Study on Detection of Avian Influenza Virus H9 Subtype by Dot-ELISA

A Dot-ELISA method was developed for the detection of avian influenza virus(AIV) H9 subtype.The optimum working concentration of rabbit anti-AIV IgG was determined to be 1∶400,and that of goat anti-rabbit IgG labeled with horseradish peroxidase(HRP)to be 1∶400 too.The assay could detect as low as 3.35×10-9 g /disc.Comparison of the Dot-ELISA with HA and HI,AGP,virus isolation were conducted.In the Dot-ELISA,36 of 63 were positive(57.14%),38 of 63 in the virus isolation were positive(60.30%).The high specify of the Dot-ELISA was shown by the specific blocking test with AIV positive serum and cross-reaction test with newcastle disease virus,infectious bronchitis virus,infectious bursal disease virus,egg drop syndrome virus.The result of test reproducibility in the Dot-ELISA was very good(93.9%).The procedure took about 3 h,and it was economical,results of reaction could be easily read by eye.This rapid and inexpensive method could be proved to be a new diagnostic technique for early diagnosis of avian influenza.