Kaliannan K, Seawright G L, Derbyshire J B
Can J Comp Med. 1975 Apr;39(2):139-45.
Three field strains of Newcastle Disease virus, designated S20, S21 and S23, isolated from chickens or turkeys in Ontario during the 1971-72 epizootic, were characterized as velogenic viscerotropic viruses. No significant antigenic differences were demonstrated among B1, LaSota and a field strain (S23) of velogenic vescerotropic virus by haemagglutination inhibition or protection tests. Primary water vaccination of chicks with commercial B1 and LaSota vaccines at five weeks of age and aerosol revaccination with the same strains four weeks later resulted in protection that lasted 16 weeks after revaccination against experimental challenge with strain S23. The differences in haemagglutination inhibition titres noted when the homologous or the heterologous viruses were used as haemagglutinating antigen were not statistically significant. The rates of decay of virus neutralizing and haemagglutination inhibition antibodies in vaccinated birds showed a divergence indicating the possible duality of antibodies measured in serum neutralization and haemagglutination inhibition tests.
1971 - 1972年疫情期间，从安大略省的鸡或火鸡中分离出三株新城疫病毒野毒株，分别命名为S20、S21和S23，被鉴定为速发型嗜内脏性病毒。通过血凝抑制试验或保护试验，未发现B1、LaSota和一株速发型嗜内脏性病毒野毒株（S23）之间存在显著的抗原差异。5周龄雏鸡用商业B1和LaSota疫苗进行初次饮水免疫，4周后用相同毒株进行气溶胶再免疫，再免疫后对S23毒株的实验性攻击产生了持续16周的保护作用。当使用同源或异源病毒作为血凝抗原时，所观察到的血凝抑制效价差异无统计学意义。接种疫苗的禽类中病毒中和抗体和血凝抑制抗体的衰减率出现差异，表明在血清中和试验和血凝抑制试验中所检测的抗体可能具有双重性。
