Thanx, Hip. You know, I actually did know that, which is why I qualified my question as an ignorant one -- I think y'all are a step or two (or three) ahead of me in looking at the difference between a regular enterovirus and a noncytopathic one. I'm still on Step 1 -- the difference between an enterovirus and a regular virus. I Googled it before I asked and couldn't find an answer. I was gonna post a separate thread to ask, but then I saw this thread, and I figured if anyone knows, you guys would know. So I'm hoping someone can explain that difference to me. Thanx!