Genetic diversity and low-level infection of Malawi polyomavirus in pediatric patients in Brazil

This is the authors' abstract. We don't add key points for this paper.

Malawi polyomavirus (MWPyV) has been detected in respiratory and gastrointestinal specimens, mostly in children; however there are limited data on its distribution and diversity. Here, we analyse n = 233 oropharyngeal swabs, collected from pediatric patients in São Paulo State, Brazil for MWPyV and potential co-infections using an integrated molecular, phylogenetic, and ultrastructural approach. We detect MWPyV DNA in 18 samples (7.7%) with low viral loads (mean 266 copies/reaction; range 13-2.3 × 103). Our phylogenetic analysis assigns six genomic sequences to genotype I and one to genotype III. The genome of genotype III shows evidence of putative recombination events with genomic regions related to genotypes II and III. One genotype I sequence forms a distinct phylogenetic branch, suggesting an unsampled or transitional lineage. Our findings provide evidence into the genomic diversity, viral recombination and potentially diverging lineages of MWPyV in pediatric patients. In this study, Slavov et al. identify MWPyV DNA in 7.7% of pediatric oropharyngeal samples from Brazil, predominantly in young children and at low viral loads. Genomic analyses reveal distinct viral lineages and evidence of recombination, while electron microscopy provides ultrastructural evidence of MWPyV particles in respiratory specimens.