By Chris Dall
The US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) confirmed last week that the recent detection of highly pathogenic avian influenza (HPAI) in a Wisconsin dairy herd represents a new spillover event from wildlife.
In a December 19 update, APHIS said whole-genome sequencing confirmed that the virus detected in a Wisconsin dairy herd on December 14 is H5N1 clade 2.3.4.4b genotype D1.1, which was implicated in two spillover events in dairy herds in Nevada and Arizona earlier this year. The Wisconsin spillover event is considered separate from those two previous spillovers, APHIS said. No additional infected dairy herds have been detected.