In this translation, note 2.14 and 2.47-54. (These sections begin "The Athenians listened to his advice" and "Such was the funeral" respectively, and section 54 ends with the words "Such was the history of the plague.")
"The Athenians listened to his [Pericles'] advice, and began to carry in their wives and children from the country, and all their household furniture, even to the woodwork of their houses which they took down. Their sheep and cattle they sent over to Euboea and the adjacent islands. But they found it hard to move, as most of them had been always used to live in the country."
Although Thucydides does not make an explicit connection, the overcrowding at Athens which resulted from the Athenian policy of evacuating the Attic countryside (referred to in the preceding quote) probably contributed to the devastating effects of the plague.
"Among other things which they remembered in their distress was, very naturally, the following verse which the old men said had long ago been uttered:
A Dorian war shall come and with it death.
So a dispute arose as to whether dearth and not death had not been the word in the verse; but at the present juncture, it was of course decided in favour of the latter; for the people made their recollection fit in with their sufferings. I fancy, however, that if another Dorian war should ever afterwards come upon us, and a dearth should happen to accompany it, the verse will probably be read accordingly."