User blog comment:Lord Loss/Monster Hunter Theory... Blog/@comment-4361439-20130313230024/@comment-5963861-20130314002247

Well see the thing is that the Unknown Rathian's skin coloration is completely black with red spikes while the infected one's skin is still green yet darker. Also the Unknown has attacks that are completely different than it's counterparts and a virus wouldn't be responsible for those. Another thing to add is that Goa Magara is indigenous to a completely different region/continent and doesn't come into contact at all with the Rathian in the 1st/2nd gen region/continent.