Originally posted by SJG
I seem to remember there were was also at least one plague that affected the Roman Empire (2nd Century?).
I think various plagues have always been a problem where there were enough people living in close proximity.
Also, trade is the main reason a plague becomes a plague rather than a localised epidemic - which explains why many of the early European plagues mainly affected the Mediterranean.
To take them backwards.. trade of
grain was a major reason of spreading the plague, since rats follow grain and you
need rats to spread the plague.
Plagues haven't always been a problem for humans since it is a rodent disease and contact with social rodents in a plague-ridden rodent population is necessary. This is probably why it disappeared sometimes, apart from the bacteria being somewhat picky about it's living conditions.
There might have been plagues before Justinian's, like the 'Plague of the Philistees' in the bible, the 'Plague of Athens' 430B.C. or the roman epidemics of 166-180 and 251-268.
But these cases all have in common that the disease(s) in question have not been identified. It might have been the plague, or something else.
Rufus of Efesos in words saved for us by the greek doctor Oribasius brings us the earliest description of what probably is the plague. He hadn't seen it himself but describes what Dionysius the Hunchback had seen in the near east and nort africa, but also upon Posidonios and Dioskorides for north africa. This would be sometime around 200B.C.
This disease was claimed to break out from time to time in Syria, Egypt and other parts of north africa, but the descriptions are too vague to say more than that it
could have been the plague.
Btw, 'various'? plagues, there is only one plague, there are lots of epidemical diseases, maybe you meant them?