Highly Divergent Partiti-like and Narna-like Viral RNA Sequences Detected in Pintomyia fischeri from São Paulo, Brazil: An Exploratory Metatranscriptomic Report

This study investigated the RNA virome associated with the phlebotomine sand fly Pintomyia fischeri using a metatranscriptomic approach applied to the Meta29 library, composed of 21 specimens collected at the São Paulo Zoo, Brazil. Read-based taxonomic analysis revealed a diverse viral community composed of viruses associated with the families Iflaviridae, Narnaviridae, Partitiviridae, Reoviridae, Solemoviridae, Tombusviridae, Totiviridae, and Tymoviridae, in addition to highly abundant unclassified RNA viruses related to the ShiM 2016 group. Assembly and annotation analyses enabled the characterization of four viral RNA genomes associated with the families Partitiviridae (PfPartitiV-1a-SP, PfPartitiV-1b-SP, and PfPartitiV-2-SP) and Narnaviridae (PfNarnaV-1-SP). Sequence comparisons revealed low amino acid identity relative to currently available reference viral sequences, supporting the classification of these sequences as highly divergent and potentially novel viral lineages. Structural modeling of the RNA-dependent RNA polymerase (RdRp) proteins identified the viral polymerase-specific catalytic motifs A, B, and C. Phylogenetic analyses further supported the evolutionary divergence of the identified viruses relative to currently described taxa. Overall, these findings expand current knowledge of viral RNA diversity associated with Neotropical sand flies and highlight the value of metatranscriptomic approaches for the detection and characterization of previously undescribed viruses associated with medically important insect vectors.