Boranis III was the inhabited third planet of the Boranis system.
At some point, thousands of the inhabitants of the planet started dying from a plague without anyone knowing why. Fortunately, Doctor Julian Bashir and an away team from Deep Space 9 were able to identify the pathogen within the hour and started to inoculate the water table. It took just three days to do so. (DS9: "The Quickening")
According to the script for this episode, the pronunciation for Boranis was "bore-ON-us". [1]
In 2375, Bashir confused Boranis III with the Teplan homeworld when asked about the Quickening by Koval. (DS9: "Inter Arma Enim Silent Leges") It is possible that the Dominion was also involved in the situation on Boranis III, though after his initial failing on the Teplan homeworld, Bashir claimed that the plague was incurable because the Dominion knew what they were doing.