Abstract
Background: Citizenship and Immigration Canada (CIC) screens immigrants for TB and permits those with inactive pulmonary TB to enter Canada conditionally, subject to medical surveillance; we studied this program in Ontario.
Method: This was an administrative database study with linkage of national and provincial data.
Results: In 1994–95, 1,341 cases of foreign-born active TB were diagnosed and a CIC record was found for 1,095. 149 (14%) were classified for surveillance and 142 were included in the analysis. A significant proportion (39/142: 27%) were diagnosed either before or as a result of immigration screening in Canada. These persons had arrived as visitors or refugees and were excluded from further analysis. Only 21 of the remaining 103 persons (20%) with immigration screening before the diagnosis of TB adhered to surveillance. Only 1 of 16 (6%) eligible persons was given therapy to prevent future episodes of active TB. Most presented with symptoms (82/103: 82%) suggesting potential for TB transmission in Ontario.
Interpretation: The current TB surveillance system for high-risk immigrants to Ontario is not effective in identifying and treating latent infection, and thus not effective in preventing future cases.
Résumé
Contexte: Le ministère de la Citoyenneté et de l’Immigration (CIC) prévoit un dépistage de la tuberculose chez les immigrants et autorise les personnes atteintes de tuberculose pulmonaire latente à entrer au Canada à condition qu’elles se soumettent à une surveillance médicale. Nous avons étudié ce programme en Ontario.
Méthode: Nous avons recoupé les données nationales et provinciales d’une base de données de gestion.
Résultats: En 1994–1995, on a diagnostiqué 1 341 cas de tuberculose active dans la population née à l’étranger, et 1 095 de ces cas étaient répertoriés par CIC. Notre analyse a porté sur 142 des 149 personnes (14 %) placées sous surveillance médicale par CIC. Une proportion significative de ces personnes (39/142: 27 %) avaient été diagnostiquées avant ou durant le dépistage exigé par l’immigration. Elles étaient entrées au Canada en qualité de visiteurs ou de réfugiés. Seules 21 des 103 personnes restantes (20 %) ayant fait l’objet d’un dépistage de l’immigration avant leur diagnostic de tuberculose respectaient l’obligation de se soumettre à une surveillance médicale. La plupart (82/103: 82 %) présentaient des symptômes, mais 1 seule des 16 personnes admissibles (6 %) était traitée pour une tuberculose latente, ce qui suggère que la tuberculose a pu se propager en Ontario.
Interprétation: Le système de surveillance de la tuberculose en vigueur en Ontario pour les immigrants très vulnérables ne parvient pas à détecter et à traiter les infections latentes, ni donc à prévenir les cas futurs.
Footnotes
Opinions expressed are those of the author and may not represent the views of the department.
References
- 1.Cowie RL, Sharpe JW. Tuberculosis among immigrants: Interval from arrival in Canada to diagnosis. A 5-year study in southern Alberta. CMAJ. 1998;158(5):599–602. [PMC free article] [PubMed] [Google Scholar]
- 2.Orr PH, Manfreda J, Hershfield ES. Tuberculosis surveillance in immigrants to Manitoba. Can Med Assoc J. 1990;14:453–58. [PMC free article] [PubMed] [Google Scholar]
- 3.Ormerod LP. Tuberculosis screening and prevention in new immigrants 1983–88. Respir Med. 1990;84(4):269–71. doi: 10.1016/S0954-6111(08)80051-0. [DOI] [PubMed] [Google Scholar]
- 4.National Guidelines for the InvestigationFollow-up of Individuals Who Were Placed Under Surveillance for Tuberculosis After Arrival in Canada. Canadian Tuberculosis Standards. 5th edition. 2000. pp. 229–35. [Google Scholar]
- 5.Wang JS, Allen EA, Enarson DA, Grzybowski S. Tuberculosis in recent Asian immigrants to British Columbia, Canada: 1982–1985. Tubercle. 1991;72(4):277–83. doi: 10.1016/0041-3879(91)90054-V. [DOI] [PubMed] [Google Scholar]
- 6.Zuber PL, McKenna MT, Binkin NJ, Onorato IM, Castro KG. Long-term risk of tuberculosis among foreign-born persons in the United States. JAMA. 1997;278(4):304–7. doi: 10.1001/jama.1997.03550040060038. [DOI] [PubMed] [Google Scholar]
- 7.Wobeser W, Yuan L, Naus M, Corey P, Edelson J, Heywood N, et al. Expanding the epidemiologic profile — Risk factors for active tuberculosis among persons immigrating to Ontario. CMAJ. 2000;163(7):823–30. [PMC free article] [PubMed] [Google Scholar]
- 8.MMWR. 2000. [PubMed]
- 9.Hoeppner V, Marciniuk D, Hershfield E. Canadian Tuberculosis Standards. 5th edition. 2000. Treatment of Tuberculosis Disease and Infection; pp. 83–111. [Google Scholar]
- 10.Verver S, Bwire R, Borgdorff MW. Screening for pulmonary tuberculosis among immigrants: Estimated effect on severity of disease and duration of infectiousness. Int J Tuberculosis Lung Disease. 2001;5(5):419–25. [PubMed] [Google Scholar]
- 11.Dasgupta K, Schwartzman K, Marchand R, Tennenbaum TN, Brassard P, Menzies D. Comparison of cost-effectiveness of tuberculosis screening of close contacts and foreign-born populations. Am J Respir Crit Care Med. 2000;162(6):2079–86. doi: 10.1164/ajrccm.162.6.2001111. [DOI] [PubMed] [Google Scholar]
- 12.Catlos EK, Cantwell MF, Bhatia G, Gedin G, Lewis J, Mohle-Boetani JC. Public health interventions to encourage TB class A/B1/B2 immigrants to present for TB screening. Am J Respir Crit Care Med. 1998;158(4):1037–41. doi: 10.1164/ajrccm.158.4.9801024. [DOI] [PubMed] [Google Scholar]
- 13.Menzies D, Adhikari N, Tannenbaum T. Patient characteristics associated with failure of tuberculosis prevention. Tuber Lung Dis. 1996;77(4):308–14. doi: 10.1016/S0962-8479(96)90094-5. [DOI] [PubMed] [Google Scholar]
- 14.MMWR. 1998. [PubMed]
- 15.Heath TC, Roberts C, Winks M, Capon AG. The epidemiology of tuberculosis in New South Wales 1975-1995: The effects of immigration in a low prevalence population. Int J Tuberc Lung Dis. 1998;2(8):647–54. [PubMed] [Google Scholar]
- 16.MacIntyre CR, Plant AJ, Streeton JA, Yung A. Missed opportunities for prevention of tuberculosis in Victoria, Australia. Intl J Tuberc Lung Dis. 1997;1(2):135–41. [PubMed] [Google Scholar]
- 17.Wells CD, Zuber PL, Nolan CM, Binkin NJ, Goldberg SV. Tuberculosis prevention among foreign-born persons in Seattle—King County, Washington. Am J Respir Crit Care Med. 1997;156(2Pt1):573–77. doi: 10.1164/ajrccm.156.2.9611101. [DOI] [PubMed] [Google Scholar]
- 18.Nolan C. Community-wide implementation of targeted testing for and treatment of latent tuberculosis infection. Clin Infect Dis. 1999;29(4):880–87. doi: 10.1086/520453. [DOI] [PubMed] [Google Scholar]