马疱疹病毒1型感染马疾病模型的建立及评价

Establishment and Evaluation of Equine Herpesvirus Type 1 Infection Equine Disease Model

试验旨在建立马疱疹病毒1型(Equine herpesvirus type1,EHV-1)人工发病模型,确定EHV-1感染马的半数感染量(ID_(50))及感染发病的判定标准,为该病的预防与治疗药物的研发奠定基础。以新疆伊犁地区某发病马场流产胎儿中分离的EHV-1 XJ2015株为研究对象,设立4组不同病毒剂量感染组及对照组,经鼻内喷雾感染马,5 mL/匹,每天观察试验马的临床症状和发病情况,14 d后进行剖检,观察各组织脏器病理变化并应用实时荧光定量PCR方法检测鼻腔排毒及病毒分布情况。结果显示,EHV-1 XJ2015株感染马的ID_(50)为10^(-6.67)/5 mL,其病毒含量为104.33 TCID_(50)/mL。与对照组相比,1×10^(6)和1×10^(5)TCID_(50)/mL感染组马临床评分显著升高,主要表现为体温升高(高达39.5℃,一般持续2~6 d)、食欲不振、流浆液性鼻液和下颌淋巴结肿大;且1×10^(6)和1×10^(5)TCID_(50)/mL感染组试验马均表现出不同程度的排毒,肺脏及脑组织中可检测出大量病毒,与对照组相比极显著或显著升高(P<0.01;P<0.05);病理学检查发现,患马脑组织出现非化脓性脑炎及神经元水肿,肺脏组织出现间质性肺炎、嗜中性粒细胞、炎性细胞浸润、出血和肺泡间隔增厚。以上结果表明,EHV-1 XJ2015株对马具有较强的致病性,患病马临床症状典型,病毒主要随鼻液排出,并富集在肺脏及脑组织,通过上述指标确定EHV-1感染马发病的判定标准,本试验成功建立EHV-1感染本体动物疾病模型。

This study was aimed to establish the artificial disease model of Equine herpesvirus type 1(EHV-1),and confirm the half infective dose(ID_(50))of equine infected with EHV-1 and the criteria for determining the incidence of infection,and lay the foundation for prevention of the disease and therapeutic drugs.Taking EHV-1 XJ2015 strain isolated from the aborted fetuses of a racetrack in Yili area of Xinjiang as the research object,4 groups of different virus dose challenge and control group were set up,and 5 mL of virus was sprayed into each horse’s nasal cavity.The clinical symptoms and pathogenesis of the horses were observed every day.14 days later,the pathological changes of tissues and organs were observed and the nasal detoxification and virus distribution were detected by Real-time PCR method.The results showed that the ID_(50)of EHV-1 XJ2015 strain was 10^(-6.67)/5 mL for the horse,and the virus content was 104.33 TCID_(50)/mL.Compared with control group,the clinical scores of horses in 1×10^(6)and 1×10^(5)TCID_(50)/mL challenge groups increased significantly,high body temperature(up to 39.5℃,generally lasting for 2-6 days),loss of appetite,fluid nasal and mandibular lymphadenopathy.And the test horses in 1×10^(6)and 1×10^(5)TCID_(50)/mL challenge groups showed different levels of detoxification,a large number of viruses could be detected in the lung and brain tissues compared with control group(P<0.01;P<0.05).Histopathological examination revealed non-suppurative encephalitis and neuronal edema in the brain tissue of the horse,interstitial pneumonia,neutrophils,inflammatory cell infiltration,hemorrhage,and alveolar septal thickening occur in lung tissue.The above results showed that EHV-1 XJ2015 strain had strong pathogenicity to horses,the clinical symptoms of diseased horses were typical,the virus was mainly excreted with nasal fluid,and enriched in lung and brain tissue,and the criteria of EHV-1 infection in horses could be determined through the above indexes.The disease model of EHV-1 infected animals was successfully established in this experiment.