On 14 February 2025, the CDC released specimen data from the first human case in Nevada. The specimen sequence clusters with the first cases of genotype D1.1 detected in dairy cows recently released by the USDA. Previously, the CDC released data from the first human fatality involving a patient from Louisiana that had been exposed to non-commercial backyard poultry and wild birds. The CDC had also released specimen data collected from farm workers in Iowa and Wisconsin with exposure to infected commercial poultry, with the same D1.1 genotype detected in poultry and wild birds, in human cases in Washington state and notably a severe human case in British Columbia. The latest trees, based on representative subsamples, are dated to 14 February 2025.