A study published in the state public health journal reveals that at least two-fifths of family members of active TB patients in Tamil Nadu had latent tuberculosis infection. The patient has the bacteria but is not sick.

Scientists in the Tiruvallur area collected blood samples from 1,200 household connections of patients with pulmonary TB to identify latent TB infection (LTBI) among close contacts of TB patients. The state public health laboratory examined the samples using whole-blood Interferon Gamma Release Assay (IGRA) tests that can help diagnose Mycobacterium tuberculosis infection, including LTBI from TB.

The analysis revealed that 520 (43%) family contacts had LTBI. More women than males (62.3%) tested positive for TB, even though more men contracted the disease and died from it. Additionally, the age ranges of 15 to 44 comprised roughly 59% of individuals who tested positive.

The bacteria in these persons can remain latent (inactive) for a lifetime without causing disease. In contrast, the bacteria become active, grow, and cause TB in patients with weakened immune systems. In order to lessen the burden of TB disease in the community, it is crucial to diagnose and treat LTBI among household contacts of TB patients as soon as possible.

According to the WHO, LTBI affects the majority of the 40% of Indians who have TB infections. Similar investigations in Chennai revealed an incidence of LTBI of 74%.

LTBI may be influenced by behavioral factors that impact sex disparities in active TB illness. Women spend more time indoors doing home chores, which may change the dynamics of exposure to intimate relationships.

(Source:  https://timesofindia.indiatimes.com/city/chennai/study-2/5ths-of-family-contacts-of-active-tb-patients-in-state-have-latent-infection/articleshow/95727809.cms)