Infecção natural por vírus em Culicídeos machos de quatro municípios de Mato Grosso, Brasil

Abstract

Vertical infection represents the main transmission route of insect-specific viruses (ISVs). This mechanism is also responsible for maintaining arboviruses in nature during interepidemic periods. This study proposed the identification of viral infection in adult male culicids captured in Cáceres, Cuiabá, Rondonópolis and Sinop, Mato Grosso State, between February 2017 and January 2018. In total, 10,569 specimens comprised 267 pools, 1,139 (10.77%) allocated in 84 pools from Aedes (Ae.) (Stegomyia) aegypti, 9,426 (89.18%) in 179 pools of Culex (Cx.) quinquefasciatus, 3 (0.03%) of Culex sp. In 03 pools and 1 (0.01%) of Psorophora albigenu allocated in 01 pool, according to species, place and date of collection. These pools were subjected to viral nucleic acid extraction and species-specific RT-PCR protocols for ten flaviviruses, five alphaviruses and the orthobunyavirus Simbu serogroup. Positive pools were subjected to three passages in VERO cells (alphavirus and orthobunyavirus) or C6/36 cells (flavivirus) and subsequently isolates were sequenced. Cx. quinquefasciatus (20/267; 7.85%) pools were positive for Chikungunya CHIKV; 7/267; 2.62%), Mayaro (MAYV; 12/267; 4.49%), Oropouche (OROV; 2/267; 0.74%) and Zika (ZIKV; 2/267; 0.74%). Ae. (Stegomya) aegypti (10/267; 3.74%) pools were positive for CHIKV 5/267; 1.87%), ZIKV (2/267; 0.74%), dengue sorotipo 4 (DENV-4; 1/267; 0.37%), Ilhéus (ILHV; 1/267; 0.37%) and Yellow Fever (YFV; 1/267; 0.37%). The infection was confirmed by viral isolation and we obtained sequences from three arboviruses, OROV (2), YFV (1) and MAYV (2). Viral nucleic acid from arbovirus positive pools was sequenced on MinION and Illumina platforms, resulting in the identification of viral sequences belonging to families Circoviridae (2), Parvoviridae (2), Totiviridae (1), Flaviviridae (1), Iflaviridae (2), Mesoniviridae (4), Nodaviridae (2), Luteoviridae (1), Phasmaviridae (1) Phenuiviridae (2), Rhabdoviridae (2), Orthomyxoviridae (1), Xinmoviridae (1), unclassified Bunyavirales (1) unclassified Picornavirales (3), unclassified Riboviria (4) and Taxon Negevirus (5). Five of these viruses represent putative novel viruses with low identity to the closest viruses,

tentatively named Mojica circovirus, Kuia iflavirus, Muxirum negevirus, Lambada picorna- like virus and Tacuru picorna-like virus. The results demonstrate a great viral diversity existing in the urban area of the four municipalities of Mato Grosso, represented either by arboviruses and, ISVs.