Haase I, Olson S, Behr M A, Wanyeki I, Thibert L, Scott A, Zwerling A, Ross N, Brassard P, Menzies D, Schwartzman K
Department of Geography, McGill University, Montreal, Quebec, Canada.
Int J Tuberc Lung Dis. 2007 Jun;11(6):632-8.
In Canada, tuberculosis (TB) is increasingly an urban health problem. Montreal is Canada's second-largest city and the second most frequent destination for new immigrants and refugees.
To detect spatial aggregation of cases, areas of excess incidence and local 'hot spots' of transmission in Montreal.
We used residential addresses to geocode active TB cases reported on the Island of Montreal in 1996-2000. After a hot spot analysis suggested two areas of overconcentration, we conducted a spatial scan, with census tracts (population 2500-8000) as the primary unit of analysis and stratification by birthplace. We linked these analyses with genotyping of all available Mycobacterium tuberculosis isolates, using IS6110-RFLP and spoligotyping.
We identified four areas of excess incidence among the foreign-born (incidence rate ratios 1.3-4.1, relative to the entire Island) and one such area among the Canadian-born (incidence rate ratio 2.3). There was partial overlap with the two hot spots. Genotyping indicated ongoing transmission among the foreign-born within the largest high-incidence zone. While this zone overlapped the area of high incidence among Canadian-born, genotyping largely excluded transmission between the two groups.
In a city with low overall incidence, spatial and molecular analyses highlighted ongoing local transmission.
在加拿大，结核病日益成为一个城市卫生问题。蒙特利尔是加拿大第二大城市，也是新移民和难民的第二大聚居地。
在蒙特利尔检测病例的空间聚集情况、发病率过高的区域以及局部的传播“热点”。
我们利用居住地址对1996 - 2000年在蒙特利尔岛报告的活动性结核病病例进行地理编码。在一项热点分析提示了两个过度集中的区域后，我们进行了一次空间扫描，以普查区（人口2500 - 8000）作为主要分析单位，并按出生地进行分层。我们将这些分析与所有可用的结核分枝杆菌分离株的基因分型相联系，采用IS6110 - RFLP和间隔寡核苷酸分型法。
我们在外国出生人群中确定了四个发病率过高的区域（发病率比为1.3 - 4.1，相对于整个岛屿），在加拿大出生人群中确定了一个这样的区域（发病率比为2.3）。这些区域与两个热点有部分重叠。基因分型表明在最大的高发病率区域内外国出生人群之间存在持续传播。虽然这个区域与加拿大出生人群中的高发病率区域重叠，但基因分型在很大程度上排除了两组之间的传播。
在一个总体发病率较低的城市，空间和分子分析突出了局部的持续传播情况。
