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.

Human enteric adenovirus species F (HAdV-F) is one of the most common pathogens responsible for acute gastroenteritis worldwide. Brazil is a country with continental dimensions where continuous multiregional surveillance is vital to establish a more complete picture of the epidemiology of HAdV-F. The aim of the current study was to investigate the molecular epidemiology of HAdV-F using full-genome data in rural and low-income urban areas in northern Brazil. This will allow a genetic comparison between Brazilian and global HAdV-F strains. The frequency of HAdV-F infections in patients with gastroenteritis and molecular typing of positive samples within this period was also analysed. A total of 251 stool samples collected between 2010 and 2016 from patients with acute gastroenteritis were screened for HAdV-F using next-generation sequencing techniques. HAdV-F infection was detected in 57.8 % (145/251) of samples. A total of 137 positive samples belonged to HAdV-F41 and 7 to HAdV-F40. HAdV-F40/41 dual infection was found in one sample. Detection rates did not vary significantly according to the year. Single HAdV-F infections were detected in 21.9 % (55/251) of samples and mixed infections in 37.4 % (94/251), with RVA/HAdV-F being the most frequent association (21.5 %; 54/251). Genetic analysis indicated that the HAdV-F strains circulating in Brazil were closely related to worldwide strains, and the existence of some temporal order was not observed. This is the first large-scale HAdV-F study in Brazil in which whole-genome data and DNA sequence analyses were used to characterize HAdV-F strains. Expanding the viral genome database could improve overall genotyping success and assist the National Center for Biotechnology Information (NCBI)/GenBank in standardizing the HAdV genome records by providing a large set of annotated HAdV-F genomes.

Aedes aegypti is associated with epidemic diseases in Brazil, such as urban yellow fever, dengue, and more recently, chikungunya and Zika viruses infections. More information about Ae. aegypti infestation is fundamental to virological surveillance in order to ensure the effectiveness of control measures in use. Thus, the present study aims to identify and compare infestation and infectivity of Ae. aegypti females in Macapa city, Amapa State (Amazon region), Brazil, between the epidemiological weeks 2017/02 and 2018/20. A total number of 303 Ae. aegypti females were collected at 21 fixed collection points, 171 at the 10 collection points in the Marabaixo neighborhood and 132 at the 11 collection points in the Central neighborhood. Among the collected samples, only two were positive for dengue virus, with a 2.08% (2/96 pools) infectivity rate for Marabaixo. The difference between the medians of Ae. aegypti females captured in Central and Marabaixo sites was not statistically significant. The findings indicate similar mosquito infestation levels between the neighborhoods, and a low-level of mosquito infectivity, although dengue virus was found only in Marabaixo. Virological surveillance of Ae. aegypti was important to identify sites of infection and determine possible routes of transmission to enable health surveillance teams to adopt preventive strategies where infected mosquitoes are present and act faster.

Human Adenovirus species C (HAdV-C) is the most common etiologic agent of respiratory disease. In the present study, we characterized the nearly full-length genome of one potential new HAdV-C recombinant strain constituted by Penton and Fiber proteins belonging to type 89 and a chimeric Hexon protein of types 1 and 89. By using viral metagenomics techniques, we screened out, in the states of Tocantins and Pará, Northern and North regions of Brazil, from 2010 to 2016, 251 fecal samples of children between 0.5 to 2.5 years old. These children were presenting acute diarrhea not associated with common pathogens (i.e., rotavirus, norovirus). We identified two HAdV-C strains in two distinct patients. Phylogenetic analysis performed using all complete genomes available at GenBank database indicated that one strain (HAdV-C BR-245) belonged to type 1. The phylogenetic analysis also indicated that the second strain (HAdV-C BR-211) was located at the base of the clade formed by the newly HAdV-C strains type 89. Recombination analysis revealed that strain HAdV-C BR-211 is a chimera in which the variable regions of Hexon gene combined HAdV-C1 and HAdV-C89 sequences. Therefore, HAdV-C BR-211 strain possesses a genomic backbone of type HAdV-C89 and a unique insertion of HAdV-C1 in the Hexon sequence. Recombination may play an important driving force in HAdV-C diversity and evolution. Studies employing complete genomic sequencing on circulating HAdV-C strains in Brazil are needed to understand the clinical significance of the presented data.

Squash mosaic virus (SqMV) is a phytovirus that infects great diversity of plants worldwide. In Brazil, the SqMV has been identified in the states of Ceará, Maranhão, Piauí, Rio Grande do Norte, and Tocantins. The presence of non-pathogenic viruses in animals, such as phytoviruses, may not be completely risk-free. Similarities in gene repertories between these viruses and viruses that affect animal species have been reported. The present study describes the fully sequenced genomes of SqMV found in human feces, collected in Tocantins, and analyzes the viral profile by metagenomics in the context of diarrhea symptomatology. The complete SqMV genome was obtained in 39 of 253 analyzed samples (15.5%); 97.4% of them belonged to children under 5 years old. There was no evidence that the observed symptoms were related to the presence of SqMV. Of the different virus species detected in these fecal samples, at least 4 (rotavirus, sapovirus, norovirus, parechovirus) are widely known to cause gastrointestinal symptoms. The presence of SqMV nucleic acid in fecal samples is likely due to recent dietary consumption and it is not evidence of viral replication in the human intestinal cells. Identifying the presence of SqMV in human feces and characterization of its genome is a relevant precursor to determining whether and how plant viruses interact with host cells or microorganisms in the human gastrointestinal tract.