Variations On A Theme

It only takes one mutation.

New York Times:

Cows Have Been Infected With a Second Form of Bird Flu  —  A new version of the virus is widespread in wild birds but had not previously been detected in cows.  —  Dairy cows in Nevada have been infected with a new form of bird flu that is distinct from the version that has been spreading through herds …

Helen Branswell / STAT:   USDA milk testing shows different strain of H5N1 bird flu in Nevada dairy herds

Beyer, Don:   Virginia Delegation Urges Immediate Resumption of Virus and Disease Communication Amid Bird Flu Outbreaks

There are many subtypes of avian influenza (bird flu), including H5, H6, H7, H9, and H10.

The subtypes are named based on the proteins on the surface of the virus.

Subtypes that have infected humans:

H5N1: A(H5N1) is the most common subtype to infect humans.

H7N9: A(H7N9) is another common subtype to infect humans.

H5N6: A(H5N6) has caused human infections in recent years.

H9N2: LPAI A(H9N2) has caused human infections in recent years.

Any day now.