Well, more like this sort of Visna. Or see the article from the USDA Agricultural Research magazine:
Toward Retrovirus-Resistant Sheep; Genetically engineered sheep; ovine progressive pneumonia; visna virus; encephalitis; pneumonia; arthritis; Caird E. Rexroad; Beltsville; MD Apr17 1994
Personally, I'd be more concerned if HPAI was the choice for a bioterror weapon- it's got far more possibilities for real economic and agricultural devestation.
-archy-/-