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.

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.

Redescription of Leptoconops (Leptoconops) brasiliensis (Lutz) and Leptoconops (Megaconops) floridensis Wirth (Diptera: Ceratopogonidae) with its first Brazilian record.

The Leptoconops Skuse genus includes many pestiferous biting midges found in coastal areas. Only two species were previously found in Brazil and some species have ancient descriptions lacking updated taxonomic features. Herein, we redescribe Leptoconops (Leptoconops) brasiliensis Lutz and L. (Megaconops) floridensis Wirth based on female type specimens and additional material from Gois and Santa Catarina, Brazil. The first Brazilian record of L. (M.) floridensis is reported.