Prevalence and factors associated with tuberculosis infection (TBI) among residents of a monastery situated in a high-TB burden area: A cross-sectional study, Sikkim, India

by Mohammad K. Siddiqui, Shagufta Khan, Rinchenla Bhutia, Vivek Nair, Ashok Rai, Nirmal Gurung, Tseten Yamphel, Peggy K. Dadul, Debya S. Kerongi, Karma Doma Bhutia, Jagat Pradhan, Kabita Khati, Sreenivas A. Nair, Shamim Mannan, Kiran K. Rade, Dinesh Gupta, Pawan Malhotra, L. Masae Kawamura, Shikha Dhawan, Asif Mohmmed

Monasteries in India house individuals from childhood to advanced age. These congregate settings amplify tuberculosis (TB) transmission and exposure when the disease is present, especially in the high burden areas like Sikkim, India. However, the prevalence of active-TB disease (ATB), tuberculosis infection (TBI), and their associated risk factors have not been studied. The diagnosis and treatment of TBI remain a major bottleneck in eradicating TB. ATB and TBI risk among residents living in the congregate setting of monasteries in Sikkim, India, a high-TB burden area, may be high due to high-density living quarters, public interaction and their frequent travel history but has never been illustrated.

A cross-sectional screening of the monks and residents of Rumtek Monastery (Sikkim, India) was carried out to assess extent of ATB and TBI in a congregate setting. TrueNat MTB and GeneXpert MTB/Rif systems were utilized for ATB diagnosis, whereas QuantiFERON-TB Gold Plus (QFT-plus) Interferon-gamma release assay (IGRA) analysis was used for TBI detection. Follow-up sputum testing by TrueNat MTB was performed on IGRA-positive individuals to exclude ATB.

Among the 350 inhabitants of the monastery, 7% (25/350) were found to be symptomatic for TB, whereas 93% (325/350) were asymptomatic. Out of them, 189 participants, including symptomatic cases, agreed to participate in the study and were screened for TBI; however, 15 participants were excluded from the study due to result discrepancies. None of the participant were diagnosed with active tuberculosis (ATB), although, 44.2% (77/174) were found to be positive for TBI; however, none of those with TBI progressed to ATB during one year follow-up. Risk factors for TBI included: advancing age, frequent travel history, family history of TB or having contacts with TB patients and abnormal Body Mass Index (BMI) ≤18.5- ≥ 25.

This study confirms the high prevalence of TBI among residents in the congregate setting of monasteries, and justify TB prevention strategies by targeted screening, TBI testing and preventive treatment in congregate settings of high TB burden areas.