Community based screening intervention for active tuberculosis case findings in a water locked setting in Kerala, India

Under-detection of tuberculosis (TB) remains a challenge in geographically isolated communities where structural barriers limit access to diagnostic services. Evidence on community-based active case finding (ACF) in water-locked settings in India is limited, despite its potential to improve equitable access to TB diagnosis. We conducted a community-based demonstration study of a multimodal ACF intervention in Kainakary Grama Panchayat, a water-locked region of Kerala, India. Two rounds of screening were implemented between February 2024 and July 2025under routine Programmatic conditions. The intervention combined door-to-door symptom screening by trained community health workers followed by portable digital chest X-ray screening and sputum collection for Cartridge-Based Nucleic Acid Amplification Test (CBNAAT) among symptomatic individuals along with mobile phone-based field coordination. Implementation outcomes included population coverage, completion of diagnostic evaluation, and TB case detection. A total of 251 individuals (0.72%) of total screening encounters (35014) were identified as presumptive TB cases. Of these, 240(95.6%) completed chest X-ray screening and 126 (50.2%) provided sputum for CBNAAT testing. Three laboratory-confirmed (CBNAAT positive) TB cases were identified, all during the first screening round, corresponding to a screening-level case detection rate of 8.6 per 100,000 population and a number needed to screen of 11,671. Three of five TB cases notified in 2024 occurred during the period of ACF implementation; this temporal overlap is descriptive and not intended to infer causality. Community-based ACF using symptom screening and sputum testing, supported by portable chest X-ray and simple digital coordination was operationally feasible in this geographically constrained, low-incidence setting. Although the laboratory-confirmed yield was low, the intervention achieved extensive population reach and provided implementation insights for TB screening in geographically constrained settings. Context-adapted ACF strategies may support equity-oriented TB control efforts in hard-to-reach communities with limited access to facility-based diagnostic services.