When clichéd scripts still ruled Bollywood, people only died of two diseases: heart attacks and tuberculosis. The rich man almost always died clutching his heart after hearing that his daughter had eloped with the local handyman, while death from hacking cough was reserved for the poor, who died the moment the errant son returned home with the lifesaving drug. Clichés such as these convinced me that tuberculosis was a poor man’s disease; a cough that killed people who could not afford an easily available cure. It certainly didn’t happen to “people like us”.
Now it turns out that tuberculosis is resurging among the affluent, urban young professionals. Pushing up the infection is stress, late nights, smoking and poor diets, all of which lower the body’s ability to fight infection.
One in three people in the world are infected with Mycobacterium tuberculosis. In most people, however, the infection remains latent and does not cause a full-blown disease. In healthy immune systems, macrophages — type of white blood cells that ingest foreign material — successfully wall off the bacteria, but fail to do so if the body’s defense against infection is low.
Among factors that weaken the immune system are chronic infections such as HIV, diabetes or cancers, and drugs such as corticosteroids, arthritis medications or anti-cancer drugs. Smoking is also a risk factor with some studies showing it doubles the risk of infection.
In urban centres, the infection shows a clear gender bias, with two in three people diagnosed with tuberculosis being young women, who have low immunity mostly because they diet to lose weight more often than men. Most cases are that of “reactivation of latent tuberculosis”, which means that an earlier exposure to infection is causing it now.
Mycobacterium tuberculosis continues to thrive because it can evade the immune response, making eradication near impossible, reported the American Journal of Pathology last year. It reports that immune responses to tuberculosis rarely result in killing the infection as the infected immune cells promote the formation of granulomas, which are areas where the bacteria are contained, but not destroyed. So despite treatment, infections exist in a latent form.
What makes the diagnosis difficult is that many young people do not display the classic symptoms such as hacking cough with sputum. In most cases, the only symptoms are weight loss, poor appetite and low-grade fever. Experts now advise everyone with unexplained weight loss and low-grade fever that lasts for over a month to get screened for tuberculosis.
In the absence of chronic cough and sputum positivity, X-rays and CT-scans have now become standard tools for diagnosis. Yet cases continue to be missed. Even though anti-tuberculosis drugs are easily available — and given free at government centres — India accounts for 3.7 lakh of the 20 lakh deaths worldwide.
Modern anti-tuberculosis treatment can cure virtually everyone if the drugs are taken for the prescribed duration, which varies between six months and two years. In India, free treatment has reduced tuberculosis deaths from 29 per cent to 4 per cent — more than seven-fold decrease — and raised cure rates from 25 per cent to 86 per cent over the past decade. Still, about 18 lakh people get infected each year, which is roughly two new infections every three minutes. And the only way to fight it is to boost immunity with nutrition and fitness.