Transmission pathways of the food-borne carcinogen Opisthorchis viverrini

项目摘要/摘要 致癌肝吸虫是一种食源性寄生虫，感染约1000万人 人口，主要是东南亚的低收入人口。人们在消费时会被感染 生或未煮熟的淡水鱼含有稻瘟原虫囊虫和感染，可导致 胆管癌。这项拟议中的研究将描述活体乳杆菌的传播途径，重点是 鱼的运动和食物分配网络在向人类传播间日圆线虫中的作用 人口。这项研究将在泰国东北部三个相连的湖泊及其周围进行，该地区 具有世界上最高的由绿僵菌引起的胆管癌的发病率。使用中性遗传 我们将评估研究区域内寄生虫的种群结构，以评估是否 存在空间上不同的传播焦点(例如，传播被限制在湖的规模)，或者如果 在整个地区都有广泛的基因流动，这表明寄生虫很容易在 湖泊和村庄。我们将描述捕捞的鱼类分销网络的特点。使用基于智能手机的 针对渔民的暴露评估协议，我们将量化源湖和 以评估这些联系是否构成区域 传输网络。此外，我们还评估了鱼类运动在寄生虫分布中的潜在作用。 在第一中间钉螺宿主中感染viverrini是罕见的(通常情况下，患病率为2%)，但鱼类感染 是很常见的(在一些地区超过90%的流行率)，这表明鱼可能从一个 受感染的蜗牛拼凑在一起，在它们的范围内传播感染。我们将研究O。 在鱼中感染viverrini，从湖内和湖之间的不同地点取样，以测试 假设活菌感染因湖泊不同而不同，如果检测到，这意味着鲤科宿主的运动 受湖泊几何形状的约束。我们将最终评估青海稻瘟病菌种群遗传的一致性 与食物分配网络和鱼类感染的空间模式相结合的结构，使我们能够推断关键 抑制或促进稻瘟病菌传播的传播途径。拟议的研究将 填补我们对这种可以用来指导感染的被忽视的热带疾病的理解上的关键空白 华支睾吸虫及其相关寄生虫的预防方案和食品安全监测， 估计有3500万人感染了这种病毒。更广泛地说，这种疾病系统提供了一个机会 评估食物分配系统和自然景观边界在确定 传染病传播。

PROJECT SUMMARY/ABSTRACT The carcinogenic liver fluke Opisthorchis viverrini is a food-borne parasite that infects approximately 10 million people, primarily in low-income populations in Southeast Asia. People become infected when they consume raw or undercooked freshwater fish harboring O. viverrini metacercariae and infection can cause cholangiocarcinoma. The proposed research will characterize transmission pathways of O. viverrini, focusing on the role of fish movement and food-distribution networks in distributing O. viverrini parasites to human populations. The research will take place in and around three connected lakes in Northeast Thailand, an area with the highest incidence of O. viverrini-induced cholangiocarcinoma in the world. Using neutral genetic markers, we will assess the population structure of the parasite in the study region in order to assess whether there exist spatially distinct foci of transmission (e.g. transmission is constrained at the scale of a lake), or if there is widespread gene flow throughout the region, suggesting parasites are readily transported between lakes and villages. We will characterize harvested fish distribution networks. Using a smartphone-based exposure assessment protocol targeting fishermen, we will quantify connections between source lakes and villages throughout the study region in order to evaluate whether these connections constitute a regional transmission network. In addition, we evaluate the potential role of fish movement in distributing parasites- O. viverrini infections in the first intermediate snail host are rare (typically, prevalence is <2%) but fish infections are common (exceeding 90% prevalence in some areas), which suggests that fish may collect parasites from a patchwork of infected snails, distributing infections across their range. We will examine the distribution of O. viverrini infections in fish, sampling fish from different sites within and between lakes in order to test the hypothesis that O. viverrini infections vary by lake, which, if detected, implies cyprinid host movements are constrained by lake geometry. We will ultimately evaluate the concordance of O. viverrini population genetic structure with the spatial patterns of food-distribution networks and fish infections, allowing us to infer key transmission pathways that act to constrain or facilitate the spread of O. viverrini. The proposed research will fill in crucial gaps in our understanding of this neglected tropical disease that can be used to guide infection prevention programs and food safety monitoring for O. viverrini and the related parasite, Clonorchis sinensis, which infects an estimated 35 million people. More generally, this disease system provides an opportunity to evaluate the role of food distribution systems and natural landscape boundaries in defining the spatial scale of infectious disease transmission.