Many questions remain unanswered. Are bats the sole reservoir hosts of SARS-like coronavirus? If so, which kinds of bats? Is the coronavirus that was detected in least horseshoe bats the direct ancestor of SARS-CoV as found in humans? If so, how did the original spillover occur? Was it just a single transmission—from one bat into one civet—or several such happenings? And from civet into human—how many occurrences, how many independent spillovers?
