鸡贫血病病毒感染雏鸡细胞周期的研究

用流式细胞仪对雏鸡感染鸡贫血病毒后不同时期胸腺和骨髓细胞的细胞周期进行了分析，结果显示感染鸡骨髓和胸腺发生了Ｇ１阻滞，这表明ＤＮＡ合成抑制，Ｇ２／Ｍ期细胞数量明显减少，这说明增殖性细胞在减少。本实验结果提示增殖性细胞减少是鸡传染性贫血病（ＣＩＡ）中胸腺淋巴细胞和骨髓造血细胞大量减少的重要原因之一，这为阐明ＣＡＶ的发病机理提供了新资料     

鸡传染性贫血病毒诱导细胞凋亡的研究进展

鸡传染性贫血病毒是鸡传染性贫血病的病原体,能引起雏鸡贫血、淋巴组织萎缩、出血及免疫抑制,是导致许多疫苗免疫失败及雏鸡死亡的主要原因之一。该病毒在世界范围内广泛存在,是养鸡业潜在的巨大威胁。近年来的研究表明,鸡传染性贫血病毒主要是通过其编码的凋亡素诱导雏鸡胸腺和骨髓中的造血祖细胞凋亡而致病的,而凋亡素诱导细胞凋亡的能力与其在细胞中的核定位及半胱氨酸蛋白酶(caspase)等因素密切有关。文章就鸡传染性贫血病毒生物学特征、诱导细胞凋亡的现象及机制的研究进行了综述。     

ALV-J和REV诱导雏鸡胸腺细胞凋亡

应用原位末端标记法和HE染色法对人工感染J亚群禽白血病病毒(ALV-J)和禽网状内皮增生症病毒(REV)的SPF雏鸡胸腺细胞的凋亡情况进行了检测,同时辅以电镜超薄切片观察。结果表明,ALV-J和REV均可诱导雏鸡胸腺细胞发生凋亡,混合感染诱导的细胞凋亡更加严重;切片中可出现局灶状凋亡,凋亡细胞多于坏死细胞。研究结果表明,细胞凋亡是导致感染鸡胸腺萎缩的主要原因。     

鸡传染性贫血

鸡传染性贫血(Chickeninfectiousanemia简写CIA)是由病毒引起的、以侵害雏鸡骨髓、胸腺和法氏囊并因此而导致严重的免疫抑制的一种疾病。雏鸡感染后对其     

鸡贫血病毒引起免疫抑制和贫血的机理

鸡贫血病毒（ＣＡＶ）可引起鸡临床和亚临床性疾病，是一种世界性的重要禽病原体。在幼龄雏鸡，由于ＣＡＶ引起骨髓中类成红细胞的破坏而引起暂时的严重贫血以及皮质胸腺的衰竭而引起的免疫缺陷，从而引发其它免疫和疫苗免疫失败，胸腺细胞和类成红细胞衰竭通过ＣＡＶ诱发的凋亡（ａｐｏｐｔｏｓｉｓ）而发生，ＣＡＶ编码蛋白凋亡素（ａｐｏｐｔｉｎ）是这种现象的主要诱导物。     

鸡贫血病毒感染鸡细胞凋亡研究

用TUNEL法检测了1 日龄SPF雏鸡感染鸡贫血病毒(CAV)后胸腺和骨髓细胞的凋亡情况。结果,接种CAV 后6、10、20 d,骨髓细胞的凋亡率分别达51% 、52% 、57% ;接种后6 d,胸腺细胞凋亡率为53% ,比对照鸡胸腺和骨髓细胞的凋亡率明显升高( P< 0.01)。用流式细胞仪对胸腺细胞悬液所作的细胞凋亡分析结果与TUNEL法检测结果一致。     

一日龄雏鸡感染鸡盆血病病毒及鸡呼肠病毒的协同作用

１日龄ＳＰＦ来航鸡经口双重感染鸡贫血病病毒（ＣＡＶ）Ｃｕｘ－１株及鸡呼肠病毒（ＲＥＯＶ）Ｓ１１３３或Ｕｃｈｉｄａ株。于接种后第１４天，检查血细胞压积（ＰＣＶ）、称体重、观察骨髓、胸腺及法氏囊病变。结果，双重感染ＣＡＶ及Ｓ１１３３株ＲＥＯＶ的雏鸡与感染其中之一病毒的雏鸡相比，其体重增重少，病变重，而且比仅感染ＣＡＶ的雏鸡在平均ＰＣＶ上也明显低。双重感染ＣＡＶ及Ｕｃｈｉｄａ株ＲＥＯＶ的雏鸡，不加重发病     

鸡传染性贫血病毒的分子生物学及其核酸检测技术

鸡传染性贫血 (CIA)是鸡的重要的免疫抑制性疾病之一 ,以引起雏鸡再生障碍性贫血和全身淋巴组织萎缩为主要特征。鸡传染性贫血病毒 (CIAV)主要引起鸡骨髓成红细胞和胸腺皮质的成淋巴细胞溶细胞感染 ,继而导致贫血和免疫抑制。该病毒在世界范围内广泛存在 ,是养鸡业潜藏的巨大威胁。文章从 CIA的危害、基本控制方法、病原的基因组及其所编码的蛋白质的功能、疾病的诊断等方面的最新进展进行了综述 ,重点介绍了病原的分子生物学研究进展及其核酸检测技术 ,并对 CIAV的研究前景进行了展望     

鸡贫血因子病全身免疫功能变化的研究

用鸡贫血病毒（ＣＡＶ）感染１日龄ＡＡ雏鸡,以未感染同龄ＡＡ雏鸡为对照,感染后不同时间检测其外周血液Ｔ、Ｂ细胞数量和ＩｇＧ,ＩｇＭ,ＩｇＡ含量,胸腺,法氏囊,脾脏ＩｇＧ,ＩｇＭ,ＩｇＡ抗体生成细胞和Ｔ细胞数量以及Ｔ、Ｂ细胞增殖功能;胸腺和脾脏白细胞介素２（ＩＬ－２）和干扰素（ＩＦＮ）诱生活性等的动态变化。     

一例鸡传染性贫血与大肠杆菌病并发的诊治

鸡传染性贫血(chickeninfectiousanemia,CIA)是由圆环病毒属的鸡传染性贫血病毒(chickeninfectiousanemiavirus,CIAV)引起的一种以雏鸡骨髓脂肪变性引发的再生障碍性贫血和胸腺等淋巴组织萎缩为主要特征的传染病,是鸡主要的免疫抑制病之一。CIAV在鸡群中广泛存在,可经水平传播和垂直传播,且病毒通过种鸡卵巢或精液传给子代是造成雏鸡暴发该病的主要原因。种鸡开产前不久或产蛋初期感染CIA,会有3~6周左右的垂直传播,种鸡本身生产性能没有明显影响,但其子代缺乏母源抗体,易感染该病毒并继发细菌感染。本文介绍了一例鸡传染性贫血病毒和大肠杆菌混合感染的诊治。     

Studies on the pathogenesis of chicken infectious anaemia virus infection in six-week-old SPF chickens

The pathogenesis of chicken infectious anaemia virus (CAV) infection was studied in 6-week-old and one-day-old SPF chickens inoculated intramuscularly with graded doses of Cux-1 strain (10(6)-10(2) TCID50/chicken). Viraemia, virus shedding, development of virus neutralizing (VN) antibodies and CAV distribution in the thymus were studied by virus isolation, polymerase chain reaction (PCR), immunocytochemistry (IP) and in situ hybridization until postinfection day (PID) 28. In 6-week-old chickens infected with high doses of CAV, viraemia and VN antibodies could be detected 4 PID and onward without virus shedding or contact transmission to sentinel birds. However, virus shedding and contact transmission were demonstrated in one-day-old infected chickens. In the 6-week-old groups infected with lower doses, VN antibodies developed by PID 14, transient viraemia and virus shedding were detected. The thymus cortex of all 1-day-old inoculated chickens stained with VP3-specific mAb. Cells with positive in situ hybridization signal were fewer and scattered throughout the thymus tissue of the one-day-old inoculated chickens as compared to IP-positive cells. These results suggest that early immune response induced by high doses of CAV in 6-week-old chickens curtails viral replication and prevents virus shedding.     

一株鸡传染性贫血病毒对不同日龄SPF鸡的致病性研究

为评价鸡传染性贫血病毒AV1550株的致病性,取1日龄、7日龄和14日龄SPF鸡分别经胸部肌肉注射不同病毒含量的病毒液,同时设置正常对照,隔离饲养观察21日。感染后14日采血测定红细胞压积,21日统计死亡率、体重变化以及胸腺、骨髓、法氏囊病变情况并测定1日龄SPF鸡感染后不同组织中的病毒载量。结果表明,1日龄SPF鸡感染AV1550株后,表现出精神沉郁、增重减缓、贫血等明显的临床症状,死亡率为53.9%;死亡鸡或观察期结束时存活鸡剖检,可见胸腺萎缩,骨髓变成淡黄色;不同剂量感染后14日,均能引起红细胞压积显著下降;21日时,胸腺病毒载量最高,可达106.7copies/mg 。7日龄SPF鸡感染后,出现增重减缓,高感染剂量（100000EID50）出现贫血,部分鸡出现胸腺萎缩和骨髓病变,但病变率低于30%。14日龄SPF鸡感染后,不引起明显临床症状。研究证实,CAV对SPF鸡的致病性具有明显的日龄依赖性,红细胞压积降低、骨髓病变、胸腺萎缩以及胸腺病毒载量测定可作为评价CAV致病的指标。     

PCR和斑点杂交检测鸡传染性贫血病毒

通过聚合酶链反应（ｐｃＲ）扩增鸡传染性贫血病毒（ｃＡＶ）ＤＮＡ特定片段，将此ｐｃＲ产物用Ｄｉｇｏｘｉｇｅｎｉｎ标记后作为探针进行斑点杂交，以此检测ＣＡＶ并作流行病学调查。对从江苏省不同地市随机采集的２月龄左右不同疾病的病鸡ＤＮＡ样品进行检测，在被检的５２个不同鸡群来源的病料中，有３６个鸡群来源的病料ＤＮＡ显示ＣＡＶ阳性（群阳性率为６９．２％）；备组织中ＣＡＶＤＮＡ含量有所差异，依次为胸腺＞脾、骨髓、肝＞肾、法氏囊、脑。用ＰＣＲ检测得到的阳性鸡的组织病料感染ＳＰＦ鸡，在感染后第２４天检查，出现贫血症状。初步调查表明，在江苏一些地区ＣＡＶ感染已相当普遍，但它与发病的关系还有待于进一步研究。     

Isolation and preliminary characterization of chicken anemia virus from chickens in Nigeria

Chicken anemia virus (CAV) was isolated for the first time from the Nigerian chicken population. The virus was recovered from necropsied birds from broiler and pullet flocks that suffered disease outbreaks tentatively diagnosed as infectious bursal disease. A sensitive polymerase chain reaction (PCR) assay detected CAV DNA in tissues of necropsied birds. Restriction endonuclease analysis performed with the 733-bp PCR product and the Cfo I enzyme indicated at least two different CAVs were circulating among the Nigerian chicken population. Four isolates were obtained from pooled liver and thymus tissues using the MDCC-MSB1 cell line. These isolates were found to be antigenically closely related to the Cuxhaven-1 (Cux-1) reference strain of CAV when reacted with four monoclonal antibodies prepared against the Cux-1 virus. One of the isolates (isolate A) induced thymus atrophy, bone marrow aplasia, and low hematocrit values when inoculated into 1-day-old specific-pathogen-free chickens. These findings not only demonstrate that CAV is present in Nigeria, but they also likely represent the first cell culture isolation of the virus in Africa.     

Pathogenesis of chicken anemia virus: comparison of the oral and the intramuscular routes of infection

The events during the pathogenesis of chicken anemia virus (CAV) infection following intramuscular (IM) and oral inoculation were further elucidated and compared by sequential clinical, pathologic, and morphometric histopathologic evaluations, and by sequential determination of CAV genome concentrations in different organs. Specific-pathogen-free chickens were inoculated by IM or oral routes with the same dose (2 x 10(6) mean tissue culture infective dose [TCID50]) of CAV isolate 03-4876 at 1 day of age. Weights and hematocrits were obtained at 7, 10, 14, 18, 21, 25, and 28 days postinoculation (DPI). Seven birds from each group were necropsied at 7, 10, 14, and 28 DPI, and samples of thymus, Harderian gland, and cecal tonsils (CT) were obtained for histopathologic examination and CAV genome quantification by real-time polymerase chain reaction. Peak CAV genome concentrations were detected in the thymus at 10 and 14 DPI in the IM and orally infected chickens, respectively. High CAV DNA concentrations were maintained throughout the experimental period until 28 DPI, despite specific seroconversion occurring by 14 DPI in the IM-inoculated chickens. CAV was isolated from both orally and IM-infected chickens 28 DPI. Peak CAV genomes in the thymuses of IM and orally infected chickens coincided with peak lymphocyte depletion in these organs. Lymphocyte repopulation of the thymus occurred by 28 DPI in spite of the presence of the virus in the organs of both infected chicken groups. CAV genomes were detected in the CT, but histopathologic changes were not observed. Compared with the IM route of infection, orally infected chickens did not show apparent signs of illness. Clinical parameters, including reduction of weight gains and hematocrits, and gross and histopathologic changes were delayed and less severe in the orally inoculated chickens. This was concurrent with a delay in accumulation of CAV genomes in the thymus of these chickens.     

Pathological and immunohistochemical studies of subclinical infection of chicken anemia virus in 4-week-old chickens

Subclinical infection of chicken anemia virus (CAV) at 4 to 6 weeks of age, after maternal antibodies have waned, is implicated in several field problems in broiler flocks. In order to understand the pathogenesis of subclinical infection with CAV, an immunopathological study of CAV-inoculated 4-week-old SPF chickens was performed. Sixty 4-week-old SPF chickens were equally divided into CAV and control groups. The CAV group was inoculated intramuscularly with the MSB1-TK5803 strain of CAV. Neither mortality nor anemia was detected in the CAV and control groups. In the CAV group, no signs were observed, except that some chickens were grossly smaller compared with the control group. Sporadic thymus lobes appeared to be reddening and atrophied. Within the first two weeks p.i. of CAV, there was a mild to moderate depletion of lymphocytes in the thymus cortex and spleen in some chickens. Moreover, lymphoid depletion of the bursa of Fabricius, proventriculus and cecal tonsils was observed. Hyperplastic lymphoid foci were observed in the liver, lungs, kidneys and heart at the 4th week p.i. of CAV. Immunohistochemically, a moderate lymphoid depletion of CD4(+)and CD8(+) T cells in the thymus cortex and spleen was observed in some chickens within two weeks p.i. of CAV. CAV inclusions and antigens were detected infrequently in the thymus cortex and spleen. It could be concluded that the immunosuppression in subclinical infection with CAV occurs as a result of reduction of cellular immunity.     

Oral infection with chicken anemia virus in 4-wk broiler breeders: lack of effect of major histocompatibility B complex genotype

The pathologic consequences of chicken anemia virus (CAV) oral inoculation in 4-wk-old broiler breeders of different major histocompatibility B complex (MHC) genotypes were evaluated. MHC B complex was determined by hemagglutination and sequence-based typing. Clinical signs, serology, gross lesions, histopathologic analysis, and CAV genome quantification were used to evaluate disease progression. Clinical disease was not apparent in the inoculated broilers throughout the experimental period. At 14 days postinoculation, antibodies against CAV were detected in 26.4% (29/110) of the inoculated birds. The distribution of percent positive was 34.6% (9/26) and 32.3% (10/31) of the chickens with B A9/A9 and B A9/A4 MHC genotypes, respectively, and seroconversion in six other genotypes was 19% (10/53). These differences among MHC genotypes for specific seroconversion rate were not statistically significant. CAV genomes were detected in the thymus of 87.7% (93/110) of the inoculated birds with no statistically significant differences between MHC genotypes. Mild thymic lymphocytolysis, lymphedema, and medullary hemorrhage were observed in the inoculated chickens. Histomorphometric analysis showed that cortical lymphocyte-to-parenchyma ratios did not differ between inoculated and uninoculated groups or among MHC genotypes. Similar findings have been reported previously in white-leghorn chickens of similar age, suggesting that broilers show a similar resistance to the effects of CAV infection at this age. The absence of significant clinical and pathological changes in the orally inoculated broilers at this age contrasts with CAV-associated thymus damage seen frequently in condemned commercial broilers at harvest.     

Biological and molecular characterization of chicken anemia virus isolates from Slovenia

The presence of chicken anemia virus (CAV) in Slovenia was confirmed by inoculation of 1-day-old chickens without antibodies against CAV and isolation of the virus on the Marek's disease chicken cell-MSB1 line and by polymerase chain reaction (PCR). Experimental inoculation of 1-day-old chickens resulted in lower hematocrit values, atrophy of the thymus, and atrophy of bone marrow. CAV was confirmed by PCR in the thymus, bone marrow, bursa of Fabricius, liver, spleen, ileocecal tonsils, duodenum, and proventriculus. The nucleotide sequence of the whole viral protein (VP)1 gene was determined by direct sequencing. Alignment of VP1 nucleotide sequences of Slovenian CAV isolates (CAV-69/00, CAV-469/01, and CAV-130/03) showed 99.4% to 99.9% homology. The VP1 nucleotide sequence alignment of Slovenian isolates with 19 other CAV strains demonstrated 94.4% to 99.4% homology. Slovenian isolates shared highest homology with the BD-3 isolate from Bangladesh. Alignment of the deduced VP1 amino acids showed that the Slovenian isolates shared 100% homology and had an amino acid sequence most similar to the BD-3 strain from Bangladesh (99.6%) and were 99.1% similar to the G6 strain from Japan and the L-028 strain from the United States. The Slovenian isolates were least similar (96.6%) to the 82-2 strain from Japan. A phylogeneric analysis on the basis of the alignment of the VP1 amino acids showed that CAV isolates used in the study formed three groups that indicated the possible existence of genetic groups among CAV strains. The CAV isolates were grouped together independent of their geographic origin and pathogenicity.     

Experimental inoculation of avian polyomavirus in chemically and virally immunosuppressed chickens.

The purpose of this series of experiments was to determine the effect of various types of immunosuppressive treatments (cyclophosphamide, infectious bursal disease virus [IBDV], chicken anemia virus [CAV], and combination infection with IBDV and CAV) on susceptibility of chickens to challenge with avian polyomavirus. In the first experiment, chickens were chemically bursectomized with intraperitoneal injections of cyclophosphamide; in the second study, chickens were orally inoculated with IBDV; in the third study, birds were intramuscularly inoculated with CAV; and in the final study, birds were inoculated with both IBDV and CAV. In all experiments, chickens were challenged with 10(4.7) tissue culture infective doses of polyomavirus intraperitoneally. Only chemically bursectomized chickens developed lesions similar to those found in the naturally occurring multisystemic fatal form of polyomavirus infection seen in psittacine nestlings, including hepatic necrosis and large pale intranuclear inclusions.