There is always more to say, and doubtless current theories – which stress the significance of population density and the type of plague flea carrying the disease – will be revised again at some point, but I discussed some aspects of this problem in an earlier answer, which pointed out the modern consensus is, increasingly, that the Black Death originated in the area around the Caspian Sea. If this is correct, it would certainly help to explain the puzzling lack of evidence for plague in India (certainly) and China (maybe), so you might like to review that response while you wait for fresh replies to your query.