السلام عليكم
اول الامر احب ان اعرفكم بنفس
انا مقداد الموسوي من العراق بغداد
ادرس في قسم العلوم التطبيقيه فرع التقنيات الكيميائيه الاحيائيه
اثرت ان اثير هذا الموضوع المهم حقيقا مع العلم انه لكم علم فيه
الا وهو التدرن الرئوي سوف ترون بشيء من التفصيل حول هذا الموضوع اتمن ان يحض برضاكم
كذالك اتمن ان قبلوني صديقا جديدا لكم
Tuberculosis
is a common and often deadly infectious disease caused by mycobacteria, mainly Mycobacterium tuberculosis. Tuberculosis usually attacks the lungs (as pulmonary TB) but can also affect the central nervous system, the lymphatic system, the circulatory system, the genitourinary system, the gastrointestinal system, bones, joints, and even the skin. Other mycobacteria such as Mycobacterium bovis, Mycobacterium africanum, Mycobacterium canetti, and Mycobacterium microti also cause tuberculosis, but these species are less common.
The typical symptoms of tuberculosis are a chronic cough with blood-tinged sputum, fever, night sweats and weight loss. Infection of other organs cause a wide range of symptoms. The diagnosis relies on radiology (commonly chest X-rays), a tuberculin skin test, blood tests, as well as microscopic examination and microbiological culture of bodily fluids. Tuberculosis treatment is difficult and requires long courses of multiple antibiotics. Contacts are also screened and treated if necessary. Antibiotic resistance is a growing problem in (extensively) multi-drug-resistant tuberculosis. Prevention relies on screening programs and vaccination, usually with Bacillus Calmette-Guérin (BCG vaccine).
Tuberculosis is spread through the air, when people who have the disease cough, sneeze or spit. One third of the world's current population have been infected with M. tuberculosis, and new infections occur at a rate of one per second.[1] However, most of these cases will not develop the full-blown disease; asymptomatic, latent infection is most common. About one in ten of these latent infections will eventually progress to active disease, which, if left untreated, kills more than half of its victims. In 2004, mortality and morbidity statistics included 14.6 million chronic active cases, 8.9 million new cases, and 1.6 million deaths, mostly in developing countries.[1] In addition, a rising number of people in the developed world are contracting tuberculosis because their immune systems are compromised by immunosuppressive drugs, substance abuse, or AIDS.
Other names
In the past, tuberculosis has been called consumption, because it seemed to consume people from within, with a bloody cough, fever, pallor, and long relentless wasting. Other names included phthisis (Greek for consumption) and phthisis pulmonalis; scrofula (in adults), affecting the lymphatic system and resulting in swollen neck glands; tabes mesenterica, TB of the abdomen and lupus vulgaris, TB of the skin; wasting disease; white plague, because sufferers appear markedly pale; king's evil, because it was believed that a king's touch would heal scrofula; and Pott's disease, or gibbus of the spine and joints.[2][3] Miliary tuberculosis—now commonly known as disseminated TB—occurs when the infection invades the circulatory system resulting in lesions which have the appearance of millet seeds on X-ray.[2][4
Symptoms
Further information: Tuberculosis classification
When the disease becomes active, 75% of the cases are pulmonary TB. Symptoms include chest pain, coughing up blood, and a productive, prolonged cough for more than three weeks. Systemic symptoms include fever, chills, night sweats, appetite loss, weight loss, pallor, and often a tendency to fatigue very easily.[1]
In the other 25% of active cases, the infection moves from the lungs, causing other kinds of TB. This occurs more commonly in immunosuppressed persons and young children. Extrapulmonary infection sites include the pleura, the central nervous system in meningitis, the lymphatic system in scrofula of the neck, the genitourinary system in urogenital tuberculosis, and bones and joints in Pott's disease of the spine. An especially serious form is disseminated TB, more commonly known as miliary tuberculosis. Although extrapulmonary TB is not contagious, it may co-exist with pulmonary TB, which is contagious.[5]Bacterial species
Tuberculosis has co-evolved with humans for many thousands of years, and perhaps as much as several million years.[14] During this evolution, M. tuberculosis has lost numerous coding and non-coding regions in its genome, losses that can be used to distinguish between strains of the bacteria. The implication is that M. tuberculosis strains differ geographically, so their genetic differences can be used to track the origins and movement of each strain.[15]
TB prevention and control takes two parallel approaches. In the first, people with TB and their contacts are identified and then treated. Identification of infections often involves testing high-risk groups for TB. In the second approach, children are vaccinated to protect them from TB. Unfortunately, no vaccine is available that provides reliable protection for adults. However, in tropical areas where the levels of other species of mycobacteria are high, exposure to nontuberculous mycobacteria gives some protection against TB.[39]
The World Health Organization (W.H.O.) declared TB a global health emergency in 1993, and the Stop TB Partnership developed a Global Plan to Stop Tuberculosis that aims to save 14 million lives between 2006 and 2015.[40] Since humans are the only host of Mycobacterium tuberculosis, eradication would be possibile: a goal that would be helped greatly by an effective vaccine.[41]
اول الامر احب ان اعرفكم بنفس
انا مقداد الموسوي من العراق بغداد
ادرس في قسم العلوم التطبيقيه فرع التقنيات الكيميائيه الاحيائيه
اثرت ان اثير هذا الموضوع المهم حقيقا مع العلم انه لكم علم فيه
الا وهو التدرن الرئوي سوف ترون بشيء من التفصيل حول هذا الموضوع اتمن ان يحض برضاكم
كذالك اتمن ان قبلوني صديقا جديدا لكم
Tuberculosis
is a common and often deadly infectious disease caused by mycobacteria, mainly Mycobacterium tuberculosis. Tuberculosis usually attacks the lungs (as pulmonary TB) but can also affect the central nervous system, the lymphatic system, the circulatory system, the genitourinary system, the gastrointestinal system, bones, joints, and even the skin. Other mycobacteria such as Mycobacterium bovis, Mycobacterium africanum, Mycobacterium canetti, and Mycobacterium microti also cause tuberculosis, but these species are less common.
The typical symptoms of tuberculosis are a chronic cough with blood-tinged sputum, fever, night sweats and weight loss. Infection of other organs cause a wide range of symptoms. The diagnosis relies on radiology (commonly chest X-rays), a tuberculin skin test, blood tests, as well as microscopic examination and microbiological culture of bodily fluids. Tuberculosis treatment is difficult and requires long courses of multiple antibiotics. Contacts are also screened and treated if necessary. Antibiotic resistance is a growing problem in (extensively) multi-drug-resistant tuberculosis. Prevention relies on screening programs and vaccination, usually with Bacillus Calmette-Guérin (BCG vaccine).
Tuberculosis is spread through the air, when people who have the disease cough, sneeze or spit. One third of the world's current population have been infected with M. tuberculosis, and new infections occur at a rate of one per second.[1] However, most of these cases will not develop the full-blown disease; asymptomatic, latent infection is most common. About one in ten of these latent infections will eventually progress to active disease, which, if left untreated, kills more than half of its victims. In 2004, mortality and morbidity statistics included 14.6 million chronic active cases, 8.9 million new cases, and 1.6 million deaths, mostly in developing countries.[1] In addition, a rising number of people in the developed world are contracting tuberculosis because their immune systems are compromised by immunosuppressive drugs, substance abuse, or AIDS.
Other names
In the past, tuberculosis has been called consumption, because it seemed to consume people from within, with a bloody cough, fever, pallor, and long relentless wasting. Other names included phthisis (Greek for consumption) and phthisis pulmonalis; scrofula (in adults), affecting the lymphatic system and resulting in swollen neck glands; tabes mesenterica, TB of the abdomen and lupus vulgaris, TB of the skin; wasting disease; white plague, because sufferers appear markedly pale; king's evil, because it was believed that a king's touch would heal scrofula; and Pott's disease, or gibbus of the spine and joints.[2][3] Miliary tuberculosis—now commonly known as disseminated TB—occurs when the infection invades the circulatory system resulting in lesions which have the appearance of millet seeds on X-ray.[2][4
Symptoms
Further information: Tuberculosis classification
When the disease becomes active, 75% of the cases are pulmonary TB. Symptoms include chest pain, coughing up blood, and a productive, prolonged cough for more than three weeks. Systemic symptoms include fever, chills, night sweats, appetite loss, weight loss, pallor, and often a tendency to fatigue very easily.[1]
In the other 25% of active cases, the infection moves from the lungs, causing other kinds of TB. This occurs more commonly in immunosuppressed persons and young children. Extrapulmonary infection sites include the pleura, the central nervous system in meningitis, the lymphatic system in scrofula of the neck, the genitourinary system in urogenital tuberculosis, and bones and joints in Pott's disease of the spine. An especially serious form is disseminated TB, more commonly known as miliary tuberculosis. Although extrapulmonary TB is not contagious, it may co-exist with pulmonary TB, which is contagious.[5]
Scanning electron micrograph of Mycobacterium tuberculosis
The primary cause of TB, Mycobacterium tuberculosis, is an aerobic bacterium that divides every 16 to 20 hours, an extremely slow rate compared with other bacteria, which usually divide in less than an hour.[6] (For example, one of the fastest-growing bacteria is a strain of E. coli that can divide roughly every 20 minutes.) Since MTB has a cell wall but lacks a phospholipid outer membrane, it is classified as a Gram-positive bacterium. However, if a Gram stain is performed, MTB either stains very weakly Gram-positive or does not retain dye due to the high lipid & mycolic acid content of its cell wall.[7] MTB is a small rod-like bacillus that 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 vitro.[8]
Using histological stains on expectorate samples from phlegm (also called sputum), scientists can identify MTB under a regular microscope. Since MTB retains certain stains after being treated with acidic solution, it is classified as an acid-fast bacillus (AFB).[7] The most common staining technique, the Ziehl-Neelsen stain, dyes AFBs a bright red that stands out clearly against a blue background. Other ways to visualize AFBs include an auramine-rhodamine stain and fluorescent microscopy.
The M. tuberculosis complex includes three other TB-causing mycobacteria: M. bovis, M. africanum and M. microti. M. africanum is a not wiespread, but in parts of Africa it is a significant cause of tuberculosis.[9][10] M. bovis was once a common cause of tuberculosis, but the introduction of pasteurized milk has largely eliminated this as a public health problem in developed countries.[11] M. microti is mostly seen in immunodeficient people, although it is possible that the prevalence of this pathogen has been underestimated.[12]
Other known pathogenic mycobacteria include Mycobacterium leprae, Mycobacterium avium and M. kansasii. The last two are part of the nontuberculous mycobacteria (NTM) group. Nontuberculous mycobacteria cause neither TB nor leprosy, but they do cause pulmonary diseases resembling TB.[13]
EvolutionThe primary cause of TB, Mycobacterium tuberculosis, is an aerobic bacterium that divides every 16 to 20 hours, an extremely slow rate compared with other bacteria, which usually divide in less than an hour.[6] (For example, one of the fastest-growing bacteria is a strain of E. coli that can divide roughly every 20 minutes.) Since MTB has a cell wall but lacks a phospholipid outer membrane, it is classified as a Gram-positive bacterium. However, if a Gram stain is performed, MTB either stains very weakly Gram-positive or does not retain dye due to the high lipid & mycolic acid content of its cell wall.[7] MTB is a small rod-like bacillus that 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 vitro.[8]
Using histological stains on expectorate samples from phlegm (also called sputum), scientists can identify MTB under a regular microscope. Since MTB retains certain stains after being treated with acidic solution, it is classified as an acid-fast bacillus (AFB).[7] The most common staining technique, the Ziehl-Neelsen stain, dyes AFBs a bright red that stands out clearly against a blue background. Other ways to visualize AFBs include an auramine-rhodamine stain and fluorescent microscopy.
The M. tuberculosis complex includes three other TB-causing mycobacteria: M. bovis, M. africanum and M. microti. M. africanum is a not wiespread, but in parts of Africa it is a significant cause of tuberculosis.[9][10] M. bovis was once a common cause of tuberculosis, but the introduction of pasteurized milk has largely eliminated this as a public health problem in developed countries.[11] M. microti is mostly seen in immunodeficient people, although it is possible that the prevalence of this pathogen has been underestimated.[12]
Other known pathogenic mycobacteria include Mycobacterium leprae, Mycobacterium avium and M. kansasii. The last two are part of the nontuberculous mycobacteria (NTM) group. Nontuberculous mycobacteria cause neither TB nor leprosy, but they do cause pulmonary diseases resembling TB.[13]
Tuberculosis has co-evolved with humans for many thousands of years, and perhaps as much as several million years.[14] During this evolution, M. tuberculosis has lost numerous coding and non-coding regions in its genome, losses that can be used to distinguish between strains of the bacteria. The implication is that M. tuberculosis strains differ geographically, so their genetic differences can be used to track the origins and movement of each strain.[15]
Transmission
When people suffering from active pulmonary TB cough, sneeze, speak, or spit, they expel infectious aerosol droplets 0.5 to 5 µm in diameter. A single sneeze, for instance, can release up to 40,000 droplets.[16] Each one of these droplets may transmit the disease, since the infectious dose of tuberculosis is very low and the inhalation of just a single bacterium can cause a new infection.[17]
http://en.wikipedia.org/wiki/Image:Aerosol_from_Sneeze.jpg
Tuberculosis is spread by aerosols created by coughing or sneezing.
People with prolonged, frequent, or intense contact are at particularly high risk of becoming infected, with an estimated 22% infection rate. A person with active but untreated tuberculosis can infect 10–15 other people per year.[1] Others at risk include people in areas where TB is common, people who inject drugs using unsanitary needles, residents and employees of high-risk congregate settings, medically under-served and low-income populations, high-risk racial or ethnic minority populations, children exposed to adults in high-risk categories, patients immunocompromised by conditions such as HIV/AIDS, people who take immunosuppressant drugs, and health care workers serving these high-risk clients.[18]
Transmission can only occur from people with active—not latent—TB. The probability of transmission from one person to another depends upon the number of infectious droplets expelled by a carrier, the effectiveness of ventilation, the duration of exposure, and the virulence of the M. tuberculosis strain.[5] The chain of transmission can therefore be broken by isolating patients with active disease and starting effective anti-tuberculous therapy. After two weeks of such treatment, people with non-resistant active TB generally cease to be contagious. If someone does become infectous, then it will take at least from 21 days, or 3–4 weeks, before the new infectous person can transmit the disease to others.[19] TB can also be transmitted http://en.wikipedia.org/wiki/Image:Aerosol_from_Sneeze.jpg
Tuberculosis is spread by aerosols created by coughing or sneezing.
People with prolonged, frequent, or intense contact are at particularly high risk of becoming infected, with an estimated 22% infection rate. A person with active but untreated tuberculosis can infect 10–15 other people per year.[1] Others at risk include people in areas where TB is common, people who inject drugs using unsanitary needles, residents and employees of high-risk congregate settings, medically under-served and low-income populations, high-risk racial or ethnic minority populations, children exposed to adults in high-risk categories, patients immunocompromised by conditions such as HIV/AIDS, people who take immunosuppressant drugs, and health care workers serving these high-risk clients.[18]
by eating meat if the cattle is infected with TB. Mycobacterium bovis causes TB in cattle. Details below.
Pathogenesis
http://en.wikipedia.org/wiki/Image:TB_in_sputum.png
http://en.wikipedia.org/wiki/Image:TB_in_sputum.png
Mycobacterium tuberculosis (stained red) in sputum
About 90% of those infected with Mycobacterium tuberculosis have asymptomatic, latent TB infection (sometimes called LTBI), with only a 10% lifetime chance that a latent infection will progress to TB disease. However, if untreated, the death rate for these active TB cases is more than 50%.[20]
TB infection begins when the mycobacteria reach the pulmonary alveoli, where they invade and replicate within alveolar macrophages.[21] The primary site of infection in the lungs is called the Ghon focus. Bacteria are picked up by dendritic cells, which do not allow replication, although these cells can transport the bacilli to local (mediastinal) lymph nodes. Further spread is through the bloodstream to other tissues and organs where secondary TB lesions can develop in other parts of the lung, peripheral lymph nodes, kidneys, brain, and bone.[22] All parts of the body can be affected by the disease, though it rarely affects the heart, skeletal muscles, pancreas and thyroid.[23]
Tuberculosis is classified as one of the granulomatous inflammatory conditions. Macrophages, T lymphocytes, B lymphocytes and fibroblasts are among the cells that aggregate to form a granuloma, with lymphocytes surrounding the infected macrophages. The granuloma functions not only to prevent dissemination of the mycobacteria, but also provides a local environment for communication of cells of the immune system. Within the granuloma, T lymphocytes (CD4+) secrete cytokines such as interferon gamma, which activates macrophages to destroy the bacteria with which they are infected.[24] T lymphocytes (CD8+) can also directly kill infected cells.[21]
Importantly, bacteria are not always eliminated within the granuloma, but can become dormant, resulting in a latent infection. Another feature of the granulomas of human tuberculosis is the development of cell death, also called necrosis, in the center of tubercles. To the naked eye this has the texture of soft white cheese and was termed caseous necrosis.[25]
If TB bacteria gain entry to the bloodstream from an area of damaged tissue they spread through the body and set up many foci of infection, all appearing as tiny white tubercles in the tissues. This severe form of TB disease is most common in infants and the elderly and is called miliary tuberculosis. Patients with this disseminated TB have a fatality rate of approximately 20%, even with intensive treatment.[26]
In many patients the infection waxes and wanes. Tissue destruction and necrosis are balanced by healing and fibrosis.[25] Affected tissue is replaced by scarring and cavities filled with cheese-like white 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 can therefore pass on infection. Treatment with appropriate antibiotics kills bacteria and allows healing to take place. Upon cure, affected areas are eventually replaced by scar tissue.[25]
Diagnosis
Mantoux tuberculin skin test
Tuberculosis can be a difficult disease to diagnose, mainly due to the difficulty in culturing this slow-growing organism in the laboratory (4–12 weeks for blood culture). A complete medical evaluation for TB must include a medical history, a chest X-ray, and a physical examination. Tuberculosis radiology is used in the diagnosis of TB. It may also include a tuberculin skin test, a serological test, microbiological smears and cultures. The interpretation of the tuberculin skin test depends upon the person's risk factors for infection and progression to TB disease, such as exposure to other cases of TB or immunosuppression.[5]
Currently, latent infection is diagnosed in a non-immunized person by a tuberculin skin test, which yields a delayed hypersensitivity type response to an extract made from M. tuberculosis. Those immunized for TB or with past-cleared infection will respond with delayed hypersensitivity parallel to those currently in a state of infection, so the test must be used with caution, particularly with regard to persons from countries where TB immunization is common.[27] New TB tests are being developed that offer the hope of cheap, fast and more accurate TB testing. These use polymerase chain reaction detection of bacterial DNA and antibody assays to detect the release of interferon gamma in response to mycobacteria.[28] These tests are not affected by immunization, so generate fewer false positive results.[29] Rapid and inexpensive diagnosis will be particularly valuable in the developing world.
PreventionPathogenesis
http://en.wikipedia.org/wiki/Image:TB_in_sputum.png
http://en.wikipedia.org/wiki/Image:TB_in_sputum.png
Mycobacterium tuberculosis (stained red) in sputum
About 90% of those infected with Mycobacterium tuberculosis have asymptomatic, latent TB infection (sometimes called LTBI), with only a 10% lifetime chance that a latent infection will progress to TB disease. However, if untreated, the death rate for these active TB cases is more than 50%.[20]
TB infection begins when the mycobacteria reach the pulmonary alveoli, where they invade and replicate within alveolar macrophages.[21] The primary site of infection in the lungs is called the Ghon focus. Bacteria are picked up by dendritic cells, which do not allow replication, although these cells can transport the bacilli to local (mediastinal) lymph nodes. Further spread is through the bloodstream to other tissues and organs where secondary TB lesions can develop in other parts of the lung, peripheral lymph nodes, kidneys, brain, and bone.[22] All parts of the body can be affected by the disease, though it rarely affects the heart, skeletal muscles, pancreas and thyroid.[23]
Tuberculosis is classified as one of the granulomatous inflammatory conditions. Macrophages, T lymphocytes, B lymphocytes and fibroblasts are among the cells that aggregate to form a granuloma, with lymphocytes surrounding the infected macrophages. The granuloma functions not only to prevent dissemination of the mycobacteria, but also provides a local environment for communication of cells of the immune system. Within the granuloma, T lymphocytes (CD4+) secrete cytokines such as interferon gamma, which activates macrophages to destroy the bacteria with which they are infected.[24] T lymphocytes (CD8+) can also directly kill infected cells.[21]
Importantly, bacteria are not always eliminated within the granuloma, but can become dormant, resulting in a latent infection. Another feature of the granulomas of human tuberculosis is the development of cell death, also called necrosis, in the center of tubercles. To the naked eye this has the texture of soft white cheese and was termed caseous necrosis.[25]
If TB bacteria gain entry to the bloodstream from an area of damaged tissue they spread through the body and set up many foci of infection, all appearing as tiny white tubercles in the tissues. This severe form of TB disease is most common in infants and the elderly and is called miliary tuberculosis. Patients with this disseminated TB have a fatality rate of approximately 20%, even with intensive treatment.[26]
In many patients the infection waxes and wanes. Tissue destruction and necrosis are balanced by healing and fibrosis.[25] Affected tissue is replaced by scarring and cavities filled with cheese-like white 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 can therefore pass on infection. Treatment with appropriate antibiotics kills bacteria and allows healing to take place. Upon cure, affected areas are eventually replaced by scar tissue.[25]
Diagnosis
Mantoux tuberculin skin test
Tuberculosis can be a difficult disease to diagnose, mainly due to the difficulty in culturing this slow-growing organism in the laboratory (4–12 weeks for blood culture). A complete medical evaluation for TB must include a medical history, a chest X-ray, and a physical examination. Tuberculosis radiology is used in the diagnosis of TB. It may also include a tuberculin skin test, a serological test, microbiological smears and cultures. The interpretation of the tuberculin skin test depends upon the person's risk factors for infection and progression to TB disease, such as exposure to other cases of TB or immunosuppression.[5]
Currently, latent infection is diagnosed in a non-immunized person by a tuberculin skin test, which yields a delayed hypersensitivity type response to an extract made from M. tuberculosis. Those immunized for TB or with past-cleared infection will respond with delayed hypersensitivity parallel to those currently in a state of infection, so the test must be used with caution, particularly with regard to persons from countries where TB immunization is common.[27] New TB tests are being developed that offer the hope of cheap, fast and more accurate TB testing. These use polymerase chain reaction detection of bacterial DNA and antibody assays to detect the release of interferon gamma in response to mycobacteria.[28] These tests are not affected by immunization, so generate fewer false positive results.[29] Rapid and inexpensive diagnosis will be particularly valuable in the developing world.
TB prevention and control takes two parallel approaches. In the first, people with TB and their contacts are identified and then treated. Identification of infections often involves testing high-risk groups for TB. In the second approach, children are vaccinated to protect them from TB. Unfortunately, no vaccine is available that provides reliable protection for adults. However, in tropical areas where the levels of other species of mycobacteria are high, exposure to nontuberculous mycobacteria gives some protection against TB.[39]
The World Health Organization (W.H.O.) declared TB a global health emergency in 1993, and the Stop TB Partnership developed a Global Plan to Stop Tuberculosis that aims to save 14 million lives between 2006 and 2015.[40] Since humans are the only host of Mycobacterium tuberculosis, eradication would be possibile: a goal that would be helped greatly by an effective vaccine.[41]
