"... slain, after all man’s devices had failed, by the humblest things that God, in his wisdom, has put upon this earth." - I suspect this might be a more likel

"... slain, after all man’s devices had failed, by the humblest things that God, in his wisdom, has put upon this earth." - I suspect this might be a more likely outcome (courtesy of Wells). A single strain or a novel virus is far more likely to have a predator on earth than be a predator to something we need to survive. That said, it would be prudent to take anything that may be living to the ISS first.