ナイジェリアの2つの矯正施設における症状に基づく活動性結核スクリーニング：横断研究

Tuberculosis (TB) remains a pressing health challenge in Nigerian correctional facilities, where the prevalence can be ten times higher than in the general population. Many facilities rely on passive TB case detection, often missing asymptomatic TB cases. This study evaluated a systematic active case-finding (ACF) approach using symptom-based screening followed by GeneXpert MTB/RIF testing across two high-volume Nigerian correctional facilities in Lagos and Ogun States.

Between April and September 2021, 2,244 inmates underwent standardized TB symptom screening (e.g., cough ≥2 weeks, weight loss, fever). Individuals with presumptive symptoms of TB provided sputum for GeneXpert analysis. The intervention comprised three strategies: (1) outreach screening in awaiting-trial mass cells, (2) cell-to-cell active case search, and (3) contact tracing of confirmed TB cases. Collected data were analysed to determine detection rates per 100,000 inmates and the overall positivity yield. Ethical clearance was obtained from the Lagos and Ogun State Ministries of Health, with formal permission granted by authorities of correctional facilities.

Of the 2,244 inmates screened, 678 were identified as presumptive and tested, 45 were confirmed TB cases with estimated prevalence of 0.5% (approximately 489 per 100,000 inmates). The estimated prevalence is more than double the national prevalence 0.2% (219 per 100,000). The overall TB positivity rate among presumptive inmates was 7%. Inmates from Lagos recorded a TB point prevalence of 500 per 100,000, while prevalence in Ogun state was 458 per 100,000. A targeted outreach in one facility achieved a 32% TB yield. All detected TB cases were rifampicin-sensitive, and no drug-resistant strains was found in this cohort.

These findings highlight the effectiveness of symptom-based GeneXpert screening within correctional facilities which was substantially higher that conventional passive TB detection rates. All confirmed TB cases (n = 45) were rifampicin-sensitive, and no MDR or XDR strains were identified, an important observation in the prison environment. Regular, systematic ACF, especially in overcrowded and high-turnover environments, can significantly enhance early TB diagnosis and treatment initiation. Policymakers should institutionalize routine ACF in correctional facilities through universal entry screening for all new admissions and at least annual facility-wide screening, with symptom checklists plus rapid molecular testi. Where feasible, this should be combined with portable digital CXR/CAD triage alongside improvement in living conditions and post-release linkage to DOTS.