My understanding is that much of the H5N1 bird flu detected in north america before this event was detected in cows and in people with exposure to cows. So if

My understanding is that much of the H5N1 bird flu detected in north america before this event was detected in cows and in people with exposure to cows. So if you want to provide background on H5N1 in america you end up talking about cows. See, for instance, https://www.cdc.gov/bird-flu/situation-summary/mammals.html https://www.cdc.gov/bird-flu/situation-summary/mammals.html