"If you hear of an outbreak of plague in a land, do not enter it; but if the plague breaks out in a place while you are in it, do not leave that place."
What seems most fascinating to me is that by proscribing this from a religious channel, you can circumvent psychological mechanisms that would otherwise cause people to act in their own self interest - and in this case it actually works for the greater good.
Here's the source in Arabic and English:
Hajj epidemiology is indeed a fairly active field.
"It's hard to imagine that the quiet village of Eyam, off the A623 in Derbyshire, could have such a fascinating, yet tragic story to tell. But .... at the end of August 1665 bubonic plague arrived at the house of the village tailor George Viccars, via a parcel of cloth from London. The cloth was damp and was hung out in front of the fire to dry, thus releasing the plague infested fleas. On 7th September 1665, George Viccars, the first plague victim, died of a raging fever. As the plague took hold and decimated the villagers it was decided to hold the church services outdoors at nearby Cucklett Delf and, on the advice of rector William Mompesson and the previous incumbent Thomas Stanley, villagers stayed within the confines of the village to minimize the spread of the disease. Cucklett Delf was also the secret meeting place of sweethearts Emmott Sydall, from Eyam, and Rowland Torre, who was from a neighbouring village. They would call to each other across the rocks, until Emmott Sydall herself became a victim of the plague. Six of the eight Sydall family died, and their neighbours lost nine family members."
"To minimize cross infection, food and other supplies were left outside the village, at either the Boundary Stones, or at Mompesson's Well, high above the village. The Earl of Devonshire, who lived at Chatsworth House, freely donated food and medical supplies. For all other goods, money, as payment, was either purified by the running water in the well or was left in vinegar soaked holes. The Riley graves, close to Riley House Farm and approximately 1/2 mile from the village house the bodies of the husband and six children of farmer Elizabeth Hancock. All died within a week of each other. Because of the high risk of infecting her neighbours she had the traumatic task of burying them all herself. Even more tragic is that the infection probably came to her family when she helped bury another villager's body. Twelve months after the death of George Vicars, the plague was still claiming its victims, and on 25th August 1666 Catherine Mompesson, wife of the recently appointed rector William Mompesson (aged 28) , died of the plague. She had loyally stayed with her husband and tended the sick, only to become a victim herself."
"The Plague in Eyam raged for 14 months and claimed the lives of at least 260 villagers. By 1st November 1666 it had run its course and claimed its last victim. Eyam's selfless villagers, with their strong Christian convictions, had shown immense personal courage and self sacrifice. They had prevented the plague from spreading to other parishes, but many paid the ultimate price for their commitment."