I raise Red Jungle Fowl and research their lineage and such.
I have run across a few zoos that raise these birds and Guinea Hens and read article that point to Guineas that have supposidly contracted the Marek's virus.
Marek's disease iis becoming a hot topic in the human world and scientist are looking into this virus as a possible cause agent typing for cancer in the human world (a different virus affecting the human world, but related to Marek's virus)
OK, I confess, I worked in the Scientific field for many years and reading a scientifid paper is OK, were others would be bored stiff.
Like I STATED, Guinea hens are resistant to virus agents that chickens turkeys and ducks contract.
However, they can become infected, however rarely.