Five states reported more highly pathogenic avian influenza outbreaks in poultry over the last few days, including California where more layer farms were hit by the virus, according to the latest updates from the US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS).
Two more outbreaks were reported from layer farms in Sonoma County, California, one with 54,000 birds and the other with 37,200. Also, officials reported an outbreak at a layer pullet farm in Marin County that houses 151,000 birds. Over the past month, California has been the state suffering the most poultry losses.
Elsewhere, South Dakota reported another outbreak at a commercial gamebird producer, this time in Edmunds County at a location that has 1,400 birds. Also, Missouri, Montana, and Texas reported outbreaks involving backyard poultry.
Since the H5N1 outbreaks in US poultry began in February 2022, the events have led to a loss of a record 79.7 million birds across 47 states.
Health officials have monitored more than 7,000 people
Sporadic H5N1 infections in humans have occurred in people exposed to infected poultry or their environments, including a positive respiratory specimen collected from a poultry culler in Colorado back in April 2022.
Since then, the Centers for Disease Control and Prevention (CDC) and its state and local partners have monitored more than 7,000 people in 52 jurisdictions who were exposed to infected birds or sick or dead mammals, the group said in a December 29 technical update. Of 175 people who had symptoms, only the Colorado patient tested positive for the virus.
Though the threat to human health remains low, the CDC said widespread geographic prevalence in wild birds and poultry poses an exposure risk to people and mammals, which could result in viral evolution or reassortment, and could change the current risk assessment.