Two weeks ago the USDA added a new species - the common house mouse (Mus musculus) - to their list of mammals with HPAI H5N1. On June 4th they posted the first 11 detections, all in Roosevelt County, New Mexico. Last Tuesday they added 36 more.
While no details were provided as to how or where these mice were sampled, last week a WOAH WAHIS dashboard carried a report stating that `Wild house mice (Mus musculus) and wild red fox (Vulpes vulpes) collected from an HPAI affected poultry premises.'
For the 3rd Tuesday running the USDA has updated their list by adding 19 more mice, all presumably from the same location (see list below). 
Among the unknowns, we don't know if all of these mice were found dead, or if some (or all) were live-trapped. We don't know how widespread they might be on the farm, or whether some were captured outside of the poultry houses.
Among the unknowns, we don't know if all of these mice were found dead, or if some (or all) were live-trapped. We don't know how widespread they might be on the farm, or whether some were captured outside of the poultry houses.
We don't even know if this is the same B3.13 clade that has affected cattle, or if they display any genetic changes of note.
The lack of detail from the USDA is particularly frustrating, as this is an unusually large (and growing) number of detections in a mammalian species that - until two weeks ago - had never been listed.
More detailed answers are eagerly awaited.
