Quebec’s public health authority is looking for people who travelled aboard a Megabus from Montreal to Toronto in late August after a passenger was diagnosed with contagious tuberculosis.

According to a news release, the Public Health Agency of Canada and Quebec authorities have managed to contact most of the passengers who travelled to and from Toronto between Aug. 20 and 23, 2015, but some have not been located.

The Public Health Agency suggests people who have travelled on the following buses get screened for tuberculosis:

• Megabus No. 771 on Thursday Aug. 20, 2015

Montreal to Toronto at 4:30 p.m., arrival in Toronto at 10:15 p.m.

Montreal to Kingston at 4:30 p.m., arrival in Kingston at 7:25 p.m.

Kingston to Toronto at 7:35 p.m., arrival in Toronto at 10:15 p.m.

• Megabus No. 718 on Sunday, Aug. 23, 2015

Toronto to Montreal at 1:30 p.m., arrival in Montreal at 7:15 p.m.

Toronto to Kingston at 1:30 p.m., arrival in Kingston at 4:10 p.m.

Kingston to Montreal at 4:20 p.m., arrival in Montreal at 7:15 p.m.

Quebec residents who were aboard one or both buses can contact 811. Residents from outside the province can call 1-844-817-0200.

People infected by tuberculosis can develop the infection but remain asymptomatic — meaning people are not contagious and show no signs of the disease until years later. Others can develop symptoms that often impact the lungs. In both cases, antibiotics are used to treat the illness.

— Postmedia Network