Diagnosis of Marek's disease in Ningdu yellow chicken as well as cloning and sequence analysis of the viral meq genes
[Objective]The study was conducted to diagnose the cause of yellow chicken disease in a chicken farm in Ningdu County,Jiangxi Province.[Method]Through pathological dissection and PCR testing,this experiment confirmed that the yellow chickens in the farm were infected with Marek's disease.In addition,the full sequence of the meq gene of the virus was amplified,cloned,sequenced,and analyzed.[Result]The diseased chickens exhibited symptoms of"splitting"neurological disorder.Pathological examination revealed varying sizes of gray-white nodules on the surface of organs such as the heart,liver,and spleen,as well as glandular stomach erosion and bleeding.PCR identification confirmed positive for Marek's disease virus(MDV).The full length of MDV meq clone gene was 1 020 bp with nucleotide identities ranging from 98.8%to 99.8%and amino acid identities ranging from 97.1%to 99.7%.There were nine mutations in amino acid in meq genes,with three mutations in proline-rich repeat sequences(PPPP)and two PPPP-PR/APP mutations.[Conclusion]This strain belongs to the same branch as recently highly virulent or very virulent strains found domestically,showing similar amino acid mutations.Therefore,it is inferred that this isolated strain is at least a highly virulent strain in pathogenicity.This study provides a theoretical basis for clinical diagnosis of Marek's disease and an important reference for analyzing MDV variations.
万方数据
维普
