Identifying areas and risk groups with localised Mycobacterium tuberculosis transmission in northern England from 2010 to 2012: spatiotemporal analysis incorporating highly discriminatory genotyping data.
Information on geographical variation in localised transmission of TB can inform targeting of disease control activities. The aim of this study was to estimate the proportion of TB attributable to localised transmission for the period 2010-2012 in northern England and to identify case characteristics associated with spatiotemporal-genotypical clusters.



We combined genotyping data with spatiotemporal scan statistics to define an indicator of localised TB transmission and identified factors associated with localised TB transmission thus defined in a multivariable logistics regression model.



The estimated proportion of TB cases in northern England attributable to localised transmission was 10% (95% CI 9% to 12%). Clustered cases (cases which were spatiotemporally clustered with others of identical genotype) were on average younger than non-clustered cases (mean age 34 years vs 43 years; p value <0.05). Being UK born (adjusted OR (aOR) 3.6, 95% CI 2.9 to 6.0), presenting with pulmonary disease (aOR 2.2, 95% CI 1.3 to 3.6) and history of homelessness (aOR 2.8, 95% CI 1.2 to 6.8) or incarceration (aOR 2.6, 95% CI 1.2 to 5.9) were independently associated with being part of a spatiotemporal-genotypical cluster in a multivariable model. Belonging to an ethnic group other than white or mixed/other was also significantly associated with localised transmission. We identified localised transmission in 103/1958 middle super output areas mostly in urban areas.



Incorporating highly discriminatory genotyping data into spatiotemporal analysis of TB incidence is feasible as part of routine surveillance and can provide valuable information on groups at greater risk and areas with localised transmission of TB, which could be used to inform control measures, such as intensified contact tracing.
Field Epidemiology Training Programme, Public Health England, Liverpool, UK Field Epidemiology Services, Public Health England, Liverpool, UK European Programme for Intervention Epidemiology Training, European Centre for Diseases Prevention and Control, Stockholm, Sweden.
María
M
Saavedra-Campos
Greater Manchester Public Health England Centre, Public Health England, Manchester, UK Manchester Academic Health Science Centre, University of Manchester, Manchester, UK.
William
W
Welfare
Field Epidemiology Services, Public Health England, Liverpool, UK.
Paul
P
Cleary
Microbiology Services, Public Health England, Newcastle upon Tyne, UK.
Andrew
A
Sails
Field Epidemiology North East, Public Health England, Newcastle upon Tyne, UK.
Andy
A
Burkitt
Field Epidemiology Services, Public Health England, Liverpool, UK.
Daniel
D
Hungerford
Yorkshire & Humber Public Health England Centre, Public Health England, Leeds, UK.
Ebere
E
Okereke
North East Public Health England Centre, Public Health England, Newcastle upon Tyne, UK.
Peter
P
Acheson
Greater Manchester Public Health England Centre, Public Health England, Manchester, UK Manchester Academic Health Science Centre, University of Manchester, Manchester, UK.
Marko
M
Petrovic
D000328:Adult; D003430:Cross-Sectional Studies; D004739:England; D005240:Feasibility Studies; D005838:Genotype; D006801:Humans; D015994:Incidence; D009169:Mycobacterium tuberculosis / Q000235:genetics* / Q000302:isolation & purification; D012307:Risk Factors; D062211:Spatio-Temporal Analysis; D014397:Tuberculosis, Pulmonary / Q000453:epidemiology / Q000382:microbiology / Q000517:prevention & control / Q000635:transmission*
Clinical Epidemiology; Respiratory Infection; Tuberculosis