Comparing the risk of Tuberculosis (TB) infection in the households with and without TB patients in Tsumkwe constituency, Otjozondjupa region, Namibia
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Date
2016
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Publisher
University of Namibia
Abstract
Namibia is among the countries with the highest per capita burden of tuberculosis. The traditional San community that are living in northern Namibia are heavily burdened by the TB disease partly due to high household density. This study compares the risk of transmission of TB among close contacts with the community contacts. A retrospective cohort study was conducted and data, of index cases registered during 2014 and their close and community contacts, was collected using health facility registers. Structured questionnaires were used to interview index cases and their contacts, and for the examination of active disease. Tuberculin skin test (TST) was performed on contacts without active disease. Risk of disease and infection in the close contacts were compared with the corresponding risks in community contact, by calculating risk ratio at 95% confidence interval. Twenty-three registered patients were visited and 66 close contacts and 102 community contacts were interviewed and screened. Eight (12%) out of the 66 close contacts and 8(8%) out of the 102 community contacts were diagnosed with active TB disease. The risk for developing the disease was higher in the close contacts than the community contacts (RR: 1.5; 95% CI: 0.6 – 2.39), but not statistically significant. When adjusted for age, the children who are close contacts had a higher risk to develop TB disease. Twelve (37.5%) out of the 32 close contact and 17(31%) out of the 54 community contacts tested, reacted positive to TST. The risk of infection in the close contacts and community contacts were the same (RR: 1.1; 95% CI: 0.65 – 2.16).Age adjusted risk ratio suggested a reduced risk of infection for children (RR: 0.66; 95% CI: 0.2 – 1.7).
Close and community contacts of TB patients in Tsumkwe constituency have an equal risk of acquiring infection and developing TB disease when infected. Young age was slightly protective against infection.
RECOMMENDATIONS: It is recommended that case finding be intensified and genotypic testing be considered to link index and secondary cases.
Description
A thesis submitted in partial fulfilment of the requirements for the Degree of Master of Science in Applied Field Epidemiology
Keywords
Tuberculosis, Tsumkwe constituency