The National AIDS Memorial Grove , or "The Grove," is located at the de Laveaga Dell in eastern Golden Gate Park , in San Francisco, California .
116-640: The Grove is a dedicated space and place in the national landscape where the millions of Americans touched directly or indirectly by AIDS can gather to heal, hope, and remember. The mission of the AIDS Memorial Grove is to provide a healing sanctuary and to promote learning and understanding of the human tragedy of the AIDS pandemic . Congress and the President of the United States approved
232-415: 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,
348-621: A 10- to 20-fold reduction in transmission risk. Pre-exposure prophylaxis for HIV (" PrEP ") with a daily dose of the medications tenofovir , with or without emtricitabine , is effective in people at high risk including men who have sex with men, couples where one is HIV-positive, and young heterosexuals in Africa. It may also be effective in intravenous drug users, with a study finding a decrease in risk of 0.7 to 0.4 per 100 person years. The USPSTF , in 2019, recommended PrEP in those who are at high risk. Universal precautions within
464-532: A brief period of influenza-like illness . During this period the person may not know that they are HIV-positive, yet they will be able to pass on the virus . Typically, this period is followed by a prolonged incubation period with no symptoms. Eventually the HIV infection increases the risk of developing other infections such as tuberculosis , as well as other opportunistic infections , and tumors which are rare in people who have normal immune function. The late stage
580-569: 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
696-406: A couple in which one person is infected, the rate of HIV infection is less than 1% per year. There is some evidence to suggest that female condoms may provide an equivalent level of protection. Application of a vaginal gel containing tenofovir (a reverse transcriptase inhibitor ) immediately before sex seems to reduce infection rates by approximately 40% among African women. By contrast, use of
812-451: A factor. During the chronic phase, the consequences of generalized immune activation coupled with the gradual loss of the ability of the immune system to generate new T cells appear to account for the slow decline in CD4 T cell numbers. Although the symptoms of immune deficiency characteristic of AIDS do not appear for years after a person is infected, the bulk of CD4 T cell loss occurs during
928-404: A high viral load and the cut was deep. In the United States, intravenous drug users made up 12% of all new cases of HIV in 2009, and in some areas more than 80% of people who inject drugs are HIV-positive. HIV is transmitted in about 90% of blood transfusions using infected blood. In developed countries the risk of acquiring HIV from a blood transfusion is extremely low (less than one in half
1044-402: A long incubation period . Lentiviruses are transmitted as single-stranded, positive- sense , enveloped RNA viruses . Upon entry into the target cell, the viral RNA genome is converted (reverse transcribed) into double-stranded DNA by a virally encoded reverse transcriptase that is transported along with the viral genome in the virus particle. The resulting viral DNA is then imported into
1160-685: 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
1276-541: A million) where improved donor selection and HIV screening is performed; for example, in the UK the risk is reported at one in five million and in the United States it was one in 1.5 million in 2008. In low-income countries, only half of transfusions may be appropriately screened (as of 2008), and it is estimated that up to 15% of HIV infections in these areas come from transfusion of infected blood and blood products, representing between 5% and 10% of global infections. It
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#17327732946901392-401: A needle during drug injection is between 0.63% and 2.4% per act, with an average of 0.8%. The risk of acquiring HIV from a needle stick from an HIV-infected person is estimated as 0.3% (about 1 in 333) per act and the risk following mucous membrane exposure to infected blood as 0.09% (about 1 in 1000) per act. This risk may, however, be up to 5% if the introduced blood was from a person with
1508-468: A normal life, and die with the virus, not of it. Effective treatment for HIV-positive people (people living with HIV ) involves a life-long regimen of medicine to suppress the virus, making the viral load undetectable. Without treatment it can lead to a spectrum of conditions including acquired immunodeficiency syndrome ( AIDS ). Treatment is recommended as soon as the diagnosis is made. An HIV-positive person who has an undetectable viral load as
1624-616: A process of cell-to-cell spread. The hybrid spreading mechanisms of HIV contribute to the virus' ongoing replication against antiretroviral therapies. Two types of HIV have been characterized: HIV-1 and HIV-2. HIV-1 is the virus that was originally discovered (and initially referred to also as LAV or HTLV-III). It is more virulent , more infective , and is the cause of the majority of HIV infections globally. The lower infectivity of HIV-2 as compared with HIV-1 implies that fewer people exposed to HIV-2 will be infected per exposure. Because of its relatively poor capacity for transmission, HIV-2
1740-430: A result of long-term treatment has effectively no risk of transmitting HIV sexually. Campaigns by UNAIDS and organizations around the world have communicated this as Undetectable = Untransmittable . Without treatment the infection can interfere with the immune system , and eventually progress to AIDS , sometimes taking many years. Following initial infection an individual may not notice any symptoms, or may experience
1856-406: A sexually transmitted illness. In many areas of the world, a third of HIV carriers only discover they are infected at an advanced stage of the disease when AIDS or severe immunodeficiency has become apparent. Most people infected with HIV develop seroconverted (antigen-specific) antibodies within three to twelve weeks after the initial infection. Diagnosis of primary HIV before seroconversion
1972-407: 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
2088-401: 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
2204-474: 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
2320-398: 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
2436-427: Is a retrovirus that attacks the immune system . It is a preventable disease . There is no vaccine or cure for HIV. It can be managed with treatment and become a manageable chronic health condition. While there is no cure or vaccine, antiretroviral treatment can slow the course of the disease and enable people living with HIV to lead long and healthy lives. An HIV-positive person on treatment can expect to live
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#17327732946902552-491: 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
2668-449: 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
2784-433: Is almost invariably associated with activation of CD8 T cells , which kill HIV-infected cells, and subsequently with antibody production, or seroconversion . The CD8 T cell response is thought to be important in controlling virus levels, which peak and then decline, as the CD4 T cell counts recover. A good CD8 T cell response has been linked to slower disease progression and a better prognosis, though it does not eliminate
2900-538: Is also believed to carry an increased risk of HIV transmission as condoms are rarely worn, physical trauma to the vagina or rectum is likely, and there may be a greater risk of concurrent sexually transmitted infections. The second-most frequent mode of HIV transmission is via blood and blood products. Blood-borne transmission can be through needle-sharing during intravenous drug use, needle-stick injury, transfusion of contaminated blood or blood product, or medical injections with unsterilized equipment. The risk from sharing
3016-653: 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
3132-478: Is called acute HIV, primary HIV or acute retroviral syndrome. Many individuals develop an illness like influenza , mononucleosis or glandular fever 2–4 weeks after exposure while others have no significant symptoms. Symptoms occur in 40–90% of cases and most commonly include fever , large tender lymph nodes , throat inflammation , a rash , headache, tiredness, and/or sores of the mouth and genitals. The rash, which occurs in 20–50% of cases, presents itself on
3248-653: Is defined as an HIV infection with either a CD4 T cell count below 200 cells per μL or the occurrence of specific diseases associated with HIV infection. In the absence of specific treatment, around half of people infected with HIV develop AIDS within ten years. The most common initial conditions that alert to the presence of AIDS are pneumocystis pneumonia (40%), cachexia in the form of HIV wasting syndrome (20%), and esophageal candidiasis . Other common signs include recurrent respiratory tract infections . Opportunistic infections may be caused by bacteria , viruses , fungi , and parasites that are normally controlled by
3364-444: 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
3480-760: Is disputed, and whether it is of benefit in developed countries and among men who have sex with men is undetermined. Programs encouraging sexual abstinence do not appear to affect subsequent HIV risk. Evidence of any benefit from peer education is equally poor. Comprehensive sexual education provided at school may decrease high-risk behavior. A substantial minority of young people continues to engage in high-risk practices despite knowing about HIV/AIDS, underestimating their own risk of becoming infected with HIV. Voluntary counseling and testing people for HIV does not affect risky behavior in those who test negative but does increase condom use in those who test positive. Enhanced family planning services appear to increase
3596-422: Is done by measuring HIV- RNA or p24 antigen . Positive results obtained by antibody or PCR testing are confirmed either by a different antibody or by PCR. Antibody tests in children younger than 18 months are typically inaccurate, due to the continued presence of maternal antibodies . Thus HIV infection can only be diagnosed by PCR testing for HIV RNA or DNA, or via testing for the p24 antigen. Much of
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3712-595: Is especially high, estimated as 1.4–1.7% per act in both heterosexual and homosexual contacts. While the risk of transmission from oral sex is relatively low, it is still present. The risk from receiving oral sex has been described as "nearly nil"; however, a few cases have been reported. The per-act risk is estimated at 0–0.04% for receptive oral intercourse. In settings involving prostitution in low-income countries, risk of female-to-male transmission has been estimated as 2.4% per act, and of male-to-female transmission as 0.05% per act. Risk of transmission increases in
3828-400: Is largely confined to West Africa . After the virus enters the body, there is a period of rapid viral replication , leading to an abundance of virus in the peripheral blood. During primary infection, the level of HIV may reach several million virus particles per milliliter of blood. This response is accompanied by a marked drop in the number of circulating CD4 T cells . The acute viremia
3944-509: 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
4060-531: Is often also associated with unintended weight loss . Without treatment a person living with HIV can expect to live for 11 years. Early testing can show if treatment is needed to stop this progression and to prevent infecting others. HIV is spread primarily by unprotected sex (including anal and vaginal sex ), contaminated hypodermic needles or blood transfusions , and from mother to child during pregnancy , delivery, or breastfeeding. Some bodily fluids, such as saliva, sweat, and tears, do not transmit
4176-489: 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
4292-501: 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
4408-423: 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
4524-565: Is possible to acquire HIV from organ and tissue transplantation , although this is rare because of screening . Unsafe medical injections play a role in HIV spread in sub-Saharan Africa . In 2007, between 12% and 17% of infections in this region were attributed to medical syringe use. The World Health Organization estimates the risk of transmission as a result of a medical injection in Africa at 1.2%. Risks are also associated with invasive procedures, assisted delivery, and dental care in this area of
4640-420: Is referred to as post-exposure prophylaxis (PEP). The use of the single agent zidovudine reduces the risk of an HIV infection five-fold following a needle-stick injury. As of 2013 , the prevention regimen recommended in the United States consists of three medications— tenofovir , emtricitabine and raltegravir —as this may reduce the risk further. PEP treatment is recommended after a sexual assault when
4756-542: Is spread by three main routes: sexual contact , significant exposure to infected body fluids or tissues, and from mother to child during pregnancy, delivery, or breastfeeding (known as vertical transmission ). There is no risk of acquiring HIV if exposed to feces , nasal secretions, saliva, sputum , sweat, tears, urine, or vomit unless these are contaminated with blood. It is also possible to be co-infected by more than one strain of HIV—a condition known as HIV superinfection . The most frequent mode of transmission of HIV
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4872-464: 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,
4988-420: 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
5104-467: Is through sexual contact with an infected person. However, an HIV-positive person who has an undetectable viral load as a result of long-term treatment has effectively no risk of transmitting HIV sexually, known as Undetectable = Untransmittable . The existence of functionally noncontagious HIV-positive people on antiretroviral therapy was controversially publicized in the 2008 Swiss Statement , and has since become accepted as medically sound. Globally,
5220-590: The WHO disease staging system for HIV infection and disease , and the CDC classification system for HIV infection . The CDC's classification system is more frequently adopted in developed countries. Since the WHO's staging system does not require laboratory tests, it is suited to the resource-restricted conditions encountered in developing countries, where it can also be used to help guide clinical management. Despite their differences,
5336-622: The World Health Organization (WHO) African Region. HIV/AIDS is considered a pandemic —a disease outbreak which is present over a large area and is actively spreading. The United States' National Institutes of Health (NIH) and the Gates Foundation have pledged $ 200 million focused on developing a global cure for AIDS. There are three main stages of HIV infection: acute infection, clinical latency, and AIDS. The initial period following infection with HIV
5452-458: 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
5568-609: The spermicide nonoxynol-9 may increase the risk of transmission due to its tendency to cause vaginal and rectal irritation. Circumcision in sub-Saharan Africa "reduces the acquisition of HIV by heterosexual men by between 38% and 66% over 24 months". Owing to these studies, both the World Health Organization and UNAIDS recommended male circumcision in 2007 as a method of preventing female-to-male HIV transmission in areas with high rates of HIV. However, whether it protects against male-to-female transmission
5684-420: 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
5800-616: The " white death ", or historically as consumption , is an infectious disease usually caused by Mycobacterium tuberculosis (MTB) bacteria . Tuberculosis generally affects 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
5916-493: The CCR5 protein when present in both chromosomes very effectively prevents HIV-1 infection. HIV seeks out and destroys CCR5 expressing CD4 T cells during acute infection. A vigorous immune response eventually controls the infection and initiates the clinically latent phase. CD4 T cells in mucosal tissues remain particularly affected. Continuous HIV replication causes a state of generalized immune activation persisting throughout
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#17327732946906032-506: The Grove is open during the park's hours. Free guided tours—excursions are given monthly for the public (except winter). 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1998 1999 2000 2001 2002 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2017 2019 2020 AIDS The human immunodeficiency virus ( HIV )
6148-698: 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
6264-643: The Omnibus Parks and Public Lands Management Act of 1996 in 1996, which officially set aside the deLaveaga Dell land in Golden Gate Park as the site for the first AIDS memorial in the nation. The Grove continues through the additional generosity of services and financial support given by numerous individuals, corporations, and foundations. Thousands of community volunteers have ensured over 20 years that continuous gardening and regular maintenance occurs, along with periodic enhancement projects, to keep
6380-516: 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
6496-568: 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
6612-565: The absence of treatment will eventually progress to AIDS, a small proportion (about 5%) retain high levels of CD4 T cells ( T helper cells ) without antiretroviral therapy for more than five years. These individuals are classified as "HIV controllers" or long-term nonprogressors (LTNP). Another group consists of those who maintain a low or undetectable viral load without anti-retroviral treatment, known as "elite controllers" or "elite suppressors". They represent approximately 1 in 300 infected persons. Acquired immunodeficiency syndrome (AIDS)
6728-499: The absence of treatment, the risk of transmission before or during birth is around 20%, and in those who also breastfeed 35%. Treatment decreases this risk to less than 5%. Antiretrovirals when taken by either the mother or the baby decrease the risk of transmission in those who do breastfeed. If blood contaminates food during pre-chewing it may pose a risk of transmission. If a woman is untreated, two years of breastfeeding results in an HIV/AIDS risk in her baby of about 17%. Due to
6844-688: 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
6960-515: The acute phase of disease. HIV/AIDS is diagnosed via laboratory testing and then staged based on the presence of certain signs or symptoms . HIV screening is recommended by the United States Preventive Services Task Force for all people 15 years to 65 years of age, including all pregnant women. Additionally, testing is recommended for those at high risk, which includes anyone diagnosed with
7076-458: 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
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#17327732946907192-423: 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
7308-497: The beauty of the grove is that as a memorial which receives no federal money, it is blessedly removed from the fight over the controversy of AIDS." The Main Portal entrance is at 856 Stanyan Street in eastern Golden Gate Park . The West Portal and South Portal are the two other designated entrances, also on park roads surrounding The Grove. Other secondary walkways enter naturally from the park roads and adjacent park areas. Access to
7424-425: 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
7540-485: 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
7656-406: The cell nucleus and integrated into the cellular DNA by a virally encoded integrase and host co-factors. Once integrated, the virus may become latent , allowing the virus and its host cell to avoid detection by the immune system. Alternatively, the virus may be transcribed , producing new RNA genomes and viral proteins that are packaged and released from the cell as new virus particles that begin
7772-425: The chronic phase. Immune activation, which is reflected by the increased activation state of immune cells and release of pro-inflammatory cytokines , results from the activity of several HIV gene products and the immune response to ongoing HIV replication. It is also linked to the breakdown of the immune surveillance system of the gastrointestinal mucosal barrier caused by the depletion of mucosal CD4 T cells during
7888-632: 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
8004-640: 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
8120-610: 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
8236-620: 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
8352-620: The early 1980s, HIV/AIDS has had a large impact on society, both as an illness and as a source of discrimination . The disease also has large economic impacts . There are many misconceptions about HIV/AIDS , such as the belief that it can be transmitted by casual non-sexual contact. The disease has become subject to many controversies involving religion , including the Catholic Church's position not to support condom use as prevention. It has attracted international medical and political attention as well as large-scale funding since it
8468-463: 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
8584-424: The end of this stage many people experience fever, weight loss, gastrointestinal problems and muscle pains. Between 50% and 70% of people also develop persistent generalized lymphadenopathy , characterized by unexplained, non-painful enlargement of more than one group of lymph nodes (other than in the groin) for over three to six months. Although most HIV-1 infected individuals have a detectable viral load and in
8700-465: The first 2.5 months of an HIV infection, a person's infectiousness is twelve times higher due to the high viral load associated with acute HIV. If the person is in the late stages of infection, rates of transmission are approximately eightfold greater. Commercial sex workers (including those in pornography ) have an increased likelihood of contracting HIV. Rough sex can be a factor associated with an increased risk of transmission. Sexual assault
8816-552: 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
8932-622: 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
9048-491: The first weeks of infection, especially in the intestinal mucosa, which harbors the majority of the lymphocytes found in the body. The reason for the preferential loss of mucosal CD4 T cells is that the majority of mucosal CD4 T cells express the CCR5 protein which HIV uses as a co-receptor to gain access to the cells, whereas only a small fraction of CD4 T cells in the bloodstream do so. A specific genetic change that alters
9164-414: The health care environment are believed to be effective in decreasing the risk of HIV. Intravenous drug use is an important risk factor, and harm reduction strategies such as needle-exchange programs and opioid substitution therapy appear effective in decreasing this risk. A course of antiretrovirals administered within 48 to 72 hours after exposure to HIV-positive blood or genital secretions
9280-431: 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
9396-425: The human immune system such as CD4 T cells, macrophages and dendritic cells . It directly and indirectly destroys CD4 T cells. HIV is a member of the genus Lentivirus , part of the family Retroviridae . Lentiviruses share many morphological and biological characteristics. Many species of mammals are infected by lentiviruses, which are characteristically responsible for long-duration illnesses with
9512-400: The immune system. Which infections occur depends partly on what organisms are common in the person's environment. These infections may affect nearly every organ system . People with AIDS have an increased risk of developing various viral-induced cancers, including Kaposi's sarcoma , Burkitt's lymphoma , primary central nervous system lymphoma , and cervical cancer . Kaposi's sarcoma is
9628-407: The increased risk of death without breastfeeding in many areas in the developing world, the World Health Organization recommends either exclusive breastfeeding or the provision of safe formula. All women known to be HIV-positive should be taking lifelong antiretroviral therapy. HIV is the cause of the spectrum of disease known as HIV/AIDS. HIV is a retrovirus that primarily infects components of
9744-400: 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
9860-409: The infection in five groups. In those greater than six years of age it is: For surveillance purposes, the AIDS diagnosis still stands even if, after treatment, the CD4 T cell count rises to above 200 per μL of blood or other AIDS-defining illnesses are cured. Consistent condom use reduces the risk of HIV transmission by approximately 80% over the long term. When condoms are used consistently by
9976-439: 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 ),
10092-613: 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
10208-444: The landscape vital and sense of place beautiful. The Grove serves as an important sanctuary for people, from locals to world visitors, a refuge for memories and a place of new enjoyment. Most memorials are built after the struggle is over. This battle rages on and we cannot wait, lest any one of our loved ones lost to AIDS be forgotten. The Grove's former executive director and current board member, Thom Weyand, has said that "part of
10324-528: The layer that lines the inner part of eyelids and the white part of the eye) is also more common in those with HIV. Additionally, people with AIDS frequently have systemic symptoms such as prolonged fevers, sweats (particularly at night), swollen lymph nodes, chills, weakness, and unintended weight loss . Diarrhea is another common symptom, present in about 90% of people with AIDS. They can also be affected by diverse psychiatric and neurological symptoms independent of opportunistic infections and cancers. HIV
10440-491: 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
10556-413: The likelihood of women with HIV using contraception, compared to basic services. It is not known whether treating other sexually transmitted infections is effective in preventing HIV. Antiretroviral treatment among people with HIV whose CD4 count ≤ 550 cells/μL is a very effective way to prevent HIV infection of their partner (a strategy known as treatment as prevention, or TASP). TASP is associated with
10672-539: The many common infectious diseases with similar symptoms. Someone with an unexplained fever who may have been recently exposed to HIV should consider testing to find out if they have been infected. The initial symptoms are followed by a stage called clinical latency, asymptomatic HIV, or chronic HIV. Without treatment, this second stage of the natural history of HIV infection can last from about three years to over 20 years (on average, about eight years). While typically there are few or no symptoms at first, near
10788-537: 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
10904-437: The most common cancer, occurring in 10% to 20% of people with HIV. The second-most common cancer is lymphoma, which is the cause of death of nearly 16% of people with AIDS and is the initial sign of AIDS in 3% to 4%. Both these cancers are associated with human herpesvirus 8 (HHV-8). Cervical cancer occurs more frequently in those with AIDS because of its association with human papillomavirus (HPV). Conjunctival cancer (of
11020-608: The most common mode of HIV transmission is via sexual contacts between people of the opposite sex ; however, the pattern of transmission varies among countries. As of 2017 , most HIV transmission in the United States occurred among men who had sex with men (82% of new HIV diagnoses among males aged 13 and older and 70% of total new diagnoses). In the US, gay and bisexual men aged 13 to 24 accounted for an estimated 92% of new HIV diagnoses among all men in their age group and 27% of new diagnoses among all gay and bisexual men. With regard to unprotected heterosexual contacts, estimates of
11136-596: 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
11252-599: 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
11368-430: The perpetrator is known to be HIV-positive, but is controversial when their HIV status is unknown. The duration of treatment is usually four weeks and is frequently associated with adverse effects—where zidovudine is used, about 70% of cases result in adverse effects such as nausea (24%), fatigue (22%), emotional distress (13%) and headaches (9%). Tuberculosis Tuberculosis ( TB ), also known colloquially as
11484-453: The presence of many sexually transmitted infections and genital ulcers . Genital ulcers increase the risk approximately fivefold. Other sexually transmitted infections, such as gonorrhea , chlamydia , trichomoniasis , and bacterial vaginosis , are associated with somewhat smaller increases in risk of transmission. The viral load of an infected person is an important risk factor in both sexual and mother-to-child transmission. During
11600-434: The replication cycle anew. HIV is now known to spread between CD4 T cells by two parallel routes: cell-free spread and cell-to-cell spread, i.e. it employs hybrid spreading mechanisms. In the cell-free spread, virus particles bud from an infected T cell, enter the blood/extracellular fluid and then infect another T cell following a chance encounter. HIV can also disseminate by direct transmission from one cell to another by
11716-487: The risk of HIV transmission per sexual act appear to be four to ten times higher in low-income countries than in high-income countries. In low-income countries, the risk of female-to-male transmission is estimated as 0.38% per act, and of male-to-female transmission as 0.30% per act; the equivalent estimates for high-income countries are 0.04% per act for female-to-male transmission, and 0.08% per act for male-to-female transmission. The risk of transmission from anal intercourse
11832-435: 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,
11948-414: 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,
12064-549: 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
12180-465: 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
12296-565: 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
12412-467: 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
12528-480: The trunk and is maculopapular , classically. Some people also develop opportunistic infections at this stage. Gastrointestinal symptoms, such as vomiting or diarrhea may occur. Neurological symptoms of peripheral neuropathy or Guillain–Barré syndrome also occur. The duration of the symptoms varies, but is usually one or two weeks. These symptoms are not often recognized as signs of HIV infection. Family doctors or hospitals can misdiagnose cases as one of
12644-552: The two systems allow a comparison for statistical purposes. The World Health Organization first proposed a definition for AIDS in 1986. Since then, the WHO classification has been updated and expanded several times, with the most recent version being published in 2007. The WHO system uses the following categories: The U.S. Centers for Disease Control and Prevention also created a classification system for HIV, and updated it in 2008 and 2014. This system classifies HIV infections based on CD4 count and clinical symptoms, and describes
12760-502: The virus. Ultimately, HIV causes AIDS by depleting CD4 T cells. This weakens the immune system and allows opportunistic infections . T cells are essential to the immune response and without them, the body cannot fight infections or kill cancerous cells. The mechanism of CD4 T cell depletion differs in the acute and chronic phases. During the acute phase, HIV-induced cell lysis and killing of infected cells by CD8 T cells accounts for CD4 T cell depletion, although apoptosis may also be
12876-463: The virus. Oral sex has little risk of transmitting the virus. Ways to avoid catching HIV and preventing the spread include safe sex , treatment to prevent infection (" PrEP "), treatment to stop infection in someone who has been recently exposed (" PEP "), treating those who are infected , and needle exchange programs . Disease in a baby can often be prevented by giving both the mother and child antiretroviral medication . Recognized worldwide in
12992-559: The world lacks access to reliable PCR testing, and people in many places simply wait until either symptoms develop or the child is old enough for accurate antibody testing. In sub-Saharan Africa between 2007 and 2009, between 30% and 70% of the population were aware of their HIV status. In 2009, between 3.6% and 42% of men and women in sub-Saharan countries were tested; this represented a significant increase compared to previous years. Two main clinical staging systems are used to classify HIV and HIV-related disease for surveillance purposes:
13108-482: The world. People giving or receiving tattoos , piercings , and scarification are theoretically at risk of infection but no confirmed cases have been documented. It is not possible for mosquitoes or other insects to transmit HIV. HIV can be transmitted from mother to child during pregnancy, during delivery, or through breast milk, resulting in the baby also contracting HIV. As of 2008, vertical transmission accounted for about 90% of cases of HIV in children. In
13224-526: 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
13340-634: Was identified in the 1980s. HIV made the jump from other primates to humans in west-central Africa in the early-to-mid-20th century. AIDS was first recognized by the U.S. Centers for Disease Control and Prevention (CDC) in 1981 and its cause—HIV infection—was identified in the early part of the decade. Between the first time AIDS was readily identified through 2024, the disease is estimated to have caused at least 42.3 million deaths worldwide. In 2023, 630,000 people died from HIV-related causes, an estimated 1.3 million people acquired HIV and about 39.9 million people worldwide living with HIV, 65% of whom are in
13456-478: 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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