Epidemiological Investigation Of Avian Leukosis Virus Infection In Zhenjiang And It’s Eradication

Avian leukosis(AL)is caused by the avian leukosis virus(ALV).ALV usually induces tumors,carcass abandoned and egg dropping to layers,and some other unknown side effects in chickens.The research about ALV could be traced back to the late 19th century,however,the disease caused by ALV had not been paid attention for a long time until 90s of the 20th century,when ALV induced a serious myeloid leukemia in breeder.So far,the diseases induced by ALV has resulted in huge losses to the poultry industry.In this paper,the epidemiology of ALV in Zhenjiang was investigated by using p27 antigen detect kit.In addition,the isolation of ALV and the sequencing of the ALV whole genome were performed.Based on the data of epidemiological surveys,two farms from Zhenjiang were selected to start the ALV eradication in the domestic chickens.1、Epidemiological investigation of ALV infection in ZhenjiangALV infection was investigated with p27 antigen detect kit in more than 7,000 breeders of some local strains from 6 large-scale farms in Zhenjiang.The results showed that the infection of ALV was very serious in the breeders in Zhenjiang.100%(6/6)of the farms was p27 antigen positive in chicken flocks.And the individual positive rate in meconium,cloacal samples and blood samples was 19.02%,18.51%and 7.73%respectively.The results will be helpful for eradication program latter.2、Isolation and identification of ALVA subgroup J avian leukosis virus(ALV-J)from blood samples,named as ALV-J ZJ180421,was isolated with DF-1 cells and identified by ELISA and immunofluorescence assay with specific monoclonal antibody JE9 to ALV-J.The complete cDNA sequence of Chinese field strain ALV-J ZJ180421 was amplified by polymerase chain reaction(PCR).The nucleotides of the virus were compared with that of other ALV-J strains.Sequence analysis demonstrated that the genome of ZJ180421 was more similar to that of HPRS-103 and the homology between the two strains was 94.7%.3.Preliminary eradication of ALV for Chinese domestic chickens in ZhenjiangA preliminary eradication program for ALV was carried in two local chickens farms No.1 and No.2.In this program,all the positive chickens detected by the p27 antigen(cloaca)and virus isolation were token away.After two generations eradication,the positive rates of ALV infection was significantly lower than the previous generation.p27 antigen positive rate in farm 1 was decreased from 17.3%to 6.9%,virus isolation positive rate from 5.3%to 2.46%;In the farm 2,p27 antigen positive rate was decreased from 18.9%to 8.2%,virus isolation positive rate from 4.3%to 0.9%.All these results indicated that the program used is very effective for ALV eradication.