Tuberculosis
Tuberculosis (TB), also known colloquially as the "white death", or historically as consumption,[7] is an infectious disease usually caused by Mycobacterium tuberculosis (MTB) bacteria.[1] Tuberculosis generally affects the lungs, but it can also affect other parts of the body.[1] Most infections show no symptoms, in which case it is known as latent tuberculosis.[1] Around 10% of latent infections progress to active disease which, if left untreated, kill about half of those affected.[1] Typical symptoms of active TB are chronic cough with blood-containing mucus, fever, night sweats, and weight loss.[1] Infection of other organs can cause a wide range of symptoms.[8]
Tuberculosis
Phthisis, phthisis pulmonalis, consumption, great white plague
Chronic cough, fever, cough with bloody mucus, weight loss[1]
Screening those at high risk, treatment of those infected, vaccination with bacillus Calmette-Guérin (BCG)[3][4][5]
25% of people (latent TB)[6]
1.3 million (2022)[6]
Tuberculosis is spread from one person to the next through the air when people who have active TB in their lungs cough, spit, speak, or sneeze.[1][9] People with latent TB do not spread the disease.[1] Active infection occurs more often in people with HIV/AIDS and in those who smoke.[1] Diagnosis of active TB is based on chest X-rays, as well as microscopic examination and culture of body fluids.[10] Diagnosis of latent TB relies on the tuberculin skin test (TST) or blood tests.[10]
Prevention of TB involves screening those at high risk, early detection and treatment of cases, and vaccination with the bacillus Calmette-Guérin (BCG) vaccine.[3][4][5] Those at high risk include household, workplace, and social contacts of people with active TB.[4] Treatment requires the use of multiple antibiotics over a long period of time.[1] Antibiotic resistance is a growing problem, with increasing rates of multiple drug-resistant tuberculosis (MDR-TB).[1]
In 2018, one quarter of the world's population was thought to have a latent infection of TB.[6] New infections occur in about 1% of the population each year.[11] In 2022, an estimated 10.6 million people developed active TB, resulting in 1.3 million deaths, making it the second leading cause of death from an infectious disease after COVID-19.[12] As of 2018, most TB cases occurred in the regions of South-East Asia (44%), Africa (24%), and the Western Pacific (18%), with more than 50% of cases being diagnosed in seven countries: India (27%), China (9%), Indonesia (8%), the Philippines (6%), Pakistan (6%), Nigeria (4%), and Bangladesh (4%).[13] By 2021, the number of new cases each year was decreasing by around 2% annually.[12][1] About 80% of people in many Asian and African countries test positive, while 5–10% of people in the United States test positive via the tuberculin test.[14] Tuberculosis has been present in humans since ancient times.[15]
Society and culture
Names
Tuberculosis has been known by many names from the technical to the familiar.[190] Phthisis (Φθισις) is a Greek word for consumption, an old term for pulmonary tuberculosis;[7] around 460 BCE, Hippocrates described phthisis as a disease of dry seasons.[191] The abbreviation TB is short for tubercle bacillus. Consumption was the most common nineteenth century English word for the disease, and was also in use well into the twentieth century. The Latin root con meaning 'completely' is linked to sumere meaning 'to take up from under'.[192] In The Life and Death of Mr Badman by John Bunyan, the author calls consumption "the captain of all these men of death."[193] "Great white plague" has also been used.[190]
Other animals
Mycobacteria infect many different animals, including birds,[242] fish, rodents,[243] and reptiles.[244] The subspecies Mycobacterium tuberculosis, though, is rarely present in wild animals.[245] An effort to eradicate bovine tuberculosis caused by Mycobacterium bovis from the cattle and deer herds of New Zealand has been relatively successful.[246] Efforts in Great Britain have been less successful.[247][248]
As of 2015, tuberculosis appears to be widespread among captive elephants in the US. It is believed that the animals originally acquired the disease from humans, a process called reverse zoonosis. Because the disease can spread through the air to infect both humans and other animals, it is a public health concern affecting circuses and zoos.[249][250]