Aedes aegypti Totivirus identified in mosquitoes in the Brazilian Amazon region.

The totiviridae family contains viruses with double-stranded RNA genomes of 4.6-7.0 kpb, which encode a capsid protein (CP) and RNA-dependent RNA polymerase (RdRp), and they are approximately 40 nm in diameter with icosahedral symmetry. Totiviruses were first isolated from mosquitoes collected in Shaanxi Province (China). Here, we report a new Aedes aegypti Totivirus (AaTV) identified in mosquitoes from the Amazon rainforest. Mosquitoes (Diptera: Culicidae) were collected from a forest reserve belonging to the Amazon forest in the city of Macapá, Amapá state, Northern Brazil. A viral sequence with a 5748 nucleotide length that was nearly identical to Aedes aegypti Totivirus (AaTV), here named Aedes aegypti Totivirus BR59AP, was detected. A detailed molecular analysis was performed and shows that AaTV-BR59AP is highly related to the AaTV strain from the Caribbean region. We emphasize the importance of the characterization of new viruses in mosquitoes to deepen our understanding of viral diversity in insects and their potential role in disease.

Chikungunya Virus Asian Lineage Infection in the Amazon Region Is Maintained by Asiatic and Caribbean-Introduced Variants.

The simultaneous transmission of two lineages of the chikungunya virus (CHIKV) was discovered after the pathogen's initial arrival in Brazil. In Oiapoque (Amapá state, north Brazil), the Asian lineage (CHIKV-Asian) was discovered, while in Bahia state, the East-Central-South-African lineage (CHIKV-ECSA) was discovered (northeast Brazil). Since then, the CHIKV-Asian lineage has been restricted to the Amazon region (mostly in the state of Amapá), whereas the ECSA lineage has expanded across the country. Despite the fact that the Asian lineage was already present in the Amazon region, the ECSA lineage brought from the northeast caused a large outbreak in the Amazonian state of Roraima (north Brazil) in 2017. Here, CHIKV spread in the Amazon region was studied by a Zika-Dengue-Chikungunya PCR assay in 824 serum samples collected between 2013 and 2016 from individuals with symptoms of viral infection in the Amapá state. We found 11 samples positive for CHIKV-Asian, and, from these samples, we were able to retrieve 10 full-length viral genomes. A comprehensive phylogenetic study revealed that nine CHIKV sequences came from a local transmission cluster related to Caribbean strains, whereas one sequence was related to sequences from the Philippines. These findings imply that CHIKV spread in different ways in Roraima and Amapá, despite the fact that both states had similar climatic circumstances and mosquito vector frequencies.

Adaptive Evolution of New Variants of Dengue Virus Serotype 1 Genotype V Circulating in the Brazilian Amazon.

Dengue virus (DENV) is a mosquito-borne viral pathogen that plagues many tropical-climate nations around the world, including Brazil. Molecular epidemiology is a growing and increasingly invaluable tool for understanding the dispersal, persistence, and diversity of this impactful virus. In this study, plasma samples (n = 824) from individuals with symptoms consistent with an arboviral febrile illness were analyzed to identity the molecular epidemiological dynamics of DENV circulating in the Brazilian state of Amapá. Twelve DENV type 1 (DENV-1) genomes were identified, which were phylogenetically related to the BR4 lineage of genotype V. Phylodynamics analysis suggested that DENV-1 BR-4 was introduced into Amapá around early 2010, possibly from other states in northern Brazil. We also found unique amino acids substitutions in the DENV-1 envelope and NS5 protein sequences in the Amapá isolates. Characterization of the DENV-1 BR-4 sequences highlights the potential of this new lineage to drive outbreaks of dengue in the Amazon region.

Guapiaçu virus, a new insect-specific flavivirus isolated from two species of Aedes mosquitoes from Brazil.

Classical insect-flaviviruses (cISFVs) and dual host-related insect-specific flavivirus (dISFV) are within the major group of insect-specific flavivirus. Remarkably dISFV are evolutionarily related to some of the pathogenic flavivirus, such as Zika and dengue viruses. The Evolutionary relatedness of dISFV to flavivirus allowed us to investigate the evolutionary principle of host adaptation. Additionally, dISFV can be used for the development of flavivirus vaccines and to explore underlying principles of mammalian pathogenicity. Here we describe the genetic characterization of a novel putative dISFV, termed Guapiaçu virus (GUAPV). Distinct strains of GUAPV were isolated from pools of Aedes terrens and Aedes scapularis mosquitoes. Additionally, we also detected viral GUAPV RNA in a plasma sample of an individual febrile from the Amazon region (North of Brazil). Although GUAPV did not replicate in tested mammalian cells, 3'UTR secondary structures duplication and codon usage index were similar to pathogenic flavivirus.

Aedes aegypti from Amazon Basin Harbor High Diversity of Novel Viral Species.

Viruses are the most diverse and abundant microorganisms on earth, highly adaptive to a wide range of hosts. Viral diversity within invertebrate hosts has gained notoriety in recent years in public health as several such viruses have been of medical importance. Aedes aegypti serves as a vector for several viruses that have caused epidemics within the last year throughout Brazil; including Dengue, Zika and Chikungunya. This study aimed to identify new viral agents within Aedes aegypti mosquito in a city of the Amazonian region, where it is highly endemic. Metagenomic investigation was performed on 60 mosquito pools and viral RNA sequences present in their microbiota were characterized using genomic and phylogenetic tools. In total, we identified five putative novel virus species related to the Sobemovirus genus, Iflavirus genus and Permutatetraviridae family. These findings indicate a diverse taxonomy of viruses present in the mosquito microbiota of the Amazon, the region with the greatest invertebrate diversity in the world.