What is the longest and shortest pandemic in the world history?

Question

I'm doing my college assignment and I beg you to include your reference, site ect.

Answer 1

I'd say the longest was the Bubonic Plague that started in Asia and was brought over by invading hordes, who tossed their dead into the beseiged city to spread it to Europe. It spent a couple of centuries on its inter-continental trek. I'd say the shortest was the 1918 flu epidemic. 20 million dead in two years.