RESUMO
Clade 2.3.4.4b highly pathogenic avian influenza (HPAI) H5N1 virus was detected in the South American sea lions found dead in Santa Catarina, Brazil, in October 2023. Whole genome sequencing and comparative phylogenetic analysis were conducted to investigate the origin, genetic diversity, and zoonotic potentials of the H5N1 viruses. The H5N1 viruses belonged to the genotype B3.2 of clade 2.3.4.4b H5N1 virus, which was identified in North America and disseminated to South America. They have acquired new amino acid substitutions related to mammalian host affinity. Our study provides insights into the genetic landscape of HPAI H5N1 viruses in Brazil, highlighting the continuous evolutionary processes contributing to their possible adaptation to mammalian hosts.
Assuntos
Virus da Influenza A Subtipo H5N1 , Filogenia , Leões-Marinhos , Sequenciamento Completo do Genoma , Animais , Leões-Marinhos/virologia , Brasil , Virus da Influenza A Subtipo H5N1/genética , Virus da Influenza A Subtipo H5N1/classificação , Infecções por Orthomyxoviridae/veterinária , Infecções por Orthomyxoviridae/virologia , Genoma Viral , Genótipo , Variação GenéticaRESUMO
This study reports a granulomatous hepatitis caused by Mycobacterium avium in an Atlantic yellow-nosed albatross (Thalassarche chlororhynchos) found dead on Brazil southern coast. At necropsy, the albatross was cachectic and the liver was severely enlarged with multifocal to coalescing white nodules. Histopathological evaluation revealed multifocal to coalescing granulomas with caseous necrosis, surrounded by an infiltrate of macrophages and multinucleated giant cells, and a thin capsule of fibrous connective tissue. The Fite-Faraco staining technique revealed multiple acid-fast bacilli (AFB) stained in magenta, predominantly in the areas of necrosis. Bacterial culture and polymerase chain reaction (PCR) analysis confirmed the presence of Mycobacterium avium in liver samples. This case underscores the importance of wildlife surveillance in coastal regions. Pelagic birds like the Atlantic yellow-nosed albatross can harbor pathogenic agents that represent a threat to wildlife and domestic animals. Enhanced monitoring and research are essential to understand the epidemiology and potential risks associated with such infections in coastal ecosystems.