Wesker's are just corpses. Ranging from your slow-shuffling types early in the franchise, to the fast running, mutating type in the most recent entry. There's also a special case that can be marginally controlled through the use of a parasite (one of the franchise's dumber moves), but we don't see those too often. But yeah, they're all science based. Viruses and parasites and what not.

He would be curious about that, though I doubt he'd believe it would be of any use to him. There's not magic where he's from.