Before the advent of COVID-19 tuberculosis had been the most deadly infectious disease. How did it become the terrible plague that it is today?

This is the question Vidya Krishnan, a science journalist, explores in her book Phantom Plague. How Tuberculosis Shaped History. It was published this month. The book traces the spread and evolution of TB from the U.S., Europe and Asia in the 19th century to low-income countries such as India (Krishn’s country) where it thrives today.

She concludes that the answer lies in overtreatment, lack of treatment and wrong treatment. The West had the financial resources to purchase antibiotics and treat TB when they became available in the 20th Century. Poorer countries didn’t. Even though antibiotics were made available in countries with lower incomes, they were frequently overused. Antibiotic overuse led to antibiotic resistance, as pathogens developed resistance to the treatments. Krishnan refers to this as “monster” TB.

Although newer treatments are available in rich countries to treat this strain of TB are very limited in the poorer countries. Multidrug-resistant TB has thrived because of this.

This reality is felt most strongly in India than anywhere else on the planet. India has the highest rate of TB in the world, with more than 25% of all cases worldwide . According to the U.S. Agency for International Development. The city of Mumbai, India — a key focus in Krishnan’s book — has been identified as a hot spot for both multidrug-resistant TB and TB.

Krishnan, a renowned writer based in India, has spoken out about TB’s enormous impact on her country. This interview was edited to be more concise and clear.

Why did this book start in New York in 19th century?

I wanted to show you how disease-spreading errors are repeated over and over again.

Spitting has become as common in Mumbai as in New York in 19th and 20th century, when men were determined not to pay fines but to spit. Spitting can spread the disease by releasing TB germs into the air. Because spitting was so common, it was difficult to enforce anti-spitting laws. In Mumbai, 100 years later, the struggles to pass laws that curb spitting remain the same.

India, like New York City in 19th century New York, is densely populated by poor people who live in unsanitary and overcrowded conditions.

This describes the housing projects for the homeless in Mumbai, and the impact on TB.

They have been transformed into incubators for TB. Mumbai’s urban planning has been focused on making urban centers more affordable. They built high-rises that had a minimum of 3m [just over 3 feet] between each building. Many neighborhoods are so densely populated that there is no natural light or fresh air, even though they are near the Arabian Sea shoreline. It is called “skylight robbery” by an architect I spoke with. The lower floors receive no natural light. Poor ventilation is a breeding ground for the disease. People live in cramped spaces.

These crowded quarters can be dangerous as TB spreads through the atmosphere — often via a cough, sneeze or spittle, or even a smile. Are TB cases in India now confined to the poor who live in unsafe areas?

No. These people go outside. They use cabs. They also take the bus. They work in the homes and offices of the wealthy. It spreads.

Why is TB so hard to control in India?

India has corruption in its health care system and a lack of accountability. We have highly privatized healthcare. Patients who are able to afford the private system will often be overtreated. Private doctors have a strong incentive to keep patients in their care until the last penny is spent.

Shreya was a patient that I wrote about. For years, she was wrongly diagnosed. Her body was covered in antibiotics. If a doctor is unable to treat TB, they are supposed to refer the patient to a tertiary centre where free medicine is available.

You instead write that her doctors kept giving her drugs that didn’t work.

Shreya’s family ran out money and sent her to a government-run hospital. She was now resistant to all antibiotics. She was unable to be treated by the drugs she needed, which were protected under patents and strictly rationed in India.

Shreya’s family sued India to get a rationed drug. It is currently in limited supply in India.

She received bedaquiline from her parents after her parents took her to court. This drug could have saved her life early in her illness. She died after it was too late. According to her doctor, she died from a “miserable” death.

Mass medical negligence is what’s going on. Poor people may find themselves under-treated because the system is overwhelmed. If you’re wealthy, or like Shreya and her parents, are able to provide private care until money runs out), you may be overtreated.

What is needed to stop the spread of TB in India?

First, charity cannot fund global health. There are conflicts of interest when philanthropists invest in pharmaceutical companies. While philanthropy may provide vaccines and drugs, it does not address structural problems. The poor are often neglected and the wealthy overtreated. Both are not good. The system must be reformed.

Both of these are equally important. Access to medicines, counseling, and care is essential for all citizens. India also needs to conduct public health awareness campaigns to educate the population about how they can protect themselves. The scale of the TB epidemic is not known to most people.

What can TB’s history tell us about the current pandemic.

In essence, nobody is safe until everyone is safe.