Antibody response of kori bustards (Ardeotis kori) and houbara bustards (Chlamydotis undulata) to live and inactivated Newcastle disease vaccines.

Adult houbara bustards (Chlamydotis undulata) and juvenile kori bustards (Ardeotis kori) were given four regimens of commercially available inactivated and live poultry paramyxovirus type 1 (PMV-1) vaccines. Immunologic response to vaccination was assessed by hemagglutination inhibition assay of serum. Kori bustards, to which a dose of 0.5 ml of a commercially available inactivated vaccine for poultry had been administered intramuscularly (0.15 ml/kg body weight), failed to develop hemagglutinating antibodies, but antibody titers of low intensity and duration were detected following administration of a second and third subcutaneous dose of 2.0 ml vaccine per bird (0.40-0.45 ml/kg). In subsequent trials, when inactivated vaccine was administered subcutaneously at 1.0 ml/kg body weight following two or four live vaccinations administered by the ocular route, juvenile kori bustards developed higher, more persistent titers of antibodies. Kori bustards given four live vaccinations followed by inactivated vaccine developed higher titers of longer duration compared with kori bustards given two live vaccines followed by inactivated vaccine. Antibody titers of kori bustards given inactivated vaccine were higher and more persistent than the antibody response to live vaccination. Houbara bustards, previously vaccinated with inactivated vaccine, that were given a booster dose of inactivated vaccine maintained high mean antibody titers (> or = log, 5) for 52 wk. The authors recommend that inactivated PMV-1 vaccine should be administered by subcutaneous injection of 1.0 ml/kg vaccine to bustards. Adult bustards, previously vaccinated with inactivated vaccine, should be vaccinated annually with inactivated vaccine. Juvenile bustards should receive a second dose of inactivated vaccine 4-6 mo after the first dose of inactivated vaccine. Even though inactivated PMV-1 vaccines induced hemagglutination inhibition antibodies and produced no adverse reactions, further studies will be required to determine the protective efficacy of the antibody.     

A型禽流感病毒核蛋白研究进展

A型禽流感是禽类的重要疾病之一。近年来,随着分子生物学的研究深入,对A型禽流感病毒核蛋白的研究也取得了显著的进展,本文概要综述了A型禽流感病毒核蛋白在诊断A型禽流感方面的研究进展。     

禽流感病毒分子生物学的研究进展

禽流行性感冒(av ian in fluenza,A I,简称禽流感)是由A型禽流感病毒(av ian in fluenza v irus,A IV)引起的禽类烈性传染病。作为被世界动物卫生组织(O IE)定为A类的传染病,A I不仅给世界养禽业造成了巨大的经济损失,而且对人类健康和生命安全构成了严重威胁。因此,A I已经成为人们关注的焦点,国内外学者也对其进行了大量研究。作者从病原基因组及其编码的蛋白质、致病力、变异性以及对人类感染A IV的分子机制等角度就A IV的分子生物学研究作一综述,为防制A I提供理论基础,并在此基础上探讨了人类禽流感的防治措施,加深人们对A I的认识。     

Host range of avian influenza virus in free-living birds

Isolation of avian influenza virus (AIV) has been reported from 12 orders and 88 species of free-living birds. Most isolations are reported from species in the orders Anseriformes and Charadriiformes and it is recognized that species in Anseriformes represent important reservoirs of AIV. Morbidity and mortality among free-living birds attributable to AIV infection are rare, but differences in prevalence of AIV occur within and between avian species. Seasonal variation has been reported from free-living and sentinel ducks with peak AIV infection occurring in late summer and early fall. Prevalence of AIV is age-related, with highest isolation rates reported from juvenile birds. Differences in susceptibility to AIV infection among species have been demonstrated under experimental conditions. The dynamics and epidemiology of species-related variation in populations of free-living birds require further study.     

Bacterial flora of the conjunctiva and nasal cavity in normal and diseased captive bustards.

A survey was carried out to describe the normal aerobic bacterial flora of the conjunctiva and nasal cavity of captive houbara bustards (Chlamydotis undulata), kori bustards (Ardeotis kori), and white-bellied bustards (Eupodotis senegalensis) maintained at the National Avian Research Center, Abu Dhabi, United Arab Emirates. A total of 58 samples were examined from the nasal cavity and 55 samples from the conjunctiva of healthy bustards. There was no bacterial growth in 45% of conjunctival samples. Bacteria isolated from the conjunctiva of healthy birds included Micrococcus spp., Staphylococcus auricularis, Staphylococcus xylosus, Staphylococcus capitis, Staphylococcus warneri, Bacillus spp., and Enterobacter amigenus. Bacteria isolated from the nasal cavity of healthy birds included Bacillus spp., Micrococcus spp., S. auricularis, S. xylosus, Staphylococcus simulans, Staphylococcus saprophyticus, Staphylococcus hyicus, Staphylococcus cohnii, Staphylococcus sciuri, Aerococcus spp., and Providencia rettgeri. These findings were compared with bacterial isolates from bustards with clinical signs of ocular or upper respiratory tract diseases. Mycoplasma spp., Pseudomonas aeruginosa, Pseudomonas stutzeri, Proteus mirabilis, Escherichia coli, Klebsiella spp., Aeromonas hydrophila, and Staphylococcus aureus were the pathogenic bacteria isolated from the conjunctiva of 34.3% bustards with ocular discharges. Mycoplasma spp., P. aeruginosa, Pseudomonas spp., P. mirabilis, E. coli, Klebsiella pneumoniae, and S. aureus were the pathogenic bacteria isolated from the nasal cavity of 74% bustards with upper respiratory tract diseases.     

自主活动鸟类禽流感及新城疫的生态学与流行病学调查分析

在2004年初H5亚型禽流感在中国内地引起暴发前后，于湖北、广西二疫区市县的生态系中，自健康的鹰、鸽子、野鸭和鹌鹑中采集了54份血清，应用血凝抑制试验（HI）对其进行了血清学检测，并将获得的血清学检测数据进行了统计学分析。分析结果显示，在总共采集的54份血清样品中，抗新城疫病毒（NDV）抗体、抗It6亚型禽流感病毒（H6）抗体、抗H9亚型禽流感病毒（H9）抗体、抗H5亚型禽流感病毒（H5）抗体阳性率分别为64．8％、64．8％、75．9％、29．6％。推断这一时期新城疫病毒（NDV）、H6亚型禽流感病毒（H6）、H9亚型禽流感病毒（H9）和H5亚型禽流感病毒（H5）共循环于该生态系中，其中新城疫病毒、H9、H6亚型禽流感病毒长期、稳定循环于该生态系中，为该生态系主要流行血清型。血凝抑制试验检测结果发现，抗H5亚型禽流感病毒抗体效价较低，最高仅为640，其阳性率为29．6％，推断其可能为新近传入的病毒或新近重组变异出现的新病毒、与该次流感暴发相关的新病毒，这一推断还有待于通过对病毒基因序列的分析而做进一步验证：另外，新城疫病毒在该生态系中的稳定循环，构成了对家禽持久、潜在的威胁。对于自1994年以来，长期稳定循环于我国生态系及家禽中的H9亚型禽流感病毒则仍然是以G9-like为优势亚组。本研究结果还提示我们，对我国自主活动鸟类的生态系中抗禽流感病毒抗体的监测是预警、预报我国家禽流感暴发的有效途径，也是十分必要的，同时，血清学的检测结果为我们进一步的分子水平的分析研究提供了明确的靶向。     

禽类基因工程重组干扰素研究进展

近年来 ,多种禽类干扰素基因已被克隆和在大肠杆菌中表达。禽类基因工程重组干扰素在抗马立克病毒、劳斯肉瘤病毒、新城疫病毒、传染性法氏囊病病毒、传染性支气管炎病毒和禽流感病毒方面效果显著 ,展现出了广阔的应用前景。文章对禽类基因工程重组干扰素的研究进展作了综述     

Cross‐Sectional Serosurvey of Avian Influenza Antibodies Presence in Domestic Ducks of Kathmandu,Nepal

Kathmandu, Nepal has been classified as a high‐risk area for highly pathogenic avian influenza (HPAI) by the Nepali Government. While ducks have an important role in the transmission of avian influenza viruses (AIV), including HPAI, seroprevalence of antibodies to AIV in domestic ducks of Kathmandu has never been assessed. The objectives of this study were (i) to estimate the prevalence of seroconversion to AIV in domestic ducks in major duck‐raising areas of Kathmandu and (ii) to assess the effect of age, sex, presence of swine and the number of ducks on the farm on the carriage of antibodies to AIV in these ducks. From April through July of 2011, a cross‐sectional study was conducted and a total of 310 ducks in the major duck‐raising areas of Kathmandu were sampled. The estimated prevalence of AIV antibodies was 27.2% [95% confidence interval (CI): 24.6–29.5]. Of 62 enrolled farms, 42% had at least one seropositive duck. Half of the enrolled farms also kept pigs of which 52% had at least one seropositive duck. Bivariate analysis indicated association between ducks' seroconversion to AIV and their age, sex and farm size. However, the final multivariable model, after controlling for clustering of ducks within farms, identified age as the only significant risk factor. Based on this model, ducks older than 1 year of age were more likely to be seropositive compared to ducks <6 months of age [odds ratio = 2.17 (1.07–4.39)]. These results provide baseline information about the AIV seroprevalence in domestic ducks in the major duck‐raising areas of Kathmandu and identify a high‐risk group that can be targeted in surveillance activities. Future studies should be conducted to differentiate the subtypes of AIV present among domestic ducks in Kathmandu, with particular interest in the presence of HPAI viruses.     

禽四种病毒多重PCR诊断技术的建立和应用

根据禽呼肠孤病毒（ARV）、禽流感病毒（AIV）、新城疫病毒（NDV）和鸡传染性支气管炎病毒（IBV）的基因保守区设计了4对特异性引物,建立了针对四种病毒的多重PCR检测体系,并对该体系进行了条件优化及特异性、敏感性试验。该体系扩增的四种病毒基因片断大小分别为199bp（ARV）、264bp（AIV）、362bp（NDV）和459bp（IBV）,且特异性、敏感性良好,能够检出1pgAIV和10PgARV、NDV、IBV的RNA。临床应用结果证明,该体系具有很高的实用价值和应用前景。     

A longitudinal study of a novel dot-enzyme-linked immunosorbent assay for detection of avian influenza virus

A monoclonal antibody (MAb)-based dot-enzyme-linked immunosorbent assay (ELISA) has been developed that detected the epitopes specifically associated with avian influenza virus (AIV). The dot-ELISA detected the antigens of AIV directly from clinical and field specimens. Data obtained from experimentally AIV-infected specific-pathogen-free chickens and also the 2001/02 AIV outbreak of serotype H7N2 positive flocks in Pennsylvania indicated that the mean sensitivity (Se) of the dot-ELISA ranged between 45% and 68% and the mean specificity (Sp), between 85% and 90%. The values were derived from various clinical and field specimens when compared with virus isolation with embryonating chicken eggs. On routine AIV surveillance samples, the dot-ELISA achieved a 92%-100% Sp on the basis of resting over 1500 AIV surveillance samples that were confirmed negative by virus isolation. The dot-ELISA detected AIV antigens with a 5-microl allantoic fluid sample that contained a concentration of 0.4 hemagglutinating units. Furthermore, the dot-ELISA retained its specificity for AIV because no cross-reactions were obtained with various other avian viruses. The findings in this study indicated that the dot-ELISA was highly sensitive and specific and comparable with the commercial Directigen test in the detection of AIV obtained from clinical and field specimens.     

不同禽流感病毒含量的新-流二联灭活疫苗免疫SPF鸡后抗体水平的监测

将未浓缩的新城疫抗原分别与未浓缩的、浓缩3倍、浓缩6倍的禽流感抗原混合,并制备成三组鸡新城疫、禽流感（H9N2 HP株）二联灭活疫苗（简称新-流二联灭活疫苗）,分别免疫21日龄SPF鸡,每羽0.3 mL,同时设置未免疫的空白对照组,免疫组与对照组均在免疫前及免疫后7、14、21、28、35 d进行采血,检测新城疫和禽流感抗体。结果发现,各免疫组在免后不同日龄的新城疫抗体基本一致,禽流感病毒抗原浓缩倍数越高（即禽流感病毒含量越高）的新-流二联灭活疫苗,免后14、21 d的抗体也越高;从免后21 d开始,各免疫组的禽流感抗体水平差异逐渐减小,免疫后禽流感抗体水平的高低可以反映该疫苗的免疫效果。试验结果表明,该疫苗可以通过浓缩提高抗原病毒含量的方法来提高免后早期抗体水平,取得良好的早期免疫效果。     

鸡IBV、NDV和AIV多重RT-PCR检测方法的初步建立

根据鸡传染性支气管炎病毒M基因、禽流感病毒NP基因和新城疫病毒F基因各设计1对引物,初步建立了针对鸡传染性支气管炎(IB)、新城疫(ND)和禽流感(AI)的多重RT-PCR鉴别诊断方法,并对其特异性和敏感性进行了检测。结果表明,所设计的3对引物可对同一样品中的IBV、NDV和AIV进行特异性扩增,所扩增的目的片断的长度分别为333bp(IBV)、438bp(NDV)和196bp(AIV);建立的多重RT-PCR检测方法能够检测出1ng/μLAIV、1ng/μLNDV和10ng/μLIBV的cDNA,说明该检测方法特异性强,敏感性较高。本研究所建立的多重RT-PCR方法可用于上述3种鸡病毒性呼吸道疾病的快速鉴别诊断,在临床诊断和流行病学调查方面具有较好的应用前景。     

Radiographic analysis of the growth rate of long bones in bustards

A serial radiographic study was conducted on seven houbara bustard (Chlamydotis undulata macqueenii), 10 rufous-crested bustard (Eupodotis ruficrista), four white-bellied bustard (Eupodotis senegalensis) and eight kori bustard (Ardeotis kori) chicks to determine the growth rate of long bones and to establish radiographic standards for assessing skeletal maturity. The growth rates of the tarsometatarsus and tibiotarsus in the bustard species investigated were similar to those in domestic fowl (Gallus domesticus) and some long-legged avian species. Maturation of long bones occurred earlier in houbara bustards compared with rufous-crested, white-bellied and kori bustards.     

禽流感病毒感染的宿主免疫应答

禽流感病毒(AIV)亚型众多、宿主广泛、抗原易变,不同种类的宿主对AIV的反应差异很大。体液免疫可提供抗疫病的保护,抗血凝素的中和抗体是主要的决定因素。细胞毒性T细胞(CTL)反应主要是针对比较保守的内部蛋白,细胞免疫在不同亚型或不同毒株间有交叉反应性,但保护性低。AIV感染的早期,CTL和细胞因子等细胞免疫对限制病毒扩散等起一定作用;感染后期,中和抗体的产生对病毒的清除和宿主恢复起重要作用。     

朗德鹅禽流感病毒的分离与鉴定

用禽流感病毒ELISA试剂盒对某朗德鹅养殖场的病鹅气管粘液进行了检测，发现5份粘液样本均呈禽流感阳性；随后取相应气管组织材料接种于9～11日龄鸡胚分离病毒．发现尿囊液能使鸡红细胞发生凝集，用禽流感病毒H5、H7、H9标准阳性血清和新城疫病毒、传染性支气管炎病毒、传染性喉气管炎病毒、传染性法氏囊炎病毒抗血清作HI试验，结果禽流感病毒H5亚型抗血清的血凝抑制滴度达到2^7，而禽流感病毒H7、H9亚型及其他病毒抗血清无血凝抑制滴度，说明从朗德鹅分离到的病毒为H5亚型禽流感病毒。