Transmission competence of a new mesonivirus, Yichang virus, in mosquitoes and its interference with representative flaviviruses.

Guoguo Ye,Qiannan Dong,Yujuan Wang,Quanxin Cai,Zhiming Yuan,Han Xia,Xiaoyun Liu,Paul O Mireji

doi:10.1371/journal.pntd.0008920

Abstract

Advances in technology have greatly stimulated the understanding of insect-specific viruses (ISVs). Unfortunately, most of these findings are based on sequencing technology, and laboratory data are scarce on the transmission dynamics of ISVs in nature and the potential effects of these viruses on arboviruses. Mesonivirus is a class of ISVs with a wide geographical distribution. Recently, our laboratory reported the isolation of a novel strain of mesonivirus, Yichang virus (YCV), from Culex mosquitoes, China. In this study, the experimental infection of YCV by the oral route for adult and larvae mosquitoes, and the vertical transmission has been conducted, which suggests that YCV could adopt a mixed-mode transmission. Controlled experiments showed that the infectivity of YCV depends on the mosquito species, virus dose, and infection route. The proliferation curve and tissue distribution of YCV in Cx. quinquefasciatus and Ae. albopictus showed that YCV is more susceptible to Ae. albopictus and is located in the midgut. Furthermore, we also assessed the interference of YCV with flaviviruses both in vitro and in vivo. YCV significantly inhibited the proliferation of DENV-2 and ZIKV, in cell culture, and reduced transmission rate of DENV-2 in Ae. albopictus. Our work provides insights into the transmission of ISVs in different mosquito species during ontogeny and their potential ability to interact with mosquito-borne viruses.

Highlights

For the last two decades, with advancements in high-throughput sequencing, metagenomics and intensified mosquito surveillance, a large number of insect-specific viruses (ISVs) and arboviruses have been discovered
Mosquitoes transmit many pathogenic viruses, such as dengue virus, Zika virus, and Japanese encephalitis virus, which are of great burden to public health worldwide, notably in the tropical regions
They harbor a number of insect-specific viruses (ISVs), little is known about the role for the ISV in mosquito populations and their interaction with arboviruses

Summary

Introduction

For the last two decades, with advancements in high-throughput sequencing, metagenomics and intensified mosquito surveillance, a large number of insect-specific viruses (ISVs) and arboviruses have been discovered. ISVs are restricted to arthropods and are unable to replicate in vertebral cells [1], whereas arboviruses can be transmitted between mosquitoes and vertebrates [2]. These two types of viruses have different host ranges, there are many similarities in virological classification and transmission methods [2]. Some scholars conjecture that ISVs may be an important evolutionary source of new arboviruses [11,12,13] and that some ISVs may inhibit arbovirus infections in their insect hosts [10]. Research on ISVs transmission models and interactions with arboviruses is becoming increasingly important

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Conclusion