Hide G, Gerwash O, Morley E K, Williams R Huw, Hughes J M, Thomasson D, Elmahaishi M S, Elmahaishi K H, Terry R S, Smith J E
Centre for Parasitology and Infectious Diseases, Biomedical Sciences Research Institute, University of Salford, Salford, M5 4WT, UK.
Parassitologia. 2007 Dec;49(4):223-6.
Toxoplasma gondii is a ubiquitous parasite with a widespread distribution both in terms of geographical and host range. Although the definitive host is the cat, it is also a major health hazard to domestic animals and humans. Three routes of transmission are recognised (infection from the cat, carnivory and congenital transmission). We aimed to assess the relative importance of congenital transmission, using sheep as a model system, due to the lack of carnivory. We report, using PCR as a diagnostic tool, that congenital transmission occurs with high frequency (69%). If transmission from oocysts was important in sheep, we would expect sheep reared under the same environmental conditions (i.e. a single farm) to have a random distribution of Toxoplasma infection. Using breeding records in conjunction with PCR, some families were found to have high Toxoplasma prevalence and abortion while others were free of Toxoplasma infection and abortion (P < 0.01). This supports the notion that Toxoplasma may be transmitted vertically. In humans, we conducted a similar study and showed that Toxoplasma was transmitted from mother to baby in 19.8% of cases. Vertical transmission in Toxoplasma may be more important than previously thought and this knowledge should be considered in any eradication strategies.
刚地弓形虫是一种分布广泛的寄生虫，在地理分布和宿主范围方面都很普遍。虽然终末宿主是猫，但它对家畜和人类也是一种主要的健康危害。已确认有三种传播途径（来自猫的感染、食肉和先天性传播）。由于缺乏食肉情况，我们以绵羊作为模型系统，旨在评估先天性传播的相对重要性。我们报告，使用聚合酶链反应（PCR）作为诊断工具，先天性传播的发生率很高（69%）。如果卵囊传播在绵羊中很重要，我们会预期在相同环境条件下饲养的绵羊（即单个农场）弓形虫感染呈随机分布。结合繁殖记录和PCR检测发现，一些家族弓形虫感染率和流产率很高，而另一些家族则没有弓形虫感染和流产现象（P<0.01）。这支持了弓形虫可能通过垂直传播的观点。在人类中，我们进行了一项类似的研究，结果表明在19.8%的病例中弓形虫是由母亲传播给婴儿的。弓形虫的垂直传播可能比以前认为的更为重要，在任何根除策略中都应考虑到这一认识。
