Compared to passive case-finding, active case-finding (ACF) is an important approach to increasing case detection rates by identifying individuals with TB who have no symptoms and improving access to diagnosis in hard-to-reach areas.

Implementing this ACF intervention in these hard-to-reach areas led to a substantial increase in TB case notifications by 183.3% and 137.5% during initial implementation and scale-up, respectively, suggesting the effectiveness of the ACF intervention in identifying previously undiagnosed cases.

This significant increase in case detection emphasizes the urgency for heightened attention, more efficient resource allocation, and use of intervention strategies to address the low TB case notifications in Nigeria, especially in hard-to-reach riverine areas with high-risk populations.

Health policymakers and TB control program managers could prioritize resources toward ACF for TB if, compared to other potential uses of resources, ACF is more cost effective.

TB control program managers could implement more and regular ACF interventions for TB in hard-to-reach areas, especially in high TB-burden countries, to boost TB case detection and facilitate the efforts toward ending TB.

A major challenge to TB control globally is low case detection, largely due to routine health facility-based passive case-finding employed by national TB control programs. Active case-finding is a risk-population-based screening approach that has been established to be effective in TB control. This intervention aimed to increase TB case detection in hard-to-reach areas in southern Nigeria.

Using a descriptive cross-sectional design, we conducted implementation research in 15 hard-to-reach riverine local government areas with historically recognized low TB case notification rates. Individuals with TB symptoms were screened using multiple strategies. Data were collected quarterly over a 4-year period using reporting tools and checklists. Descriptive analysis was done with Microsoft Excel spreadsheet 2019.

A total of 1,089,129 individuals were screened: 16,576 in 2017; 108,102 in 2018; 697,165 in 2019; and 267,286 in 2020. Of those screened, 24,802 (2.3%) were identified as presumptive TB, of which 88.8% were tested and 10% were diagnosed with TB (0.23% of those screened). TB notifications more than doubled, increasing by 183.3% and 137.5% in the initial implementation and scale-up, respectively. On average, 441 individuals needed to be screened to diagnose 1 TB case. The cases, predominantly males (56.1%) and aged 15 years and older (77.4%), comprised 71.9% bacteriologically confirmed drug-sensitive TB, 25.8% clinically diagnosed drug-sensitive TB, and 2.3% drug-resistant cases. Detection sources included community outreach (1,786), health facilities (505), people living with HIV (57), and household contacts of bacteriologically confirmed TB cases (123). Remarkably, 98.1% of diagnosed TB cases commenced treatment.

We found a significant yield in TB case notifications, more than doubling the baseline figures. Given these successful results, we recommend prioritizing resources to support active case-finding strategies in national programs, especially in hard-to-reach areas with high-risk populations, to address TB more comprehensively.

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