Chikungunya, Zika, Mayaro, and Equine Encephalitis virus detection in adult Culicinae from South Central Mato Grosso, Brazil, during the rainy season of 2018.

INTRODUCTION: Several arboviruses causing human disease have been reported in Brazil. In nature, arboviruses maintain a lifecycle involving vertebrates and vectors, which may contribute for periodical reemergence of those of public health concern in tropical regions, as Mato Grosso State (MT). In this study, we searched for arboviruses in mosquito body pools sampled during the rainy season of 2018 in 21 bird watching points of Cuiabá and Varzea Grande, South Central MT. METHODS: In total, 2873 (57%) males and 2167 (43%) females belonging to six urban and sylvatic mosquito genera allocated to 398 pools were subjected to RNA extraction and RT-PCR for arboviruses. Positive pools were subjected to virus isolation in C6/36 cells. RESULTS: A total of 102/398 pools, 66/233 (29.6%) of females, and 36/165 (21.8%) of males, mostly sampled in May (31/102), were positive for arboviruses. Chikungunya virus (CHIKV) was distributed in 19 points, Zika virus (ZIKV) was found in 14 points, Mayaro virus (MAYV) in 10 points, and East Equine encephalitis virus (EEEV) in three points. Culex quinquefasciatus pools (39/89 of females and 24/99 of males) were positive for CHIKV, ZIKV, and MAYV; Aedes (Stg) aegypti pools (11/46 of females and 12/33 of males) for CHIKV, ZIKV, MAYV, and EEEV; Aedes albopictus female pools (8/29) for CHIKV, ZIKV, and EEEV; and Psorophora albigenu (2/12) and Psorophora ferox female pools (4/16) for CHIKV. CONCLUSIONS: Arbovirus molecular detection in mosquito populations varies considerable between geographical regions and epidemics, influenced by genetic characteristics and microbiome interference on virus replication. Although infected females are responsible for the transmission to vertebrates during bloodfeeding, male infection by CHIKV, ZIKV, and MAYV resultant from vertical route could lead to interepidemic maintenance of these arboviruses in their natural reservoirs.

Sialovirome of Brazilian tropical anophelines.

Anophelinae is a widely dispersed Culicidae subfamily that may carry a unique virome. Here we herein report the set of viruses found in 323 salivary glands of 16 anopheline species sampled at Upper Pantanal, Chapada dos Guimarães National Park and Coxipó river basin, South Central Mato Grosso, Brazil, pooled (n = 11) and subjected to high throughput sequencing. Metagenomics revealed the presence of nine viral sequences belonging to novel viruses from seven viral families: Purunga is a putative novel orbivirus sharing 74% and 65% aa identity, respectively, with the VP1 and VP3 segments of Changuinola serogroup, Jaracatiá flavivirus shares 60% amino-acid (aa) identity with Aedes flavivirus. Coxipó dielmovirus and Chapada dielmovirus shared 51% and 39% aa identity with Merida virus. Coloiado-orthomyxo like virus is 57.1-64.8% identical at aa level to Aedes albonnulatus orthomyxo-like virus. Mujica picorna-like virus shares 49% aa identity with Flen picorna-like virus and Chiquitos virus is 50% similar to Ista virus, both from Picornavirales order. Cerrado partiti-like-virus shares 75-86% aa identity with Atrato partiti-like virus 2. We also found the S and L segments of Anopheles triannulatus orthophasmavirus (92% identity) in Anopheles lutzi from Chapada dos Guimarães. The identification of these putative novel viruses underscore the wide dispersion of viruses in culicid hosts contributing to extensions on mosquito virome descriptions.

Insect-specific viruses and arboviruses in adult male culicids from Midwestern Brazil.

Viruses were identified from male anthropophilic mosquitoes from Mato Grosso (MT) State, Midwest Brazil from February 2017 to January 2018. Mosquitoes tested included Aedes (Stegomyia) aegypti (1139 males; 84 pools), Culex quinquefasciatus (9426 males; 179 pools), Culex sp. (3 males; 3 pools) and Psorophora albigenu (1 male; 1 pool) collected from four cities of MT. Pools were subjected to viral RNA extraction followed by RT-PCRs specific for ten flaviviruses, five alphaviruses and Simbu serogroup of orthobunyaviruses. Positive pools were passaged three times in VERO cells (alphavirus and orthobunyavirus) or C6/36 cells (flavivirus), with isolates confirmed through RT-PCR and nucleotide sequencing. We detected pools positive for Ilhéus (1 pool), dengue serotype 4 (1), Mayaro (12), equine encephalitis virus (1) yellow fever (1), Oropouche (2), Zika (4) and chikungunya (12) viruses. High throughput sequencing of arbovirus positive pools identified 35 insect-specific viruses (ISVs) from the 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), and unclassified Bunyavirales (1), unclassified Picornavirales (3), unclassified Riboviria (4) and taxon Negevirus (5). From these, five novel viruses were tentatively named Mojica circovirus, Kuia iflavirus, Muxirum negevirus, Lambada picorna-like virus and Tacuru picorna-like virus. Our findings underscore the diversity and wide geographical distribution of ISVs and arboviruses infecting male culicids.