BACKGROUND Urbanization is occurring rapidly on a global scale and is altering mosquito communities, creating assemblages that are characteristically less diverse. Despite high rates of urbanization and ample examples of vector-borne diseases transmitted by multiple species, the effects of urbanization-driven mosquito diversity losses on disease transmission has not been well explored. We investigated this question using the dog heartworm, a filarial parasite vectored by numerous mosquito species. METHODS We trapped host-seeking mosquitoes in undeveloped areas and neighborhoods of different ages in Wake County, North Carolina, USA, analyzing captured mosquitoes for heartworm DNA. We compared within-mosquito heartworm infection across land-use types by Kruskal-Wallis and likelihood ratio tests. Using zip code level data acquired from dogs in a local shelter, we performed linear regressions of within-host heartworm prevalence by within-mosquito heartworm prevalence as well as by three mosquito diversity measures. We also determined the best predictor of host-level prevalence among models including within-mosquito infection, mosquito diversity and abundance, and socioeconomic status as variables. RESULTS Suburban areas had lower within-mosquito heartworm prevalence and lower likelihood of heartworm-positive mosquitoes than did undeveloped field sites, although no differences were seen between suburban and undeveloped wooded sites. No relationships were noted between within-mosquito and within-host heartworm prevalence. However, mosquito diversity metrics were positively correlated with host heartworm prevalence. Model selection revealed within-host prevalence was best predicted by a positive relationship with mosquito Shannon-Wiener diversity and a negative relationship with household income. CONCLUSIONS Our results demonstrate that decreases in mosquito diversity due to urbanization alter vector-borne disease risk. With regard to dog heartworm disease, this loss of mosquito diversity is associated with decreased heartworm prevalence within both the vector and the host. Although the response is likely different for diseases transmitted by one or few species, mosquito diversity losses leading to decreased transmission could be generalizable to other pathogens with multiple vectors. This study contributes to better understanding of the effects of urbanization and the role of vector diversity in multi-vectored pathosystems.

中文翻译：

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郊区的蚊子多样性和犬心丝虫患病率。

背景技术城市化在全球范围内正在迅速发生，并且正在改变蚊子群落，从而产生特征性地多样性较低的组合。尽管城市化的速度很高，并且有多种物种传播的媒介传播疾病的例子很多，但尚未很好地探索城市化驱动的蚊虫多样性丧失对疾病传播的影响。我们使用犬心丝虫（一种由许多蚊子引导的丝状寄生虫）调查了这个问题。方法我们在美国北卡罗来纳州韦克县的不发达地区和不同年龄的社区中捕获了寻求宿主的蚊子，分析了捕获的蚊子中的心丝虫DNA。我们通过Kruskal-Wallis和似然比检验比较了不同土地利用类型的蚊内心丝虫感染。使用从当地收容所中的狗那里获得的邮政编码水平数据，我们通过蚊内心丝虫患病率以及三种蚊虫多样性测度对宿主内心丝虫患病率进行了线性回归。我们还确定了模型中宿主水平流行的最佳预测指标，包括蚊内感染，蚊子多样性和丰度以及社会经济地位作为变量。结果郊区地区与未开发的林地相比，蚊内心丝虫的患病率更低，且心丝虫阳性蚊子的可能性更低，尽管郊区和未开发的林地之间没有差异。蚊内和宿主内心丝虫的流行之间没有关系。但是，蚊子多样性指标与宿主心丝虫患病率呈正相关。通过与蚊香农-维纳多样性的正相关和与家庭收入的负相关，可以最好地预测宿主内流行的模型选择。结论我们的结果表明，由于城市化导致蚊子多样性的减少改变了媒介传播疾病的风险。关于犬心丝虫病，这种蚊虫多样性的丧失与载体和宿主内丝虫的患病率降低有关。尽管对于一种或几种物种传播的疾病的反应可能有所不同，但导致传播减少的蚊虫多样性损失可能会推广到具有多种载体的其他病原体。这项研究有助于更好地理解城市化的影响以及媒介多样性在多媒介病理系统中的作用。