As of April 2025, the CDC has reported 70 confirmed and probable human cases of H5N1 avian influenza since the outbreak began in 2024 in the United States. The majority of these cases have been linked to exposure through commercial agricultural settings, with 41 individuals exposed through infected dairy herds and 24 associated with poultry farms and culling operations. Two additional cases were connected to other animal exposures, including backyard flocks and wild birds, and three remain of unknown origin. Most human cases have been mild. Although, one fatality has been recorded in Louisiania this past January, marking the first H5N1-related death in the US.
This Louisiana case was the first severe human infection with H5N1 reported in the country and was identified as the D11 genotype, a strain previously associated with more serious illness. This includes a critical case in a Canadian child who required ECMO but ultimately recovered. In contrast, the B313 genotype, which has caused most cases among farm workers in the US has been linked to only mild symptoms. Investigations found no evidence of additional infections or person-to-person transmission, and this remains the only reported case in Louisiana.