Latent TB Infection Diagnosis in Population Exposed to TB Subjects in Close and Poor Ventilated High TB Endemic Zone in India

Abstract

BackgroundThe present study was designed to investigate the utility of Quantiferon TB gold (QFT-G) and Tuberculin skin test (TST) for diagnosis of latent TB infection (LTBI) in high crowding TB endemic zone of Nagpur, India and their comparison with associated risk factors.MethodsOut of 342 eligible participants, QFT-G and TST were performed in 162 participants.ResultsThe prevalence of LTBI observed according to QFT-G and TST was 48% and 42% respectively, with an agreement of 52.47%. QFT-G positivity was associated with age while TST positivity was associated with body mass index (BMI). Duration of exposure emerged as a key risk factor significantly associated with both the tests.ConclusionThe prevalence of LTBI was quite high in the studied zone as detected by both the evaluated tests and thus, the combination of both the tests will be best predictive for LTBI in such high TB endemic regions.

Social Activity Patterns Drive High Rates of Latent Tuberculosis Infection among Adolescents in Urban Tanzania<br/>—Latent TB Infection in Adolescents, Tanzania

“…Residing close to a health facility might increase adolescents' risks for contact with active TB patients who attend those facilities for TB treatment. Consistent with findings from previous studies [14] [15], these results showed the duration of contact with MTB within a shared environment increases the risk of acquiring the bacterium, thus indicating a significant contribution of environmental exposure to MTB to its transmission [8] [29].…”

“…This observation point to an increase in LTBI risk associated with poor ventilation inside the living rooms, supporting reports that overcrowding and poor ventilation increase the risk of acquiring MTB [14] [15]. Our study also showed poor socioeconomic status increased the to avoid stigma and discrimination since HIV/AIDS is prevalent in Tanzania [32].…”

“…Living in a house with four or more bedrooms was shown to increase the risk of LTBI, in contrast to previous studies [14] [15]. This may have been partly due to the Tanzania's extended family tradition, whereby those residing in urban areas and in houses with many bedrooms tend to host relatives migrating from rural areas in search of TB treatment services in urban Dar es Salaam [30] [31].…”

“…Risk factors for LTBI reported from other settings include household contact with infectious TB [12] [13], overcrowding and poor ventilation within households [14] [15], HIV infection [16], underweight [16] and high TB incidence [17]. Most of these studies have been conducted in settings where BCG immunization is routine and have used the TST to identify LTBI.…”

T-SPOT. TB assay and tuberculin skin test for diagnosis and screening of tuberculosis: First report in a Sri lankan population

“…The TST positive rate is similar to that reported in other low and middle income countries, where household contacts had a 40-50% positivity rate. 28,29 The T-SPOT.TBpositivity rate was lower than reported in household contacts in India (48-53%) 29,30 and Gambia (40%) 31 but was similar to that reported in a Swiss study where 20% of close contacts were T-SPOT. TBpositive.…”