| Avian Leukosis (AL) is caused by the Avian Leukosis Virus (ALV), usually induce tumors, carcass abandoned and egg dropping to layers, and some other unknown side effects in chickens. ALV research could be traced back to the late19th century, but people did not pay attention to ALV for a long time until90s of the20th century, when ALV induced a serious myeloid leukemia in breeder. It was reported that ALV has resulted in huge losses to the poultry industry recent years. In this paper, we inves-tigated the epidemiology of ALV in Jiangsu and Anhui provinces with p27antigen detect kit, ALV A/B and J subgroup antibodies detect kits.At the same time we isolated the ALV and sequencing ALV whole gene. Based on the data of epidemiological surveys we selected two serious infected farms to start the eradication of ALV in Chinese local lines of chickens.1、 Epidemiological investigation of ALV infection in Jiangsu and Anhui provincesALV infection was investigated with three kinds of commercial kits for the detections of antibodies against subgruops A/B, J or specific antigen p27in more than7,000breeders including Highland, Roman, and some local strains from12large-scale farms in Jiangsu and Anhui provinces. The results showed that the infection of ALV was very serious in the breeders in these two provinces.66.7%(8/12) of the farms was found the infection of ALV A/B, and individual positive rate was6.4%;83.3%(10/12) of the farms had the infection of ALV J, individual positive rate was5.6%;100%(12/12) of the farms was p27antigen positive in chicken flocks, individual positive rate was21.2%. Besides62.5%(5/8)of the farms also showed mixture infections of ALV J and ALV AB in the same chickens. The tracing detection of different ages showed that the positive rates were higher at6w and22w. The results will be helpful for eradication program latter.2、Isolation, identification and sequences analysis of the virus A subgroup J avian leukosis virus (ALV-J) from hy-line layer suspected ALV infection in clinic, designated as ALV-J JS09GY07. was isolated with DF-1cells and identified by ELISA, PCR and immunofluorescence assay with specific monoclonal antibody JE9to ALV-J. With immunohistological assay, positive antigens could been found in kidney and lung from the infected chickens. The complete cDNA sequence of Chinese field strain ALV-J JS09GY07was amplified by polymerase chain reaction (PCR). The genome of the virus has long7659nucleotides (nt). The nucleotides of the virus were compared with that of other ALV-J strains.205bp deletion was found in Non-functional TM sequence compared with HPRS-103. The results revealed that the homology of full nucleotide sequences was95.2%and94.3%with the reference strains ADOL-7501and HPRS103respectively,94.6%～95.0%with4Chinese commercial meat-type chickens reference strains (NX010、 YZ9902、 JS-nt、 NM2002-1),94.7%～99.4%with the other4Chinese commercial layers reference strains (SD07LK1、NHH、 JS09GY3、JS09GY6).3、 Preliminary eradication of ALV for Chinese local lines of chickensA preliminary eradication program for ALV was carried in two local chickens farms DYAH91and DYJS31.This program included all positive chickens were token away for the p27antigen (cloaca), p27antibody, A/B subgroup of antibody, J subgroup of antibodies or virus isolation. After two generations detection, the positive rates of ALV infection was significantly lower than the previous generation. p27antigen positive rate in farm DYAH91was decreased from14.4%to8.1%, p27antibody positive rate from3.4%to1.0%, A/B antibody positive rate from5.7%to2.2%, virus isolation positive rate from3.1%to0.45%;In the farm DYJS31, p27antigen positive rate was decreased from40.7%to2.8%, p27antibody positive rate from18.7%to3.3%, A/B subgroup antibody positive rate from10.2%to1.4%, J subgroup antibodies positive rate from1.7%to1.4%, virus isolation positive rate from4.1%to0%. The results indicated that this program is very effective in ALV eradication. |
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