Hsu S T, Chang L C, Lin S Y, Chuang T Y, Ma C H, Inoue Y K, Okuno T
Bull World Health Organ. 1972;46(4):465-71.
Since an excellent candidate strain (M) for live virus vaccination of swine against Japanese encephalitis was developed, a number of large vaccination programmes have been implemented in Japan with the aim of controlling Japanese encephalitis epidemics in man by reducing the population size of nonimmune swine. Encouraging results have been obtained but no studies have been made on the benefits of live-virus vaccination to the industry. In order to determine the effect of vaccination upon the number of stillbirths occurring in the Japanese encephalitis post-emergence season, a total of 74 vaccinated, and subsequently mated, gilts at a large breeding farm in subtropical Taiwan were subjected to follow-up observations in comparison with a control group. The total incidence of litter stillbirths in the vaccinated group (1/74) was significantly lower than that in the control group (21/68). Over 92% of the newborn piglets from the vaccinated gilts were healthy, while 31.6-54.1% of the newborn piglets in the control groups were stillborn. The litter size of vaccinated gilts was larger than that of the control gilts. The vaccine was shown by tests in 22 swine to have an adequate degree of safety. Four weeks after vaccination with either 10(5.6) or 10(8.0) smicLD(50) of virus, all the swine developed an adequate level of antibody. The results indicate that live virus vaccination could benefit the industry in addition to achieving the main aim of controlling Japanese encephalitis viraemia in swine.
自从开发出一种用于猪日本脑炎活病毒疫苗接种的优良候选毒株（M）以来，日本已实施了多项大型疫苗接种计划，目的是通过减少未免疫猪的数量来控制人类日本脑炎疫情。已取得了令人鼓舞的成果，但尚未对活病毒疫苗接种对该行业的益处进行研究。为了确定疫苗接种对日本脑炎发病季节死胎数量的影响，在亚热带台湾的一个大型种猪场，对74头接种疫苗并随后配种的后备母猪进行了随访观察，并与一个对照组进行了比较。接种疫苗组的窝产死胎总发生率（1/74）显著低于对照组（21/68）。接种疫苗的后备母猪所产新生仔猪中，超过92%健康，而对照组新生仔猪的死胎率为31.6 - 54.1%。接种疫苗的后备母猪产仔数多于对照后备母猪。对22头猪的测试表明该疫苗具有足够的安全性。用10(5.6)或10(8.0)半数最小感染剂量（smicLD(50)）的病毒接种疫苗四周后，所有猪都产生了足够水平的抗体。结果表明，活病毒疫苗接种除了实现控制猪日本脑炎病毒血症这一主要目标外，还可能使该行业受益。
