Human groups that still maintain traditional modes of subsistence (hunter–gatherers and rural agriculturalists) represent human groups non-impacted by urban-industrialized lifestyles, and therefore their gut microbiome provides the basis for understanding the human microbiome evolution and its association with human health and disease. The Yanomami is the largest semi-nomadic hunter–gatherer group of the Americas, exploring different niches of the Amazon rainforest in Brazil and Venezuela. Here, based on shotgun metagenomic data, we characterized the gut microbiome of the Yanomami from Brazil and compared taxonomically and functionally with the Yanomami from Venezuela, with other traditional groups from the Amazon and an urban-industrialized group. Taxonomic biomarkers were identified to each South American traditional group studied, including each Yanomami group. Broader levels of functional categories poorly discriminated the traditional and urban-industrialized groups, but the stratification of these categories revealed clear segregation of these groups. The Yanomami/Brazil gut microbiome presented unique functional features, such as a higher abundance of gene families involved in regulation/cell signaling, motility/chemotaxis, and virulence, contrasting with the gut microbiomes from the Yanomami/Venezuela and the other groups. Our study revealed biomarkers, and taxonomic and functional features that distinguished the gut microbiome of Yanomami/Brazil and Yanomami/Venezuela individuals, despite their shared lifestyle, culture, and genetic background. These differences may be a reflection of the environmental and seasonal diversity of the niches they explore. Overall, their microbiome profiles are shared with South American and African traditional groups, probably due to their lifestyle. The unique features identified within the Yanomami highlight the bias imposed by underrepresented sampling, and factors such as variations over space and time (seasonality) that impact, mainly, the hunter–gatherers.

Mansonella ozzardi and Mansonella perstans infections both cause mansonellosis but are usually treated differently. Using a real-time polymerase chain reaction assay and deep sequencing, we reveal the presence of mansonellosis coinfections that were undetectable by standard diagnostic methods. Our results confirm mansonellosis coinfections and have important implications for the disease’s treatment and diagnosis.

Chikungunya virus (CHIKV) is a mosquito-borne pathogen that emerged in Brazil by late 2014. In the country, two CHIKV foci characterized by the East/Central/South Africa and Asian genotypes, were established in North and Northeast regions. We characterized, by phylogenetic analyses of full and partial genomes, CHIKV from Rio de Janeiro state (2014-2015). These CHIKV strains belong to the Asian genotype, which is the determinant of the current Northern Brazilian focus, even though the genome sequence presents particular single nucleotide variations. This study provides the first genetic characterisation of CHIKV in Rio de Janeiro and highlights the potential impact of human mobility in the spread of an arthropod-borne virus.

Background: The gut microbiome has been increasingly acknowledged as playing a pivotal role in human health. Therefore, a number of studies have focused on variables that impact its microbial structure and consequent functionality. A wide range of factors, such as diet, age, sex, life stage, behavior, ethnicity, and diseases have been considered, and strong links were set out. However, some aspects regarding the microbiome determinants are still under-explored. Discussion: Recently, Bosman et al. presented evidence that skin exposure to narrowband UVB light modulated the gut microbiome of a specific human cohort. This cohort presented an increase of biodiversity, Firmicutes and Proteobacteria, and a decrease of Bacteroidetes. Based on these findings, we revisited our data on a hunter-gatherer gut microbiome (Yanomami) and identified similarities in the gut microbiome of these two cohorts. Both presented a high abundance of Proteobacteria, which had been observed as a unique feature in the Yanomami gut microbiome, and based on Bosman et al study, could be associated with their natural sunlight exposure. Conclusion: In this commentary, we would like to point out that the human lifestyle concerning sunlight exposure should be considered as one force modulating the gut microbiome, highlighting, as proposed by Bosman et al, a novel skin-gut axis which is associated with health and disease.