禽类呼肠孤病毒(Avian reoviruses)感染

1病原学 1.1病毒特征禽类呼肠孤病毒为无囊膜,呈球形,双层衣壳和二十面对称的dsRNA病毒.粒子直径约60～80 nm,外层衣壳上有92颗中空的颗粒.在CsCl梯度离心中,感染病毒子的密度为1.29～1.30g/ml,无感染性空衣壳为1.29～1.30g/ml,病毒芯髓为1.44 g/ml.纯化病毒只含有RNA和蛋白质,平均含量分别为18.7%和81.3%.病毒在胞浆内复制,有时呈晶格排列.对热、pH 3和DNA代谢抑制物有抵抗力.MgCl2能增强病毒对热的稳定性,但当浓度太大时反而促其灭活.70%乙醇和0.5%有机碘可灭活病毒.一般无血凝活性. ……

Effect of Maternal Antibodies on the Pathogenesis of Avian Reovirus Infections in Broiler Chickens Using Real-Time Reverse Transcriptase Polymerase Chain Reaction

The effect of maternal antibodies on the pathogenesis of avian reovirus （ARV） was studied in commercial and specific pathogen free broilers （SPF） using a real-time reverse transcriptase （RT）-polymerase chain reaction （PCR） assay, along with the incidence and severity of morbidity, mortality, and gross lesions. ARV RNA was detected in cloacal swabs in both bird groups from the first day throughout the 21 days experiment. Commercial broiler chickens, which had high maternal antibodies against ARV, showed minimum clinical signs, gross lesions, and lower numbers of birds with viral RNA excretion, whereas specific pathogen free （SPF） broiler chickens, which did not have antibody against ARVs, had 30% mortality, more severe signs, and higher numbers of birds excreting viral RNA. The highest peak of SPF birds excreting viral RNA occurred during the time of maximum mortality. The protective effect of maternal antibody on ARV pathogenesis in broiler chickens correlated with the detection of ARV RNA using the real-time RT-PCR.

Construction of Short Hairpin RNA Vector with σNS & σC Genes of Avian Reovirus and Determination of Interference Effect

[ Objective] The aim was to explore novel method for treatment of Avian Reovirus. [ Method] According to the design principle of siRNA target sequences, siRNA templates were designed and synthesized and then cloned into the shRNA expression vector, namely, pSilencer-CMV 4.1 neo. Short hairpin RNA vector C1, C2, C3, which contain σC gene, and shRNA vector NS1, NS2, NS3, which contain aNS gene, were constructed separately. The constructed shRNA vectors and negative control were co-transfected into DF-1 cells with the eukaryotic expression vector pEG- FP-σC and pEGFP-σNS, respectively. [ Result] Observation through fluorescence microscope indicated that the constructed 6 shRNA could inhibit the expression of fusion protein to different degrees. In addition, results of Real-time PCR suggested that C3 and NS1 have the best interference effect to the viral duplication in vitro. [ Conclusionl Construction and selection of specific shRNA expression vectors inhibiting Avian Reovirus are significant for researching effects of σC and oNS proteins in infection and duplication of ARV, providing new idea for ARV antiviral therapy.

Circulation of Immunosuppressive Viruses and Avian Encephalomyelitis Virus in Backyard Chicken Flocks

The objective of this study was to evaluate the circulation of Chicken Anemia Virus (CAV), Infectious Bursal Disease Virus (IBDV), Avian Reovirus (ARV) and Avian Encephalomyelitis virus (AEV) in properties of backyard chickens and carry out an epidemiological analysis. We evaluated 200 samples of chickens from 19 backyard chicken property. Only one property (P10) did not present serological titers for the diseases evaluated. This property is close to industrial farms as well as the other properties, however, P10 remained a few years without the breeding of chicks and these were the first poultry to be housed on site. This reinforces the importance of the fallow period for poultry production. The prevalence of virus-seroreactive birds was 78% (156/200), 64.5% (129/200), 78% (156/200), 78% (156/200) for CAV, IBDV, ARV and, EA, respectively. All the free-range farms studied are within a radius of 500 meters to 6 Km away from some establishments of industrial poultry. There was a correlation between serological titers for CAV and the frequency of disease in poultry (r = 0.6178). In places where birds are frequently sick, 30.76% reported that the disease occurs in chicks, 30.76% in broilers, 23.07% in broiler chickens and 7.69% in birds of all ages. Birds get sick more often in the summer period. The owners reported that the most common signs of disease were respiratory signs (snoring and nasal discharge) (46.15%), diarrhea (30.76%), and paralysis of wings and/or paws (38.46%). There was a correlation between the presence of untreated water in the property and serological titers for ARV (r = 0.5576). This report draws attention not only to high serological prevalence for the viruses studied but also important epidemiological aspects of backyard chicken diseases that may indirectly influence the industrial production.

Sequence and phylogenetic analysis of chicken reoviruses in China

supported by the China Animal Disease Prevention and Control Center;the China Agriculture Research System Poultry-Related Science and Technology Innovation Team of Peking, China （CARS-PSTP）

禽源呼肠孤病毒S1基因节段分子生物学研究进展

呼肠孤病毒广泛的宿主性以及自身基因组的结构特征使其在进化过程中呈现遗传多样性,新型禽源呼肠孤病毒在此过程中不断出现,引起家禽和水禽养殖业的严重经济损失。其中,关于S1基因节段的科学研究对于理解病毒致病性改变以及疫苗开发有关键作用。因此,本文拟就禽源呼肠孤病毒的发生、S1基因的结构及其编码的非结构蛋白P10、P17和结构蛋白σC的生物学功能最新研究进展作一概述。

商品肉鸡群中MDV、REV、CAV和ARV多重感染的检测

从山东省东营、日照、潍坊、聊城等地区自然发病和临床健康AA商品肉鸡群中分别采集脏器样品,用特异性核酸探针对样品进行马立克氏病病毒(Marek′s disease virus,MDV)、网状内皮组织增生症病毒(Reticuloendotheli-osis virus,REV)、鸡传染性贫血病病毒(Chicken anemia virus,CAV)和禽呼肠孤病毒(Avian reoviruses,ARV)检测。结果显示,自然发病AA商品肉鸡群中MDV、REV、CAV和ARV的检出率均较高,分别为69.30%、57.46%、63.60%和67.11%;临床健康AA商品肉鸡群中MDV、REV、CAV的检出率分别为36.96%、43.48%和30.42%,且自然发病和健康鸡群中均存在不同病毒组合的多重感染,感染率分别为85.96%和43.46%。用X2检验进行分析发现,自然发病商品肉鸡群与临床健康商品肉鸡群中MDV、CAV、MDV+REV、REV+CAV的检出率和未检出的比例差异极显著(P<0.01);REV、MDV+CAV检出率差异显著(P<0.05)。对自然发病商品肉鸡的肝脏、脾脏、法氏囊中4种病毒检出率进行X2检验分析发现,MDV在脾脏中检出率显著高于肝脏和法氏囊;REV在法氏囊中检出率显著高于肝脏和脾脏,而CAV和ARV分别在脾脏和肝脏中检出率较高。结果表明,多种免疫抑制性病毒的共感染已普遍存在,是目前AA商品肉鸡易发病且生长缓慢的重要流行病学因素之一。