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Sequence and phylogenetic analysis of chicken anaemia virus obtained from backyard and commercial chickens in Nigeria : research communication  [cached]
D.O. Oluwayelu,D. Todd,O.D. Olaleye
Onderstepoort Journal of Veterinary Research , 2010, DOI: 10.4102/ojvr.v75i4.111
Abstract: This work reports the first molecular analysis study of chicken anaemia virus (CAV) in backyard chickens in Africa using molecular cloning and sequence analysis to characterize CAV strains obtained from commercial chickens and Nigerian backyard chickens. Partial VP1 gene sequences were determined for three CAVs from commercial chickens and for six CAV variants present in samples from a backyard chicken. Multiple alignment analysis revealed that the 6 % and 4 % nucleotide diversity obtained respectively for the commercial and backyard chicken strains translated to only 2 % amino acid diversity for each breed. Overall, the amino acid composition of Nigerian CAVs was found to be highly conserved. Since the partial VP1 gene sequence of two backyard chicken cloned CAV strains (NGR/Cl-8 and NGR/Cl-9) were almost identical and evolutionarily closely related to the commercial chicken strains NGR-1, and NGR-4 and NGR-5, respectively, we concluded that CAV infections had crossed the farm boundary.
Clinical and serological examination of a parental flock latently infected with chicken anemia virus
Kapetanov Milo?,Orli? Du?an B.,Velhner Maja,Ko?ar?i? Slavica
Acta Veterinaria , 2003, DOI: 10.2298/avb0304239k
Abstract: At the beginning of etiopathogenic research on chicken anaemia virus (CAV) it was thought that groups of chickens at risk for CAV infection were those coming from a parental flock infected before laying. Therefore it is important to know the level and persistence of transfered maternal antibodies (MaAt) and to measure specific antibody development during rearing. The goal of this research was to assess the necessity for prophylactic measures by determining the humoral immune response to CAV and any clinical changes in breeder chickens. Chickens from the parental Hybro flock were examined from the first day until the end of production. Maternal antibodies for CAV, which were present initially, were not detected at 4 weeks old. At 6 weeks old specific antibodies for CAV were found in 45% of the serum samples. These antibodies increased until the 18th week when the experiment was terminated. The state of health of the parental flock in the period when MaAt antibodies could not be detected and until specific antibodies appeared did not differ significantly. The results of these investigations are the first evidence of CAV infection in Yugoslavia, based on serological examination.
Prevalence of antibodies against chicken anaemia virus (CAV) in broiler breeders in Southern Brazil
Canal, Cláudio W.;Ferreira, Danilo José;Macagnan, Marisa;Fallavena, Luiz C. B.;Moraes, Hamilton L. S.;Wald, Vera B.;
Pesquisa Veterinária Brasileira , 2004, DOI: 10.1590/S0100-736X2004000200008
Abstract: chicks infected during the first two weeks of life with chicken anaemia virus (cav) manifest clinical disease that can be avoided if the breeder hens transfer enough antibodies to their progeny. the objective of the present work was to establish the prevalence and titer of anti-cav antibodies in some brazilian broiler hen breeder flocks and verify in which phase of life the birds were infected. a total of 1,709 serum samples from 12 broiler hen flocks vaccinated against cav and 64 unvaccinated flocks were analyzed for cav antibodies with an enzyme-linked immunosorbent assay (elisa). all non-vaccinated breeder flocks were found to be infected with cav, with 89% of the hens tested presenting antibodies, 52% of these with titers considered high enough to protect their progeny against cav infection. likewise, all vaccinated hens had antibody titer to cav capable of conferring protection to their progeny. thus, vaccination of hens seems capable of conferring protection to chicks against clinically apparent cav-associated disease.
Improving the potency of DNA vaccine against Chicken Anemia Virus (CAV) by fusing VP1 protein of CAV to Marek's Disease Virus (MDV) Type-1 VP22 protein
Hassan Moeini, Abdul Omar, Raha Rahim, Khatijah Yusoff
Virology Journal , 2011, DOI: 10.1186/1743-422x-8-119
Abstract: The VP1 and VP2 genes of CAV isolate SMSC-1 were amplified and inserted into eukaryotic co-expression vector, pBudCE4.1 to construct pBudVP2-VP1. We also constructed pBudVP2-VP1/VP22 encoding CAV VP2 and the VP22 of MDV-1 linked to the CAV VP1. In vitro expression of the genes was confirmed by using RT-PCR, Western blot and indirect immunofluorescence. The vaccines were then tested in 2-week-old SPF chickens which were inoculated with the DNA plasmid constructs by the intramuscular route. After in vivo expression studies, immune responses of the immunized chickens were evaluated pre- and post-immunization.Chickens vaccinated with pBudVP2-VP1/VP22 exhibited a significant increase in antibody titers to CAV and also proliferation induction of splenocytes in comparison to the chickens vaccinated with pBudVP2-VP1. Furthermore, the pBudVP2-VP1/VP22-vaccinated group showed higher level of the Th1 cytokines IL-2 and IFN-γ.This study showed that MDV-1 VP22 gene is capable of enhancing the potency of DNA vaccine against CAV when fused with the CAV VP1 gene.Chicken anemia virus (CAV) is a small non-enveloped virus of genus Gyrovirus from Circoviridae family, which causes anemia in young susceptible chickens and subclinical infections in older chickens [1-3]. Commercially available vaccines against CAV infection which are based on non-attenuated virulent CAV propagated in chicken embryos [4] or attenuated live vaccine [5] cannot be used in chickens in lay and within 21 days of slaughter. Furthermore, live attenuated vaccine may cause clinical disease if not attenuated sufficiently and sometimes spreading of the modified viruses to young chickens may cause the disease. In a recent development, plasmid DNA-based vaccines have emerged as one of the more promising applications of non-viral gene therapy. One such subunit vaccine against infectious chicken anemia was developed by using recombinant baculovirus as a vector for the expression of the CAV proteins [6]. They found that co-
Novel Gyroviruses, including Chicken Anaemia Virus, in Clinical and Chicken Samples from South Africa  [PDF]
Heidi E. M. Smuts
Advances in Virology , 2014, DOI: 10.1155/2014/321284
Abstract: Introduction. Chicken anaemia virus, CAV, was until recently the only member of the Gyrovirus genus. 6 novel gyroviruses, AGV2, HGyV1, and GyV3-6, have since been discovered in human and chicken samples. Methods. PCR amplification of the VP2 gene was used to detect AGV2/HGyV1, GyV3, and CAV in a range of clinical samples including stool, respiratory, CSF, and HIV-positive plasma. Screening of fresh local chicken meat was also performed. Results. AGV2/HGyV1 or GyV3 was detected in stools from healthy children (17/49, 34.7%) and patients with diarrhoea (22/149, 14.8%). 1.2% (3/246) nasopharyngeal respiratory samples were positive. No AGV2/HGyV1 or GyV3 was detected in nasal swabs from wheezing patients, in CSF from patients with meningitis, and in HIVpositive plasma. CAV was found in 51% (25/49) of stools from healthy children and 16% (24/149) in diarrhoea samples. Screening of 28 chicken samples showed a higher prevalence of gyrovirus (20/28, 71%) compared to CAV (1/28, 3.6%). Phylogenetic analysis of the CAV VP1 gene showed South African sequences clustering with Brazilian isolates from genotypes D2 and A2. Conclusion. Novel gyroviruses, including CAV, are present in the South African population with diarrhoea and respiratory illness as well as in healthy children. Their presence suggests an origin from chicken meat consumption. 1. Introduction Until recently chicken anaemia virus (CAV) was the only member of the genus Gyrovirus in the Circoviridae family. This genus is characterized by small nonenveloped DNA viruses with a negative sense single-stranded circular DNA of about 2.3?kb [1]. Circoviruses, in contrast, have an ambisense genome. The similarity of the gyrovirus genome organization to annelloviruses, with 3 overlapping open reading frames (ORFs), has led to the recommendation that gyroviruses become a subfamily, Gyrovirinae, within the Anelloviridaefamily [2]. In early 2011 Rijsewijk et al. [3] reported the discovery of a distant relative to CAV, avian gyrovirus 2 (AGV2), in diseased chicken from Brazil, with only 40% homology to CAV. Later that year, Sauvage et al. [4] identified a very closely related gyrovirus on human skin (HGyV1). Subsequently 4 other novel gyroviruses have been described. Gyrovirus 3 (GyV3) was identified by viral metagenomics in faeces from Chilean children with acute gastroenteritis and also in chicken meat [5]. A phylogenetically distinct gyrovirus (GyV4) was also discovered in both human stool samples and chicken meat by 454 pyrosequencing [6]. Further 2 divergent gyroviruses, GyV5 and GyV6, were found in the stools
Epidemiology of chicken anemia virus in Central African Republic and Cameroon  [cached]
Snoeck Chantal J,Komoyo Giscard F,Mbee Bonya P,Nakouné Emmanuel
Virology Journal , 2012, DOI: 10.1186/1743-422x-9-189
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.
Gene Cloning and Sequencing of Chicken Anemia Virus(CAV) Isolated From Harbin
鸡贫血病毒哈尔滨分离株全基因克隆和序列分析

Chengqing He,Naizheng Ding,Jingpeng Li,Yunlong Li,
何成强
,丁乃峥,李景鹏,李云龙

微生物学报 , 2002,
Abstract: A Chicken anemia virus has been isolated from a chicken flock in Harbin of China.The genome of the ivrus was cloned through polymerase chain reaction(PCR) and sequence of the genome was analyzed.The cycle genome is made of 2298 base pairs including three overlapping open reading frames(vp1,vp2,vp3)and a regulative region.Comparing sequence of the genome through BLAST in GenBank,this sequence exhibits 96.9% identity with other genome of CA Vs and least.Multiple alignment of this genome of this virus, 26p4,strain isolated in Germany,strain isolated in Malaysia and Cux 1 found that this sequence exhibits 98.2%(42/2298),98.2%(42/2298),96.9%(72/2298)and 97.5%(60/2319)identify with them,respectively.A new CAV strain was isolated and it has better identify with CAV isolated in Europe countries than is Asia country Malaysia.Multiple alignment of VP1,VP2,VP3 of 26p4,strain isolated in Germany,strain isolated in Malaysia,Cux 1 and strain isolated in Harbin of China found the VP2 the most conservative.
A VP3/VP1 gene polymerase chain reaction assay for detection of chicken anemia virus in broiler samples
Nogueira, E.O.;Brentano, L.;Ferreira, A.J.P.;
Arquivo Brasileiro de Medicina Veterinária e Zootecnia , 2005, DOI: 10.1590/S0102-09352005000800001
Abstract: a pcr assay was designed for amplification of the highly conserved vp3 gene and a 5' region of the vp1 gene, for the diagnosis of cav in organ samples of broiler flocks suspected of chicken infectious anemia. a comparison of the vp3/vp1 pcr with in vivo virus isolation revealed 100% agreement of the results, with 13 positive and 3 negative samples in both assays, indicating that the vp3/vp1 pcr is a specific diagnostic method. tissues from additional 24 broiler chicken flocks, with cav-like lesions and clinical history were then tested only by the vp3/vp1 pcr and a reference pcr with published primers for the vp1 gene. nineteen samples resulted positive and one negative in both pcr, while another 4 samples were positive only in the vp3/vp1 pcr. these results indicate that the vp3/vp1 pcr is a sensitive, specific diagnostic test, suitable as an alternative to the expensive and time consuming in vivo virus isolation method, specially considering the difficult diagnosis of cav strains not readily adaptable to msb-1 cell culture.
High yield expression in a recombinant E. coli of a codon optimized chicken anemia virus capsid protein VP1 useful for vaccine development
Meng-Shiou Lee, You-Cheng Hseu, Guan-Hua Lai, Wen-Te Chang, Hsi-Jien Chen, Chi-Hung Huang, Meng-Shiunn Lee, Min-Ying Wang, Jung-Yie Kao, Bang-Jau You, Wen- Lin, Yi-Yang Lien, Ming-Kuem Lin
Microbial Cell Factories , 2011, DOI: 10.1186/1475-2859-10-56
Abstract: Significantly increased expression of the recombinant full-length VP1 capsid protein from chicken anemia virus was demonstrated using an E. coli expression system. The VP1 gene was cloned into various different expression vectors and then these were expressed in a number of different E. coli strains. The expression of CAV VP1 in E. coli was significantly increased when VP1 was fused with GST protein rather than a His-tag. By optimizing the various rare amino acid codons within the N-terminus of the VP1 protein, the expression level of the VP1 protein in E. coli BL21(DE3)-pLysS was further increased significantly. The highest protein expression level obtained was 17.5 g/L per liter of bacterial culture after induction with 0.1 mM IPTG for 2 h. After purification by GST affinity chromatography, the purified full-length VP1 protein produced in this way was demonstrated to have good antigenicity and was able to be recognized by CAV-positive chicken serum in an ELISA assay.Purified recombinant VP1 protein with the gene's codons optimized in the N-terminal region has potential as chimeric protein that, when expressed in E. coli, may be useful in the future for the development of subunit vaccines and diagnostic tests.Chicken anemia virus (CAV), is the causative agent of chicken anemia disease. The disease results in severe anemia, lymph organ atrophy and immunosuppression [1-3]. CAV is the sole member of the genus Gyrovirus of the Circoviridae family. Histopathological studies have also shown that CAV infection leads to aplasia of the bone marrow and the destruction of T lymphoid tissue in young chickens [4,5]. When chicks are infected with CAV, the mortality rate is often as high as 55% and morbidity rates of 80% have been reported [6]. Therefore, worldwide, CAV is an economically important veterinary virus that can seriously affect the poultry industry.VP1 protein (51 kDa) is the sole structural protein found within the CAV capsid. At a very late stage of the virus life
Molecular Characterization of Chicken Anemia Virus Circulating in Chicken Flocks in Egypt  [PDF]
Mohammed AboElkhair,Alaa G. Abd El-Razak,Abd Elnaby Y. Metwally
Advances in Virology , 2014, DOI: 10.1155/2014/797151
Abstract: Introduction. Although many previous studies reported detection of chicken anemia virus (CAV) in Egypt since 1990, genomic characterization of this circulating CAV has not been published. In the present study, four nucleotide sequences of detected CAV were genetically characterized. Methods. These nucleotide sequences were obtained from commercial chicken flocks in two different locations of Egypt during 2010. The target region for sequencing was 675?bp nucleotide of partial coding region of VP1 protein. The nucleotide and deduced amino acid sequences of the detected CAV were aligned and compared to worldwide CAV isolates including commonly used vaccine strains. Phylogenetic analysis of these sequences was also carried out. Results. Our results showed that all the Egyptian CAV sequences were grouped in one group with viruses from diverse geographic regions. This group is characterized by amino acids profile 75I, 97L, 139Q, and 144Q in VP1. The phylogenetic and amino acid analyses of deduced amino acid indicated that the detected CAV sequences differ from CAV vaccine strains. Conclusion. This is the first report that describes molecular characterization of circulating CAV in Egypt. The study showed that the detected CAV, in Egypt are field viruses and unrelated to vaccine strains. 1. Introduction Chicken anemia virus (CAV) is an economically important pathogen with a worldwide distribution. CAV is a small DNA virus with a closed circular, negative, single stranded DNA genome. It belongs to genus Gyrovirus of family Circoviridae [1]. The genome consists of three partially overlapping open reading frames encoding three viral proteins: VP1 (51.6?kDa), the major viral capsid protein, VP2 (24?kDa), a novel dual specificity protein phosphatase [2] that also probably acts as scaffolding protein during virion assembly [3], and VP3 (13.6?kDa), also called apoptin, which has been shown to have apoptotic activity in transformed cell lines [4]. VP1 shows the highest nucleotide variability; therefore, it is usually used for genetic characterization and molecular studies of CAV [5, 6]. Infection with CAV constitutes a serious economic threat, especially to the broiler industry and the producers of specific pathogen free (SPF) eggs. The clinical signs are mainly noticed in young chicks of 10–14 days of age, which acquire the infection vertically. Chickens older than 2-3 weeks of age are also susceptible to infection but only develop a subclinical disease evidenced by poor vaccine response [7]. The disease is characterized by aplastic anemia and generalized lymphoid
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