Detection and Genomic Characterization of a Bat Orthohepadnavirus in Urban Areas of Brazil: Implications for Zoonotic Surveillance

Bats are recognized reservoirs for a vast array of viral diversity, including members of the Hepadnaviridae family. Within a One Health framework, genomic surveillance of these animals is fundamental to understanding viral diversity and the potential risks of zoonotic spillover in high-density human population areas. This study describes the detection of a bat hepadnavirus through agnostic viral metagenomics in samples from passive surveillance collected in urban and peri-urban areas in Brazil. Sequencing was performed using the Oxford Nanopore Technologies (MinION) platform, and the bioinformatics pipeline involved de novo assembly and taxonomic identification against viral databases. We identified several contigs with similarity to the Tent-making bat hepatitis B virus (TBHBV) in a single liver sample. The largest contig (3,182 bp) represents the complete genome, exhibiting a nucleotide identity of 80.93% with the original reference isolate. Our findings document the circulation of this viral lineage in a new epidemiological setting (the Brazilian urban interface), underscoring the importance of continuous surveillance to monitor the evolution and geographic distribution of bat orthohepadnaviruses and their relevance to public health.