Why Bill Gates? Or why start with him?
Get a grant from anywhere reputable. You need to work your way up the ladder through a ton of hard work. I don't mean that's how the system should work, but each rung of the ladder will be a signal to the next rung that your idea is worth the opportunity cost of not considering a competing idea.
Waiting for Gates or another almost god-like figure can be an excuse to avoid hard work or the pain of failure. I don't think it matters that this is "in the public interest" instead of purely for personal gain.
If you're right about these strains being out there, I don't think you'd have to do a worldwide search. A local search in any metro area should be successful. Unless I misunderstand your proposal.