In all of human history, tuberculosis has killed more people than any other disease. Discovered in 1882 by Robert Koch, the M. tuberculosis bacterium was responsible for the Great White Plague that began in the 1600s and has not yet truly ended. It was the primary cause of death in Europe in the mid-1600s, and even in the 1800s, the high mortality from TB among young adults earned it the nickname of “the romantic disease,” which glosses over the symptoms that earned TB other nicknames such as “consumption", “phthisis" (bless you), and "scrofula".
Public awareness of Koch’s bacillus gave rise in the early 1980s to the National Tuberculosis Association (now the American Lung Association) and sanatoria for isolating those afflicted. The sanatoria helped reduce transmission and some provided excellent care, for the rich – the poor, in most cases, were simply imprisoned. But even among those receiving the best of care, the death rate was 50 percent until 1944 when streptomycin was discovered.
TB has been reduced to a very low incidence in developed countries. Most of us are unaware that it is still on the top 10 list of causes of death worldwide – up to the year 2000 TB caused more deaths than any other infectious disease, including HIV/AIDS and malaria combined. Given the fact that it is treatable, why has tuberculosis not gone the way of smallpox, bubonic plague, and measles?
An Excess of Opportunity
Although the pathogen responsible is a bacterium, it can be argued that the real cause of tuberculosis is “appalling social conditions," to quote Rudolf Virchow. Virchow was a German physician, public health/political activist, anthropologist, and pathologist as well as a prolific writer. Although he's known as the “Father of Pathology,” his public health achievements are arguably far more significant. Among other accomplishments, he designed a clean water/sewage system in Berlin, as well as meat inspections, after determining that trichinosis was spread in undercooked pork. Thanks to Virchow's work and efforts, Berlin in the later 1800s was one of the healthiest cities in Europe. His perspective was “disease is never purely biological, but often socially derived or spread,” and accordingly, he campaigned vigorously for social reform.
Consistent with Virchow’s observations, TB finds abundant opportunity in conditions of poverty and crisis. The organism’s talent for survival stems from several factors:
- It is estimated that the microbe resides in a third of the world’s population as a latent infection—the host has no symptoms and is not infectious. However, in those subject to malnutrition, poor sanitation, and other health problems related to crises or lack of resources, the microbe quickly takes hold; one case of TB rapidly becomes hundreds. The illness can so easily emerge from a widespread disaster that following Hurricane Katrina, the CDC issued a special report on TB patients temporarily lost to follow-up and treatment.
- TB cannot be controlled by eliminating a vector (i.e., mosquitoes, rats, undercooked meat, etc.).
- The microbe is readily transmitted in airborne droplets produced by coughing and sneezing.
- We still don't have any effective vaccine.
- Infections are very difficult to treat – the Mycobacterium has a waxy lipid coating on its cell surface that protects it from both the host immune system and antibiotics.
- The treatment is long and side effects miserable – first-line treatment consists of four drugs taken at high dose for two months and at a lower dose for four more months. Patients' cooperation is challenging in the best of circumstances.
- Given that 95 percent of TB deaths occur in low- and middle-income countries, treatment and control of TB likely also require infrastructure beyond just access to antibiotics: sufficient food and nutritional support, a clean water supply, and decent housing.
- If the extended treatment regimen is not explicitly followed, the result is often development of multiple drug-resistant disease (MDR-TB) which is even more difficult to treat.
Another great difficulty in treating TB is the cost – until recently, the drugs' price-per-dose was already high, and compounded by the length of treatment. Treatment of MDR-TB can last two years, and the cost of treating a single MDR-TB patient in the US could run as high as $100,000.
The TB Turnaround
Despite the organism’s ability to survive and thrive, the death rate from TB dropped around 50 percent between 1990 and 2015. That drop in mortality rate is good news, but in 2014, the number of new cases of TB globally was still 9.6 million, with 1.5 million deaths, including about 140,000 children. These numbers are still appalling, but it's encouraging that after hundreds of years at the top of the causes-of-mortality list, it is possible that M. tuberculosis may join Y. pestis and other pathogens that barely exist outside of test tubes. In fact, the World Health Organization has adopted a target for eradicating the disease by the year 2030.
While there has been no discovery of a dramatic cure, nor is there yet any vaccine, these are both possibilities in the near future. TB is in decline because of a dramatic change in the economics of treatment combined with a global public health research campaign. Both changes began with two doctors named Paul Farmer and Jim Kim who, with several others, started an organization called Partners in Health (PIH). Both Farmer and Kim were also trained as anthropologists, and were following in the footsteps of Virchow as they took their ideas and discoveries from Boston to Haiti, to Peru, to Russia, to Geneva – to even the World Health Organization – who is taking the “End TB” campaign global. We'll be covering that bit in Part 2.
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