Community diversity and infectious diseases : habitats, hosts, and microbes

Abstract

Background: Anthropogenic environmental change is among the most frequently identified factor linked to emergence of infectious diseases. Recently, growing interest in disease ecology has focused on the hypothesis that decline in ecological community diversity as a result of human activities can mediate infection and disease transmission intensity. The specific objective of this study is to characterize the diversity of mosquitoes, their associated microbial communities, and potential pathogens along a forestagro-urban habitat gradient in Thailand. Methods: Adult mosquito trap stations were set-up along a habitat transect to capture components of mosquito communities in each characterized habitat. Mosquitoes were pooled by species and 16s, 18s rRNA gene sequences were sequenced from the pools using 454 pyrosequencing technology to assess genetic and taxon-based diversity of the non-eukaryotes and eukaryotes associated with vector species from different habitats. The presence of flaviviruses, as pathogens of interest in the region, was assayed in mosquitoes using Real-time RT-PCR. Results: The geatest abundance of mosquitoes was found in the rice field habitat; while the forest was found to have the least mosquitoes were found in the forest. Based on extrapolated species richness estimators, forest and fragmented forest habitats had the most diverse mosquito communities, followed by the rural, rice field, suburban and urban habitats. The density of two vector species, Ae. aegypti and Cx. quinquefasciatus, were inversely correlated with diversity of mosquito communities using ACE indices. The patterns of microbiome community assembly and diversity in vectors across habitat types are complex and correlate with specific environmental variables. Conclusion: In this study, mosquito community diversity varied across a continuum of habtitat types in a pattern reflecting habitat change. Moreover, changes in the abundance of important mosquito vectors tended to follow a predictable pattern. Collectively, these findings help illuminate how mosquitoes and their associated microbial communities vary across habitat types and how these dynamics could contribute to emergence of arboviral disease in Thailand.