The Prophet ﷺ said, "I saw (in a dream) a black woman with unkempt hair going out of Medina and settling in Mahai'a. I interpreted that as (a symbol of) epidemic of Medina being transferred to Mahai'a, namely, Al-Juhfa."  

أَنَّ النَّبِيَّ ﷺ قَالَ رَأَيْتُ امْرَأَةً سَوْدَاءَ ثَائِرَةَ الرَّأْسِ خَرَجَتْ مِنَ الْمَدِينَةِ حَتَّى قَامَتْ بِمَهْيَعَةَ فَأَوَّلْتُ أَنَّ وَبَاءَ الْمَدِينَةِ نُقِلَ إِلَى مَهْيَعَةَ وَهْىَ الْجُحْفَةُ