The CDC has said in their embargo order that the virus has been found in "at least six different species of potentially infected rodents have been implicated in the current outbreak mpx virus in humans." Let's hope that species such as squirrels, field mice, guinea pigs, etc. don't get & spread this illness.
Also, the CDC web site shows that mpx was found in pigs in the Congo during the 1996-1997 outbreak there.