ABSTRACT
In 2021, the H5N1 virus lineage 2.3.4.4b spread to the Americas, causing high mortality in wild and domestic avian populations. South American countries along the Pacific migratory route have reported wild bird deaths due to A/H5Nx virus since October 2022. However, limited genomic data resulted in no cases reported in Brazil until May 2023. Brazil reported its first case of highly pathogenic avian influenza virus (HPAI A/H5N1) in May 2023. The virus was detected in Cabot's tern specimen in Marataízes, Espírito Santo. Cases were also found in backyard poultry and other wild birds, but no human or commercial poultry cases occurred. HPAI poses risks to the poultry industry, food security, and public health. Researchers used next-gen sequencing and phylogenetic analysis to study the Brazilian sample. It confirmed its affiliation with the 2.3.4.4b clade and proximity to sequences from Chile and Peru. This sheds light on the spread and evolution of HPAI A/H5N1 in the Americas, emphasizing continuous monitoring to mitigate risks for both avian and human populations. Understanding the virus's genetics and transmission allows implementing effective control measures to protect public health and the poultry industry.
ABSTRACT
The ongoing H5N1 outbreak in the Americas caused by clade 2.3.4.4 is causing unprecedented impact in poultry and wild birds. In November 2022, a highly pathogenic avian influenza A outbreak was declared in poultry in Ecuador, affecting more than 1.1 million heads of poultry in two farms by February 2023. Phylogenetic analysis shows that the virus clade is 2.3.4.4b, and to the best of our knowledge, this is the first scientific publication reporting this clade in South America.
