Epidemiology of chicken anemia virus in Central African Republic and Cameroon

ABSTRACT: BACKGROUND: Although chicken anemia virus (CAV) has been detected on all continents, little is known about this virus in sub-Saharan Africa. This study aimed to detect and characterize CAV for the first time in Central African Republic and in Cameroon. RESULTS: An overall flock seroprevalence of 36.7% was found in Central African Republic during the 2008--2010 period. Virus prevalences were 34.2% (2008), 14.3% (2009) and 10.4% (2010) in Central African Republic and 39% (2007) and 34.9% (2009) in Cameroon. CAV DNA was found in cloacal swabs of 76.9% of seropositive chickens, suggesting that these animals excreted the virus despite antibodies. On the basis of VP1 sequences, most of the strains in Central African Republic and Cameroon belonged to 9 distinct phylogenetic clusters at the nucleotide level and were not intermixed with strains from other continent. Several cases of mixed infections in flocks and individual chickens were identified. CONCLUSIONS: Our results suggest multiple introductions of CAV in each country that later spread and diverged locally. Mixed genotype infections together with the observation of CAV DNA in cloacal samples despite antibodies suggest a suboptimal protection by antibodies or virus persistence.     

A single chicken anemia virus protein induces apoptosis.

Chicken anemia virus (CAV) causes cytopathogenic effects in chicken thymocytes and cultured transformed mononuclear cells via apoptosis. Early after infection of chicken mononuclear cells, the CAV-encoded protein VP3 exhibits a finely granular distribution within the nucleus. At a later stage after infection, VP3 forms aggregates. At this point, the cell becomes apoptotic and the cellular DNA is fragmented and condensed. By immunogold electron microscopy VP3 was shown to be associated with apoptotic structures. In vitro, expression of VP3 induced apoptosis in chicken lymphoblastoid T cells and myeloid cells, which are susceptible to CAV infection, but not in chicken embryo fibroblasts, which are not susceptible to CAV. Expression of a C-terminally truncated VP3 induced much less pronounced apoptosis in the chicken lymphoblastoid T cells.     

Avian tumor virus interactions with chicken fibroblast plasma membranes

A method is described which will rapidly measure the binding of avian tumor viruses (ATV) to plasma membrane receptors. With this procedure it may be shown that Rous sarcoma virus pseudotypes bind to protease-labile, heat-stable structures on the surface of chicken embryo fibroblast (CEF) plasma membranes. The binding sites for ATV subgroups A and B appear distinct, and membranes from genetically resistant CEF bind as well those of sensitive CEF.     

Complete genome sequence analysis of a recent chicken anemia virus isolate and comparison with a chicken anemia virus isolate from human fecal samples in china

A new isolate of chicken anemia virus (CAV) was designated GD-1-12. GD-1-12 was isolated from a 12-day-old commercial broiler in Guangdong province, China, in 2012. The GD-1-12 CAV caused high mortality, severe anemia, thymic atrophy, and subcutaneous hemorrhage in commercial broilers. Here, we report the complete genome sequence of GD-1-12 CAV and comparison with the complete genome sequence of another CAV that was isolated from human fecal samples in China (GenBank accession no. JQ690762). The genomes of the two CAV isolates shared high homology, although a deletion was identified by comparison. The findings from this study provide additional insights into the molecular characteristics of the CAV genomes and should advance knowledge for continuous monitoring and, perhaps, preventing the spread of the virus in chickens as well as in humans.     

Identification of the first human gyrovirus, a virus related to chicken anemia virus

We have identified in a skin swab sample from a healthy donor a new virus that we have named human gyrovirus (HGyV) because of its similarity to the chicken anemia virus (CAV), the only previously known member of the Gyrovirus genus. In particular, this virus encodes a homolog of the CAV apoptin, a protein that selectively induces apoptosis in cancer cells. By PCR screening, HGyV was found in 5 of 115 other nonlesional skin specimens but in 0 of 92 bronchoalveolar lavages or nasopharyngeal aspirates and in 0 of 92 fecal samples.     

Partial antiviral activities of the Asn631 chicken Mx against newcastle disease virus and vesicular stomatitis virus

Conflicting data existed for the antiviral potential of the chicken Mx protein and the importance of the Asn631 polymorphism in determination of the antiviral activity. In this study we modified the chicken Mx cDNA from the Ser631 to Asn631 genotype and transfected them into COS-I cells, chicken embryonic fibroblast (CEF) or NIH 3T3 cells. The Mx protein was mainly located at the cytoplasm. The transfected cell cultures were challenged with newcastle disease virus (NDV) or vesicular stomatitis virus (VSV), cytopathic affect (CPE) inhibition assay showed that the times for development of visible and full CPE were significantly postponed by the Asn631 cDNA transfection at 48 h transfection, but not by the Ser631 cDNA transfection. Viral titration assay showed that the virus titers were significantly reduced before 72 h postinfection. CEF cells was incubated by the cell lysates extracted from the COS-I cells transfected with pcDNA-Mx/Asn631, could resist and delayed NDV infection. These data suggested the importance of the Asn631 polymorphism of the chicken Mx in determination of the antiviral activities against NDV and VSV at early stage of viral infection, which were relatively weak and not sufficient to inhibit the viral replication at late stage of viral infection.     

Receptor interaction between eastern equine encephalitis virus and chicken embryo fibroblasts.

The attachment of eastern equine encephalitis virus to chicken embryo fibroblasts was studied at 0 degrees C. The binding specifically responsible for initiating infection was studied in the initial experiments by employing plaque-forming ability as the measured response. Results from these initial studies were closely paralleled in studies of binding of radiolabeled virus under the same conditions. Binding that had occurred at the pH optimum, pH 6.5, could be reversed only at higher pH. The observed pH dependence of virus attachment suggested the interaction of at least two ionizable species in the initial binding of virus to cell, and that one to three attachments must occur between virus and cell prior to infection.     

Complementary RNA in the chicken sarcoma cells and Rous sarcoma virus]

The subcellular localization in chicken Rous sarcoma of nucleotide sequence, complementary to Rous sarcoma virus RNA was examined by RNA/RNA molecular hybridization. The preparations of radioiodinated virion RNA were annealed with RNAs from different fractions (nuclei, mitochondria, free and membrane-bound polyribosomes) isolated from chicken Rous sarcoma. Formation of RNA-ase resistant hybrids between the viral 125I-RNA and RNA from the mitochondria and membrane-bound polyribosomes was revealed. The latter were characterized by a higher relative redundancy of nucleotide sequences complementary to virion RNA than that in the former, by factor 446. The role of complementary ribonucleotide sequences is discussed.     

鸡胚细胞的传代培养和麻疹病毒的增殖

为了建立原代鸡胚细胞的传代培养工艺,探究传代鸡胚细胞对麻疹病毒的敏感性和适应性,本研究将原代鸡胚细胞进行传代培养,分别采用原代鸡胚细胞和传代鸡胚细胞培养麻疹病毒沪-191(Shanghai-191,S-191)株毒种,并对病毒收获液进行滴度检测和基因序列测定。结果显示,原代鸡胚细胞可稳定传代培养至第10代,各代次细胞生长趋势相似;第5代鸡胚细胞染色体检查为正常染色体核型;第8代鸡胚细胞成瘤性检查未见成瘤;采用第3、5代鸡胚细胞制备的麻疹病毒滴度水平高于原代鸡胚细胞,但无显著性差异(n=3,P>0.05),编码病毒核蛋白(nucleoprotein,N)和血凝素蛋白(hemagglutinin,H)的基因序列与S-191株完全一致,未发生变异。本研究证实,原代鸡胚细胞可进行传代培养,各代次鸡胚细胞对麻疹病毒的敏感性不变,产毒水平无显著差异,可用于培养麻疹病毒。