Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
Am J Trop Med Hyg. 2010 Nov;83(5):990-5. doi: 10.4269/ajtmh.2010.10-0049.
Many factors influence variation in Plasmodium infection levels, including parasite/host genetics, immunity, and exposure. Here, we examine the roles of host genetics and exposure in determining parasite density, and test whether effects differ with age. Data for 1,711 residents of an eastern Ugandan community were used in pedigree-based variance component analysis. Heritability of parasite density was 13% (P < 0.001) but was not significant after controlling for shared household. Allowing variance components to vary between children (< 16 years) and adults (≥ 16 years) revealed striking age differences; 26% of variation could be explained by additively acting genes in children (P < 0.001), but there was no genetic involvement in adults. Domestic environment did not explain variation in children and explained 5% in adults (P = 0.09). Genetic effects are an important determinant of parasite density in children in this population, consistent with previous quantitative genetic studies of Plasmodium parasitaemia, although differences in environmental exposure play a lesser role.
许多因素会影响疟原虫感染水平的变化，包括寄生虫/宿主遗传、免疫和暴露。在这里，我们研究了宿主遗传和暴露在决定寄生虫密度中的作用，并检验了其作用是否随年龄而变化。在基于家系的方差成分分析中，我们使用了乌干达东部一个社区的 1711 名居民的数据。寄生虫密度的遗传率为 13%（P<0.001），但在控制了共享家庭因素后，这一数字并不显著。允许方差成分在儿童（<16 岁）和成人（≥16 岁）之间变化，揭示了惊人的年龄差异；在儿童中，可由累加作用基因解释的变异为 26%（P<0.001），而在成人中则没有遗传参与。家庭环境并不能解释儿童的变异，只能解释 5%的成人变异（P=0.09）。遗传效应是该人群中儿童寄生虫密度的重要决定因素，与之前对疟原虫感染的定量遗传研究一致，尽管环境暴露的差异所起的作用较小。
