title: Development of a loop-mediated isothermal amplification assay for rapid detection of subgroup J avian leukosis virus.
abstract: Infection of breeder flocks in China with subgroup J avian leukosis virus (ALV-J) has increased recently. In this study, we have developed a loop-mediated isothermal amplification (LAMP) assay for rapid detection of ALV-J from culture isolates and clinical samples. The ALV-J-specific LAMP assay efficiently amplified the target gene within 45 min at 63 degrees C using only a simple laboratory water bath. To determine the specificity of the LAMP assay, various subgroup ALVs and other related viruses were detected. A ladder pattern on gel electrophoresis was observed for ALV-J isolates but not for other viruses. To evaluate the sensitivities of the LAMP assay and conventional PCR, the NX0101 isolate plasmid DNA was amplified by them. The detection limit of the LAMP assay was 5 target gene copies/reaction, which was up to 20 times higher than that of conventional PCR. To evaluate the application of the LAMP assay for detection of ALV-J in clinical samples, 49 samples suspected of ALV infection from breeder flocks were tested by the LAMP assay and PCR. Moreover, virus isolation from these samples was also performed using cell culture. The positive-sample ratios were 21/49 (43%) by conventional PCR, 26/49 (53%) by the LAMP assay, and 19/46 (41%) by virus isolation. Additionally, a positive LAMP reaction can be visually ascertained by the observation of turbidity or a color change after addition of SYBR green I dye. Consequently, the LAMP assay is a simple, rapid, and sensitive diagnostic method and can potentially be developed for rapid detection of ALV-J infection in the field.
authors.affiliation: Key Laboratory of Animal Disease Control and Prevention of the Ministry of Agriculture, College of Veterinary Medicine, South China Agricultural University, 483 Wushan Road, Tianhe District, Guangzhou 510642, People's Republic of China.
authors.forename: Xiaotao
authors.initials: X
authors.lastname: Zhang
authors.forename: Ming
authors.initials: M
authors.lastname: Liao
authors.forename: Peirong
authors.initials: P
authors.lastname: Jiao
authors.forename: Kaijian
authors.initials: K
authors.lastname: Luo
authors.forename: Henan
authors.initials: H
authors.lastname: Zhang
authors.forename: Tao
authors.initials: T
authors.lastname: Ren
authors.forename: Guihong
authors.initials: G
authors.lastname: Zhang
authors.forename: Chenggang
authors.initials: C
authors.lastname: Xu
authors.forename: Chaoan
authors.initials: C
authors.lastname: Xin
authors.forename: Weisheng
authors.initials: W
authors.lastname: Cao
mesh_terms: D000818:Animals; D001353:Avian Leukosis / Q000175:diagnosis* / Q000821:virology; D001354:Avian Leukosis Virus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D002645:Chickens; D002681:China; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D011201:Poultry Diseases / Q000175:diagnosis* / Q000821:virology; D012680:Sensitivity and Specificity; D013696:Temperature; D013997:Time Factors; D014773:Virology / Q000379:methods*