Detection of Tuberculosis Infection Hotspots Using Activity Spaces Based Spatial Approach in an Urban Tokyo, from 2003 to 2011

• Published in: PloS one 2015-09, Vol.10 (9), p.e0138831-e0138831
• Main Authors: Izumi, Kiyohiko, Ohkado, Akihiro, Uchimura, Kazuhiro, Murase, Yoshiro, Tatsumi, Yuriko, Kayebeta, Aya, Watanabe, Yu, Ishikawa, Nobukatsu
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Analysis; Censuses; Cities; Cluster Analysis; Clustering; Cross-Sectional Studies; Demographic aspects; Demographics; Development and progression; Disease hot spots; Disease transmission; DNA fingerprints; Environmental statistics; Epidemiology; Female; Genotypes; Health aspects; Health surveillance; Homeless people; Homeless Persons; Homelessness; Households; Housework; Humans; Infections; Inhabitants; Male; Medical diagnosis; Middle Aged; Mortality; Mycobacterium tuberculosis; Mycobacterium tuberculosis - isolation & purification; Patient outcomes; Patients; Population; Population Surveillance; Prevention; Public health; Railroads; Railway stations; Random variables; Risk factors; Spatial analysis; Spatial distribution; Statistical analysis; Tokyo; Tuberculosis; Tuberculosis - diagnosis; Urban areas; Urban environments; Urban Population; Young Adult
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0138831

Identifying ongoing tuberculosis infection sites is crucial for breaking chains of transmission in tuberculosis-prevalent urban areas. Previous studies have pointed out that detection of local accumulation of tuberculosis patients based on their residential addresses may be limited by a lack of matching between residences and tuberculosis infection sites. This study aimed to identify possible tuberculosis hotspots using TB genotype clustering statuses and a concept of "activity space", a place where patients spend most of their waking hours. We further compared the spatial distribution by different residential statuses and describe urban environmental features of the detected hotspots. Culture-positive tuberculosis patients notified to Shinjuku city from 2003 to 2011 were enrolled in this case-based cross-sectional study, and their demographic and clinical information, TB genotype clustering statuses, and activity space were collected. Spatial statistics (Global Moran's I and Getis-Ord Gi* statistics) identified significant hotspots in 152 census tracts, and urban environmental features and tuberculosis patients' characteristics in these hotspots were assessed. Of the enrolled 643 culture-positive tuberculosis patients, 416 (64.2%) were general inhabitants, 42 (6.5%) were foreign-born people, and 184 were homeless people (28.6%). The percentage of overall genotype clustering was 43.7%. Genotype-clustered general inhabitants and homeless people formed significant hotspots around a major railway station, whereas the non-clustered general inhabitants formed no hotspots. This suggested the detected hotspots of activity spaces may reflect ongoing tuberculosis transmission sites and were characterized by smaller residential floor size and a higher proportion of non-working households. Activity space-based spatial analysis suggested possible TB transmission sites around the major railway station and it can assist in further comprehension of TB transmission dynamics in an urban setting in Japan.