Insect‐specific viruses used in biocontrol of mosquito‐borne diseases

Abstract Mosquito‐borne diseases, such as malaria, dengue, Zika, and West Nile, have caused substantial disease burdens to the people living in tropical and subtropical regions. Despite decades of efforts in control, the prevalence, geographic distribution, and severity of these diseases are still deteriorating and the options for vector control are limited. Insect‐specific viruses (ISVs) can naturally infect and replicate in mosquitoes, and even be vertically transmitted from generation to generation, interfering with arbovirus' proliferation, and disturbing mosquito's physiology, which are harmless to vertebrates and have great potential for bio‐control. Insect‐specific RNA viruses (ISRVs) infection will inhibit the replication of mosquito‐borne viruses, which may be due to the close phylogeny of ISRVs and the arboviruses. Mosquito baculoviruses (MBVs) and mosquito densoviruses (MDVs) belong to insect‐specific DNA viruses. The former has limited pathogenicity to mosquitoes, while the latter can be horizontally and vertically transmitted in mosquitoes, resulting in habitat pollution, abnormal development or death of larvae and adults. In addition, ISVs can be used as fusion expression vectors to express insect virulence proteins in mosquitoes or directly inactivate important genes of mosquitoes. However, there are still many deficiencies in ISVs research studies. Clarification of the host limit mechanism for each ISVs and application of more targeted and efficient ISVs or toxins will be the future research directions.