Does Wolbachia affect virus diversity in an Aedes aegypti field population?

Abstract

Arboviruses are arthropod-born RNA viruses that can cause serious diseases in the human population. Mosquitoes from the genus Aedes and Culex are known for being vectors of arboviruses that have epidemic potential, such as Dengue, Zika, Chikungunya, Yellow Fever and West Nile viruses. Blocking the transmission of arboviruses relies on the control of its mosquito vectors. Strategies to control mosquito populations includes biological control, insecticides, and sterile insect technique. However, these methods have proven to be unsustainable and inefficient. More recently, the use of the bacterial endosymbiont Wolbachia to control insect born human-diseases became an outstanding option because of Wolbachia's mutualistic effect of protecting its hosts against virus infection. Recent studies performed on Aedes aegypti have shown that Wolbachia is able to limit replication of Dengue, Chikungunya, Yellow Fever and Zika viruses, reducing vector competence and transmission of these viruses. Besides reducing replication and transmission of arboviruses, Wolbachia can also affect replication of insect-specific viruses that can increase the chances of arboviruses occurring in mosquitoes. Although Wolbachia's antiviral effect has been intensely studied in the last decade in fly and mosquito hosts, its importance in wild populations has rarely been addressed. Just recently some studies started to test for Wolbachia's antiviral effects in wild fly populations using metagenomics and Next Generation Sequencing techniques. However, Wolbachia's antiviral effects in wild mosquito population has not been addressed yet. Investigating if Wolbachia's protection against virus infection occurs in wild populations may help us understand if this mutualistic effect is one of the reasons for the extremely high prevalence of Wolbachia in arthropod populations. Furthermore, because Wolbachia plays an important role in reducing viral loads of arboviruses and insect-specific viruses, knowing if Wolbachia is able to limit replication of these viruses in field populations of A. aegypti is essential to control transmission of arboviruses in humans. Here, we propose to investigate whether Wolbachia protects a field population of A. aegypti against viral infection using metagenomics and Next Generation Sequencing techniques. Specifically, we propose to assess which arboviruses and insect-specific viruses are infecting A. aegypti in the field, if Wolbachia is able to reduce the diversity and abundance of viruses infecting A. aegypti, and if Wolbachia reduces the prevalence of the most common viruses infecting A. aegypti. (AU)