Tuberculosis and homelessness in Montreal: a retrospective cohort study

Abstract

BackgroundMontreal is Canada's second-largest city, where mean annual tuberculosis (TB) incidence from 1996 to 2007 was 8.9/100,000. The objectives of this study were to describe the epidemiology of TB among homeless persons in Montreal and assess patterns of transmission and sharing of key locations.MethodsWe reviewed demographic, clinical, and microbiologic data for all active TB cases reported in Montreal from 1996 to 2007 and identified persons who were homeless in the year prior to TB diagnosis. We genotyped all available Mycobacterium tuberculosis isolates by IS6110 restriction fragment length polymorphism (IS6110-RFLP) and spoligotyping, and used a geographic information system to identify potential locations for transmission between persons with matching isolates.ResultsThere were 20 cases of TB in homeless persons, out of 1823 total reported from 1996-2007. 17/20 were Canadian-born, including 5 Aboriginals. Homeless persons were more likely than non-homeless persons to have pulmonary TB (20/20), smear-positive disease (17/20, odds ratio (OR) = 5.7, 95% confidence interval (CI): 1.7-20), HIV co-infection (12/20, OR = 14, 95%CI: 4.8-40), and a history of substance use. The median duration from symptom onset to diagnosis was 61 days for homeless persons vs. 28 days for non-homeless persons (P = 0.022). Eleven homeless persons with TB belonged to genotype-defined clusters (OR = 5.4, 95%CI: 2.2-13), and ten potential locations for transmission were identified, including health care facilities, homeless shelters/drop-in centres, and an Aboriginal community centre.ConclusionsTB cases among homeless persons in Montreal raise concerns about delayed diagnosis and ongoing local transmission.

Outbreak of tuberculosis among substance users and homeless people in Greater Montréal, Canada, 2003–2016

“…Our spatial analysis confirmed previous reports that identified drug use sites as a potential area for transmission (7). A specific area of downtown Montréal is known as a hot spot for drug use with numerous crack houses (16).…”

“…As in most low-incidence countries, TB is concentrated in specific groups-mainly Indigenous populations and migrants from endemic countries. However, outbreaks have been reported in Vancouver, Toronto, Edmonton and Ottawa as well as in several US cities, typically among groups with overlapping risk factors, such as HIV/AIDS coinfection, homelessness, substance use and incarceration (2)(3)(4)(5)(6)(7)(8)(9)(10)(11). While data on incidence rates of active TB in these groups are scarce, an incidence of 13.2/100,000 person-year has been reported among the homeless in Montréal (7).…”

Tuberculosis among the homeless, United States, 1994–2010

“…2 Substance abuse, incarceration and human immunodeficiency virus (HIV) infection—conditions that more frequently affect homeless persons—are also risk factors for tuberculosis (TB). 3–6 Persons without stable housing and employment often lack access to medical care, 7,8 which delays the diagnosis of TB, 9 resulting in prolonged infectious periods. 10 TB genotyping data suggest that homelessness is associated with greater transmission, 11,12 and homeless-associated outbreaks can be substantial, involving large numbers of patients and multiple sites of transmission.…”

Éclosion de tuberculose chez les consommateurs de drogues et les sans-abri du Grand Montréal, Canada, de 2003 à 2016

“…Comme dans la plupart des pays où l'incidence est faible, la tuberculose est concentrée dans des groupes précisprincipalement au sein de populations autochtones et chez les migrants en provenance de pays où la maladie est endémique. Toutefois, des éclosions ont été déclarées à Vancouver, à Toronto, à Edmonton et à Ottawa ainsi que dans plusieurs villes des États-Unis, généralement au sein de groupes présentant des facteurs de risque, tels qu'une co-infection VIH (sida), l'itinérance, la consommation abusive d'alcool ou de drogues et l'incarcération (2)(3)(4)(5)(6)(7)(8)(9)(10)(11). Bien que les données sur les taux d'incidence de tuberculose active au sein de ces groupes sont rares, un taux d'incidence de 13,2/100 000 personnes-années a été rapporté chez les sans-abri à Montréal (7).…”

“…Direction régionale de santé publique du Centre intégré universitaire de santé et de services sociaux du Centre-Sud-de-l'Île-de-Montréal, Montréal (Québec) 2 Programme canadien d'épidémiologie de terrain, Agence de la santé publique du Canada, Ottawa (Ontario) 3 Direction de santé publique du Centre intégré de santé et de services sociaux de la Montérégie-Centre, Longueuil (Québec) 4 Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke (Québec) 5 Direction de santé publique du Centre intégré de santé et de services sociaux de Laval, Laval (Québec) 6 Direction de la protection de la santé publique, Ministère de la Santé et des Services sociaux du Québec, Montréal (Québec) 7 Département d'épidémiologie, biostatistique et santé au travail, Université McGill, Montréal (Québec) 8 Laboratoire de santé publique du Québec, Sainte-Anne-de-Bellevue (Québec)…”