Six dairy herds in Nevada have tested positive for a newer variant of the H5N1 bird flu virus that’s been associated with severe infections in humans, according to the Nevada Department of Agriculture.

A version of the H5N1 virus that has killed one person and severely sickened another has been detected in milk samples collected from Nevada dairy herds.

The USDA Animal and Plant Health Inspection Service (APHIS) recently confirmed the deadly bird flu genotype responsible for killing flocks nationwide was found in Nevada dairy cattle. The APHIS National Veterinary Services Laboratories (NVSL) on Friday found the highly pathogenic avian influenza (HPAI) genotype D1.