Aynaud J M, Corthier G, Laude H, Galicher C, Gelfi J
Ann Rech Vet. 1976;7(1):57-64.
Sera harvested from breeding farms where reproductive failures were observed but where swine fever vaccination was not carried out, where tested for the presence of neutralizing antibodies specific for swine fever virus. Neutralization tests were performed in tissue culture using two viruses strains: the american serological variant "331" strain isolated by MENGELING (1969) and the virulent "normal strain" Alfort. For comparison, sera harvested from healthy, vaccinated and unvaccinated breeding farms were also tested. Results show absence of antibodies against these two strains in healthy and unvaccinated animals. All sera harvested from healthy and vaccinated breeding farms have high levels of neutralizing activity against the two strains. From 1,251 harvested unvaccinated breeding farms have reproductive failures, 6.2 p. 100 had neutralizing antibodies against the "Alfort" strain and 17.1 p. 100 contained neutralizing antibodies against the "331" strain. In 87 out of these 189 breeding farms, positive serological reactions were observed. Considering the respective intensity of neutralizing activity against the two strains , the vaccination with live virus vaccines ("Chinese strain" or "Thiverval" strain) induces high levels of antibodies but a higher titer against "Alfort" strain. Inversely, low virulent strains responsible for sub-clinical swine fever induce low or moderate levels against the "331" strain and nil or low levels against the "Alfort" strain. These results suggest that low virulent strains having common antigenic properties with the serological variant "331" strain are circulating among pigs in unvaccinated breeding farms having reproductive failures. These features are important for future development and establishment of routine serological checking for diagnosis and herd testing.
从出现繁殖障碍但未进行猪瘟疫苗接种的养殖场采集血清，检测其中是否存在猪瘟病毒特异性中和抗体。使用两种病毒株在组织培养中进行中和试验：由MENGELING（1969年）分离的美国血清学变异株“331”株和强毒株“正常株”阿尔福特株。作为对照，还检测了从健康、已接种和未接种疫苗的养殖场采集的血清。结果显示，健康未接种疫苗的动物体内不存在针对这两种毒株的抗体。从健康且已接种疫苗的养殖场采集的所有血清对这两种毒株均具有高水平的中和活性。在1251个出现繁殖障碍的未接种疫苗的养殖场中，6.2%的血清含有针对“阿尔福特”株的中和抗体，17.1%的血清含有针对“331”株的中和抗体。在这189个养殖场中的87个，观察到了阳性血清学反应。考虑到针对两种毒株的中和活性强度，用活病毒疫苗（“中国株”或“蒂韦尔瓦尔”株）接种可诱导产生高水平抗体，但针对“阿尔福特”株的滴度更高。相反，引起亚临床猪瘟的低毒株诱导产生的抗体水平针对“331”株较低或中等，针对“阿尔福特”株则为零或低水平。这些结果表明，与血清学变异株“331”株具有共同抗原特性的低毒株在出现繁殖障碍的未接种疫苗的养猪场猪群中传播。这些特征对于未来诊断和畜群检测的常规血清学检查的发展和建立具有重要意义。
