Bukhari

Hadith Commentary:
Ta‘un is also called plague; it is a very ancient disease and some mention of it is found in most books.
Qastallani said: Ta‘un is a pustule or swelling in which there is severe fever along with intense burning; most often this swelling occurs in the armpit and neck, and sometimes it appears in other places as well.
Reciting Surah Taghabun every day is a practice for protection from ta‘un.
Hazrat Maulana Waheed al-Zaman rahimahullah has written his own beneficial personal experiences regarding ta‘un, which can be seen in Sharh Waheedi.
Previously, this disease, by Allah’s command, would suddenly appear and spread on a large scale; there are many such details in history. Nowadays, by Allah’s grace, this disease does not exist. One should pray to Allah that He always keeps His servants safe from such diseases. Amin.

Hadith Commentary:
Although the time of death is fixed and it does not occur a moment before or after its appointed time, even so, it is prohibited to go to a place afflicted by an epidemic or to move from there to another place so that people's beliefs are not corrupted. For example:
Someone might say:
Going there became the cause of my destruction, or coming from the place of epidemic became the cause of my safety. Just as it is prohibited to go near a person afflicted with leprosy, further details of this will be clarified in the upcoming incident.