Development of loop-mediated isothermal amplification for rapid detection of avian leukosis virus subgroup A

This study aimed to establish a loop-mediated isothermal amplification (LAMP) method for distinguishing avian leukosis virus (ALV) subgroup A from other subgroups of the virus. On the basis of the results of sequence comparison and the sequence characteristics of ALV subgroups, a LAMP method was designed to target the gp85 segment for detection of ALV-A. Under optimal reaction conditions, ALV-A LAMP produced neither cross-reactions with other major subgroups (including subgroups J, B, C, and E) nor nonspecific reactions with other common avian infectious diseases. A sensitivity test showed that this method can detect 20 copies of proviral nucleic acid sequence within 45 min, which is 100 times more sensitive than the conventional polymerase chain reaction (PCR). This method can detect subgroup A virus rapidly and the results can be assessed based on color changes. The whole reaction process can be performed without opening the lid of the reaction tube, which reduces the possibility of contamination greatly and simplifies the detection process, indicating the considerable potential of this method for in situ application in the future.