The Fall Of The Roman Empire Was Caused By Mosquito and Malaria
So according to this theory, malaria joined perhaps by smallpox or some other plaque
moved outward to the frontiers of the empire decimating the garrisons, depopulating the towns - and eventually leading to the final breakthrough of the barbarians. If this theory is true, then the Roman Empire was actually destroyed by mosquito.
The Fall Of The Roman Empire Was Caused By Mosquito and Malaria