Evaluation of vector susceptibility in Aedes aegypti and Culex pipiens pallens to Tibet orbivirus

Abstract

Mosquito-borne viruses cause various infectious diseases in humans and animals. Tibet orbivirus (TIBOV), a newly identified arbovirus, efficiently replicates in different types of vertebrate and mosquito cells, with its neutralizing antibodies detected in cattle and goats. However, despite being isolated from Culicoides midges , Anopheles, and Culex mosquitoes, there has been a notable absence of systematic studies on its vector competence. Thus, in this study, Aedes aegypti and Culex pipiens pallens were reared in the laboratory to measure vector susceptibility through blood-feeding infection. Furthermore, RNA sequencing was used to examine the overall alterations in the Ae. aegypti transcriptome following TIBOV infection. The results revealed that Ae. aegypti exhibited a high susceptibility to TIBOV compared to Cx. p. pallens . Effective replication of the virus in Ae. aegypti midguts occurred when the blood-feeding titer of TIBOV exceeded 10 5 plaque-forming units mL −1 . Nevertheless, only a few TIBOV RNA-positive samples were detected in the saliva of Ae. aegypti and Cx. p. pallens , suggesting that these mosquito species may not be the primary vectors for TIBOV. Moreover, at 2 dpi of TIBOV, numerous antimicrobial peptides downstream of the Toll and Imd signaling pathways were significantly downregulated in Ae. aegypti , indicating that TIBOV suppressed mosquitos’ defense to survive in the vector at an early stage. Subsequently, the stress-activated protein kinase JNK, a crucial component of the MAPK signaling pathway, exhibited significant upregulation. Certain genes were also enriched in the MAPK signaling pathway in TIBOV-infected Ae. aegypti at 7 dpi. IMPORTANCE Tibet orbivirus (TIBOV) is an understudied arbovirus of the genus Orbivirus . Our study is the first-ever attempt to assess the vector susceptibility of this virus in two important mosquito vectors, Aedes aegypti and Culex pipiens pallens . Additionally, we present transcriptome data detailing the interaction between TIBOV and the immune system of Ae. aegypti , which expands the knowledge about orbivirus infection and its interaction with mosquitoes.

Evaluating the mosquito vector range for two orthobunyaviruses: Oya virus and Ebinur Lake virus

“…All mosquito individuals, tissues, and saliva were stored in 250 μl Roswell Park Memorial Institute (RPMI) 1640 medium (Gibco, Grand Island, USA) supplemented with 2% penicillin/streptomycin/gentamicin solution (Gibco, Grand Island, USA) and kept at − 80 °C until use. The vector competence of the mosquitoes was evaluated by calculating the infection rate (IR; number of positive bodies/the total number of mosquitoes tested), dissemination rate (DR; number of positive heads/the number of positive bodies), transmission rate (TR; number of positive saliva/the number of positive bodies), and transmission efficiency (number of infected saliva/the total number of mosquitoes tested) [ 32 , 37 ].…”