Science Time Machine | Tuberculosis, which historically caused nine out of ten deaths, is now a common disease.

On March 24, 1995, the World Health Organization designated this day as "World Tuberculosis Day" to commemorate the important discovery of the tuberculosis pathogen by German microbiologist Robert Koch in 1882, and to take this opportunity to enhance public awareness of tuberculosis.

Historically, tuberculosis was known as the "leader of death" in the West. This situation did not improve until the discovery of Mycobacterium tuberculosis in 1882, and the isolation of streptomycin in 1944 brought a breakthrough in treatment. With the development and application of antibiotics, BCG and chemotherapy drugs, the mortality rate of tuberculosis has dropped significantly, and its "death label" has been removed.

Tuberculosis and human history

On a cold winter night thousands of years ago, people gathered around a fire in an African cave to keep warm, accompanied by bursts of coughing. At this time, a microorganism lurking in the soil quietly invaded their inflamed respiratory tracts - biologists at the University of New South Wales believe that this may be the origin of tuberculosis, one of the oldest diseases in human history.

Archaeologists have further revealed the long history of tuberculosis through in-depth research on ancient human remains. In the Stone Age site of Heidelberg, Germany, people found typical tuberculous lesions on the fourth and fifth thoracic vertebrae of ancient people dating back about 7,000 years, indicating that tuberculosis already existed at that time.

Similarly, tuberculous lesions were found on the spines of mummies excavated from ancient Egyptian tombs. There were five cases of spinal tuberculosis in mummies in the Nubian region, and mummies from the Fifth Dynasty of Egypt in 2500 BC had bone and joint tuberculosis. In addition, a female corpse unearthed from the No. 1 Han Tomb of Mawangdui in my country was found to have tuberculous calcifications in its left lung, a discovery that pushed the history of pulmonary tuberculosis forward by another 2,100 years.

The latest scientific hypothesis is that tuberculosis may have originally been a human disease, which was then gradually transmitted to other animals. This view is supported by archaeological evidence, because scientists have found tuberculosis-causing bacteria in the remains of African elephants 4,000 years ago. Even more shocking is that at the end of the last ice age, the giant mastodons were also extinct due to the epidemic of tuberculosis.

"Nine out of ten people with tuberculosis die"

For a long time, the lack of human knowledge about tuberculosis has failed to curb its rapid spread. In the West, tuberculosis was once known as the "number one killer of mankind" and became one of the diseases with the highest mortality rate in history.

In the 17th century, tuberculosis was rare in rural areas of Britain, and limited interpersonal communication limited the spread of the virus. However, with the wave of the Industrial Revolution in the 18th century, the urbanization process accelerated the frequent migration of the population, and many workers poured into the city from the countryside. The dark and damp industrial factories, the poor environment of the slums, the heavy physical labor and the widespread malnutrition provided a breeding ground for the growth and spread of tuberculosis bacteria.

The UK was immediately hit by a full-scale tuberculosis outbreak, with one in every 3.8 deaths in 1799. The disaster quickly spread throughout Europe, killing one in four Europeans. In the 19th century, tuberculosis spread to the United States, killing four hundred people out of every 100,000 people.

In the first half of the 20th century, tuberculosis spread rapidly in China. As of 1949, the number of tuberculosis patients in China was still as high as 27 million, with an annual death toll of more than 1.38 million and a mortality rate of 307 per 10,000 people. What is particularly serious is that 90% of people infected with tuberculosis are over 18 years old.

Before the discovery of streptomycin, tuberculosis treatment in China was in a blank state. There was a lack of effective hemostatic, analgesic and antibacterial drugs, and patients could only watch their condition worsen. Even though streptomycin was later used in clinical practice, the high cost made ordinary patients reluctant to buy it. The saying "nine out of ten tuberculosis patients die" was by no means an exaggeration at the time.

Effective treatment for tuberculosis

In 1882, German scientist Robert Koch discovered a transparent bacterium that was difficult to observe directly under a microscope through in-depth research on the lungs of people who died of tuberculosis. With the help of methylene blue staining technology, Koch successfully discovered the thin rod shape of tuberculosis bacteria and announced the discovery of Mycobacterium tuberculosis at the Berlin Physiological Society on March 24 of that year, marking the first time that the cause of tuberculosis was clearly identified. Koch was therefore known as the "Father of Bacillus."

At the same time, vaccine research and development also saw a glimmer of hope. In 1921, BCG was introduced and is still widely used as the first choice vaccine for preventing tuberculosis. The name BCG comes from the initials of its two French inventors, Calmotte and Geran. Its principle is based on the smallpox vaccine. By cultivating bovine tuberculosis strains for a long time and reducing their toxicity, the human body can produce immunity without causing disease after vaccination.

In 1944, American scientists successfully isolated streptomycin, the first antibiotic effective against Mycobacterium tuberculosis. The clinical application of streptomycin marked a new stage in the treatment of tuberculosis and ended its fate as a terminal illness.

In 1951, pharmaceutical companies such as Bayer, Bristol-Myers Squibb and Roche almost simultaneously developed isoniazid, a more effective, less toxic and affordable tuberculosis treatment drug. Isoniazid, streptomycin and sodium para-aminosalicylate together constitute the standard chemotherapy regimen (long-term therapy). The subsequent addition of drugs such as remifampicin, rifampicin and ethambutol further promoted the decline in the incidence and mortality of pulmonary tuberculosis.

By examining the history of humanity's struggle against tuberculosis, we may be able to more deeply understand the complexity of infectious disease medicine - although the virus brings death and pain, it also prompts us to seek the light of life and the path to the future in the struggle.

Reference sources: Cover News, "The History of Plagues", "Twenty Plagues That Changed Human Society"