Molecular Parasitology and Entomology Unit, Faculty of Science, University of Dschang, Dschang, Cameroon.
College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala, Uganda.
Front Immunol. 2021 Feb 15;12:613468. doi: 10.3389/fimmu.2021.613468. eCollection 2021.
Schistosomiasis remains the fourth most prevalent parasitic disease affecting over 200 million people worldwide. Control efforts have focussed on the disruption of the life cycle targeting the parasite, vector and human host. Parasite burdens are highly skewed, and the majority of eggs are shed into the environment by a minority of the infected population. Most morbidity results from hepatic fibrosis leading to portal hypertension and is not well-correlated with worm burden. Genetics as well as environmental factors may play a role in these skewed distributions and understanding the genetic risk factors for intensity of infection and morbidity may help improve control measures. In this review, we focus on how genetic factors may influence parasite load, hepatic fibrosis and portal hypertension. We found 28 studies on the genetics of human infection and 20 studies on the genetics of pathology in humans. and infection intensity have been showed to be controlled by a major quantitative trait locus , on chromosome 5q31-q33 containing several genes involved in the T2 immune response, and three other loci of smaller effect on chromosomes 1, 6, and 7. The most common pathology associated with schistosomiasis is hepatic and portal vein fibroses and the quantitative trait locus on chromosome six has been linked to intensity of fibrosis. Although there has been an emphasis on T2 cytokines in candidate gene studies, we found that four of the five QTL regions contain T17 pathway genes that have been included in schistosomiasis studies: and in and in 6p21-q2, in 1p21-q23 and in . The T17 pathway is known to be involved in response to schistosome infection and hepatic fibrosis but variants in this pathway have not been tested for any effect on the regulation of these phenotypes. These should be priorities for future studies.
血吸虫病仍然是全球第四大流行寄生虫病，影响超过 2 亿人。控制工作集中在破坏寄生虫、媒介和人类宿主的生命周期。寄生虫负担高度偏倚，大多数卵由感染人群中的少数人排入环境。大多数发病率是由肝纤维化导致门静脉高压引起的，与蠕虫负担相关性不佳。遗传因素以及环境因素可能在这些偏倚分布中发挥作用，了解感染强度和发病率的遗传风险因素可能有助于改善控制措施。在这篇综述中，我们重点关注遗传因素如何影响寄生虫负荷、肝纤维化和门静脉高压。我们发现了 28 项关于人类感染遗传学的研究和 20 项关于人类病理学遗传学的研究。感染强度已被证明受到主要数量性状基因座的控制，该基因座位于 5q31-q33 染色体上，包含几个参与 T2 免疫反应的基因，以及另外三个较小效应的基因座位于染色体 1、6 和 7 上。与血吸虫病最相关的常见病理学是肝和门静脉纤维化，染色体 6 上的数量性状基因座与纤维化强度有关。尽管候选基因研究强调了 T2 细胞因子，但我们发现五个 QTL 区域中有四个包含 T17 途径基因，这些基因已被纳入血吸虫病研究：和在 6p21-q2 中，在 1p21-q23 中，在 中。T17 途径已知参与对血吸虫感染和肝纤维化的反应，但尚未测试该途径中的变体对这些表型的调节有任何影响。这些应该是未来研究的优先事项。
