It had left Toronto at midday on August 31 with 33 passengers, made a stop in nearby London, where nine more passengers boarded, then stopped in Windsor across the Canada-US border from Detroit, where 27 people got off the bus.
"Public health officials are trying to identify these 27 people so they can be contacted and advised of the need to be tested for tuberculosis," officials said in a statement.
The infected passenger was detained at Windsor-Detroit border crossing by US customs officials, and put into quarantine in Windsor under the Canadian Federal Quarantine Act to ensure there was no further exposure to the public.
The remaining 14 passengers who had stayed on the bus for the last leg of its journey "are being looked after" by US and Canadian public health officials, said the statement.
The infectious form of TB is a lung infection which can be passed on to other people by coughing in close contact.