Mortality in sea lions is associated with the introduction of the H5N1 clade 2.3.4.4b virus in Brazil October 2023: whole genome sequencing and phylogenetic analysis
Andreina de Carvalho Araújo, Andrew Y. Cho, Laura Morais Nascimento Silva, Thaís Camilo Corrêa, Gabriela Cristini de Souza, Adriana Silva Albuquerque, Eduardo Macagnan, Cristiane K. M. Kolesnikvoas, Rafael Meurer, Jenyffer Vierheller Vieira, Giulia Gaglianone Lemos, André S. Barreto, Jeferson Luis Dick, Karina Rejane Groch, Pedro Volkmer de Castilho, Deyvid Amgarten, Fernanda de Mello Malta, Michael E. Miller, Erick Gustavo Dorlass, Soledad Palameta, Sun-Hak Lee, Clarice Weis Arns, Edison Luíz Durigon, João Renato Rebello Pinho, Dong‐Hun Lee, Helena Lage Ferreira
Abstract
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.