Some immigration officials at the Lacolle, Quebec, border crossing have a new problem to deal with in the wake of last month's unprecedented wave of refugee claimants. One of the hundreds of claimants who tried to enter Canada before new immigration legislation took effect had an active case of tuberculosis.

Now authorities are testing hundreds of people to see if they have contracted the disease.

At the height of the crush of refugee claimants, dozens of people at a time were crammed into the tiny waiting room. Many stayed there for days, sleeping on the floor, or small couches.

One of those people, who was at Lacolle at the beginning of June had an active case of tuberculosis. Because of that, more than 100 people who work at the border have been tested for infection.

"We're talking about something like a dozen people, individuals who ... may have ... contracted the tuberculosis," said Robert Gervais of Citizenship and Immigration Canada.

Gervais says Montreal-area public health officials are contacting other people who have may have come in contact with the infected refugee claimant.

Dr. Terry Tannenbaum, with the Montreal Public Health Department, is the doctor responsible for controlling TB. She points out the city deals with 150-200 cases of active tuberculosis a year, so this case is nothing to worry about.

"It's not something that's transmissible easily, and this is not a case that we think is of particular risk to the population or concern."

Tannenbaum says thanks to her department's control of the disease, the rate of infection in Montreal is quite low.

Immigration Canada says the infected refugee claimant was detained at the border, so the public is not at risk.