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58-434: High Park Forest School was opened in the 1910s (there are sources that point to 1912, 1914 and 1915). It was initially a place for children with tuberculosis but through the years it became a summer school for underprivileged and/or undernourished children. For the school’s first 18 years in operation, it occupied three outdoor tents, a permanent building was constructed only in 1932. The forest schools ceased existence as

116-415: A Rasmussen aneurysm , resulting in massive bleeding. Tuberculosis may become a chronic illness and cause extensive scarring in the upper lobes of the lungs. The upper lung lobes are more frequently affected by tuberculosis than the lower ones. The reason for this difference is not clear. It may be due to either better air flow, or poor lymph drainage within the upper lungs. In 15–20% of active cases,

174-569: A common ancestor, remains unclear. A comparison of the genes of M. tuberculosis complex (MTBC) in humans to MTBC in animals suggests humans did not acquire MTBC from animals during animal domestication, as researchers previously believed. Both strains of the tuberculosis bacteria share a common ancestor, which could have infected humans even before the Neolithic Revolution . Skeletal remains show some prehistoric humans (4000 BC ) had TB, and researchers have found tubercular decay in

232-685: A microscope. Since MTB retains certain stains even after being treated with acidic solution, it is classified as an acid-fast bacillus . The most common acid-fast staining techniques are the Ziehl–Neelsen stain and the Kinyoun stain , which dye acid-fast bacilli a bright red that stands out against a blue background. Auramine-rhodamine staining and fluorescence microscopy are also used. The M. tuberculosis complex (MTBC) includes four other TB-causing mycobacteria : M. bovis , M. africanum , M. canettii , and M. microti . M. africanum

290-473: A school for poor and/or undernourished children in 1963. In 1970, the area around the school was the site of an International Sculpture Symposium. Several sculptures are still in place around the school. Others have been moved to other locations. After the 1960s, the building was used by various organizations and was vacated in 2013. In 2015, High Park Nature Centre moved into the building. Poor and/or undernourished children from Toronto 's public schools attended

348-407: A small decrease in case numbers. Some countries have legislation to involuntarily detain or examine those suspected to have tuberculosis, or involuntarily treat them if infected. The only available vaccine as of 2021 is bacillus Calmette-Guérin (BCG). In children it decreases the risk of getting the infection by 20% and the risk of infection turning into active disease by nearly 60%. It

406-401: A tuberculosis infection does become active, it most commonly involves the lungs (in about 90% of cases). Symptoms may include chest pain and a prolonged cough producing sputum. About 25% of people may not have any symptoms (i.e., they remain asymptomatic). Occasionally, people may cough up blood in small amounts, and in very rare cases, the infection may erode into the pulmonary artery or

464-474: A wide range of symptoms. 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 . People with latent TB do not spread the disease. Active infection occurs more often in people with HIV/AIDS and in those who smoke . Diagnosis of active TB is based on chest X-rays , as well as microscopic examination and culture of bodily fluids. Diagnosis of latent TB relies on

522-398: Is Mycobacterium tuberculosis (MTB), a small, aerobic , nonmotile bacillus . The high lipid content of this pathogen accounts for many of its unique clinical characteristics. It divides every 16 to 20 hours, which is an extremely slow rate compared with other bacteria, which usually divide in less than an hour. Mycobacteria have an outer membrane lipid bilayer. If a Gram stain

580-491: Is a growing problem, with increasing rates of multiple drug-resistant tuberculosis (MDR-TB). In 2018, one quarter of the world's population was thought to have a latent infection of TB. New infections occur in about 1% of the population each year. 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 . As of 2018, most TB cases occurred in

638-449: Is able to reproduce inside the macrophage and will eventually kill the immune cell. The primary site of infection in the lungs, known as the Ghon focus , is generally located in either the upper part of the lower lobe, or the lower part of the upper lobe . Tuberculosis of the lungs may also occur via infection from the blood stream. This is known as a Simon focus and is typically found in

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696-653: Is also rare and is seen almost only in immunodeficient people, although its prevalence may be significantly underestimated. Other known pathogenic mycobacteria include M. leprae , M. avium , and M. kansasii . The latter two species are classified as " nontuberculous mycobacteria " (NTM) or atypical mycobacteria. NTM cause neither TB nor leprosy , but they do cause lung diseases that resemble TB. When people with active pulmonary TB cough, sneeze, speak, sing, or spit, they expel infectious aerosol droplets 0.5 to 5.0 μm in diameter. A single sneeze can release up to 40,000 droplets. Each one of these droplets may transmit

754-444: Is difficult, as is diagnosing the disease in those who have a weakened immune system. A diagnosis of TB should, however, be considered in those with signs of lung disease or constitutional symptoms lasting longer than two weeks. A chest X-ray and multiple sputum cultures for acid-fast bacilli are typically part of the initial evaluation. Interferon-γ release assays (IGRA) and tuberculin skin tests are of little use in most of

812-509: Is not widespread, but it is a significant cause of tuberculosis in parts of Africa. M. bovis was once a common cause of tuberculosis, but the introduction of pasteurized milk has almost eliminated this as a public health problem in developed countries. M. canettii is rare and seems to be limited to the Horn of Africa , although a few cases have been seen in African emigrants. M. microti

870-489: Is often used to screen people at high risk for TB. Those who have been previously immunized with the Bacille Calmette-Guerin vaccine may have a false-positive test result. The test may be falsely negative in those with sarcoidosis , Hodgkin's lymphoma , malnutrition , and most notably, active tuberculosis. Interferon gamma release assays , on a blood sample, are recommended in those who are positive to

928-501: Is performed, MTB either stains very weakly "Gram-positive" or does not retain dye as a result of the high lipid and mycolic acid content of its cell wall. MTB can withstand weak disinfectants and survive in a dry state for weeks. In nature, the bacterium can grow only within the cells of a host organism, but M. tuberculosis can be cultured in the laboratory . Using histological stains on expectorated samples from phlegm (also called sputum), scientists can identify MTB under

986-423: Is poor as of 2019 . The Centers for Disease Control and Prevention (CDC) stopped recommending yearly testing of health care workers without known exposure in 2019. Tuberculosis prevention and control efforts rely primarily on the vaccination of infants and the detection and appropriate treatment of active cases. The World Health Organization (WHO) has achieved some success with improved treatment regimens, and

1044-464: Is termed caseous necrosis . If TB bacteria gain entry to the blood stream from an area of damaged tissue, they can spread throughout the body and set up many foci of infection, all appearing as tiny, white tubercles in the tissues. This severe form of TB disease, most common in young children and those with HIV, is called miliary tuberculosis. People with this disseminated TB have a high fatality rate even with treatment (about 30%). In many people,

1102-483: Is the most widely used vaccine worldwide, with more than 90% of all children being vaccinated. The immunity it induces decreases after about ten years. As tuberculosis is uncommon in most of Canada, Western Europe, and the United States, BCG is administered to only those people at high risk. Part of the reasoning against the use of the vaccine is that it makes the tuberculin skin test falsely positive, reducing

1160-434: The lungs , but it can also affect other parts of the body. Most infections show no symptoms, in which case it is known as latent tuberculosis . Around 10% of latent infections progress to active disease that, if left untreated, kill about half of those affected. Typical symptoms of active TB are chronic cough with blood-containing mucus , fever , night sweats , and weight loss . Infection of other organs can cause

1218-458: The lymphatic system (in scrofula of the neck), the genitourinary system (in urogenital tuberculosis ), and the bones and joints (in Pott disease of the spine), among others. A potentially more serious, widespread form of TB is called "disseminated tuberculosis"; it is also known as miliary tuberculosis . Miliary TB currently makes up about 10% of extrapulmonary cases. The main cause of TB

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1276-420: The tuberculin skin test (TST) or blood tests. Prevention of TB involves screening those at high risk, early detection and treatment of cases, and vaccination with the bacillus Calmette-Guérin (BCG) vaccine. Those at high risk include household, workplace, and social contacts of people with active TB. Treatment requires the use of multiple antibiotics over a long period of time. Antibiotic resistance

1334-698: The Mantoux test. These are not affected by immunization or most environmental mycobacteria , so they generate fewer false-positive results. However, they are affected by M. szulgai , M. marinum , and M. kansasii . IGRAs may increase sensitivity when used in addition to the skin test, but may be less sensitive than the skin test when used alone. The US Preventive Services Task Force (USPSTF) has recommended screening people who are at high risk for latent tuberculosis with either tuberculin skin tests or interferon-gamma release assays . While some have recommend testing health care workers, evidence of benefit for this

1392-516: The United States test positive via the tuberculin test. Tuberculosis has been present in humans since ancient times . Tuberculosis has existed since antiquity . The oldest unambiguously detected M. tuberculosis gives evidence of the disease in the remains of bison in Wyoming dated to around 17,000 years ago. However, whether tuberculosis originated in bovines, then transferred to humans, or whether both bovine and human tuberculosis diverged from

1450-617: The WHO 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%). By 2021, the number of new cases each year was decreasing by around 2% annually. About 80% of people in many Asian and African countries test positive, while 5–10% of people in

1508-688: The active disease. Use of certain medications, such as corticosteroids and infliximab (an anti-αTNF monoclonal antibody), is another important risk factor, especially in the developed world . Other risk factors include: alcoholism , diabetes mellitus (3-fold increased risk), silicosis (30-fold increased risk), tobacco smoking (2-fold increased risk), indoor air pollution , malnutrition, young age, recently acquired TB infection, recreational drug use, severe kidney disease, low body weight, organ transplant, head and neck cancer, and genetic susceptibility (the overall importance of genetic risk factors remains undefined ). Tobacco smoking increases

1566-458: The arrival of streptomycin and other antibiotics, although the disease remained a significant threat. In 1946, the development of the antibiotic streptomycin made effective treatment and cure of TB a reality. Prior to the introduction of this medication, the only treatment was surgical intervention, including the " pneumothorax technique", which involved collapsing an infected lung to "rest" it and to allow tuberculous lesions to heal. Because of

1624-423: The bacterium is enveloped by the macrophage and stored temporarily in a membrane-bound vesicle called a phagosome. The phagosome then combines with a lysosome to create a phagolysosome. In the phagolysosome, the cell attempts to use reactive oxygen species and acid to kill the bacterium. However, M. tuberculosis has a thick, waxy mycolic acid capsule that protects it from these toxic substances. M. tuberculosis

1682-425: The cattle and human tuberculosis diseases were similar, which delayed the recognition of infected milk as a source of infection. During the first half of the 1900s, the risk of transmission from this source was dramatically reduced after the application of the pasteurization process. Koch announced a glycerine extract of the tubercle bacilli as a "remedy" for tuberculosis in 1890, calling it "tuberculin". Although it

1740-485: The cause of pulmonary tuberculosis. J. L. Schönlein first published the name "tuberculosis" (German: Tuberkulose ) in 1832. Between 1838 and 1845, John Croghan, the owner of Mammoth Cave in Kentucky from 1839 onwards, brought a number of people with tuberculosis into the cave in the hope of curing the disease with the constant temperature and purity of the cave air; each died within a year. Hermann Brehmer opened

1798-528: The children would line up once again inside the building, pick up their bed rolls which consisted of a pillow, a sheet and an army-type blanket. There were cots set up near each classroom and the children would take their bedrolls to the cots for an afternoon nap of one hour. When they awoke from their naps, they returned their bedrolls to the room inside where they were stored, then lined up to wash hands and faces and brush their teeth. The children returned to their classrooms for more education and then were served

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1856-711: The declaration of a global health emergency by the World Health Organization (WHO) in 1993. There is a popular misconception that tuberculosis is purely a disease of the lungs that manifests as coughing . Tuberculosis may infect many organs, even though it most commonly occurs in the lungs (known as pulmonary tuberculosis). Extrapulmonary TB occurs when tuberculosis develops outside of the lungs, although extrapulmonary TB may coexist with pulmonary TB. General signs and symptoms include fever, chills , night sweats, loss of appetite , weight loss, and fatigue . Significant nail clubbing may also occur. If

1914-640: The developing world. IGRA have similar limitations in those with HIV. A definitive diagnosis of TB is made by identifying M. tuberculosis in a clinical sample (e.g., sputum, pus , or a tissue biopsy ). However, the difficult culture process for this slow-growing organism can take two to six weeks for blood or sputum culture. Thus, treatment is often begun before cultures are confirmed. Nucleic acid amplification tests and adenosine deaminase testing may allow rapid diagnosis of TB. Blood tests to detect antibodies are not specific or sensitive , so they are not recommended. The Mantoux tuberculin skin test

1972-610: The disease became common among the urban poor. In 1815, one in four deaths in England was due to "consumption". By 1918, TB still caused one in six deaths in France. After TB was determined to be contagious, in the 1880s, it was put on a notifiable-disease list in Britain. Campaigns started to stop people from spitting in public places, and the infected poor were "encouraged" to enter sanatoria that resembled prisons. The sanatoria for

2030-620: The disease, since the infectious dose of tuberculosis is very small (the inhalation of fewer than 10 bacteria may cause an infection). People with prolonged, frequent, or close contact with people with TB are at particularly high risk of becoming infected, with an estimated 22% infection rate. A person with active but untreated tuberculosis may infect 10–15 (or more) other people per year. Transmission should occur from only people with active TB – those with latent infection are not thought to be contagious. The probability of transmission from one person to another depends upon several factors, including

2088-463: The emergence of multidrug-resistant tuberculosis (MDR-TB), surgery has been re-introduced for certain cases of TB infections. It involves the removal of infected chest cavities ("bullae") in the lungs to reduce the number of bacteria and to increase exposure of the remaining bacteria to antibiotics in the bloodstream. Hopes of eliminating TB ended with the rise of drug-resistant strains in the 1980s. The subsequent resurgence of tuberculosis resulted in

2146-552: The first TB sanatorium in 1859 in Görbersdorf (now Sokołowsko ) in Silesia . In 1865, Jean Antoine Villemin demonstrated that tuberculosis could be transmitted, via inoculation, from humans to animals and among animals. (Villemin's findings were confirmed in 1867 and 1868 by John Burdon-Sanderson . ) Robert Koch identified and described the bacillus causing tuberculosis, M. tuberculosis , on 24 March 1882. In 1905, he

2204-622: The first genuine success in immunization against tuberculosis in 1906, using attenuated bovine-strain tuberculosis. It was called bacille Calmette–Guérin (BCG). The BCG vaccine was first used on humans in 1921 in France, but achieved widespread acceptance in the US, Great Britain, and Germany only after World War II. By the 1950s mortality in Europe had decreased about 90%. Improvements in sanitation, vaccination, and other public-health measures began significantly reducing rates of tuberculosis even before

2262-431: The host's immune system. Macrophages and dendritic cells in the granulomas are unable to present antigen to lymphocytes; thus the immune response is suppressed. Bacteria inside the granuloma can become dormant, resulting in latent infection. Another feature of the granulomas is the development of abnormal cell death ( necrosis ) in the center of tubercles . To the naked eye, this has the texture of soft, white cheese and

2320-400: The infected macrophages. When other macrophages attack the infected macrophage, they fuse together to form a giant multinucleated cell in the alveolar lumen. The granuloma may prevent dissemination of the mycobacteria and provide a local environment for interaction of cells of the immune system. However, more recent evidence suggests that the bacteria use the granulomas to avoid destruction by

2378-439: The infection spreads outside the lungs, causing other kinds of TB. These are collectively denoted as extrapulmonary tuberculosis. Extrapulmonary TB occurs more commonly in people with a weakened immune system and young children. In those with HIV, this occurs in more than 50% of cases. Notable extrapulmonary infection sites include the pleura (in tuberculous pleurisy), the central nervous system (in tuberculous meningitis ),

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2436-613: The infection waxes and wanes. Tissue destruction and necrosis are often balanced by healing and fibrosis . Affected tissue is replaced by scarring and cavities filled with caseous necrotic material. During active disease, some of these cavities are joined to the air passages ( bronchi ) and this material can be coughed up. It contains living bacteria and thus can spread the infection. Treatment with appropriate antibiotics kills bacteria and allows healing to take place. Upon cure, affected areas are eventually replaced by scar tissue. Diagnosing active tuberculosis based only on signs and symptoms

2494-491: The life from the other family members. Although Richard Morton established the pulmonary form associated with tubercles as a pathology in 1689, due to the variety of its symptoms, TB was not identified as a single disease until the 1820s. Benjamin Marten conjectured in 1720 that consumptions were caused by microbes which were spread by people living close to each other. In 1819, René Laennec claimed that tubercles were

2552-537: The middle and upper classes offered excellent care and constant medical attention. What later became known as the Alexandra Hospital for Children with Hip Disease (tuberculous arthritis) was opened in London in 1867. Whatever the benefits of the "fresh air" and labor in the sanatoria, even under the best conditions, 50% of those who entered died within five years ( c. 1916). Robert Koch did not believe

2610-406: The mornings they were brought snacks of whole wheat bread and butter and hot chocolate in the cooler months and milk in the warmer months. At lunch time, the children would line up and go into the main building, entering through the main right hand door in the picture where whey were seated according to age. They were served a hot nutritious meal, milk and a cod liver oil pill every day. After lunch,

2668-596: The newly infected person becomes infectious enough to transmit the disease to others. A number of factors make individuals more susceptible to TB infection and/or disease. The most important risk factor globally for developing active TB is concurrent HIV infection; 13% of those with TB are also infected with HIV. This is a particular problem in sub-Saharan Africa , where HIV infection rates are high. Of those without HIV infection who are infected with tuberculosis, about 5–10% develop active disease during their lifetimes; in contrast, 30% of those co-infected with HIV develop

2726-599: The number of infectious droplets expelled by the carrier, the effectiveness of ventilation, the duration of exposure, the virulence of the M. tuberculosis strain , the level of immunity in the uninfected person, and others. The cascade of person-to-person spread can be circumvented by segregating those with active ("overt") TB and putting them on anti-TB drug regimens. After about two weeks of effective treatment, subjects with nonresistant active infections generally do not remain contagious to others. If someone does become infected, it typically takes three to four weeks before

2784-435: The risk of developing active TB increases to nearly 10% a year. If effective treatment is not given, the death rate for active TB cases is up to 66%. TB infection begins when the mycobacteria reach the alveolar air sacs of the lungs, where they invade and replicate within endosomes of alveolar macrophages . Macrophages identify the bacterium as foreign and attempt to eliminate it by phagocytosis . During this process,

2842-414: The risk of infections (in addition to increasing the risk of active disease and death). Additional factors increasing infection susceptibility include young age. About 90% of those infected with M. tuberculosis have asymptomatic , latent TB infections (sometimes called LTBI), with only a 10% lifetime chance that the latent infection will progress to overt, active tuberculous disease. In those with HIV,

2900-467: The school from May 1 to October 31 to augment their education and also get good nutritious foods and exercise to help them become healthy. Children attended the school Monday through Saturday (half days on Saturdays). On Saturdays, if the weather was good the children were all bussed to Sunnyside Swimming Pool where they were entitled to free admission and free swimming (no classes). Mondays through Fridays children would attend at outdoor classrooms and in

2958-549: The spines of Egyptian mummies dating from 3000 to 2400 BC. Genetic studies suggest the presence of TB in the Americas from about AD 100. Before the Industrial Revolution , folklore often associated tuberculosis with vampires . When one member of a family died from the disease, the other infected members would lose their health slowly. People believed this was caused by the original person with TB draining

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3016-465: The test's usefulness as a screening tool. Several vaccines are being developed. Intradermal MVA85A vaccine in addition to BCG injection is not effective in preventing tuberculosis. Public health campaigns which have focused on overcrowding, public spitting and regular sanitation (including hand washing) during the 1800s helped to either interrupt or slow spread which when combined with contact tracing, isolation and treatment helped to dramatically curb

3074-555: The things the Toronto Board of Education felt poor and/or undernourished children would miss out on without this program. 43°39′04″N 79°27′49″W  /  43.6512°N 79.4635°W  / 43.6512; -79.4635 Tuberculosis Tuberculosis ( TB ), also known colloquially as the " white death ", or historically as consumption , is an infectious disease usually caused by Mycobacterium tuberculosis (MTB) bacteria . Tuberculosis generally affects

3132-565: The top of the lung. This hematogenous transmission can also spread infection to more distant sites, such as peripheral lymph nodes, the kidneys, the brain, and the bones. All parts of the body can be affected by the disease, though for unknown reasons it rarely affects the heart , skeletal muscles , pancreas , or thyroid . Tuberculosis is classified as one of the granulomatous inflammatory diseases. Macrophages , epithelioid cells , T lymphocytes , B lymphocytes , and fibroblasts aggregate to form granulomas, with lymphocytes surrounding

3190-467: The transmission of both tuberculosis and other airborne diseases which led to the elimination of tuberculosis as a major public health issue in most developed economies. Other risk factors which worsened TB spread such as malnutrition were also ameliorated, but since the emergence of HIV a new population of immunocompromised individuals was available for TB to infect. During the HIV/AIDS epidemic in

3248-435: The whole wheat bread and hot chocolate or milk again. When 4 o'clock came...the teachers would escort each child up to Bloor Street and made sure each child got on the street cars for their journey home. The objective was to provide underprivileged and/or undernourished children who ordinarily would have spent their summer days on the streets of Toronto a place to go for good food, good activities, good health and education. All

3306-526: Was awarded the Nobel Prize in Physiology or Medicine for this discovery. In Europe, rates of tuberculosis began to rise in the early 1600s to a peak level in the 1800s, when it caused nearly 25% of all deaths. In the 18th and 19th century, tuberculosis had become epidemic in Europe , showing a seasonal pattern. Tuberculosis caused widespread public concern in the 19th and early 20th centuries as

3364-478: Was not effective, it was later successfully adapted as a screening test for the presence of pre-symptomatic tuberculosis. World Tuberculosis Day is marked on 24 March each year, the anniversary of Koch's original scientific announcement. When the Medical Research Council formed in Britain in 1913, it initially focused on tuberculosis research. Albert Calmette and Camille Guérin achieved

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