Pseudomonas aeruginosa is an emergent threat due to the antimicrobial resistance crisis. Bacteriophages (phages) are promising agents for phage therapy approaches against P. aeruginosa. It has been proposed that metazoans harbor phages on their mucosal surfaces, and this could be exploited for the rational design of prophylactic phage therapy. The goal of this study was to evaluate the potential of phage-mucus interaction to prevent infections caused by P. aeruginosa. We isolated two phages capable of infecting P. aeruginosa. Both are similar in morphology and closely related genetically. However, phage VAC3 is more efficient in replicating in mucin-exposed P. aeruginosa in vitro and is preferentially held in the respiratory tract of C57BL/6 mice. Pre-treatment with VAC3 phage protects mice from a lethal dose of P. aeruginosa while VAC1 does not. This shows that phages adapted to mucosal conditions have potential to be applied as prophylactic measures against an ESKAPE pathogen.

Numerous studies have shown that viruses are present in a variety of environments on Earth, acting as drivers of biogeochemical cycles and powerful selective forces. Among them, giant viruses of amoebae have garnered attention from the scientific community due to their large particles and extensive genomes. Here, we describe the discovery of one of the largest tailed viruses in the known virosphere (averaging 1350 nm), named Naiavirus. This virus, isolated from a swamp biome in Brazil, has particles with a never-before-seen morphology and composition, and represents the first giant amoeba virus with an external envelope covering the capsid and extending over a flexible tail region. The Naiavirus genome, with nearly 1 million base pairs, reveals a unique set of genes, and does not resemble any other virus previously isolated so far.

The evolutionary origin of coronaviruses is related to bats (order Chiroptera), and their association with pathologies in animals and humans is expected. Anthropic threats reduce bat diversity and expose humans to extraordinary transmission and spread of associated viruses, putting health and food security at risk owing to the multiple ecological roles that bats play. This study aimed to determine the presence of coronaviruses in bats in the Department of Córdoba, Colombia. Between 2022 and 2023, 11 municipalities were selected using non-probabilistic sampling methods. A total of 262 bats belonging to 16 species of five families were captured and identified. Serological tests were performed to detect SARS-CoV-2, and nested polymerase chain reaction (PCR) was performed to detect the coronavirus RdRp gene. RdRp-positive samples were sequenced using Sanger sequencing. Five specimens (2.7%) had antibodies against the coronavirus N protein, and the RdRp gene was detected in 55 specimens (21.0%), all belonging to the family Phyllostomidae. Phylogenetic analysis of the RdRp gene revealed that the newly generated sequences represented alphacoronaviruses. Bats tested in ecoregions with greater anthropogenic intervention were shown to be carriers of coronaviruses, unlike bats from conserved ecoregions. Coronavirus surveillance in bats has revealed previous infections through serology and circulating infections in natural populations of different ecoregions of the Department of Córdoba, where inter-species jumps could be generated by contact between bats and domestic/wild animals, or humans.

Avian influenza viruses (AIVs) are widely distributed and have a wide range of hosts. Recently, the number of cases of infection associated with the circulation of highly pathogenic avian influenza H5N1 2.3.4.4b has raised concerns about its high transmission capacity in birds and mammals. This study analyzed swabs from bird and mammal species from the coast of Paraná and the northwest region of São Paulo, Brazil, for the presence of AIV in animals that did not present clinical or histopathological lesions of infection that indicated the need for molecular characterization during monitoring. Of the 661 animals analyzed, three tested positive, two of which were birds (Sula leucogaster and Thalasseus acuflavidus) while one was a mammal (Otaria flavescens) (0.45%, CI 95%: 0.16–1.33). A complete genome sequence of H5N1 AIV was obtained from a brown booby (Sula leucogaster) from the Paraná coast (GISAID accession number: EPI_ISL_1897537). Our study reinforces the importance of continuous genomic surveillance, especially in AIV hosts that do not show signs of infection, to enhance the One-Health assessment approach.