Doing a retrospective record view of household contacts between 2007 and 2013, scientists at the institute found that at least 5% of relatives of TB patients in Chennai had the infection. This, apparently, is more than double the normal. “Contacts of index cases who had a history of TB in the family had 2.5 times the risk for TB as compared to those whithout a family history of TB,” the study said.
For the study recently published in the medical journal PlosOne, scientists concluded that active screening of contacts is an effective way to improve TB case detection. These contacts were screened for tuberculosis as per the recommendations of the national TB programme.
India has nearly a quarter of the world’s TB incidence and it is estimated that about 40% of the population is infected with TB bacteria; a vast majority does not show symptoms as the infection is in a latent form.
In the national programmes, screening is recommended for people living with and sharing food from the same kitchen as the infected person for at least three months before diagnosis of tuberculosis. The objective of the study was to “evaluate the yield of active case finding in household contacts of newly diagnosed smear positive TB patients and the factors associated with increased yield.”