Natural infection by Culex flavivirus in Culex quinquefasciatus mosquitoes captured in Cuiabá, Mato Grosso Mid‐Western Brazil

Abstract

New species of insect‐specific viruses (ISV) have been reported worldwide. In the present study, the complete genome of Culex flavivirus (CxFV) and partial sequences of other ISVs in Culex quinquefasciatus Say 1823 females (n = 3425) sampled in 200 urban areas census tracts of Cuiaba, state of Mato Grosso, were identified via reverse transcriptase‐polymerase chain reaction for a NS5 region of flaviviruses, nucleotide and high‐throughput sequencing, and viral isolation in C6/36 cells. CxFV was detected in 16 of 403 mosquito pools; sequences found in the study presented a high similarity with isolates from São Paulo, Brazil and other countries in Latin American that belong to genotype II, supporting the geographical influence on CxFV evolution. The monthly maximum likelihood estimation for CxFV ranged from 1.81 to 9.94 per 1000 mosquitoes. In addition to the CxFV complete genome, one pool contained an ORF1 sequence (756 bp) that belongs to a novel Negevirus from the Sandewavirus supergroup most similar to the Santana virus (77.1%) and another pool presented an RNA‐dependent RNA polymerase sequence (1081 bp) of a novel Rhabdovirus most similar to Wuhan mosquito virus 9 (44%). After three passages in C6/36 cells, only CxFV was isolated from these co‐infected pools. The importance of ISVs relies on their possible ability to interfere with arbovirus replication in competent vectors.

Detection of Zika and dengue viruses in wild-caught mosquitoes collected during field surveillance in an environmental protection area in São Paulo, Brazil

“…The frequency of species of the genus Flavivirus detected in this study (2.6%) was similar to that observed in other studies in Italy (2.3%) [ 59 ], China (5.1%) [ 60 ] and Brazil (2.8%; 4.0%) [ 19 , 61 ]. Cunha et al [ 4 ] found a frequency of 0.29% of mosquitoes infected with YFV during the 2016–2017 outbreak in the state of São Paulo.…”

Detailed Analyses of Zika Virus Tropism in Culex quinquefasciatus Reveal Systemic Refractoriness

“…Given the persistent detection of ZIKV in C. quinquefasciatus tissues despite this species' resistance to infection in our study and others (22, 23, 52-56), we hypothesized that ZIKV may be blocked downstream of cell entry in Culex mosquitoes but found TEM to be insufficient to address this question. Guedes et al used TEM to identify ZIKV particles in the salivary glands of C. quinquefasciatus and also observed cytopathic disruptions deemed consistent with viral infection (29); however, the high potential for mosquito cells and tissues to be persistently infected with ISFVs, which would be impossible to distinguish from ZIKV by TEM, hampers the use of TEM for the virus-specific identification of flavivirus particles in mosquito cells (46)(47)(48)(49)(50)(51). We therefore assessed virus internalization in cells by in vitro methods to test our hypothesis that ZIKV infection in Culex cells was blocked downstream of cell entry.…”

Novel Viruses in Mosquitoes from Brazilian Pantanal

“…Previous studies from our group already described new ISVs from Chuviridae, Rhabdoviridae, Partitiviridae, and Totiviridae families infecting the salivary glands of mosquitoes [19,20]. A novel phlebotomus fever serogroup member from Phlebovirus genus, Phenuiviridae family, named Viola virus was identified in Lutzomiya longipalpis from the High Pantanal region [21].…”