Tuberculosis: The Forever Plague

Tuberculosis (TB) is a disease it has become easy to forget about.  Pria Anand reminds us that it has not gone away and we still don’t have effective means to deal with it.  Her article, The Plague That Won’t Die, appeared in the New York Review of Books.  It mainly focused on the volume “Phantom Plague: How Tuberculosis Shaped History” by Vidya Krishnan.

TB has been around as long as humans have been recording their history, perhaps even longer.  For much of its history it was better known as “consumption.”  TB was first identified as a bacterial disease by Robert Koch in 1882.  It is best known as a disease of the lungs, but it is more complicated than that.

“Tuberculosis can seem inscrutable, a protean disease that can settle in virtually any organ in the body. In the lungs it causes the bloody cough and gasping breath that ravaged the Brown family; in the lymphatic system it causes swollen masses that can press on the soft muscles of the vocal cords, robbing victims of their voices; in the guts it causes raw, bleeding ulcers and obstructed bowels. The disease is airborne: colonies of bacteria are exhaled from the lungs of a person with pulmonary TB in a fine mist of particles that can linger suspended in the air for hours. How long the bacteria survive in the air depends on the surrounding conditions; in spaces with poor ventilation—an enclosed car, for instance, or a windowless room—they can last hours or even days.”

“Our lungs are a strange paradox: they are protected by the hard carapace of our ribs but also tremendously exposed to airborne bacteria, which can slip in with a single breath. To prevent infections, the labyrinthine passages that make up each lung are lined with white blood cells. But Mycobacteria tuberculosis are impenetrable. Each cell is surrounded by a thick barricade made of fats and proteins. In the lungs they are consumed by white blood cells but not digested, surviving undisturbed as more white blood cells arrive to wall off the infection, forming scarred balls called tubercles. Here the bacteria can live for decades or even a lifetime, forming a latent infection and replicating slowly within an unwitting host, undetected until they take advantage of an aging or suppressed immune system to explode into full-blown consumption… Malnutrition, pollution, and illnesses like HIV and diabetes can all contribute to TB activation.” 

In the nineteenth century, when Koch identified the cause of the disease, TB was the primary cause of death.  Poor sanitation and overcrowding seemed to be contributing factors in infection rates.  In moving from the nineteenth to the twentieth century overall hygiene improved for most people and the disease became more closely identified with the urban poor and less of a threat to the financially well off.  Treatments were essentially nonsensical until the development of antibiotics in the 1940s.  In 1921 the BCG (Bacillus Calmette–Guérin) vaccine became available providing some benefits but it is incapable of controlling the disease.  It took 40 years to develop this vaccine.  A century later and we still have nothing better.  Even with antibiotics capable of treating an infected person the treatments are complex and last for several months.  To make matters worse, antibiotic resistant strains of bacteria have appeared and are becoming more common.

One gets the feeling that TB is not getting sufficient attention as a dangerous disease.  It suffers from being mostly a disease of the unfortunate, making it easy for the fortunate to ignore.  In addition, the need for vaccines and antibiotics face severe market disadvantages because they are one-time treatments when there is more money to be made in long-term treatments.  Pria Anand has similar feelings.

“The treatment regimen for an active tuberculosis infection is crude: months of toxic antibiotics that have the potential to harm nearly every part of the body. One of the treatments can strip the nerves and leave patients’ feet numb and tingling, while another turns both tears and sweat orange—patients are advised not to wear white T-shirts when taking the drug. Both medications can damage the liver. The treatment can take anywhere from three to nine months depending on the drug combination, and once it has begun, a patient cannot miss a dose. The first-line drugs we use to treat TB were all developed decades ago—one more than a century ago—and many of our second-line treatments for drug-resistant TB were originally developed to combat other infections before they were repurposed for the burgeoning plague of consumption.”

“…tuberculosis remains the leading infectious cause of death worldwide. Nearly a century and a half after Koch’s first attempts to devise an inoculation, we still have no effective vaccines. Globally, one in four people carries tuberculosis, though most are neither contagious nor symptomatic. In the United States, where the prevalence is closer to three in one hundred, the disease thrives primarily in the conditions created by social injustice: overcrowded prisons, for instance, or temporary shelters. Yet programs to curb the spread of TB are among those hit hardest by both the Trump administration’s closure of USAID and its assault on the National Institutes of Health, attacks that are projected to lead to millions of avoidable TB deaths over the coming decade.”

The three-in-one-hundred rate of infection means there are about 13 million infected people in the United States.  About ten percent are expected to end up with an active infection, predicting over a million tuberculosis outbreaks in our future.  This is not a negligible threat.  Perspective is provided by the article Recent Tuberculosis outbreaks in the U.S. are a call to action.

“Yet more than 30 years after an emergency declaration for TB - the world's next-most lethal infectious disease, which is both preventable and curable - progress has been woefully inadequate and there is no end in sight.”

“In just the last few months we've seen TB outbreaks in Alabama, Virginia, Arizona, New York and Canada. In Washington state, a woman with active TB disease who refused to isolate or be treated was imprisoned.”

“It is estimated that one person with active TB disease has the potential to infect 10 other people around them. Like COVID, TB could very quickly create a large scale public health emergency - one that can only be contained with robust TB infection testing and contact tracing.”

Anand finishes by telling us what Krishnan hoped to accomplish with her book.

“Her book, she writes, ‘has one intended audience: readers who have the good fortune to have remained ignorant of TB but can ill afford to be so any longer.’ To imagine that Black and brown people, incarcerated people, and poor and unhoused people are somehow uniquely vulnerable is to be ignorant of TB’s long history, forever linked with our own.  ‘No one is safe,’ she writes, ‘until everyone is’.”