Titus Livius (Livy), The History of Rome, Book 25
Frank Gardener Moore, Professor Emeritus in Columbia University, Ed.

26. Marcellus, after getting possession of Euryalus and garrisoning it, was relieved of one fear, that some troops of the enemy in the rear might be admitted to the citadel and embarrass his men, hemmed in and hampered by the walls. [2] He thereupon laid siege to Achradina with three camps placed in suitable positions, in the hope of reducing the beleaguered to absolute want. [3] When the outposts on both sides had been inactive for some days, suddenly the arrival of Hippocrates and Himilco had the effect that the Romans were actually besieged on all sides. [4] For Hippocrates, after fortifying a camp by the Great Harbour and giving the signal to the forces occupying Achradina, attacked the old Roman camp,¹ which was commanded by Crispinus, at the same time that Epicydes made a sally against Marcellus' outposts, and just when the Carthaginian fleet put in to the shore lying between the city and [p. 443]the Roman camp, to make it impossible for any force² to be sent to the aid of Crispinus by Marcellus. [5] However, it was more of an uproar than a battle that the enemy offered. For Crispinus not only drove Hippocrates back from his fortifications, but also pursued him as he fled in disorder, and Marcellus likewise forced Epicydes into the city. [6] And now, even for the future, he seemed to have sufficiently insured that there should be no danger from their sudden raids. [7] Then in addition pestilence brought to both sides a calamity which forthwith diverted the attention of the two armies from strategy. For owing to the autumn season and places naturally unhealthy, unendurable heat affected the health of nearly all the men in both camps, but much more outside the city than within. And at first they sickened and died owing to the season and their position. [8] Later the mere care of the ill and contagion spread the disease, so that those who had fallen ill died neglected and abandoned, or else they carried off with them those who sat by them and those who nursed, having caught the same malignant disease. [9] And so every day funerals and death were before their eyes, and wailings were heard on all sides day and night. [10] Finally, from habituation to misery they had so lost their humane feelings that, so far from escorting the dead with tears and the wailing that was their due, they did not even carry them out and bury them; and dead bodies lay strewn about before the eyes of men awaiting a like death, and the dead seriously affected the ill, the ill the sound, not only through fear, but also by putrefaction and the pestilent odour of corpses. [11] And some choosing to die by the sword, dashed into the outposts of [p. 445]the enemy single-handed. [12] A much more violent³ epidemic, however, had attacked the Carthaginian camp than the Roman. For the Romans in their long blockade of Syracuse had grown more accustomed to the climate and the water. [13] Of the enemy's army, the Sicilians scattered, each to his own neighbouring city, as soon as they saw that the disease [14??] was spreading owing to the unwholesomeness of the place, while the Carthaginians, who had no refuge anywhere, with even their generals, Hippocrates and Himilco, perished to the last man. [15] Marcellus, as soon as the pestilence began to be so serious, had transferred his soldiers into the city, and shelter and shade had revived the invalids. Nevertheless many in the Roman army were carried off by the same pestilence.