Incidence and Prevalence of Tuberculosis among Household Contacts of Pulmonary Tuberculosis Patients in a Peri-Urban Population of South Delhi, India

Abstract

BackgroundTuberculosis (TB), caused by Mycobacterium tuberculosis, is one of the leading causes of mortality and morbidity across all age groups throughout the world, especially in developing countries.Methodology/Principal FindingsIn this study, we have included 432 open index cases with their 1608 household contacts in a prospective cohort study conducted from May 2007 to March 2009. The follow-up period was 2 years. All Index cases were diagnosed on the basis of suggestive signs and symptoms and sputum being AFB positive. Among the 432 index patients, 250 (57.9%) were males and 182 (42.1%) females; with mean age of 34±14.4 yr and 26±11.1 yr, respectively. Out of 1608 household contacts, 866 (53.9%) were males and 742 (46.1%) females; with mean age of 26.5±15.8 and 26.5±16.0 yr, respectively. Of the total 432 households, 304 (70.4%) had ≤4 members and 128 (29.6%) had ≥5 members. The median size of the family was four. Of the 1608 contacts, 1206 were able to provide sputum samples, of whom 83 (6.9%) were found MTB culture positive. Household contacts belonging to adult age group were predominantly (74, 89.2%) infected as compared to the children (9, 10.8%). On screening the contact relationship status with index patients, 52 (62.7%) were first-degree relatives, 18 (34.6%) second-degree relatives and 12 (14.5%) spouses who got infected from their respective index patients. Co-prevalent and incident tuberculosis was found in 52 (4.3%) and 31 (2.6%) contacts, respectively. In incident cases, the diagnosis could be made between 4 to 24 months of follow-up, after their baseline evaluation.ConclusionActive household contact investigation is a powerful tool to detect and treat tuberculosis at early stages and the only method to control TB in high-TB-burden countries.

Prevalence and Associated Factors of Tuberculosis among Adult Household Contacts of Smear Positive Pulmonary Tuberculosis Patients Treated in Public Health Facilities of Haramaya District, Oromia Region, Eastern Ethiopia

“…Tuberculosis is exclusively transmitted based on environmental and personal risk factors, especially in a social mixing setting (together with overcrowding) and conditions which prolong the length of exposure to an infectious patient like health system-related factor including delay in diagnosis can increase TB transmission [4,5]. In addition, the risk of infection following TB exposure is primarily governed by exogenous factors and intrinsic combination of the infectiousness of the source case, proximity to contact and social and behavioral risk factors including smoking, alcohol, and indoor air pollution [4].…”

Identification of subclinical tuberculosis in household contacts. The relevance of tuberculosis exposure scores and contact investigations.

“…replicating Mtb in respiratory specimen were asymptomatic. The discrepancy between symptoms, X- (4.3%) (41). We do though, acknowledge that our definition of subclinical TB that relied on Mtbculture results only, and not on chest X-ray findings as suggested by Drain et al (14), might have underestimated the number of subclinical TB cases.…”

“…We acknowledge though, that the relevance of Mtb-replication and transient excretion in the early phase of Mtb-infection reported in children (46), that probably also occurs in adults, could be questioned, as successful containment and spontaneous recovery can be expected in an unknown proportion of subjects (14). in a semi-urban population in Delhi (41). Interestingly, scar rates of only 47.5 % were reported in newborns with low birthweight (51).…”

Risk factors for Tuberculosis in Mwea West Sub-County, Kirinyaga County, Kenya

“…In this study, more than half had more than 5 people in their households and in that population, more than half had history of other family members ever having suffered from TB. Large family size was evident in this region and this might have increased the risk of an individual in that family contracting tuberculosis at any one point in their lives [11,12]. Figure 5.…”