A Primary Study of Virulent Characteristics On the Geese's Paramyxovirus

The virulence of Newcastle disease virus (NDV)has been determined by measuring the mean death time(MDT)of chicken embryos ,the intracerebral pathogenicity index(ICPI) in day_old chicks and the intravenous pathgenicity index (ICPI) in 6_week_old chickens at the international. The authors selected three strains of virus, names HG 97 C 5、YG 97 F 11 、YG 98_2 C 4, which from eleven strains isolated by our laboratory,to make a series of pathogenicity test.The MDT of the three strains were 56.7、52.0、53.2,the ICPI were 1.64、1.69、1.70,the IVPI were 2.62、2.6、2.6.At the same time we made a series of virulence test on Geese's embroys and Geese.The MDT of thirteen_day_old Geese's embloys were 68.8、67.4、70.2,the ICPI in day_old Geese were 1.52、1.64、1.66 and the IVPI in 6_week_old Geese were 1.26、1.65、 1.675. At present how to assess the virulence of GPMV doesn't determined,but the results indicated that the three strains all had a high pathogenicity for chickens and geese.