School of Life Sciences, University of Warwick, Warwick, UK
Institute of Applied Mathematics, University of British Columbia, Vancouver, Canada.
Proc Biol Sci. 2018 Jan 31;285(1871). doi: 10.1098/rspb.2017.2253.
It is well known that individuals in the same community can be exposed to a highly variable number of mosquito bites. This heterogeneity in bite exposure has consequences for the control of vector-borne diseases because a few people may be contributing significantly to transmission. However, very few studies measure sources of heterogeneity in a way which is relevant to decision-making. We investigate the relationship between two classic measures of heterogeneity, spatial and individual, within the context of lymphatic filariasis, a parasitic mosquito-borne disease. Using infection and mosquito-bite data for five villages in Papua New Guinea, we measure biting characteristics to model what impact bed-nets have had on control of the disease. We combine this analysis with geospatial modelling to understand the spatial relationship between disease indicators and nightly mosquito bites. We found a weak association between biting and infection heterogeneity within villages. The introduction of bed-nets increased biting heterogeneity, but the reduction in mean biting more than compensated for this, by reducing prevalence closer to elimination thresholds. Nightly biting was explained by a spatial heterogeneity model, while parasite load was better explained by an individual heterogeneity model. Spatial and individual heterogeneity are qualitatively different with profoundly different policy implications.
众所周知，同一社区的个体可能会受到数量极不相同的蚊子叮咬。这种叮咬暴露的异质性对控制媒介传播疾病有影响，因为少数人可能对传播做出了重大贡献。然而，很少有研究以与决策相关的方式测量异质性的来源。我们在淋巴丝虫病的背景下研究了两种经典的异质性衡量标准（空间异质性和个体异质性）之间的关系。利用巴布亚新几内亚五个村庄的感染和蚊子叮咬数据，我们测量了叮咬特征，以模拟蚊帐对控制该疾病的影响。我们将这种分析与地理空间建模相结合，以了解疾病指标与夜间蚊子叮咬之间的空间关系。我们发现，村庄内的叮咬和感染异质性之间存在微弱的关联。蚊帐的引入增加了叮咬的异质性，但由于接近消除阈值的患病率降低，平均叮咬的减少足以弥补这一点。夜间叮咬可以用空间异质性模型来解释，而寄生虫负荷可以用个体异质性模型来更好地解释。空间异质性和个体异质性在性质上是不同的，具有截然不同的政策意义。
