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.

Recombinant Strains of Human Parechovirus in Rural Areas in the North of Brazil.

We characterized the 24 nearly full-length genomes of human parechoviruses (PeV) from children in the north of Brazil. The initial phylogenetic analysis indicated that 17 strains belonged to genotype 1, 5 to genotype 4, and 1 to genotype 17. A more detailed analysis revealed a high frequency of recombinant strains (58%): A total of 14 of our PeV-As were chimeric, with four distinct recombination patterns identified. Five strains were composed of genotypes 1 and 5 (Rec1/5); five strains shared a complex mosaic pattern formed by genotypes 4, 5, and 17 (Rec4/17/5); two strains were composed of genotypes 1 and 17 (Rec1/17); and two strains were composed of genotype 1 and an undetermined strain (Rec1/und). Coalescent analysis based on the Vp1 gene, which is free of recombination, indicated that the recombinant strains most likely arose in this region approximately 30 years ago. They are present in high frequencies and are circulating in different small and isolated cities in the state of Tocantins. Further studies will be needed to establish whether the detected recombinant strains have been replacing parental strains or if they are co-circulating in distinct frequencies in Tocantins.

Recombination Located over 2A-2B Junction Ribosome Frameshifting Region of Saffold Cardiovirus.

Here we report the nearly full-length genome of a recombinant Saffold virus strain (SAFV-BR-193) isolated from a child with acute gastroenteritis. Evolutionary analysis performed using all available near-full length Saffold picornavirus genomes showed that the breakpoint found in the Brazilian strain (SAFV-BR-193) is indeed a recombination hotspot. Notably, this hotspot is located just one nucleotide after the ribosomal frameshift GGUUUUU motif in the SAFV genome. Empirical studies will be necessary to determine if this motif also affects the binding affinity of RNA-dependent RNA-polymerase (RdRp) and therefore increases the changes of RdRp swap between molecules during the synthesis of viral genomes.

Near full length genome of a recombinant (E/D) cosavirus strain from a rural area in the central region of Brazil.

In the present article we report the nearly full length genome of a Cosavirus strain (BRTO-83) isolated from a child with acute gastroenteritis, and who is an inhabitant of a rural area in the central region of Brazil. The sample was previously screened and negative for both: common enteric viruses (i.e. rotavirus and norovirus), bacteria, endoparasites and helminthes. Evolutionary analysis and phylogenetic inferences indicated that the Brazilian BRTO-83 Cosavirus strain was a recombinant virus highly related to the E/D recombinant NG385 strain (Genbank JN867757), which was isolated in Nigeria from an acute flaccid paralysis patient. This is the first report of a recombinant E/D Cosavirus strain detected in Brazil, and the second genome described worldwide. Further surveillance and molecular studies are required to fully understand the epidemiology, distribution and evolution of the Cosavirus.

Complete Genome Sequences of Six Human Bocavirus Strains from Patients with Acute Gastroenteritis in the North Region of Brazil.

Human bocavirus (HBoV) is commonly associated with acute respiratory tract illness and gastroenteritis. We report six complete genomic sequences of HBoV strains from patients with gastroenteritis in Belém do Pará and Tocantins in the North Region of Brazil. Phylogenetic analysis indicated that the six HBoV strains belong to genotypes 1, 2, and 3.

Wuhan large pig roundworm virus identified in human feces in Brazil.

We report here the complete genome sequence of a bipartite virus, herein denoted WLPRV/human/BRA/TO-34/201, from a sample collected in 2015 from a two-year-old child in Brazil presenting acute gastroenteritis. The virus has 98-99% identity (segments 2 and 1, respectively) with the Wuhan large pig roundworm virus (unclassified RNA virus) that was recently discovered in the stomachs of pigs from China. This is the first report of a Wuhan large pig roundworm virus detected in human specimens, and the second genome described worldwide. However, the generation of more sequence data and further functional studies are required to fully understand the ecology, epidemiology, and evolution of this new unclassified virus.

Detection and Characterization of Enterovirus B73 from a Child in Brazil.

Enterovirus B73 is a new member of the Enterovirus B species. First detected in the USA, it has been subsequently identified in China, India, Oman, and the Netherlands. In this study, we characterize the first B73 strain (named TO-127) to be detected in South America. TO-127 was obtained from a child with acute gastroenteritis living in a rural area in Northern Brazil. The subject was not infected with any known enteric pathogens such as norovirus, rotavirus, helminths, or enteric bacteria. Analysis of the nearly full-length TO-127 genome (6993 nt) indicated a 74⁻75% nucleotide similarity with EV-B73 strains from other countries. Evolutionary analysis suggests that B73 is endemic and widespread.