Officers at Canadian ports of entry and exit can detain and quarantine people in order to control the transmission of certain diseases. For example, quarantine helped control the worldwide outbreak of SARS in 2003. Similarly, quarantine helped minimize the effects of the 2009 outbreak of H1N1 influenza. Canada's earliest quarantine station, Grosse Île, near the port of Québec, was established in 1832 because of a cholera epidemic.
In Vancouver, in the early 20th century, authorities quarantined all arriving Chinese for three months in a low-rise building adjacent to the dock. It mattered not that each passenger had already been examined aboard ship by a White doctor, and that they had already been made to stand in line naked while they and their belongings were fumigated with sulphur. The building where arrivals were kept under guard was made of brick, had barred windows and was crowded and filthy inside. The Chinese called the building "the pig pen." It evoked the conditions of the coolie trade of the mid-1800s and the "pig pens" that unscrupulous recruiters would use to lock up labourers awaiting shipment out. But unlike the coolies who, a century earlier, often had been kidnapped or tricked into signing up, these men had gone of their own accord to Canada. It was a choice many must have questioned as they languished under detainment, bewildered and lonely for wives and family left behind.