The U.S. Department of Agriculture confirmed a second Idaho dairy herd with avian flu late last week.
This herd, like the first group of cows that tested positive nearly three weeks ago, is at a farm in Cassia County.
Cows with the virus have reduced milk production and thicker milk consistency.
Unlike the first affected farm, which had recently imported cattle from Texas, the infected cows in this case have no connection to out-of-state cattle carrying the virus, according to the Idaho State Department of Agriculture.
Federal officials have determined that the virus is spreading from cow to cow, from cows back to poultry, between dairy farms through cattle movements and among cows not showing symptoms.
In response, ISDA has issued a quarantine on the second Cassia County farm, meaning no livestock are allowed in or out, and a ban on cattle and bison imports from out-of-state facilities where animals have tested positive remains in effect. ISDA said it recommends farmers test groups of at-risk cattle “whenever necessary,” and testing asymptomatic cattle is voluntary.
Rick Naerebout, the CEO of the Idaho Dairymen’s Association, previously said that it appeared the virus had been contained to the first Cassia County farm, as the eight sick cows there had recovered.
The Food and Drug Administration said this week it found nonviable viral evidence of the H5N1 bird flu in pasteurized milk, but stressed it believes milk is still safe to consume.
Scientists analyzing the USDA’s genetic data also hypothesize that bird flu has been spreading among cows for longer than officials initially realized.
As of Tuesday, the virus had been detected in 33 dairy herds across eight states.
The USDA also announced additional mandatory requirements for testing dairy cattle being transported across state lines and for reporting influenza cases, effective next week.
The agency said it has not found changes in the virus that would make it more transmissible to humans or between people.
Find reporter Rachel Cohen on Twitter @racheld_cohen
Copyright 2024 Boise State Public Radio
