宁远县小反刍兽疫流行病学调查

对湖南省宁远县保安镇某羊场调入的黑山羊疑似小反刍兽疫疫情进行了流行病学调查。结果表明,引起该疫情的为输入性小反刍兽疫,来源追踪显示病羊来自Y省某活羊交易市场,该起疫情向周围羊场扩散的风险很低。     

一起绵羊小反刍兽疫疫情的紧急流行病学调查

2014年1月,甘肃省古浪县黄花滩乡黄花滩村移民区养殖小区发生了一起小反刍兽疫可疑疫情。通过流行病学调查和实验室检测,证实该起疫情为小反刍兽疫。经疫源追踪调查分析,判定该起疫情是由羊只贩运人员携带病原进入小区引起的。本文综合分析了该起疫情的发生背景、病例定义、溯源调查、干预措施等,提出了在养殖小区建设、综合管理、疫病防疫等方面的对策建议。     

辽宁省一起小反刍兽疫疫情的紧急流行病学调查

2020年5月15日,辽宁省抚顺市清原县动物疫病预防控制中心报告,该县某养羊户发生山羊急性发病,且死亡率较高;5月16日,经市级专家组现场临床诊断和省级实验室复核,诊断为疑似小反刍兽疫疫情,经国家小反刍兽疫参考实验室检测,确诊为小反刍兽疫。5月18日,农业农村部公布了该起疫情。为追溯疫情可能来源,分析疫情扩散风险,科学指导疫情处置工作,开展了紧急流行病学调查。现场调查结果显示,该起疫情的袭击率为72.7%（136/187）,病死率为55.9%（76/136）。溯源调查表明,疫情由羊贩运人及其运输车辆带毒传入和外购未经检疫羔羊带毒传入的风险较大,新生或外购羔羊未及时免疫小反刍兽疫疫苗是内在风险因素;追踪调查结果显示,疫情局限于该养羊户,向外扩散的风险较低。本起疫情提示,应做好养殖场区内的生物安全综合防控,重点加强相关人员及运输车辆、工具的移动控制,及时做好羔羊的疫苗免疫,降低疫情发生风险。     

辽宁省一起输入性小反刍兽疫紧急流行病学调查

2014年3月9-17日,辽宁省北镇市和黑山县的两个养羊户发生小反刍兽疫,为了解疫情来源并评估疫点向外传播疫病的风险,开展本次调查。调查发现本次发病局限于2户羊群中,在总共67只羊中检出24只PPR疑似病例,其中11只死亡。经临床和实验室诊断,该起疫情被确定为输入性小反刍兽疫;来源追踪分析显示发病羊来自S省某活羊交易市场;扩散风险评估结果表明,该起疫情向周围羊场扩散的风险较低。     

2018—2019年山东省小反刍兽疫专项流行病学调查

为全面掌握山东省小反刍兽疫的病原分布和免疫效果，按照《山东省动物疫病监测与流行病学调查实施方案》，分别于2018年 和2019年，通过问卷调查结合实验室检测，在全省开展了小反刍兽疫专项流行病学调查。结果显示：2018—2019年山东省小反刍兽疫免疫抗体合格率均在80%以上，达到了国家和省级的要求，抗体水平平稳（χ2=0.003，P=0.956 32，P>0.05）；病原学检测均未发现阳性样品。问卷统计结果显示：疫病方面，目前养羊场以细菌性疾病感染为主，没有发现小反刍兽疫疫情；饲养场（户）基本能够做到调入羊只的隔离、检疫，以及养殖场的定期消毒。结果表明，山东省羊群的小反刍兽疫免疫保护水平较高，防控措施执行较为到位，防控形势比较理想。今后需持续开展小反刍兽疫专项流行病学调查，从而为今后小反刍兽疫免疫政策的制定和强制免疫退出提供数据支撑。     

浦东新区羊小反刍兽疫流行病学调查

2018年下半年和2019年上半年上海浦东新区兽医实验室对各乡镇规模羊场及散养户进行羊小反刍兽疫的血清学和病原学调查,血清抗体检测采用ELISA方法,病毒检测采用荧光RT-PCR方法。2018年下半年共采集血清样品833份,抗体阳性数750份,抗体阳性率为90.03%;采集口鼻棉拭子样品356份,检测结果全为阴性。2019年上半年共采集血清样品471份,抗体阳性数432份,抗体阳性率91.72%;采集口鼻棉拭子样品171份,检测结果全为阴性。羊小反刍兽疫的免疫抗体平均阳性率90.64%,病原学检测结果为阴性。通过本次调查,得知上海浦东新区羊小反刍兽疫的免疫状况比较良好,发生该疫病的风险比较低,同时为评估该区羊小反刍兽疫的防控状况提供了科学依据。     

云南西双版纳州羊小反刍兽疫流行病学调查

为了解云南省西双版纳州羊小反刍兽疫免疫效果及病原学流行情况,应用酶联免疫吸附试验对采自该州3个县(市)的789份羊血清进行免疫抗体检测,同时应用反转录-聚合酶链反应对242份羊眼结膜拭子进行病原学检测。结果表明,该州规模养殖场和散养户养殖羊的小反刍兽疫免疫抗体合格率分别为74.44%、81.98%,均超过农业部规定的最低标准;病原学检测均为阴性。说明该州养殖羊小反刍兽疫免疫效果良好,发生疫情的风险较低,但需要加强对规模场羊群的免疫管理。     

一例输入性小反刍兽疫疫情流行病学的调查分析

2014年4月,云南省某县发生不明山羊疫情,经国家外来动物疫病研究中心确诊为小反刍兽疫。为调查该县小反刍兽疫疫情的感染来源,开展了疫情排查、疫源调查、临床症状、病理解剖等流行病学调查分析,以期对小反刍兽疫疫情防控提供参考。     

双抗体夹心ELISA检测小反刍兽疫病毒抗原方法的建立及病原流行病学调查

应用表达纯化的小反刍兽疫病毒(peste des petits ruminants virus,PPRV)N蛋白制备的多克隆抗体,建立了检测PPRV抗原的双抗体夹心ELISA方法,并对吉林省和内蒙古地区羊群感染PPRV进行了调查。方阵法确定了抗PPRV兔源IgG作为捕获抗体的包被量为0.2μg,酶标抗体的最佳稀释度为1∶1 000。对大量小反刍兽疫阴性粪便样品进行检测及统计学处理,确定了双抗体夹心ELISA检测PPRV的判定标准,即被检粪便样品D490≥0.221,判定为阳性。特异性、敏感性等试验结果表明,建立的检测PPRV抗原方法具有特异、敏感和快速等优点。与RT-PCR方法相比,该方法省时省力、简单快速。应用建立的检测PPRV抗原的双抗体夹心ELISA对吉林省和内蒙古不同地区的羊粪样进行检测,发现羊群均存在程度不同的PPRV隐性感染。本研究在国内首次揭示出临床健康羊群携带PPRV,为今后小反刍兽疫的诊断与防控提供了新的流行病学理论依据。     

小反刍兽疫流行病学调查及防控措施

小反刍兽疫（又名小反刍兽伪牛瘟）是由小反刍兽疫病毒引起的一种急性高度接触性传染性疾病。世界动物卫生组织,将该病定为A类疾病。其特征是发病急剧,高热稽留,眼鼻分泌物增加。口腔糜烂,腹泻和肺炎,本病主要感染山羊和绵羊。     

Pathogenicity of attenuated peste des petits ruminants virus in sheep and goats

Progressive loss of virulence for goat kids was noticed when peste des petits ruminants (PPR) virus was passaged in Vero cells. While goats inoculated with the 60th passage suffered from the clinical PPR disease and mortality, goats inoculated with the 80th passage did not show any sign of the disease. If the progressive loss of virulence of the virus with passage continues, it will not be long before a homologous PPR vaccine will be obtained at the National Veterinary Institute, Vom.     

The isolation of peste des petits ruminants virus from Nigerian sheep and goats.

Four isolates of peste des petits ruminants virus were obtained from sick Nigerian sheep and goats. One was identical antigenically with the prototype Senegalese strain. A cross relationship was found between peste des petits ruminants virus and rinderpest virus based on neutralisation in vitro.     

Prevalence of peste des petits ruminants among sheep and goats in India

This study measured the clinical prevalence of peste des petits ruminants (PPR) among sheep and goats in India between 2003 and 2009 by analyzing clinical samples from suspected cases of PPR that were submitted to the Rinderpest and Allied Disease Laboratory, Division of Virology, IVRI, Mukteswar for PPR diagnosis. PPR outbreaks were confirmed by detecting PPR virus (PPRV)-specific antigen in the clinical samples. Clinical samples (blood, nasal swabs, spleen, lymph node, kidney, liver, intestine, and pooled tissue materials) were taken from a total of 592 sheep and 912 goats in different states of India and screened for the presence of PPRV antigen using a monoclonal antibody-based sandwich ELISA kit. A total of 20, 38, and 11 laboratory-confirmed PPR outbreaks occurred among sheep, goat, and combined sheep and goat populations, respectively. Our findings provide evidence of widespread PPR endemicity in India. The underlying reasons could be variations in husbandry practices in different geographical regions, agro-climatic conditions, and livestock migration. Furthermore, decrease in the number of PPR outbreaks over time might be due to the effectiveness of current live PPR vaccines and timely vaccination of target species. Vaccination against PPR has been practiced in India since 2002 to control this disease.     

Experimental peste des petits ruminants (goat plague) in goats and sheep.

In order to study the pathomorphology and immunohistochemistry of peste des petits ruminants, four goats and two sheep were inoculated intranasally with the Malig-Yemen strain of peste des petits ruminants virus. The animals developed fever, nasal discharge, oral erosions, cough and diarrhea. One goat and one sheep died and one moribund goat was killed. Three animals survived the infection. At necropsy, erosive stomatitis, pneumonia and gastroenteritis were found. Histopathologically the pneumonocytes and epithelial cells of the ileum had eosinophilic cytoplasmic and nuclear inclusions. By an indirect immunoperoxidase method, the nuclei and cytoplasm of the ileal epithelial cells of one goat contained positively (brown) stained antigen, which corresponded to viral nucleocapsids by electron microscopy. Virus appeared to be released through the microvilli of the epithelial cells. We also confirmed the formation of giant cells due to peste des petits ruminants virus.     

Pathogenicity of peste des petits ruminants virus isolated from Egyptian goats in Egypt

2 Egyptian goats and Boscat rabbits were experimentally inoculated with peste des petits ruminants (PPR) local Egyptian strain (PPR, Egypt 87). The inoculated animals contracted the disease with minor clinical manifestations, accompanied by rise of neutralizing antibodies to PPR virus. Virus was isolated from ocular and nasal secretions, buffy coat, spleen, and liver. No contact infection was observed between inoculated and healthy goats.     

Pathological and immunohistochemical study of experimental peste des petits ruminants virus infection in goats

Peste des petits ruminants (PPR) is an emerging, economically important viral disease of goats and sheep in the Indian subcontinent. In the present investigation, 15 hill goats were experimentally infected with 2 ml of 10% splenic suspension of a virulent isolate of PPR virus (PPR/Izatnagar/94) that had caused heavy mortality (>75%) in goats during 1994 outbreaks in northern India. More than 86% (13 of 15) animals died between 9 and 13 days post inoculation at the height of temperature or when temperatures were declining. Necropsy findings included congestion of gastrointestinal tract (GIT), nasal sinuses, consolidation of antero-ventral lobes of lungs, engorged spleen, and occasionally oedematous lymph nodes. Histopathological examination of major organs of GIT revealed degeneration and necrosis of labial mucosa, severe mucosal and submucosal congestion, degeneration and necrosis of intestinal epithelium and lymphoid cell depletion from Peyer's patches along with presence of syncytia at times. Lungs showed broncho-interstitial changes and presence of intracytoplasmic and intranuclear eosinophilic inclusions in alveolar macrophages and syncytial cells. These changes in lungs were frequently complicated with serofibrinous pneumonia (57%, eight of 14). Lymphocytolysis and occasional syncytia formation were evident in the lymphoid tissues. Immunohistochemical (IHC) findings included presence of PPR virus antigen in the labial, intestinal, and bronchiolar epithelial cells, pneumocytes, macrophages and syncytial cells in lungs, and lymphoid (intact and necrotic) and reticular cells in lymphoid organs. The findings of the study indicated the highly virulent nature of the PPR virus isolate (PPR/Izatnagar/94), causing 100% mortality and characteristic pathological changes in the target organs such as lungs, intestines and lymphoid tissues. The results of the IHC study suggested that indirect immunoperoxidase could be an alternative method in the absence of more sophisticated methods of laboratory diagnosis of PPR virus infection in goats.