant protein D could represent a potentially valuable and readily accessible blood biomarker of equine lower airway inflammation.

At least five equine herpesviruses are known to infect horses : three alpha herpesviruses (equine herpesvirus-1, -3 and -4) and two gamma herpesviruses (equine herpesvirus-2 and -5). Equine herpesvirus-1 is responsible for three clinical presentations : respiratory, abortigenic and neurological. This latter, widely known as EHV-1 associated, myeloencephalopathy has been thoroughly investigated over the past years. Most of the studies focused on the relation between the presence of a mutation in ORF 30 coding for DNA polymerase and the expression of the paralytic (neurological) form. Even if this mutation seems to play a role, other factors related to the host and the environment are certainly involved in the development of the disease. Equine herpesvirus-4 is better known as the rhinopneumonia virus and is responsible for a large part of respiratory disorders in young foals. Equine herpesvirus-3 is responsible for equine coital exanthema, whose transmission through the respiratory tract is now proven. Equine herpesvirus-2 and -5 are associated with subclinical respiratory diseases in equine athletes, even though their pathogenic role has yet to be clarified as they were detected in all continents only relatively recently. The development of molecular genetic tools lead to major progress in the detection of these viruses, but the differentiation between latent and infectious forms is still unresolved. Although studies are currently performed on the typing of strains responsible for different clinical presentations involving equine herpesviruses as well as in other equine viruses (influenza, equine viral arteritis), there is no international consensus on a phylogenic tree for any of the 5 equine herpesviruses. Further studies are definitely required to monitor and characterise the different strains of EHV., Au moins cinq herpèsvirus équins peuvent infecter le cheval : trois alpha-herpèsvirus (les herpèsvirus 1, 3 et 4) et deux gamma-herpèsvirus (les herpèsvirus équins 2 et 5). L’herpèsvirus équin 1 est responsable de trois formes cliniques : une forme respiratoire, une forme abortive et une forme neurologique. Cette dernière, plus connue sous le nom de myéloencéphalopathie à HVE-1, a fait l’objet de nombreuses études ces dernières années. La plupart des travaux ont porté sur la relation entre la présence d’une mutation dans l’ORF 30 codant l’ADN polymérase et l’expression de la forme paralytique. Si cette mutation semble jouer un rôle, d’autres facteurs liés à l’hôte et à l’environnement participent certainement au développement de la maladie. L’herpèsvirus équin 4 est plus connu sous le nom de virus de la rhinopneumonie et est responsable d’une part importante des affections respiratoires chez les jeunes poulains. L’herpèsvirus équin 3 est responsable de l’exanthème coïtal équin et l’on sait aujourd’hui qu’il peut se transmettre par les voies respiratoires. Les herpèsvirus équins 2 et 5 sont associés aux maladies respiratoires subcliniques du cheval athlète même si leur rôle reste à préciser, leur découverte sur l’ensemble des continents étant relativement récente. Le développement des outils de génétique moléculaire a permis de faire des progrès importants dans la détection de ces virus même si un challenge demeure : différencier les formes latentes des formes infectieuses. Si comme pour d’autres virus équins (ex : grippe, artérite virale équine), des travaux sont réalisés pour typer les différentes souches responsables de différentes formes d’expression de la maladie, il n’existe toujours pas de consensus international sur un arbre phylogénique pour aucun de ces cinq herpèsvirus équins. Le suivi et la caractérisation des différentes souches d’HVEs sont très certainement l’autre défi de demain., Pronost Stéphane, Hue Érika, Legrand Loïc, Pitel Pierre-Hugues, Fortier Guillaume. Herpèsviroses des équidés: intérêts et limites des outils de génétique moléculaire. In: Bulletin de l'Académie Vétérinaire de France tome 164 n°4, 2011. pp. 305-316.

Summary Reasons for performing study: Dorsal displacement of the soft palate (DDSP) is one of the most common obstructive conditions of the upper respiratory tract in the racehorse. This condition has a complex aetiology which may be caused or exacerbated by pharyngeal inflammation. Additionally, lower respiratory airway diseases may be associated with DDSP thereby contributing to exercise intolerance in these horses. Objective: The aim of this study was to measure physiological variables during a standardised exercise test and to assess the prevalence and consequences of lower respiratory airway disease in horses with DDSP. Methods: A total of 46 horses were included in this study: 22 in the control and 24 in the DDSP groups. All horses performed a SET with measurement of heart rate (HR) and blood lactate concentration. One hour post exercise, respiratory samples were collected for cytological and bacteriological analysis. Results: During exercise, the DDSP group had higher blood lactate concentration than the control group. According to BAL results, 50 and 63% of control and DDSP group horses, respectively, had evidence of inflammatory airway disease (IAD). In the DDSP group, 42% of horses had a syndrome of tracheal inflammation (STI) with 71% of this group having bacteria isolated at >105 CFU/ml. Conclusions: Horses with DDSP showed evidence of a high prevalence of IAD and STI with an associated positive bacteriology in 55% of the cases. Even if DDSP is treated by surgery, the authors' recommendation would be to investigate the possibility of lower respiratory airway problems which may also be impacting the horse's performance and/or surgery efficiency.

Summary Reasons 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.

Any disorder impairing a performance horse's ability to ventilate its lungs and exchange oxygen compromises exercise performance in any discipline. Since bronchoalveolar lavage was described in horses in the early 1980s, laboratory evaluation of respiratory fluids, along with clinical and functional assessment of the respiratory system, has become a relevant step in the diagnosis of respiratory disease affecting performance. The aim of this review is to provide objective information to assist clinicians in interpreting laboratory findings by (1) summarising published cytological references values in both clinically healthy horses and those with various airway diseases, (2) assessing the influence of physiological circumstances, such as exercise, on the cytological evaluation, (3) discussing the relationship between cytological and microbiological analyses, clinical signs and respiratory function, and (4) suggesting how this latter relationship may affect performance.

International audience; The objectives of this study were to determine the prevalence of sub-clinical diseases in poorly-performing Standardbred horses, compare their physiological response to exercise with control horses, and identify predictive parameters of poor-performance. Fifty horses underwent thorough clinical and ancillary examinations, including haematological and biochemical evaluation, Doppler echocardiography, standardised exercise tests (SETs) on both treadmill and racetrack, treadmill video-endoscopy and collection of respiratory fluids. Most of the poorly-performing horses exhibited many concomitant diseases. The most frequently diagnosed problems involved the lower and upper respiratory tract and the musculoskeletal system. Poor-performers had lower speeds at a blood lactate (LA) concentration of 4 mmol/L (V(LA4)) and a heart rate (HR) of 200 bpm (V(200)) on treadmill and racetrack, as well as lower values for haematological parameters, plasma angiotensin-converting enzyme and antioxidants, compared to control horses. Problems of the respiratory system were the most frequently diagnosed sub-clinical diseases affecting performance. SETs, together with some blood markers, may be useful as a non-specific diagnostic tool for early detection of diseases that may affect performance.

Bovine neosporosis : from life cycle to prophylaxis. Neospora caninum is an apicomplexan parasite, identified about twenty years ago. Although it can cause neurological symptoms in newborn cattle, its main economic and health repercussion in breeding is due to abortions. The life cycle of N. caninum is not yet fully understood. Its currently identified final hosts are dogs and coyotes, but foxes are also strongly suspected. To be effective, treatment and prophylaxis must be based on sound knowledge of the life cycle and pathophysiology of this protozoosis. There is no treatment currently available. Many vaccine studies are being performed using various strategies, but only disease control methods are possible for the moment, alongside the crucial advisory role of veterinary practitioners., Le parasite N. caninum est un protozoaires identifié il y a une vingtaine d’années. Bien que l’infection par Neospora caninum puisse semanifester par des symptômes neurologiques en pathologie bovine néonatale, sa principale répercussion économique et sanitaire en élevage est due aux avortements. Son cycle parasitaire est encore imparfaitement connu. Ses hôtes définitifs actuellement identifiés avec certitude sont le chien, le coyote et le dingo, mais le renard est aussi fortement suspecté. Une bonne connaissance du cycle évolutif du parasite et de la physiopathologie de la néosporose est indispensable pour définir des méthodes de lutte efficaces. À ce jour, il n’existe pas de traitement. De nombreux essais vaccinaux sont réalisés avec différentes stratégies. Seules des méthodes de lutte sanitaire sont envisageables avec un rôle essentiel de conseil pour le vétérinaire sanitaire., Pitel Pierre-Hugues, Legrand Loïc, Pronost Stéphane, Maillard Karine, Marcillaud Christel, Richard Eric, Fortier Guillaume. Néosporose bovine: de l'étude du cycle parasitaire à la définition des méthodes de lutte. In: Bulletin de l'Académie Vétérinaire de France tome 163 n°2, 2010. pp. 131-142.

The objectives of this study were to estimate the prevalence and the potential role of equine herpesviruses (EHVs) detection in both bronchoalveolar lavage (BAL) and tracheal wash (TW). The population included a control group (CTL; 37 TW and 25 BAL) and a pathological group (PAT; 259 TW and 387 BAL), including horses either suffering from respiratory diseases including syndrome of tracheal inflammation, inflammatory airway disease, recurrent airway obstruction, or submitted to respiratory investigation because of exercise intolerance or poor performance. Each respiratory liquid was submitted to a standardised cytological analysis, mentioning the morphological abnormalities of exfoliated epithelial cells (ECAb) and ciliocytophthoria (CCPh) as markers of potential viral infection, as well as PCR assays including a consensus PCR and virus-specific PCR for both equine alphaherpesviruses (EHV-1; EHV-4) and gammaherpesviruses (EHV-2; EHV-5). The EHV infections were more prevalent in the TW of PAT group (P = 0.004), with the highest prevalence being for EHV-2 (P = 0.006). The EHV detection in BALs was not significantly different between groups. The EHVs detection in TW was correlated to the polymorphonuclear neutrophil (PMN) counts in the respiratory liquid but not with CCPh or ECAb. CCPh or ECAb were associated with both consensus PCR and EHV-2 and EHV-5 virus-type PCR in the BAL only. The significant detection of EHVs in the TW of PAT group in association with the PMN increased counts could lead to further investigations about their putative role in equine syndrome of tracheal inflammation.

International audience; In the horse, the risk of,excretion of two major equine pathogens (equine herpesvirus types 1 (EHV-1) and 4 (EHV-4,)) in semen is unknown. The objective of our study was to assess the possible risks for the horizontal transmission of equine rhinopneumonitis herpesviruses via the semen and the effect of the viruses on stallion fertility. Samples of stallion semen (n = 390) were gathered from several different sources. Examination of the semen involved the detection of viral DNA using specific PCR. The mean fertility of the stallions whose sperm tested positive for viral DNA and the mean fertility of stallions whose sperm did not contain viral DNA, were compared using the Student's t-test. EHV-4 viral DNA was not detected in any of the semen samples. EHV-1 DNA was identified in 51 of the 390 samples, (13%). One hundred and eighty-two samples came front 6 studs and there was significant difference (p < 0.05) among the proportion of stallions whose semen tested positive for viral DNA from 0 to 55% between the studs. There was a significant difference (p < 0.014) between the fertility of stallions whose semen tested positive for viral DNA and those whose semen was free from viral DNA. The stallions that excreted the EHV-1 virus in their semen appeared to be more fertile than the non-excretors, but this difference was in fact related to the breeding technique since higher proportion of excretors were found among those whose semen was used fresh rather than preserved by cooling or freezing. In conclusion, this study suggests that the EHV-1 virus may be transmitted via the semen at mating or by artificial insemination as demonstrated with other herpes viruses in other species.

International audience; The paper investigates robotic assembly by focusing on the manipulation of microparts. This task is formalized through the notion of basic tasks which are organized in a logical sequence represented by a function chart and interpreted as the model of the behavior of the experimental setup. The latter includes a robotic system, a gripping system, an imaging system, and a clean environment. The imaging system is a photon videomicroscope able to work at multiple scales. It is modelled by a linear projective model where the relation between the scale factor and the magnification or zoom is explicitly established. So, the usual visual control law is modified in order to take into account this relation. The manipulation of some silicon microparts (400 μm×400 μm×100 μm) by means of a distributed robotic system (xyθ system, ϕz system), a two-finger gripping system and a controllable zoom and focus videomicroscope shows the relevance of the concepts. The 30 % of failure rate comes mainly from the physical phenomena (electrostatic and capillary forces) instead of the accuracy of control or the occultations of microparts.

This study was designed to compare the efficacy of oral prednisolone and intramuscular (IM) dexamethasone in heaves-affected horses with environmental control. A total of 16 horses, aged 8-20years, with heaves were included in the study. Complete examinations were performed on Day 0 (before treatment), Day 13 (after treatment) and Day 30. Clinical variables, arterial blood gases, mucus scoring and carina evaluation (during endoscopy), and bronchoalveolar lavage (BAL) cytological analysis were all assessed. The horses were randomly assigned to receive either oral prednisolone (1mg/kg) or IM dexamethasone (0.1mg/kg). The animals were clinically scored and mucus accumulation evaluated. Results were analysed by repeated measures ANOVA with time (days of treatment) and treatment as the main effects. When combined with environmental control, prednisolone and dexamethasone treatments had similar effects on heaves score, blood gases and endoscopic scores. However, dexamethasone had a more beneficial effect on BAL cytology.

The 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.

International audience; The protocol describes a quantitative RT-PCR method for the detection and quantification of EHV-2 in equine respiratory fluids according to the NF U47-600 norm. After the development and first validation step, two distinct characterization steps were performed according to the AFNOR norm: (a) characterization of the qRT-PCR assay alone and (b) characterization of the whole analytical method. The validation of the whole analytical method included the portrayal of all steps between the extraction of nucleic acids and the final PCR analysis. Validation of the whole method is very important for virus detection by qRT-PCR in order to get an accurate determination of the viral genome load. Since the extraction step is the primary source of loss of biological material, it may be considered the main source of error of quantification between one protocol and another. For this reason, the AFNOR norm NF-U-47-600 recommends including the range of plasmid dilution before the extraction step. In addition, the limits of quantification depend on the source from which the virus is extracted. Viral genome load results, which are expressed in international units (IU), are easier to use in order to compare results between different laboratories. This new method of characterization of qRT-PCR should facilitate the harmonization of data presentation and interpretation between laboratories.

International audience; Horses are usually infected during the first months of life by several equine herpesviruses, such as EHV-1, EHV-4 or EHV-2. The persistence of these respiratory viruses through establishment of latency, often characterised by an absence of clinical signs, represents a real risk to the horse population. Reactivation of latent EHV could cause disease in both carriers and naive animals in contact. A better understanding of the immune response to EHV infection is necessary to improve our methods of prevention and decrease the risk of transmission. The objectives of this study were 1/ to characterise the cytokine gene expression profile of PBMC after in vitro EHV infection (EHV-1, EHV-4 and EHV-2) and 2/ To determine the efficacy of the inactivated Parapoxvirus ovis (iPPVO), a known immunomodulator in horses , against these same viruses. PBMC were isolated from 3 horses and infected in vitro with EHV-1, EHV-4 or EHV-2, in the presence or absence of iPPVO. In vitro culture of PBMC with EHV-1, EHV-4, EHV-2 and iPPVO induced a significant increase of IFN-α, IFN-β and IFN-γ gene expression. Moreover, EHV-2 induced a significant increase of IL-1β, IL-6 and TNF-α mRNA. The presence of iPPVO induced an earlier and stronger expression of IFN-α, IFN-β and IFN-γ during EHV infection. The presence of iPPVO reduced also the inflammatory response induced by EHV-2. In conclusion, this study suggests that the presence of iPPVO potentiates the development of the immune response during infection EHV in vitro.

Studies 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.

Sarcocystis neurona is considered a leading cause of equine protozoal myeloencephalitis (EPM), a common infectious neurological disease in horses in the Americas. EPM-like cases associated with S. neurona peptide reactive antibodies in Western blots were recently described in Normandy, France. In this report, antibodies reacting with S. neurona merozoites were detected using an agglutination assay at titers ranging from 50 to 500 in sera from 18/50 healthy horses from two farms with a previous EPM-like case. Higher values were found in older animals. Four out of six horses which traveled or stayed in the US exhibited titers over 50, a higher figure than in the group which did not travel out of France or stayed in an other European country. No correlation was found between anti-S. neurona and anti-Neospora sp. antibody titers. Data prompt further study of significance of anti-S. neurona antibodies in clinically healthy or diseased European horses, and identification of putative immunizing parasite(s) and their host(s).

We used radioimmunoassay (RIA) to measure monthly serum levels of unconjugated and conjugated sex steroids (testosterone T, androstenedione A, estradiol E(2), and estrone E(1)) in 4 male and 4 female foals during their first year of life. Maximal production of sex steroids was detected from April to August with hormonal peaks, corresponding to the natural breeding season in adults. In males, only A levels were more steady. Total estrogens (unconjugated plus conjugated E(2) and E(1)) were the major steroids in immature males in contrast to adults. Estrogens generally peaked in young females before males; the major estrogen was E(1), and total estrogens overtook total androgens (unconjugated and conjugated T and unconjugated A). We also sampled 3 male and 3 female foals with bone alterations in adulthood. For all animals, serum levels of four bone formation markers were obtained: osteocalcin (O), hydroxyproline (HP), and alkaline phosphatase (AP), and a radiographic score was determined. Only male foals with normal skeletal frame (good radiographic score GRS) in adulthood showed a correlation (P < 0.01) between the distribution frequency of each bone formation marker and unconjugated E(2) or E(1) levels; this finding highlighted the role of unconjugated estrogens in bone maturation in horses, since this was not found in the groups with bone alterations. In females, the threshold of estrogen synthesis and sensitivity was probably sufficient to be a nonlimiting factor at this stage of development. Our results strongly suggest a differential regulation of the estrogen/androgen balance in horses according to sex, sexual maturation, and photoperiod. Moreover, estrogens appear to be crucial for skeletal development in male colts, and these steroids are good modulators of skeletal frame characteristics in adulthood.

International audience; Equine herpesviruses (EHV) infect horses early during life and the persistence of these viruses through establishment of latency represents a real risk. A better understanding of the immune response to EHV infection is necessary to improve our methods of prevention and decrease the risk of transmission. The objectives of this study were to characterise the cytokine gene expression profile of peripheral blood mononuclear cells (PBMC) after in vitro EHV-1, EHV-4, and EHV-2 infection and to determine the efficacy of inactivated Parapoxvirus ovis (iPPVO) against these 3 viruses. PBMC were isolated from 3 horses and infected in vitro with EHV-1, EHV-4, or EHV-2 in the presence or absence of iPPVO. In vitro culture of PBMC with EHV-1, EHV-4, and iPPVO induced a significant increase of IFN-α, IFN-β, and IFN-γ gene expression. EHV-4 also triggered a significant increase of IL-6 and TNF-α mRNA. EHV-2 triggered a significant increase of IFN-α, IFN-β, IFN-γ, IL-1β, IL-6, and TNF-α mRNA. The presence of iPPVO induced an earlier and stronger expression of IFN-α, IFN-β, and IFN-γ mRNA during EHV infection and reduced the inflammatory response induced by EHV-2. In conclusion, this study suggests that the presence of iPPVO potentiates the development of the immune response to in vitro EHV infection.

This study showed that under specifically defined conditions with respect to nucleic acid extraction method and testing reagents, a previously described real-time reverse transcription-PCR (rRT-PCR) assay (T1 assay) provides sensitivity equal to or higher than that of virus isolation for the detection of equine arteritis virus in semen.

Background Multiple cytological patterns occur in bronchoalveolar lavage fluid (BALF) of horses with inflammatory airway disease (IAD). Only few data on BALF cytokine profiles are available for horses with IAD, and are limited to mRNA expression. Hypothesis/Objective Cytological profiles of IAD are associated with different BALF immunological pathways. To investigate BALF cytokine concentrations in a large number of horses with neutrophilic IAD. Animals One hundred and thirty-eight client-owned Standardbred racehorses in active training. Methods Prospective observational study. BALF samples were obtained from left and right lungs. Interleukin (IL)-4, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α concentrations were determined by ELISA. Results Fourteen horses had normal BALF cytological profiles and 56 exhibited evidence of bilateral neutrophilic IAD. Twenty-four horses showed BALF with, respectively, IAD- and CTL consistent cytology and were excluded; as were 44 horses because of evidence of pulmonary hemorrhage. TNF-α (56 ± 115 pg/mL; P = .034) and IFN-γ concentrations (104 ± 247 pg/mL; P = .044) were significantly higher for IAD horses, compared with controls (respectively 19 ± 41 and 80 ± 116 pg/mL). Horses with ‘neutrophil’ subtype had significantly higher IFN-γ concentrations (110 ± 154 pg/mL), than ‘neutrophil/metachromatic’ (56 ± 54 pg/mL; P = .028) and ‘neutrophil/metachromatic/eosinophil’ subtypes (44 ± 23 pg/mL; P = .012). Conclusions and Clinical Importance Cytokine concentrations in BALF suggested that neutrophilic IAD is associated with activation of the innate immune system and a possible T-helper (Th)-1 polarized response. This study also suggested that immunological pathways vary according to cytological IAD subtypes.

Equine herpesvirus type 1 (EHV-1) can cause respiratory disease, abortion, respiratory illness and death in neonatal foals and neurological disease in horses (Allen et al. 2004; Lunn et al. 2009). Primary infection of young foals typically results in establishment of a latent carrier state and the potential for viral reactivation during the life of the infected individual. Reactivation leads to the production of infectious virus that can be shed into the nasopharynx for a limited period of time and also result in a cell-associated viraemia, which may give rise to clinical disease and abortion in mares. Over the past decade, there has been an unexpected increase in incidence of equine herpesvirus neurological disease (equine herpesvirus myeloencephalopathy [EHM]) (Perkins et al. 2009; Vissani et al. 2009; Fritsche and Borchers 2010; Pronost et al. 2010; Smith et al. 2010). Recent studies suggest that EHM is associated with a single nucleotide polymorphism at position 2254 in the EHV-1 DNA polymerase gene (encoded by open reading frame 30 [ORF30]) (Nugent et al. 2006; Goodman et al. 2007; Perkins et al. 2009; van de Walle et al. 2009). Based on these findings, EHV-1 strains possessing guanine (G2254) at this site are considered to have neuropathogenic potential, whereas those strains with adenine (A2254) are thought to be non-neuropathogenic and usually but not invariably associated with abortion and respiratory disease in horses. The nonsynonymous A to G substitution at nucleotide position 2254 in ORF30 results in replacement of asparagine (N) with a negatively charged aspartic acid (D) residue at amino acid position 752 (N752→D752) in the viral DNA polymerase enzyme. EHV-1 strains of the G2254 genotype have been shown to replicate more efficiently in the horse and produce significantly higher viral loads (Allen and Breathnach 2006; Allen 2008). It is believed that this increased replicative capacity enhances the ability of the virus to infect capillary endothelial cells, leading to interference with the blood supply to the central nervous system and the development of neurological signs. The evidence supporting this association between the G2254 substitution and EHM is derived from nucleotide sequence analysis of a relatively small region of ORF30 (251 nucleotides [10% of the DNA polymerase gene]) from 131 field isolates of EHV-1 involving both neurological and non-neurological clinical episodes (Nugent et al. 2006) and subsequent nucleotide substitution experiments conducted using infectious EHV-1 molecular clones (Goodman et al. 2007; van de Walle et al. 2009; Ma et al. 2010). Furthermore, the recently observed increased incidence of EHM correlates with the higher prevalence of viruses with a G2254 genotype currently being isolated in diagnostic laboratories in Europe and the USA (Perkins et al. 2009; Pronost et al. 2010; Smith et al. 2010). Recently, Perkins et al. (2009) performed statistical analysis of ORF30 from a large number of EHV-1 isolates (n = 176) and demonstrated that the odds of neurological disease being associated with the ORF30 G2254 genotype are 162 times greater than those with the A2254 genotype. A comprehensive analysis of a large panel of archived EHV-1 isolates collected from sporadic cases of equine abortion between 1951 and 2006 in Kentucky using a real-time Taq-Man allelic discrimination PCR, revealed that viruses with the G2254 neuropathogenic genotype existed at least as far back as the 1950s (Smith et al. 2010). Furthermore, such isolates increased in prevalence from 3.3% in the 1960s to 14.4% in the 1990s, with indications of an even higher incidence from 2000 onwards. The studies outlined above certainly support an association between EHM and the G2254 genotype. However, there is an increasing body of very compelling evidence to indicate that this nucleotide substitution is not the only determinant of neurological disease. In the Perkins et al. (2009) survey, 24% of isolates from horses with neurological disease possessed the A2254 and not the G2254 genotype. This finding is supported by our own investigations comparing results from the real-time allelic discrimination assay with detailed case histories provided by attending veterinarians (U.B.R. Balasuriya, unpublished data; Pronost et al. 2010). We identified a number of A2254 genotype EHV-1 isolates from cases of neurological disease, as well as G2254 genotype isolates from numerous horses with no evidence of neurological involvement. In addition, we have identified viruses with nonsynonymous nucleotide substitutions in ORF30 besides A→G2254, from horses without signs of neurological disease, which presents the possibility that these may have an attenuating effect on the viral phenotype (Smith et al. 2010). Conversely, if mutations exist within ORF30 that attenuate the phenotype, there may be many other substitutions not associated with position 2254 and outside the small region included in the study of Nugent et al. (2006) with the capability of enhancing viral replication rates in vivo. This could explain, for example, why some viruses with the A2254 genotype have been isolated from cases of neurological disease. The neuropathogenic potential of such strains to this point has not been fully investigated. Furthermore, it should be emphasised that

Equine piroplasmosis is a tick-borne disease, the aetiological agents of which are either Theileria equi or Babesia caballi parasites. Piroplasmosis is commonly encountered in acute or sub-acute clinical forms although clinically recovered horses may remain asymptomatic but infected for several years. The clinical detection of such apparently healthy carrier horses (that serve as a host for subsequent infecting ticks), remains a worldwide challenge for controlling the spread of the disease. The aim of the present paper is to report on the detection of both T. equi and B. caballi by PCR in the bone marrow of naturally infected asymptomatic horses. Among 35 bone marrow samples evaluated for orthopaedic clinical research purposes, three samples from clinically healthy horses were found to be positive for T. equi , one of which was also positive for B. caballi . Even if the precise localisation of these parasites as well as the underlying mechanisms for persistence still remains unknown, one should not exclude bone marrow as a potential reservoir site for T. equi and B. caballi in infected asymptomatic horses. We suggest that, this possible localisation site (the bone marrow) should be considered as a therapeutic target when treating parasitic infection in apparently healthy horses.

During a case control study undertaken in 2006–2007, a screening and consensus polymerase chain reaction (PCR) was performed to evaluate the potential role of equid herpesviruses (EHV) in several occurrences of respiratory disorders in 661 horses. Of 785 bronchoalveolar or tracheal lavage fluid samples submitted for analysis, 20 were positive for EHV-5 DNA by sequential analysis of the consensus PCR product. Nineteen of those samples were confirmed using a specific EHV-5 PCR. No particular changes in cytological profile could be associated with the detection of EHV-5 in contrast to suggestions in previous reports of natural or experimental respiratory viral infections in horses or ponies. This is the first description of EHV-5 isolation in equine respiratory fluids in Europe, but further investigations are needed to determine the potential pathogenic role of this gammaherpesvirus in the horse.

International audience

International audience; The aim of this study was to investigate neutrophil stimulation following experimentally-induced airway inflammation in healthy horses. Six horses received dexamethasone and four were then inoculated with equid herpesvirus-2 (EHV-2). Significant neutrophilia was detected in tracheal wash and bronchoalveolar lavage fluid for up to 6 days. Concentrations of neutrophil elastase (NE) and myeloperoxidase (MPO) were significantly increased compared to baseline for up to 14 days in tracheal washes and both markers were significantly correlated with neutrophil counts. Serum levels of surfactant protein D were not significantly modified throughout the study. These results suggest that dexamethasone administration with or without EHV-2 inoculation is associated with a sustainable activation and degranulation of neutrophils in the trachea along with moderate modifications detectable in the lower airways.

International audience; The aim of this trial was to investigate the putative involvement of equid herpesvirus 2 (EHV-2) in airway inflammation of adult horses. Six horses received corticosteroid treatment, before either mock infection (n = 2) or EHV-2 strain LK4 inoculation (n = 4). These four horses were also submitted to immunosuppression 84 days post inoculation. EHV-2 was detected by quantitative PCR in respiratory samples up to respectively 21 days and 14 days. Nested PCR, cloning and sequencing allowed the detection of five different ‘field’ strains throughout the trial. Neutrophils proportions were transiently increased in respiratory fluids; neutrophilia being significantly associated with concomitant EHV-2 detection. The laboratory findings reproduced in this trial were compatible with sub-clinical lower airway inflammation and suggest that EHV-2 infection should be suspected when investigating poorly-performing horses.

International audience; The aim of this study was to determine whether the lung side being sampled would significantly influence bronchoalveolar lavage (BAL) cytological profiles and subsequent diagnosis in Standardbred racehorses. One hundred and thirty-eight French Trotters in active training and racing were included in a prospective observational study. BAL was performed using videoendoscopy in both right and left lungs during summer meetings in 2011 (64 horses) and 2012 (74 horses). Cytological data performed 24h later from right and left lungs were compared and specifically used to classify horses as affected with exercise-induced pulmonary haemorrhage (EIPH), inflammatory airway disease (IAD), or were 'controls'. For IAD, cytological definition was based on two different cut off values. Neutrophil percentages, haemosiderophage percentages and the haemosiderophage/macrophage (H/M) ratios were significantly higher in the right compared to the left lung. Measures of intra-class correlation coefficients revealed a fair agreement between left and right lungs for percentages of mast cells, eosinophils, and for the H/M ratio, and a moderate agreement for neutrophil percentages. Fair to moderate agreements were observed between left and right lungs for the diagnosis of IAD and/or EIPH based on kappa coefficients. When sampling one lung only, the risk of incorrectly classifying a horse as a 'control' increased with the use of the restraint cut-off values for IAD. As BAL from one lung is not representative of the other lung in the same horse, both lungs should be sampled for a better assessment of lung cellularity and for a precise diagnosis of lower airway diseases.

International audience