Abstract: A pair of primers based on NS5 gene sequences of different strains of genus Flavivirus was designed for amplification of 470 bp fragments.No positive target fragment was available from H9 subtype influenza virus,Muscovy duck reovirus,duck plague,duck hepatitis virus(DHV-Ⅰ) or duck-origin avian paramyxovirus typeⅠ.The detection limit reached 20 pg under the optimized conditions.The results showed that the RT-PCR was sensitive,specific and applicable for rapid laboratory diagnosis and epidemiologic surveillance.

Key words: ducks hemorrgagic ovaritis, Flavivirus, RT-PCR