鹅高致病性禽流感病理组织学观察

本文对发生H5N1高致病性禽流感禽场的鹅进行了病理学观察，证实此场鹅禽流感在剖检上以眼结膜潮红出血；心肌条纹状坏死，条带样出血；胰腺有白垩状或透明坏死点；胃肠出血等为特征。组织学观察以非化脓性脑炎，胰腺坏死，心肌坏死，坏死性脾炎为主要病变，揭示了鹅禽流感的病理学变化特征。     

鸭H5N1型高致病性禽流感的病理组织学观察

对发生H5N1型高致病性禽流感鸭场的鸭进行了病理组织学观察。结果显示，该养鸭场患鸭禽流感病鸭的剖检变化以眼结膜潮红出血，心肌白色条纹状坏死、条带样出血，胰腺有白色或透明坏死点，胃肠出血等为特征。组织学以非化脓性脑炎、胰腺坏死、心肌坏死、坏死性脾炎的病理变化为主。     

雉鸡免疫器官组织学观察

雉鸡为环颈雉的简称,通常也叫作野鸡、山鸡等,是一种很有经济价值的禽,既可观赏,又可食用(李培合等,2005)。目前对雉鸡免疫器官的组织结构研究较少,为了探讨雉鸡脾脏、法氏囊、胸腺和盲肠扁桃体的结构特点,为雉鸡的科学饲养和繁育提供形态学依据,故而进行了本研究。     

猪弓形虫自然感染病例病理组织学观察

为探究猪弓形虫感染对猪器官组织学结构的影响,对信阳某猪场自然发病猪进行病理学诊断。处死病猪后采取肝脏组织用福尔马林固定,姬姆萨染色法进行染色。采集肺、肝、肾、淋巴结和心等组织,石蜡包埋,HE染色,光学显微镜下观察。在用姬姆萨染色的肝脏切片上能够观察到弓形虫的速殖子,分别在肺、肝、肾、脾脏、淋巴结和心脏等组织器官切片中发现弓形虫滋养体或假囊,表明该场疾病是由猪弓形虫引起的,各组织器官出现出血、炎性细胞浸润、嗜酸性粒细胞和中性粒细胞增多等病理变化。     

高致病性禽流感

禽流感是禽流行性感冒的简称,是由A型流感病毒引起的一种禽类（家禽和野禽）的传染病,又称真性鸡瘟或欧洲鸡瘟。禽流感病毒感染后可以表现为轻度的呼吸道症状、消化道症状、死亡率较低;或表现为严重的全身性、出血性、败血性症状、死亡率较高。这种症状上的不同,主要是由禽流感病毒的毒力所决定的。根据禽流感病毒致病性和毒力的不同,可以将禽流感分为高致病性禽流感、低致病性禽流感和无致病性禽流感。     

高致病性禽流感病理观察

去冬今春,在泰国、越南、日本、韩国、老挝、印度尼西亚、巴基斯坦等亚州国家和地区先后发生H5N1亚型高致病性禽流感。我国2004年1～2月份经国家禽流感参考实验室确诊,也有少量疫点。笔者在某发生疫病的禽场选择典型临床症状的禽只进行了肉眼剖检和病理组织学观察,现将结果报道     

正确对待高致病性禽流感

高致病性禽流感在禽群之间的传播主要依靠水平传播，从感染禽的气管和泄殖腔拭子分离出病毒，表明可以通过气溶胶或粪便的污染传播病毒。我国目前流行的高致病性禽流感的潜伏期很短，几乎不表现临床症状就大批发病死亡，通常，一旦家禽感染上高致病性禽流感病毒，产蛋率急剧下降，大多     

浅谈高致病性禽流感

高致病性禽流感是由A型禽流感病毒（AIV）的高致病力毒株引起的一种人兽共患的烈性传染病，禽类感染后具有“急、快、高”的特点，即发病急、传播快、发病率和病死率都很高，受到感染的鸡群常常“全军覆没”。高致病性禽流感除直接影响养禽业的发展，还影响禽类产品的安全和影响国际、国内贸易，另外还会引起严重的公共卫生问题。文章就高致病性禽流感的流行特点、临床症状、诊断及防控措施做出阐述，以便更好的防控高致病性禽流感的发生。     

浅谈高致病性禽流感的防控

简要回顾了禽流感发生的历史,介绍了禽流感的病原、流行病学、临床诊断、防疫、消毒等兽医诊断防制技术,并结合生产实践,讨论和总结了高致病性禽流感的防控措施和经验,有助于各地更好地预防、控制和扑灭禽流感疫情.     

高致病性禽流感综合症及其防控

目前．高致病性禽流感在世界各地肆虐流行．不仅使养禽业遭受毁灭性打击而且导致人员感染甚至死亡．世界各国正面临禽流感的严峻考验。因此，正确认识禽流感和加强禽流感知识的宣传提高对禽流感的认识是应对禽流感疫情的重要举措．     

Molecular and phylogenetic analysis of the H5N1 avian influenza virus caused the first highly pathogenic avian influenza outbreak in poultry in the Czech Republic in 2007

On 19th July 2007 re-occurrence of the H5N1 highly pathogenic avian influenza (HPAI) virus was noticed in Europe. The index strain of this novel H5N1 lineage was identified in the Czech Republic where it caused historically the first HPAI outbreak in commercial poultry. In the present study we performed molecular and phylogenetic analysis of the index strain of the re-emerging H5N1 virus lineage along with the Czech and the Slovak H5N1 strains collected in 2006 and established the evolutionary relationships to additional viruses circulated in Europe in 2005-2006. Our analysis revealed that the Czech and the Slovak H5N1 viruses collected during 2006 were separated into two sub-clades 2.2.1 and 2.2.2, which predominated in Europe during 2005-2006. On the contrary the newly emerged H5N1 viruses belonged to a clearly distinguishable sub-clade 2.2.3. Within the sub-clade 2.2.3 the Czech H5N1 strains showed the closest relationships to the simultaneously circulated viruses from Germany, Romania and Russia (Krasnodar) in 2007 and were further clustered with the viruses from Afghanistan and Mongolia circulated in 2006. The origin of the Czech 2007 H5N1 HPAI strains was also discussed.     

Experimental infection of chickens, ducks and quails with the highly pathogenic H5N1 avian influenza virus

Highly pathogenic avian influenza viruses (HPAIV) of the H5N1 subtype have spread since 2003 in poultry and wild birds in Asia, Europe and Africa. In Korea, the highly pathogenic H5N1 avian influenza outbreaks took place in 2003/2004, 2006/2007 and 2008. As the 2006/2007 isolates differ phylogenetically from the 2003/2004 isolates, we assessed the clinical responses of chickens, ducks and quails to intranasal inoculation of the 2006/2007 index case virus, A/chicken/Korea/IS/06. All the chickens and quails died on 3 days and 3-6 days post-inoculation (DPI), respectively, whilst the ducks only showed signs of mild depression. The uninoculated chickens and quails placed soon after with the inoculated flock died on 5.3 and 7.5 DPI, respectively. Both oropharyngeal and cloacal swabs were taken for all three species during various time intervals after inoculation. It was found that oropharyngeal swabs showed higher viral titers than in cloacal swabs applicable to all three avian species. The chickens and quails shed the virus until they died (up to 3 to 6 days after inoculation, respectively) whilst the ducks shed the virus on 2-4 DPI. The postmortem tissues collected from the chickens and quails on day 3 and days 4-5 and from clinically normal ducks that were euthanized on day 4 contained the virus. However, the ducks had significantly lower viral titers than the chickens or quails. Thus, the three avian species varied significantly in their clinical signs, mortality, tissue virus titers, and duration of virus shedding. Our observations suggest that duck and quail farms should be monitored particularly closely for the presence of HPAIV so that further virus transmission to other avian or mammalian hosts can be prevented.     

Highly pathogenic avian influenza virus subtype H5N1 in ducks in the Northern part of Cameroon

Highly pathogenic avian influenza (HPAI) virus was first detected in Cameroon in February 2006. Analysis of NA sequences of the virus demonstrated that it is closely related to the H5N1 isolates from Northern Nigeria, Sudan and Ivory Coast, suggesting a common virus ancestor.     

The first specific detection of a highly pathogenic avian influenza virus (H5N1) in Ivory Coast

The Virology Laboratory of the Central Laboratory of Animal Diseases in Ivory Coast at Bingerville received samples of wild and domestic avian species between February and December 2006. An RT-PCR technique was used to test for avian influenza (AI) and highly pathogenic AI subtype viruses. Among 2125 samples, 16 were type A positive; of which, 12 were later confirmed to be H5N1. Fifteen of these 16 type A positive samples were inoculated into the chorioallantoic cavity of 11-day-old embryonated hens' eggs for virus isolation. Eight produced virus with hemagglutination titres from 1/64 to 1/512. The 4/16 M-RT-PCR positive samples, which were H5N1 negative, were shown to be H7 subtype negative. The diagnostic efficiency of the laboratory for the surveillance of H5N1 in Ivory Coast was demonstrated. The positive cases of H5N1 were from a sparrowhawk (Accipter nisus); live market poultry and in free-range poultry, where the mortality rate was approximately 20% (2/10) and 96.7% (29/30) respectively. Currently, investigations into intensive poultry farms have proved negative for H5N1. No human cases have been reported this time.     

Surveillance for highly pathogenic avian influenza in wild birds in the USA

As part of the USA's National Strategy for Pandemic Influenza, an Interagency Strategic Plan for the Early Detection of Highly Pathogenic H5N1 Avian Influenza in Wild Migratory Birds was developed and implemented. From 1 April 2006 through 31 March 2009, 261 946 samples from wild birds and 101 457 wild bird fecal samples were collected in the USA; no highly pathogenic avian influenza was detected. The United States Department of Agriculture, and state and tribal cooperators accounted for 213 115 (81%) of the wild bird samples collected; 31, 27, 21 and 21% of the samples were collected from the Atlantic, Pacific, Central and Mississippi flyways, respectively. More than 250 species of wild birds in all 50 states were sampled. The majority of wild birds (86%) were dabbling ducks, geese, swans and shorebirds. The apparent prevalence of low pathogenic avian influenza viruses during biological years 2007 and 2008 was 9.7 and 11.0%, respectively. The apparent prevalence of H5 and H7 subtypes across all species sampled were 0.5 and 0.06%, respectively. The pooled fecal samples (n= 101 539) positive for low pathogenic avian influenza were 4.0, 6.7 and 4.7% for biological years 2006, 2007 and 2008, respectively. The highly pathogenic early detection system for wild birds developed and implemented in the USA represents the largest coordinated wildlife disease surveillance system ever conducted. This effort provided evidence that wild birds in the USA were free of highly pathogenic avian influenza virus (given the expected minimum prevalence of 0.001%) at the 99.9% confidence level during the surveillance period.     

H5N1亚型禽流感变异株灭活疫苗种毒Re-4株的生物学特性及免疫原性研究

本实验对经反向遗传方法构建的重组禽流感H5N1亚型变异株灭活疫苗种毒Re-4株的生物学特性及免疫效力进行研究.将Re-4株接种SPF鸡胚后37℃培养72 h,鸡胚存活,无病变,HA滴度达29;以0.1 mL(106.0EID50/0.1 mE)的剂量鼻腔感染4周龄SPF鸡7 d后血清HI抗体转阳,无任何症状,也不排毒;SPF鸡静脉致病指数(IVPI)为0;以Re-4重组株为种毒制备灭活疫苗,免疫SPF鸡后,3周后平均HI抗体效价达8.75 log2:免疫鸡对亲本强毒株CKSX/06,以及变异株CKNX/06和流行株GSGD/96攻击提供完全保护.以上结果表明变异株灭活疫苗种毒Re-4株对SPF鸡胚和SPF鸡无致病性、适合鸡胚增殖、抗原针对性强,并且以该毒株制备的灭活疫苗具有良好的免疫效力,是研制预防H5N1亚型禽流感病毒山西变异株的理想疫苗种毒株.     

Isolation and characterization of influenza A virus (subtype H5N1) that caused the first highly pathogenic avian influenza outbreak in chicken in Bhutan

We characterized Influenza A/H5N1 virus that caused the first outbreak of highly pathogenic avian influenza (HPAI) in chickens in Bhutan in 2010. The virus was highly virulent to chicken, killing them within two days of the experimental inoculation with an intravenous pathogenicity index (IVPI) of 2.88. For genetic and phylogenetic analyses, complete genome sequencing of 4 viral isolates was carried out. The isolates revealed multiple basic amino acids at their hemagglutinin (HA) cleavage site, similar to other "Qinghai-like" H5N1 isolates. The receptor-binding site of HA molecule contained avian-like amino acids ((222)Q and (224)G). The isolates also contained amino acid residue K at position 627 of the PB2 protein, and other markers in NS 1 and PB1 proteins, highlighting the risk to mammals. However, the isolates were sensitive to influenza drugs presently available in the market. The sequence analysis indicated that the Bhutan viruses shared 99.1-100% nucleotide homology in all the eight genes among themselves and 2010 chicken isolate from Bangladesh (A/chicken/Bangladesh/1151-11/2010) indicating common progenitor virus. The phylogenetic analysis indicated that the Bhutan isolates belonged to sub-clade 2.2.3 (EMA 3) and shared common progenitor virus with the 2010 Bangladesh virus. Based on the evidence of phylogeny and molecular markers, it could be concluded that the outbreaks in Bhutan and Bangladesh in 2010 were due to independent introductions of the virus probably through migratory birds.     

禽流感病毒H5N1亚型NS1蛋白的真核表达及其在细胞中的分布

为构建禽流感病毒(AIV) H5N1亚型非结构蛋白NS1的真核表达载体,并鉴定其在哺乳动物细胞中的表达与分布,本研究采用RT-PCR技术,从甲型流感病毒的总RNA中扩增NS1全长基因,并将其克隆于pXJ40中,构建真核表达载体pXJ40-HA-NSl.将该重组质粒转染293T细胞,通过western blot方法鉴定表达的NS1蛋白;并以免疫荧光技术观察NS1在H1299细胞中的分布与定位.Western blot结果显示NS1基因编码蛋白获得表达,免疫荧光检测显示NS1蛋白主要存在于细胞核中.本研究为NS1蛋白功能和H5N1亚型AIV致病机制的研究奠定了基础.     

禽流感病毒RT-PCR及多重RT-PCR检测技术的建立

研究建立了禽流感病毒（AIV）A型、H5、N1、H9、N2亚型特异性RT-PCR及HS／N1、H9／N2、A／H5／Nl多重RT-PCR检测技术，用于检测或同时检测和鉴别A型及H5N1、H9N2亚型AIV。所建立的RT-PCR和多重RT-PCR从核酸提取、基因扩增到产物分析在3～4h内即可完成，经对36株AIV及相关病毒分离物检测，与病毒分离鉴定的结果完全一致，且与相关病毒或其他亚型无交叉反应。采用多重RT-PCR检测80份棉拭子样品，并与病毒分离鉴定方法比较，二者H5N1、H9N2亚型的鉴定结果完全吻合。结果表明，该方法具有快速、敏感、特异等优点，为临诊样品中AIV型及H5N1、H9N2亚型鉴定和诊断的有效方法。