Most people in a room infected? Some? All? One sneeze? Incubation period?
Regarding #1 : unknown, best to use CDC safety protocol as used in control of Ebola- (though Ebola is a virus).
Regarding #2 : One sneeze produces hundreds of droplets of infection, which allows the bacteria to remain virulent longer.
The problem is magnified as this religious festival takes place during the 'rainy season', thus giving the bacteria more longevity, and thus potentially involving more people.
Regarding #3 : The aerolized/ aerosol bacteria finds additional hosts when it becomes pneumatic, thus taken in through normal breathing into the lungs.
Pneumatic exposure has been linked to a fatality in 24 hours; however, unknown is whether there may have been other additional contributing medical complications.