Avian leukosis virus subgroup – J as a contaminant in live commercially available poultry vaccines distributed in Nigeria (original) (raw)
Related papers
2020
In this study the reverse transcriptase polymerase chain reaction (RT- PCR) and the enzyme linked immunosorbent assay (ELISA) were utilized for screening of different live avian viral vaccines to detect biocontamination with avian leukosis virus (ALV). By using ELISA test, the group specific antigen of avian leukosis virus was detected in three batches of Marek's disease virus (MDV) vaccines as well as in one batch of avian encephalomyelitis virus (AEV) vaccine. To identify the subgroup of the contaminant ALV, contaminated samples were tested by RT – PCR using sets of primers specific to the envelope <em>(env)</em> gene of avian leukosis virus. Virus subgroup was determined by running simultaneously 6 RT- PCR reactions. Results of RT- PCR revealed detection of subgroup E specific product in all four ELISA – positive vaccine batches. No PCR products were detected with primers designed for detection of exogenous virus subgroups A, B, C, D, or J. Trials for isolation of...
Veterinary World
Avian leukosis viruses (ALVs) in poultry may induce a variety of deleterious effects including tumors, increased mortalities, growth retardation and decrease in egg size and production that led to considerable economic losses. The identification of avian leukosis viruses (ALVs) in imported Marek’s disease (MD) vaccines has raised concern about transmission of these retroviruses to vaccine recipients esp. poultry breeding stocks, so Egypt as one of importing countries requires freedom of infection with ALVs in such vaccines. Subgroup specific RT-PCR was undertaken on isolated RNA from 13 obtained commercial MD vaccines using six pairs of primers that correspond to envelope glycoprotein gene (gp85) which determines possible contamination with the six ALV subgroups: A, B, C, D, E, and J. The results indicated that RT-PCR assay for ALV-gp85 subgroup-E was positive for eight out of thirteen (61.5%) tested MD vaccines, while primers designed to detect subgroup A and J ALVs were positive f...
Detection and Characterization of Avian Leukosis Virus in Marek's Disease Vaccines
Avian Diseases, 2006
Avian leukosis virus (ALV) infection in chickens is known to induce increased mortality, tumors, delayed growth, and suboptimal egg production. Countries importing specified pathogen-free eggs, vaccines, and poultry breeding stock require freedom of infection or contamination with ALV in such products among other avian pathogens. Recently, ALV was found as a contaminant in a limited number of commercial poultry vaccines, even after routine quality assurance procedures cleared the vaccines for commercialization. The contaminated vaccines were promptly withdrawn from the market, and no direct detrimental effects were reported in poultry vaccinated with such vaccines. We describe herein the characterization in vitro of the contaminant viruses. All exogenous viruses detected in four vaccine lots belong to subgroup A of ALV based on cell receptor interaction, subgroup-specific polymerase chain reaction (PCR), envelope gene sequencing, and virus neutralization. A combination of thermal treatment and serial dilutions of the contaminated vaccines facilitated detection of contaminating ALVs in cell culture coupled with antigen-capture enzyme-linked immunosorbent assay. Subgroup-specific PCR readily detected ALV-A directly in the contaminated vaccines but not in naive vaccines or cell controls. Our methods are proposed as complementary procedures to the currently required complement fixation for avian leukosis test for detection of ALV in commercial poultry vaccines.
Avian leukosis virus (ALV) belongs to the family Retroviridae and causes considerable economic losses to the poultry industry. Following an outbreak associated with high mortality in a broiler flock in northern part of Malaysia, kidney tissues from affected chickens were submitted for virus isolation and identification in chicken embryonated egg and MDCK cells. Evidence of virus growth was indicated by haemorrhage and embryo mortality in egg culture. While viral growth in cell culture was evidenced by the development of cytopathic effects. The isolated virus was purified by sucrose gradient and identified using negative staining transmission electron microscopy. Further confirmation was achieved through next-generation sequencing and nucleotide sequence homology search. Analysis of the viral sequences using the NCBI BLAST tool revealed 99-100% sequence homology with exogenous ALV viral envelope protein. Phylogenetic analysis based on partial envelope sequences showed the Malaysian isolate clustered with Taiwanese and Japanese ALV strains, which were closer to ALV subgroup J, ALV subgroup E, and recombinant A/E isolates. Based on these findings, ALV was concluded to be associated with the present outbreak. It was recommended that further studies should be conducted on the molecular epidemiology and pathogenicity of the identified virus isolate.
Diversity of endogenous avian leukosis virus subgroup E (ALVE) insertions in indigenous chickens
Article, 2020
Background: Avian leukosis virus subgroup E (ALVE) insertions are endogenous retroviruses (ERV) that are restricted to the domestic chicken and its wild progenitor. In commercial chickens, ALVE are known to have a detrimental effect on productivity and provide a source for recombination with exogenous retroviruses. The wider diversity of ALVE in non-commercial chickens and the role of these elements in ERV-derived immunity (EDI) are yet to be investigated. Results: In total, 974 different ALVE were identified from 407 chickens sampled from village populations in Ethiopia, Iraq, and Nigeria, using the recently developed obsERVer bioinformatics identification pipeline. Eighty-eight percent of all identified ALVE were novel, bringing the known number of ALVE integrations to more than 1300 across all analysed chickens. ALVE content was highly lineage-specific and populations generally exhibited a large diversity of ALVE at low frequencies, which is typical for ERV involved in EDI. A significantly larger number of ALVE was found within or near coding regions than expected by chance, although a relative depletion of ALVE was observed within coding regions, which likely reflects selection against deleterious integrations. These effects were less pronounced than in previous analyses of chickens from commercial lines. Conclusions: Identification of more than 850 novel ALVE has trebled the known diversity of these retroviral elements. This work provides the basis for future studies to fully quantify the role of ALVE in immunity against exogenous ALV, and development of programmes to improve the productivity and welfare of chickens in developing economies. © The Author(s) 2020. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article' s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article'
Zenodo (CERN European Organization for Nuclear Research), 2022
Avian Leukosis virus (ALV) is known to cause oncogenic diseases in chickens world over. This study aimed to determine the seroprevalence of ALV among indigenous chickens in Karmo and Gwagwa, two suburban communities in the Federal Capital Territory, Nigeria. A total of 180 indigenous chickens were tested for ALV p27 antigen using an Enzyme linked immunosorbent assay technique (Ringbio, Beijing China). The overall prevalence of ALV was 47.2 %, ALV was found to be higher among chickens in Karmo than in Gwagwa 54.1% vs.45.15, but this was not statistically different (Chi: 0.3917, P=0.531). This study envisages the establishment of an effective control strategy in our study area, because of known deleterious economic impact of ALV on chickens.
In an attempt to determine the seroprevalence of avian leukosis virus (ALV) in exotic broiler chickens and Nigerian local chickens in Zaria, Nigeria, a total of 600 sera (300 from exotic broiler chickens and 300 from Nigerian local chickens), obtained from the live bird market in Zaria, Nigeria, were tested for ALV p27 antigen by the antigen capture-enzyme linked immunosorbent assay (ac-ELISA) technique. The age range of the Nigerian local chickens sampled in this study was 6-24 months, while that of the exotic broiler chickens used in this study was 2-3 months. Fourteen out of the 300 sera obtained from the exotic broiler chickens tested positive to ALV p27 antigen, which represents 4.70%, while 180 of the 300 Nigerian local chicken sera were confirmed positive to the antigen, representing 60.00%. Thirteen (92.86%) of the fourteen sera from the exotic broiler chickens were lowly positive (ELISA Units range of 10-20%) to ALV p27 antigen, while only one (7.14%) serum sample was moderately positive to ALV p27 antigen with an ELISA Unit of 29.33%. Of the 180 sera from the Nigerian local chickens that tested positive to ALV p27 antigen , 79 (43.89%) were lowly positive with ELISA Units ranging from 10.67% to 21.33%, while 101 (56.11%) serum samples were moderately positive to ALV p27 antigen with ELISA Units ranging from 28.0% to 73.33%. A higher seroprevalence of ALV was detected in Nigerian local chickens than the exotic broiler chickens.
2016
The present study was designed with a view to identify the Avian Leukosis Virus (ALV) by direct Enzyme Linked Immunosorbent Assay (ELISA) as well as to know the prevalence of ALV in different age groups of layer birds at Dinajpur district of Bangladesh. The birds were categorized into three groups, namely group A (brooder) included bird aged 13 days, group B (grower) included bird aged 16 weeks and lastly group C (layer) included bird aged 32 weeks. In this study a total of 92 cloacal swab samples were examined and 13 positive cases of ALV was found among which 5, 4 and 4 positive samples were in grower, brooding and layer chickens respectively. This study showed that ALV positive cases were 14.13% in layer birds whereas 14.5% positive cases in Sonali chicken and 13.3% in case of Hy-Line brown chicken. The inoculation of cloacal swab was done into five 10 days old embryonated chicken eggs through yolk sac route. After 5 days of inoculation death of the all embryos with haemorrhage was observed indicating the prevalence of Avian Leukosis Virus in the study area of Bangladesh. Since Avian Leukosis Virus transmitted both horizontally and vertically therefore measures to prevent spread are more demanding.
Acta Veterinaria, 2021
Previous reports indicate high seroprevalence of avian leukosis virus (ALV) p72 antigen in layer flocks suspected to have Marek’s disease (MD) in Kaduna and Plateau States. However, the specific subgroups responsible for ALV infection in layers in the States are still unknown, hence the need for this study. Therefore, the objective of this study was to determine the antibody profiles of ALV subgroups A/B and J in layer flocks suspected to have MD in Kaduna and Plateau States. Sera from 7 and 16 layer flocks suspected to have MD in Kaduna and Plateau States respectively, were screened for the presence of antibodies to ALV subgroups A/B and J using IDEXX enzyme linked immunosorbent assay (ELISA) kits. Out of the seven layer flocks screened in Kaduna State, antibodies to ALV subgroup A/B was detected in six of the flocks (85.7%), while antibodies to ALV subgroup J was detected in only one flock (14.3%). Antibodies to both ALV subgroups A/B and J were detected in one flock (14.3%), whic...