Theileria parva live vaccination:: parasite transmission, persistence and heterologous challenge in the field
Theileria parva live vaccination:: parasite transmission, persistence and heterologous challenge in the field
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DOI：
10.1017/s0031182007002557
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发表时间：
2007-08-01
期刊：
影响因子：
2.4
通讯作者：
Tait, A.
中科院分区：
文献类型：
--
作者：
Oura, C. A. L.;Bishop, R.;Tait, A.
通过感染和治疗方案提供的“穆古加鸡尾酒”活疫苗已在非洲东部、中部和南部广泛部署，以保护牛免受由细小泰勒虫引起的东海岸热病。该疫苗包含 3 种成分库存（Muguga、Serengeti 转化疫苗和 Kiambu 5）。在之前的一项研究中，使用一组微卫星和小卫星标记对来自已接种疫苗和未接种疫苗的动物的寄生虫进行了基因分型（Oura 等人，2004 年 a），结果表明，只有 Kiambu 5 种群建立了长期携带者状态，但没有证据表明该种群的传播。在已接种疫苗的动物中还发现了与 3 种成分疫苗种群不同的寄生虫基因型。我们现在报告了在同一农场进行的一项后续研究，即初次疫苗接种约 4 年后，旨在确定在接种疫苗的牛中发现的新型寄生虫基因型的来源，确定 Kiambu 5 疫苗库存建立的携带者状态的寿命，并重新检查疫苗传播是否可以在更长的时间范围内发生。为此，从接种疫苗和未接种疫苗的牛身上采集样本，并使用一系列微卫星和小卫星标记对寄生虫进行基因分型。数据表明，疫苗稳定物含有至少 6 种寄生虫基因型，Kiambu 5 种群可以在许多（但不是所有）接种牛身上检测到长达 4 年，并且可以传播给共享放牧的未接种疫苗的牛，并且一些接种疫苗的动物感染了当地基因型而不会引起明显的疾病。
The 'Muguga cocktail' live vaccine, delivered by an infection and treatment protocol, has been widely deployed in Eastern, Central and Southern Africa to protect cattle against East Coast fever, caused by Theileria parva. The vaccine contains 3 component stocks (Muguga, Serengeti-transformed and Kiambu 5). In a previous study, parasites from vaccinated and unvaccinated animals were genotyped with a panel of micro- and minisatellite markers (Oura et al. 2004 a) and it was shown that only the Kiambu 5 stock establishes a long-term carrier state but there was no evidence for the transmission of this stock, Also parasite genotypes different from the 3 component vaccine stocks were identified in vaccinated animals. We now report a follow-up study on the same farm, some 4 years after the initial vaccination, aimed at establishing the source of the novel parasite genotypes identified in vaccinated cattle, determining the longevity of the carrier state established by the Kiambu 5 vaccine stock and re-examining whether vaccine transmission can occur over a longer time-scale. To do this, samples were taken from vaccinated and unvaccinated cattle and the parasites were genotyped with a series of micro- and minisatellite markers. The data indicate that the vaccine stabilates contain at least 6 parasite genotypes, the Kiambu 5 stock can be detected in many but not all vaccinated cattle for up to 4 years and can be transmitted to unvaccinated cattle which share grazing and that some of the vaccinated animals become infected with local genotypes without causing overt disease.