Reddacliff L, Eppleston J, Windsor P, Whittington R, Jones S
NSW Department of Primary Industries, PMB 8, Camden, NSW 2570, Australia.
Vet Microbiol. 2006 Jun 15;115(1-3):77-90. doi: 10.1016/j.vetmic.2005.12.021. Epub 2006 Feb 3.
A field trial was undertaken from 1999 until 2004 to determine the efficacy of a killed M. a. paratuberculosis vaccine, Gudair, for the control of ovine Johne's disease (OJD) in merino sheep run under Australian pastoral conditions. On each of three farms experiencing significant OJD losses (5-15% per annum), 200 merino lambs (age 1-4 months) were vaccinated, and 200 lambs were left unvaccinated. Animal assessments and sample collections were conducted twice yearly until 4 or 5 years of age. The impact of vaccination on mortality rate, faecal shedding of M. a. paratuberculosis (by pooled and individual faecal culture), liveweight, wool productivity, vaccine injection site lesions and cellular (BOVIGAM) and humoral (PARACHEK) immunity was examined. Vaccination stimulated cell-mediated and humoral immune responses, reduced mortalities due to OJD by 90% and delayed faecal shedding for the first year post-vaccination. Thereafter, the prevalence of shedders among vaccinates was reduced by 90%. The numbers of M. a. paratuberculosis excreted by the vaccinated groups were also reduced by at least 90% at most sampling times. However, high levels of excretion by vaccinates occurred on some occasions, and although only 7 of 600 vaccinates died from OJD, all 7 had multibacillary lesions. Thus there remains a risk that some vaccinated sheep will transfer the disease. Small reductions in liveweight were found in vaccinated lambs in the first year, but there was little effect on wool production. Vaccine injection site lesions were detected in almost 50% of sheep after 2 months, and these persisted for at least 4 years in 20-25% of vaccinates. Data from this trial enabled the registration of Gudair in Australia in 2002 and underpins the pivotal role of vaccination in the current management of OJD.
1999年至2004年进行了一项田间试验，以确定一种灭活的副结核分枝杆菌疫苗Gudair在澳大利亚牧区条件下饲养的美利奴绵羊中控制绵羊副结核病（OJD）的效果。在三个每年遭受严重OJD损失（5%-15%）的农场中，各有200只美利奴羔羊（1-4月龄）接种疫苗，200只羔羊不接种疫苗。在动物4至5岁之前，每年进行两次动物评估和样本采集。研究了疫苗接种对死亡率、副结核分枝杆菌粪便排菌情况（通过混合和个体粪便培养）、体重、羊毛产量、疫苗注射部位病变以及细胞免疫（BOVIGAM）和体液免疫（PARACHEK）的影响。疫苗接种刺激了细胞介导免疫和体液免疫反应，将因OJD导致的死亡率降低了90%，并在接种疫苗后的第一年延迟了粪便排菌。此后，接种疫苗的羊中排菌者的比例降低了90%。在大多数采样时间，接种疫苗组排出的副结核分枝杆菌数量也减少了至少90%。然而，接种疫苗的羊在某些情况下会出现高水平排菌，尽管600只接种疫苗的羊中只有7只因OJD死亡，但所有7只都有多菌型病变。因此，仍有一些接种疫苗的绵羊会传播疾病的风险。在接种疫苗的羔羊中，第一年体重略有下降，但对羊毛产量影响不大。2个月后，近50%的绵羊检测到疫苗注射部位病变，其中20%-25%的接种羊至少持续了4年。该试验的数据使得Gudair于2002年在澳大利亚注册，并支持了疫苗接种在当前OJD管理中的关键作用。
