Marek’s Disease and Differential Diagnosis with Other Tumor Viral Diseases of Poultry

Gimeno, Isabel M.

doi:10.1016/b978-0-444-52512-3.00193-5

Cited by 4 publications

(3 citation statements)

References 94 publications

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“…CVI988/Rispens). In the field, economic losses due to MD are mostly associated with the acute form of the disease, characterized by visceral lymphomas; however, virus‐induced immunosuppression might be relevant too, even if its impact is very difficult to assess (Gimeno, ; Gimeno & Schat, ).…”

Section: Introductionmentioning

confidence: 99%

Marek's disease viruses circulating in commercial poultry in Italy in the years 2015–2018 are closely related by their meq gene phylogeny

Mescolini

Lupini

Davidson³

et al. 2019

Transbound Emerg Dis

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Marek's disease (MD) is a lymphoproliferative disease important to the poultry industry worldwide; it is caused by Gallid alphaherpesvirus 2 (GaHV‐2). The virulence of GaHV‐2 isolates has shifted over the years from mild to virulent, very virulent and very virulent +. Nowadays the disease is controlled by vaccination, but field strains of increased virulence are emerging worldwide. Economic losses due to MD are mostly associated with its acute form, characterized by visceral lymphomas. The present study aimed to molecularly classify a group of 13 GaHV‐2 strains detected in vaccinated Italian commercial chicken flocks during acute MD outbreaks, and to scrutinize the ability of predicting GaHV‐2 virulence, according to the meq gene sequence. The full‐length meq genes were amplified, and the obtained amino acid (aa) sequences were analysed, focusing mainly on the number of stretches of four proline molecules (PPPP) within the transactivation domain. Phylogenetic analysis was carried out with the Maximum Likelihood method using the obtained aa sequences, and the sequences of Italian strains detected in backyard flocks and of selected strains retrieved from GenBank. All the analysed strains showed 100% sequence identity in the meq gene, which encodes a Meq protein of 339 aa. The Meq protein includes four PPPP motifs in the transactivation domain and an interruption of a PPPP motif due to a proline‐to‐serine substitution at position 218. These features are typically encountered in highly virulent isolates. Phylogenetic analysis revealed that the analysed strains belonged to a cluster that includes high‐virulence GaHV‐2 strains detected in Italian backyard flocks and a hypervirulent Polish strain. Our results support the hypothesis that the virulence of field isolates can be suggested by meq aa sequence analysis.

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Section: Introductionmentioning

confidence: 99%

Marek's disease viruses circulating in commercial poultry in Italy in the years 2015–2018 are closely related by their meq gene phylogeny

Mescolini

Lupini

Davidson³

et al. 2019

Transbound Emerg Dis

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“…Marek's disease (MD) causes huge economic impact by directly causing significant levels of mortality due to visceral lymphomas. In addition, the sub‐clinical immunosuppression induced by virulent strains also cause production loss indirectly (Gimeno, 2014). The Marek's disease virus (MDV), classified as gallid alphaherpes virus 2 (GaHV‐2), belongs to the genus Mardivirus of the sub‐family Alphaherpesvirinae , family Herpesviridae (International Committee on Taxonomy of Viruses, 2017).…”

Section: Introductionmentioning

confidence: 99%

Molecular detection and phylogenetic analysis of Marek's disease virus virulence‐associated genes from vaccinated flocks in southern India reveals circulation of virulent MDV genotype

Kannaki

Priyanka

Nishitha

et al. 2021

Transbounding Emerging Dis

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Marek's disease (MD) is a re‐emerging viral disease of chickens and a serious economic threat to the poultry industry worldwide. Continuous surveillance with molecular investigation is essential to monitor the emergence of virulent Marek's disease virus (MDV) strains and to devise any appropriate vaccination strategy and implement bio‐security programmes. In the present study, we investigated the cases of MD outbreaks in vaccinated poultry flocks. The MD outbreak was confirmed through necropsy (mainly visceral tumours), histopathology and viral gene specific PCR. The pathotypes of the field MDV strains were assessed by molecular analysis of three virulence‐associated genes, meq, pp38 and vIL‐8. The Meq sequence of the field strains analyzed in this study lacked the 59 aa unique to mild strains, indicating that they are potentially virulent strains. Mutation at position 71 and the presence of five proline rich repeats in the transactivation domain, both associated with virulence were observed in these strains; however, the signature sequences specific to very virulent plus strains were absent. Phylogenetic analysis of meq oncogene sequences revealed clustering of the field strains with North Indian strains and with a very virulent plus ATE 2539 strain from Hungary. Analyses of pp38 protein at positions 107 and 109 and vIL‐8 protein at positions 4 and 31 showed signatures of virulence. Sequence and phylogenetic analysis of oncogene and virulence‐associated genes of field MDVs from vaccinated flock indicated that these strains possessed molecular features of virulent strains.

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“…Marek's disease (MD) causes huge economic impact by directly causing significant levels of mortality due to visceral lymphomas. In addition, the sub-clinical immunosuppression induced by virulent strains also cause production loss indirectly (Gimeno, 2014). The Marek's disease virus (MDV), classified as gallid alphaherpes virus 2 (GaHV-2), belongs to the genus Mardivirus of the subfamilyAlphaherpesvirinae , family Herpesviridae (International Committee on Taxonomy of Viruses, 2017).…”

Section: Introductionmentioning

confidence: 99%

Molecular detection and phylogenetic analysis of Marek's disease virus oncogenes from vaccinated flocks in southern India reveals circulation of very virulent MDV genotype

Ramasamy

Priyanka

Nishitha

et al. 2021

Preprint

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Marek’s disease (MD) is a re-emerging viral disease of chicken and a serious economic threat to poultry industry worldwide. Continuous surveillance with molecular investigation is mandatory to monitor the emergence of virulent MDV strains and to devise any appropriate vaccination strategy and implement bio-security programs. In the present study, we investigated the cases of MD outbreaks in vaccinated poultry flocks. The MD outbreak was confirmed through necropsy (majorily visceral tumors), histopathology and viral gene specific PCR. The pathotypes of the field MDV strains were assessed by molecular analysis of three oncogenes -Meq, pp38 and vIL-8. The Meq sequence of the field strains analyzed in this study lacked the 59 aa unique to mild strains indicating that they are virulent strains. Mutation at position 71 and presence of five proline rich repeats in the transactivation domain, both associated with virulence were observed in these strains, however, the signature sequences specific to very virulent plus strains were absent. Phylogenetic analysis of Meq gene sequences revealed clustering of the field strains with North Indian strains and with a very virulent plus ATE 2539 strain from Hungary. Analyses of pp38 protein at positions 107 and 109 and vIL-8 protein at positions 4 and 31 showed signatures of virulence. Sequence and phylogenetic analysis of oncogenes from field MDVs from vaccinated flock indicated these strains possessing molecular features of very virulent strains. Our data shows here that Meq, vIL-8 and pp38 genes can be used as markers for molecular analysis to decipher the pathotype of MDV strains. Our present study suggests evolution of virulent MDV induced by vaccination.

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Marek’s Disease and Differential Diagnosis with Other Tumor Viral Diseases of Poultry

Cited by 4 publications

References 94 publications

Marek's disease viruses circulating in commercial poultry in Italy in the years 2015–2018 are closely related by their meq gene phylogeny

Marek's disease viruses circulating in commercial poultry in Italy in the years 2015–2018 are closely related by their meq gene phylogeny

Molecular detection and phylogenetic analysis of Marek's disease virus virulence‐associated genes from vaccinated flocks in southern India reveals circulation of virulent MDV genotype

Molecular detection and phylogenetic analysis of Marek's disease virus oncogenes from vaccinated flocks in southern India reveals circulation of very virulent MDV genotype

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