RESUMO
In order to visually detect H1, N1 and N2 subtype of avian influenza virus (AIV), three reverse transcription loop-mediated isothermal amplification (RT-LAMP) assays were developed. According to the sequences of AIV gene available in GenBank, three degenerate primer sets specific to HA gene of H1 subtype AIV, NA gene of N1 and N2 subtype AIV were designed, and the reaction conditions were optimized. The results showed that all the assays had no cross-reaction with other subtype AIV and other avian respiratory pathogens, and the detection limit was higher than that of conventional RT-PCR. These assays were performed in water bath within 50 minutes. Without opening tube, the amplification result could be directly determined by inspecting the color change of reaction system as long as these assays were fin-ished. Fourteen specimens of H1N1 subtype and eight specimens of H1N2 subtype of AIV were identified from the 120 clinical samples by RT-LAMP assays developed, which was consistent with that of virus isolation. These results suggested that the three newly developed RT-LAMEP assays were simple, specific and sensitive and had potential for visual detection of H1, N1 and N2 subtype of AIV in field.