Family members of TB patient at high risk to get the disease
Living with someone who is infected with tuberculosis can push up the risk of infection by more than two times, a study by National Institute for Research in Tuberculosis has found.
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 without 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.”
During the study, doctors screened 544 relatives of 280 TB patients and found 71 of them with an abnormal chest x-ray. More than 5% tested positive for TB. Nearly 15% of relatives refused the test for reasons such as no symptoms, lack or time or already investigated.
While 23 people had smear and culture positive TB, three of them had smear negative and culture positive TB. In addition, three more people were tested positive for extra pulmonary TB.
“Active screening among household contacts is an effective way to improve TB case detection.
The yield for new TB cases among contacts with abnormal x-ray was high in this study and use of chest x-rays in combination with symptom screen is recommended,” said corresponding author of the study Dina Nair who works with National Institute of Tuberculosis.
Doctors say it important to diagnose the disease early because it is a highly infectious and is transmitted through air, and usually affects the lungs. It can also affect other parts of the body including the spine, brain and the kidneys.
People with undiagnosed TB can spread the infection and it can be worse if it is a drug-resistant strain.
People with tuberculosis are given a cocktail of antibiotics known as first-line drugs for up to nine months.
