Serological Investigation Of Subgroup J Avian Leukosis And Strains Isolation And Dentification In Anhui Province

Subgroup J avian leukosis in chickens is a myelocytomaIosis induced by ALV-J(Avian leukosis virus subgroup J). Lots of cases were reported since ALV-J was discoveredin meat-type chickens in1988by Payne L and his companions. In1999， ALV-J wasdetected first from commercial broiler in China， then ALV-J was reported throughout allthe country， not only meat-type chickens and egg-type chickens， also local chickenfound strains，the phenomenon indicated that ALV-J had existed widely in China. To obtaindetailed message of ALV-J， we had gathered randomly sample of890from22farms ofdifferent areas in Anhui province， had detected serum antibody against ALV-J by ELISAkit. The results showed that different regions， different varieties (lines)， differentgenerations， different genders and different ages in chickens were prevalence positiveinfection of ALV-J. Different chickens were different degree of positive infection and theoverall positive infection rate was9.9%.The Jiangnan area positive infection rate was100%and Jianghuai area positive infection rate was71.4%， but the Huaibei area was60%.Local varieties (lines) of chicken positive infection rate was18.8%， and meat-typechickens positive infection rate was8.2%， but egg-type chickens positive infection ratewas5.9%Goods generation of layer farms positive infection rate was10.8%but the rate ofpositive infection of generation parents was9.7%. The rate of positive infection of cockswas12.6%， but hens was8.1%.In the date of growth on chickens， young chickenpositive infection rate higher than adult chickens.One ALV-J，which named AH1101strain，was isolated from a broiler chicken in thecity of Taihu and the oher ALV-J，which named AH1102strain，was isolated from agoods generation of layer farms in the city of Susong in Anhui Province by inoculated thesamples into DF-1and PCR detected method.The gp85sequences deduced amino acid oftwo strains isolated had9.3％～29.7％homology to reference strains from A to Esubgroups. And the homology among subgroups J was in the range of82.1％～99.4％.Strain isolated from the boiler chicken had97.1％homology to Strain HPRS-103fromBritish and had99.4％homology to strain SD09TA04and SDYC02J ALV-J from China.Sequence analysis showed that the mutation rates of nucleotide and amino acid was1.0%and6.5%.The Layer flock isolated strain had89.0％. the mutation rates of nucleotide andamino acid was8.0％and为9.1％.The homology of the two strains isolated was85.4％.There were48mutations and6defections of bases and26mutations and the3deletion of amino acid Between AH1101strain and AH1102strain. Most mutations and deletion of nucleotide and amino acid in the hypervariable region of hr1、hr2and variableregion of vr2、vr3and surrounding areas. Evolutionary analysis further indicated thatisolated strain AH1101and separation strains SD09TA04and SDYC02J from Shandongprovince might be the same origin. Isolated strain AH1102might be recombinant strainbecause of genetic and variation.The results showed that two isolated strains might befurther relationship.We had determined that ALV-J of different area， different varieties (lines)， ages，gender and ages of the flock prevalence existed in Anhui Province by systematicserological survey，but positive infection rates were not the same.Two strains isolated ofALV-J will provide theoretical basis and material basis for molecular epidemiology andALV-J control investigation.