Detection and molecular characterization of a highly oncogenic Marek's disease virus from vaccinated hens in Turkey

Hasan, Asif; Karabulut, Burak; Ozbek, Remziye; Öngör, Hasan; Timurkaan, Necati; Tonbak, Şükrü

doi:10.4149/av_2021_212

Cited by 5 publications

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“…In the last decade, the vv + pathotype of MDV-1 has been reported to be predominant [ 16 , 17 , 38 ] that may explain why the disease occurred in vaccinated chicken flocks. Previous studies conducted in our country have also revealed the presence of MDV-1 field isolates (pathotype vv+) in vaccinated chickens with disease manifestations [ 24 , 25 ]. Very virulent (vv) and vv + pathotypes of MDV-1 frequently induce higher mortality and more visceral lymphomas, and have the tendency to more frequently break through genetic host resistance or immunity induced by vaccination.…”

Section: Discussionmentioning

confidence: 91%

First report of Serotype-1 Marek’s disease virus (MDV-1) with oncogenic form in backyard turkeys in Turkey: a molecular analysis study

et al. 2022

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Background Marek’s disease (MD) is a lymphoproliferative disease caused by Gallid alphaherpesvirus 2 (GaHV-2, MDV-1), which primarily affects chickens. However, the virus is also able to induce tumors and polyneuritis in turkeys, albeit less frequently than in chickens. Results This is the first study in Turkey reporting the molecular characterization of a MDV-1 strain detected in a flock of backyard turkeys exhibiting visceral lymphoma. Here, MEQ, vIL-8, pp38 and 132-bp tandem repeat regions, which are frequently preferred in the pathotyping of MDV-1, were examined. It was determined that the MEQ gene of MDV-1/TR-21/turkey strain obtained in the present study encoded 339 amino acids (1020 nt) and had four proline-rich repeat regions (PPPP). Based on the nucleotide sequence of the MEQ gene of the MDV-1/TR-21/turkey strain, a phylogenetic tree was created using the MEGA-X software with the Maximum Likelihood Method (in 1000 replicates). Our strain was highly identical (> 99.8) to the Italian/Ck/625/16, Polish (Polen5) and some Turkish (Layer-GaHV-2-02-TR-2017, Tr/MDV-1/19) MDV-1 strains. Also, nt and aa sequences of the MEQ gene of our strain were 99.1 and 99.41% identical to another Turkish strain (MDV/Tur/2019) originated from chickens. Sequence analysis of pp38 and vIL-8 genes also supported the above finding. The identity ratios of nucleotide and amino acid sequences of vIL-8 and pp38 genes of MDV-1/TR-21/turkey strain were 99.64–100% and 99.79–100%, respectively, when compared with those of the Polish strain. According to 132-bp tandem repeat PCR results, the MDV-1/TR-21/turkey strain had five copies. Conclusions These results suggested that the MDV-1/TR-21/turkey strain obtained from backyard turkeys can be either very virulent or very virulent plus pathotype, though experimental inoculation is required for precise pathotyping.

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Section: Discussionmentioning

confidence: 91%

First report of Serotype-1 Marek’s disease virus (MDV-1) with oncogenic form in backyard turkeys in Turkey: a molecular analysis study

et al. 2022

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“…vvMDV-1 and vv+MDV-1 field strains are increasingly reported in many countries of the world, including Turkey, and cause significant yield and economic losses by affecting broilers, breeders, and com- mercial layers (Zhuang et al, 2015;Kennedy et al, 2017;Yilmaz et al, 2020;Abayli et al, 2021, Lounas et al, 2021.…”

Section: Discussionmentioning

confidence: 99%

Viral analysis of tumor-bearing chicken flocks in Turkey over the last decade (2011-2020)

Abayli,

Tonbak,

Ozbek

et al. 2023

J Hellenic Vet Med Soc

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Marek’s disease virus (MDV), avian leukosis virus (ALV), and reticuloendotheliosis virus (REV) are important viral agents associated with neoplastic diseases that cause economic losses for the poultry industry worldwide. Immunosuppressive agents such as infectious bursal disease virus (IBDV), REV, and chicken anemia virus (CIAV) expose birds to other infections and reduce production performance. In this context, we aimed to identify and perform molecular analysis of the aforementioned viral infections (ALV, CIAV, IBDV, MDV, and REV) in the tissues of tumor-bearing chickens. Clinical samples were taken from 11 chicken flocks of different ages and races from some provinces (Adıyaman, Diyarbakır, Elazığ and Malatya) in Turkey between 2011 and 2020. MDV positivity was determined in all 11 chicken flocks, while ALV endogenous sequences were determined in two of 11 MDV positive chicken flocks. CIAV and ALV sequences were found together in two of 11 MDV positive chicken flocks. The ALV subgroup J, IBDV, and REV were not detected in any of the chicken flocks. According to phylogenetic analysis, Turkish MDV strains obtained from this study were included in two different genogroups (genogroups I and II) with other MDV strains with pathotypes ranging from virulent (v) to very virulent plus (vv+). Co-infections of ALV and CIAV with MDV may worsen the current clinical situation. In this study, MDV was detected in two flocks vaccinated with HVT. Other chickens were not vaccinated against any of the viral agents studied. Increasing vaccination and preventive measures against these viral pathogens in poultry in Turkey is recommended.

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“…MDV reduces the performance of innate and adaptive immunity in chickens ( 38 , 39 ), and vaccination prevents and controls disease occurrence ( 3 , 4 ). CVI988/Rispens is the most effective vaccine currently available, but as more highly virulent viruses emerge, vaccine-induced immunity may be breached ( 7 , 40 , 41 ). Our previous studies have shown that vIL8 deletion in the 686BAC Δ meq virus eliminated lymphoid organ atrophy and protected against vv+ MDV challenge ( 9 ).…”

Section: Discussionmentioning

confidence: 99%

Fully Attenuated meq and pp38 Double Gene Deletion Mutant Virus Confers Superior Immunological Protection against Highly Virulent Marek’s Disease Virus Infection

et al. 2022

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Detection and molecular characterization of a highly oncogenic Marek's disease virus from vaccinated hens in Turkey

Cited by 5 publications

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First report of Serotype-1 Marek’s disease virus (MDV-1) with oncogenic form in backyard turkeys in Turkey: a molecular analysis study

First report of Serotype-1 Marek’s disease virus (MDV-1) with oncogenic form in backyard turkeys in Turkey: a molecular analysis study

Viral analysis of tumor-bearing chicken flocks in Turkey over the last decade (2011-2020)

Fully Attenuated meq and pp38 Double Gene Deletion Mutant Virus Confers Superior Immunological Protection against Highly Virulent Marek’s Disease Virus Infection

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