| A polymerase chain reaction(PCR) methold was developed for detecting duck plague virus.We found a 765-EcoR I fragment which cloned frome the genome of the duck plague vaccine(DP-VAC) virus in the GeneBank.The fragment sequence was similar to the 3'ends of an undefined open read frame and the gene for DNA polymerase protein in other herpesviruses.A set of primers were found to be specific for the DP-VAC virus.The specificity was tested with genome templates from other avian herpesviruses,including those from the chicken (Marek's Disease Virus,MDV and Infectious Laryngotracheitis VirusJLTV) and the duck(Duck Hepatitis Virus DHV, Pasteurella multocida, Escherichia coli, Salmonella anatum and Riemerella Anatipestifer),but amplicons were not produced.This PCR test is highly specific for duck plague vaccine strain,equivalent to five genome copies.The PCR can detect lOfg of DNA from the duck plague vaccine strain. The test is more 10 times sensitive than tissue culture for detecting duck plague virus.The speed,sensitivity,and specificity of this PCR provide a greatly improved diagnostic and reaction tool for studying the epizootiology of duck plague.In this paper the study on the regularity of duck plague virus vaccine strain distributing in the ducklings was reported. The ducklings were Sichuan Duck with maternal antibody, which have been immunized by different routes(Subcutaneous, Nose dripping and Orally). The results indicated:(2)The DPV DNA can be detected in the heart,liver,spleen, kidney,bursa of fabricius,thymus,pancreas,medulla oblongata,cerebrum,cerebellum from vaccined ducklings 4 hours after subcutaneous injected.8 hours past, all the tissues's DPV DNA can be found out.(2)The DPV DNA can be detected in tongue and esophagus from ducklings 4 hours past vaccined orally,and be detected in heart,liver,spleen,kidney,thymus,pancrea,medulla oblongata,, cerebrum, cerebellum,tongue, esophagus and blood.(3)There was no DPV DNA in 4 hours after nose dripping route immunized in any tissues of duckling. 8 hours later, the DPV DNA were found out in heart,liver,spleen,kidney,thymus,medulla oblongata,cerebrum, cerebellum,tongue,esophagus and blood.(4)The tissues which be detected the earliest and the highest efficiency were the liver and brain (cerebrum, cerebellum and medulla oblongata). |
