MOLECULAR EVIDENCE OF MAREK’S DISEASE VIRUS EVOLUTION FROM COMMERCIAL POULTRY FLOCKS IN IRAQ | ||
| Assiut Veterinary Medical Journal | ||
| Article 50, Volume 71, Issue 187, October 2025, Pages 655-669 PDF (1.69 M) | ||
| Document Type: Research article | ||
| DOI: 10.21608/avmj.2025.353190.1560 | ||
| Authors | ||
| ABDULRASOOL, LAYTH MOHAMMED SALIH* ; ALLAWE, AIDA BARA | ||
| Department of Microbiology, College of Veterinary Medicine, University of Baghdad, Baghdad, Iraq. | ||
| Abstract | ||
| The poultry industry is facing serious threats caused by avian pathogens, which cast a shadow over its economic impact, among them Marek’s Disease Virus (MDV). The threat of MDV appeared due to oncogenicity and immunosuppression, controlled successfully by vaccination and biosafety measures. A successful vaccination outcome requires identifying circulating viruses; otherwise, vaccine failure occurs. To better understand the circulating virus, 160 samples were collected from different layers of farms in Iraq. Samples were filtered initially by real-time PCR, and positive samples were used to amplify viral genes Meq, PP38, and later to study viral virulence by detection of the 132bp repeat region. PCR products of Meq and PP38 genes were sent to a commercial sequence company (Macrogene Inc./South Korea). Feedback data were analyzed by MEGA11 software; phylogenetic trees were created by Bio Edit software. The results showed a high matching rate of the two studied Meq gene samples against the reference strain, as well as with already described strains from Japan, Germany, France, and China, but varied from the previously described isolates from Iraq. Regarding PP38, the four analyzed isolates occupied two clusters: the less variable isolates (A1, A2, and A3) located adjacent to the Thailand strain, while the other involved the higher variable isolate 2P close to the Pakistan isolate. All recent local isolates were of high virulence based on 132 tandem repeat region amplification. In conclusion, the recent study provides molecular evidence for mutations with MDV virulence genes that require more attention for vaccine selection to control the disease. | ||
| Keywords | ||
| 132 tandem repeat; Marek’s virus; Meq genPP38 gene; Phylogenic analysis | ||
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