Immigrants and tuberculosis
===========================

* W. Wallace Watson

The article by Neil Heywood and associates1 presents an algorithm for tracking potential cases of tuberculosis (TB) in recent arrivals to Canada, but it should not give Canadians a sense of security.

In my experience of practising in northwest metropolitan Toronto for over 20 years, I have seen many immigrants and refugees with TB that was probably active at the time of their arrival in Canada. However, the medical examination before arrival and the screening after arrival were inadequate to identify the disease.

The implication that skin testing would yield too many false-positive results is indefensible. If the test result is positive and the patient is deemed a “low-risk reactor,” at least the information will be in the patient's dossier. Should the person become ill, this information should alert medical personnel of possible reactivation of TB. We must also be aware of the possibility of anergy. In Ontario, all health care workers are required to undergo skin testing for TB.

Heywood and associates1 also discuss surveillance for pulmonary TB; however, no provision is made for identifying extrapulmonary disease, of which I have seen many cases. For example, patients have been referred to me with a tentative diagnosis of inflammatory bowel disease or a “funny skin swelling.” The former had gastrointestinal TB, the latter classic “cold abscesses.” Like syphilis, TB is a great mimic of other diseases and conditions.

Immigrants and refugees from areas where TB is endemic should be thoroughly screened, and a skin test is essential for people from regions such as the Indian subcontinent and Somalia.

**W. Wallace Watson** Surgeon William Osler Health Centre Etobicoke Hospital Campus Etobicoke, Ont.

## Reference

1.  1. Heywood N, Kawa B, Long R, Njoo H, Panaro L, Wobeser W, on behalf of the Immigration Subcommittee of the Canadian Tuberculosis Committee. Guidelines for the investigation and follow-up of individuals under medical surveillance for tuberculosis after arriving in Canada: a summary. CMAJ 2003;168(12):1563-5.
    
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