Merced County CA Turkey Flock Hit by Avian Influenza

Subtype, clade and size of flock not yet announced

The USDA website today posted a new HPAI detection in Merced County California, as reported here:

After 2-month hiatus, avian flu returns to US poultry | WATTPoultry.com (wattagnet.com)

This is particularly troubling news, given the county’s large poultry populations and a very difficult bout with multiple H5N1 HPAI infections in 2022:

Why experts say Merced County was hit hard by nationwide bird flu outbreak (kvpr.org)

Additionally, California currently reports 10 dairy herds diagnosed with H5N1 in the past 2 weeks (locations not provided). As the map below shows, Merced County hosts the second largest number of dairy cows in the state:

Wherever the current infected herds are located, this large county dairy inventory increases the potential that H5N1 infection in dairy herds may have been a factor in the turkey flock outbreak, assuming that the infection is confirmed as H5N1 2.3.4.4b B3.13. Poultry flock H5N1 outbreaks were diagnosed in several other states adjacent to infect dairy herds since the initiation of the dairy outbreaks in March of 2024.

This is a situation that bears close attention in the coming days given the high concentrations of both poultry and dairy cattle in central California. An earlier blog had briefly referred to the risk for this scenario when the first dairy cases were diagnosed in California: New California, New Mexico, and Michigan Cases, CO Bulk Tank Progress Analysis, and a Lab Mask Fomite Study?? (substack.com)

As always, our thoughts, prayers, and best wishes go out to the many producers, responders, veterinarians, animal health officials, and workers in the trenches who will be under tremendous pressure responding to this emergency in the coming days. This is very likely to get much more challenging before it gets better if the “chatter” is any guide.

Stay strong,

John