Department of Pathobiological Sciences, University of Wisconsin, Madison, Wisconsin, United States of America.
PLoS One. 2011;6(8):e23767. doi: 10.1371/journal.pone.0023767. Epub 2011 Aug 19.
The influence of host diversity on multi-host pathogen transmission and persistence can be confounded by the large number of species and biological interactions that can characterize many transmission systems. For vector-borne pathogens, the composition of host communities has been hypothesized to affect transmission; however, the specific characteristics of host communities that affect transmission remain largely unknown. We tested the hypothesis that vector host use and force of infection (i.e., the summed number of infectious mosquitoes resulting from feeding upon each vertebrate host within a community of hosts), and not simply host diversity or richness, determine local infection rates of West Nile virus (WNV) in mosquito vectors. In suburban Chicago, Illinois, USA, we estimated community force of infection for West Nile virus using data on Culex pipiens mosquito host selection and WNV vertebrate reservoir competence for each host species in multiple residential and semi-natural study sites. We found host community force of infection interacted with avian diversity to influence WNV infection in Culex mosquitoes across the study area. Two avian species, the American robin (Turdus migratorius) and the house sparrow (Passer domesticus), produced 95.8% of the infectious Cx. pipiens mosquitoes and showed a significant positive association with WNV infection in Culex spp. mosquitoes. Therefore, indices of community structure, such as species diversity or richness, may not be reliable indicators of transmission risk at fine spatial scales in vector-borne disease systems. Rather, robust assessment of local transmission risk should incorporate heterogeneity in vector host feeding and variation in vertebrate reservoir competence at the spatial scale of vector-host interaction.
宿主多样性对多宿主病原体传播和持续存在的影响可能因许多传播系统中大量的物种和生物相互作用而变得复杂。对于媒介传播病原体，宿主群落的组成被假设会影响传播；然而，影响传播的宿主群落的具体特征在很大程度上仍然未知。我们测试了这样一个假设，即媒介宿主的利用和感染力度（即，在一个宿主群落中，每只脊椎动物宿主被感染的蚊子数量的总和），而不仅仅是宿主多样性或丰富度，决定了西尼罗河病毒（WNV）在蚊子媒介中的局部感染率。在美国伊利诺伊州芝加哥郊区，我们利用关于库蚊（Culex pipiens）蚊子对宿主的选择以及每种宿主物种的WNV 脊椎动物储存能力的数据，来估计西尼罗河病毒的社区感染力度。我们发现，宿主群落的感染力度与鸟类多样性相互作用，影响了整个研究区域内库蚊中的 WNV 感染。两种鸟类，美洲知更鸟（Turdus migratorius）和家麻雀（Passer domesticus）产生了 95.8%的感染性库蚊，并且与 Culex spp. 蚊子中的 WNV 感染呈显著正相关。因此，群落结构的指标，如物种多样性或丰富度，可能不是在媒介传播疾病系统的精细空间尺度上传输风险的可靠指标。相反，应在媒介-宿主相互作用的空间尺度上，纳入对媒介宿主摄食的异质性和脊椎动物储存能力的变化，来对局部传播风险进行稳健评估。
