Littérature scientifique sur le sujet « Equine rhinopneumonitis »

Equine rhinopneumonitis is an acute, highly contagious disease found virtually worldwide. The object of the studies was the AK-2011 strain isolated from the horses suffering from rhinopneumonitis during an outbreak of abortions. The viability of the AK-2011 strain was assessed using a continuous line of calf trachea cells, a continuous line of calf kidney cells, a continuous line of sheep kidney cells, a continuous line of bovine kidney cells, a continuous line of green monkey kidney cells, a continuous line of Syrian hamster kidney cells, a primary trypsinized culture of horse kidney cells grown in tubes and flasks, and the AK-2011 laboratory strain of equine rhinopneumonitis virus with biological activity of 6.0 lg TCID50/cm3. Sequencing and polymerase chain reaction (PCR) analysis were performed. The virus isolated from the ORF68 gene in Kazakhstan appeared to be the most similar to the T-953 and 2222-03 strains isolated in the USA and Australia, respectively, in terms of phylogenetics. As to primary infections, cytopathic effects (CPE) induced by the AK-2011 virus stain (dilution 101) in calf trachea and horse kidney cell cultures were stable from the 1st to 10th passages, with biological activity of 5.75-6.00 lg TCID50/cm3. CPE caused by the virus were apparent on days 2-3, further developed intensively, and extended to 60-80% of the cell monolayer on days 5-7. In calf kidney, sheep kidney, green monkey kidney, and bovine kidney cell cultures, the same changes were observed 1-2 days later. The changes were slow, and by day 7-10 CPE extended to no more than 30-50% of ​​the cell monolayer. An attenuated strain AK-2011 of equine rhinopneumonitis virus was obtained. It was considered a candidate for the manufacture of a vaccine for equine rhinopneumonitis. Thus, the attenuated strain AK-2011 of the equine rhinopneumonitis virus was characterized.

В статье представлены современные сведения о герпесвирусах, вызывающих ринопневмонию у лошадей. Приводятся данные о клинических проявлениях болезни, методах диагностики и вакцинопрофилактики. Приведены результаты серологических исследований в ИФА поголовья лошадей Алматинской области - найдены антитела как к EHV-1, так и к EHV-4. Разработанная тест-система для ПЦР позволяет эффективно диагностировать ринопневмонию у лошадей в коневодческих хозяйствах Казахстана. Полногеномное секвенирование местного штамма EHV-1 показало изменения в геноме после аттенуирования штамма методом многократных пассажей в культуре клеток. Contemporary data on equine herpesviruses causing rhinopneumonitis in horses are present in this paper. Data on clinical manifestations, methods of diagnosing and vaccine prophylaxis are given. The results of serological studies of the population of horses in the Almaty region in ELISA are presented - antibodies were found both to EHV-1 and EHV-4. The developed PCR makes it possible to effectively diagnose rhinopneumonitis in horse breeding farms in Kazakhstan. Whole genome sequencing of the local strain EHV-1 showed changes in the genome after strain attenuation after multiple passages in cell culture.

Equine alphaherpesviruses ― causative agents of rhinopneumonitis−viral abortion (EHV-1) and rhinopneumonitis (EHV-4) ― represent the subfamily Alphaherpesvirinae, genus Varicellovirus. EHV-1 causes abortion, respiratory pathology, and neurological disorders in horses of different ages. EHV-4 causes predominantly respiratory disease in foals and sporadic abortions in mares. In the etiopathogenesis of herpesvirus infections EHV-1 and EHV-4, the determining factors are pronounced tropism to epithelial cells, persistence in a non-replicative form, and unpredictable reactivation of a persistent virus with its release into the environment. EHV-1 and EHV-4 have similar antigenic determinants and cross-react in serological reactions. The high level of antigenic relationship between EHV-1 and EHV-4 can make it difficult to interpret serologic results in natural infections. The EHV-1 and EHV-4 strains in active circulation are genetically rather conservative. The exception is the new EHV-1 strains with a mutation in the gene encoding viral DNA polymerase, which caused outbreaks of neuroparalytic disease in some European countries and the United States. In several cases, the neurological syndrome has been reported due to use of some commercial vaccines

Dez cavalos adultos clinicamente saudáveis foram inoculados por via intranasal com a estirpe A4/72 do herpesvírus eqüino tipo 1 (HVE-1). Com o intuito de estudar o efeito da dose infectante na severidade da rinopneumonite, os animais foram distribuídos em dois grupos experimentais: (a) grupo I (106,6 DICT50) e (b) grupo II (5×106,6 DICT50). Nos primeiros dez dias após a inoculação viral, todos os cavalos apresentaram manifestações de infecção respiratória leve e restrita às vias aéreas anteriores. Poucos animais desenvolveram leucopenia sangüínea envolvendo linfócitos (n=4) e neutrófilos (n=2). Somente em um houve aumento na contagem dos neutrófilos no lavado broncoalveolar (LBA). Apesar de possuírem elevados títulos de anticorpos neutralizantes antes da inoculação, alguns cavalos apresentaram soroconversão após o desafio viral. Esse padrão de resposta humoral foi determinado pelo aumento da dose infectante. O HVE-1 não foi isolado a partir das secreções nasais de nenhum animal. Entretanto, o DNA viral foi detectado pela reação em cadeia pela polimerase (PCR) nas células mononucleares sangüíneas entre o terceiro e o oitavo dias pós-inoculação (d.p.i.) em todos os animais, indicando a ocorrência de viremia. Além disso, a prova de PCR detectou o vírus nas amostras de LBA a partir do nono d.p.i. no grupo II, demonstrando que a disseminação do HVE-1 pelo trato respiratório após o desafio viral foi dose-dependente. Com base nos resultados obtidos, foi possível concluir que a PCR é uma técnica com alta sensibilidade para o diagnóstico do HVE-1, capaz de detectar a presença do DNA viral mesmo quando não ocorre a constatação do agente pelos métodos tradicionais
Ten clinically healthy adult horses were inoculated intranasally with the A4/72 strain of equine herpesvirus 1 (EHV-1). The animals were divided into two experimental groups in order to study the influence of the infective dose in the severity of rhinopneumonitis: (a) group I (106,6 TCID50) and (b) group II (5×106,6 DICT50). In the first ten days after the inoculation, they showed signs of a mild, self-limiting upper respiratory tract infection. Very few animals developed transient blood leukopenia, involving lymphocytes (n=4) as well as neutrophils (n=2). Only one horse had an increase in the neutrophils count of the bronchoalveolar lavage (BAL) samples. In spite of the presence of neutralizing antibodies before the trial, seroconversion was observed in some horses. The pattern of antibody response was determined by the increase of the challenge exposure. The virus was not isolated from nasal swabs of any horse. However, the EHV-1 was detected through the polymerase chain reaction (PCR) from peripheral blood mononuclear cells (PBMC) of all horses in the experiment within the third to the eighth day after the inoculation that illustrated the viremia. In addition, the PCR assay also detected the virus in BAL samples starting on the ninth day after the experimental infection of group II. For that reason, the dissemination of the EHV-1 throughout the respiratory tract after virus exposure was dose-dependent. Based on the results obtained from this study, it can be affirmed that the PCR is a highly effective technique in detecting the EHV-1. It may be used in circumstances where traditional methods are not efficient due to the fact that it provides an enhanced diagnostic procedure for underdiagnosed diseases

Jusqu’en 1981, l’herpèsvirus équin 4 (HVE-4) et l’HVE-1, responsables de la rhinopneumonie, étaient considérés comme deux sous-types d’un même virus. Il a depuis été démontré que l’HVE-4 était très peu impliqué dans les avortements et son implication dans la forme nerveuse de la maladie n’est pas démontrée à ce jour. C’est probablement la raison qui fait que ce virus est moins étudié que l’HVE-1. Ce travail de thèse a porté sur trois aspects importants de la rhinopneumonie chez le cheval afin d’apporter de la connaissance sur l’HVE-4 et d’évaluer l’intérêt d’utiliser ce virus comme modèle. Nous avons pu démontrer en comparant deux épizooties dans deux haras au profil vaccinal différents et en mesurant l’excrétion d’HVE-4 et la virémie par qPCR, l’apparition de séroconversions, l’intérêt de la vaccination. Si la contamination se fait essentiellement par contact, l’impact de la survie du virus dans l’environnement doit être étudiée. Nous avons montré que l’HVE-4 pouvait survivre au moins 28 jours à 4°C dans l’eau mais également sur différentes surfaces. Nous avons aussi développé une méthode d’integrity-PCR pour différencier les virus infectieux des virus non infectieux. Enfin, nous avons criblé un nombre de molécules importants par RTCA et démontré l’efficacité de plusieurs d’entre elles dont la décitabine pour laquelle nous avons réalisé une étude préliminaire du mode d’action par une analyse transcriptomique
Until 1981, equine herpesvirus 4 (EHV-4) and EHV-1, which cause rhinopneumonitis, were considered to be two subtypes of the same virus. Since then, it has been shown that EHV-4 is only marginally involved in abortions, and its involvement in the nervous form of the disease has not yet been demonstrated. This is probably why this virus is less studied than HVE-1. This thesis focused on three important aspects of rhinopneumonitis in horses in order to gain a better understanding of EHV 4 and to assess the value of using this virus as a model. By comparing two epizootics at two stud farms with different vaccination profiles and measuring EHV-4 excretion and viremia by qPCR, we were able to demonstrate the benefits of vaccination and the appearance of seroconversions. Although contamination occurs mainly through contact, the impact of the virus's survival in the environment needs to be studied. We have shown that EHV-4 can survive for at least 28 days at 4 °C in water and on various surfaces. We have also developed an integrity-PCR method to differentiate between infectious and non-infectious viruses. Finally, we have screened a number of compounds using RTCA and demonstrated the efficacy of several of them, including decitabine, for which we have carried out a preliminary study of the mode of action using transcriptomic analysis

This expanded abstract addresses the importance of health management in Veterinary Medicine, emphasizing vaccine prophylaxis and deworming in horses, cattle, dogs and cats. Health management aims to prevent diseases such as Equine Influenza, Encephalomyelitis, Tetanus, Rhinopneumonitis, Rabies and Leptospirosis, which are relevant to public healthand the efficiency of treatments