艾滋病病毒英文论文

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Acquired immune deficiency syndrome or acquired immunodeficiency syndrome (AIDS) is a set of symptoms and infections resulting from the damage to the human immune system caused by the human immunodeficiency virus (HIV).[1] This condition progressively reduces the effectiveness of the immune system and leaves individuals susceptible to opportunistic infections and tumors. HIV is transmitted through direct contact of a mucous membrane or the bloodstream with a bodily fluid containing HIV, such as blood, semen, vaginal fluid, preseminal fluid, and breast milk.[2][3] This transmission can involve anal, vaginal or oral sex, blood transfusion, contaminated hypodermic needles, exchange between mother and baby during pregnancy, childbirth, or breastfeeding, or other exposure to one of the above bodily is now a pandemic.[4] In 2007, an estimated million people lived with the disease worldwide, and it killed an estimated million people, including 330,000 children.[5] Over three-quarters of these deaths occurred in sub-Saharan Africa,[5] retarding economic growth and destroying human capital.[6] Most researchers believe that HIV originated in sub-Saharan Africa during the twentieth century.[7] AIDS was first recognized by the . Centers for Disease Control and Prevention in 1981 and its cause, HIV, identified by American and French scientists in the early 1980s.[8]Although treatments for AIDS and HIV can slow the course of the disease, there is currently no vaccine or cure. Antiretroviral treatment reduces both the mortality and the morbidity of HIV infection, but these drugs are expensive and routine access to antiretroviral medication is not available in all countries.[9] Due to the difficulty in treating HIV infection, preventing infection is a key aim in controlling the AIDS epidemic, with health organizations promoting safe sex and needle-exchange programmes in attempts to slow the spread of the symptoms of AIDS are primarily the result of conditions that do not normally develop in individuals with healthy immune systems. Most of these conditions are infections caused by bacteria, viruses, fungi and parasites that are normally controlled by the elements of the immune system that HIV damages. Opportunistic infections are common in people with AIDS.[10] HIV affects nearly every organ system. People with AIDS also have an increased risk of developing various cancers such as Kaposi's sarcoma, cervical cancer and cancers of the immune system known as lymphomas. Additionally, people with AIDS often have systemic symptoms of infection like fevers, sweats (particularly at night), swollen glands, chills, weakness, and weight loss.[11][12] The specific opportunistic infections that AIDS patients develop depend in part on the prevalence of these infections in the geographic area in which the patient infections X-ray of Pneumocystis jirovecii caused pneumonia. There is increased white (opacity) in the lower lungs on both sides, characteristic of Pneumocystis pneumoniaPneumocystis pneumonia (originally known as Pneumocystis carinii pneumonia, and still abbreviated as PCP, which now stands for Pneumocystis pneumonia) is relatively rare in healthy, immunocompetent people, but common among HIV-infected individuals. It is caused by Pneumocystis jirovecii. Before the advent of effective diagnosis, treatment and routine prophylaxis in Western countries, it was a common immediate cause of death. In developing countries, it is still one of the first indications of AIDS in untested individuals, although it does not generally occur unless the CD4 count is less than 200 cells per µL of blood.[13]Tuberculosis (TB) is unique among infections associated with HIV because it is transmissible to immunocompetent people via the respiratory route, is easily treatable once identified, may occur in early-stage HIV disease, and is preventable with drug therapy. However, multidrug resistance is a potentially serious problem. Even though its incidence has declined because of the use of directly observed therapy and other improved practices in Western countries, this is not the case in developing countries where HIV is most prevalent. In early-stage HIV infection (CD4 count >300 cells per µL), TB typically presents as a pulmonary disease. In advanced HIV infection, TB often presents atypically with extrapulmonary (systemic) disease a common feature. Symptoms are usually constitutional and are not localized to one particular site, often affecting bone marrow, bone, urinary and gastrointestinal tracts, liver, regional lymph nodes, and the central nervous system.[14]Gastrointestinal infectionsEsophagitis is an inflammation of the lining of the lower end of the esophagus (gullet or swallowing tube leading to the stomach). In HIV infected individuals, this is normally due to fungal (candidiasis) or viral (herpes simplex-1 or cytomegalovirus) infections. In rare cases, it could be due to mycobacteria.[15]Unexplained chronic diarrhea in HIV infection is due to many possible causes, including common bacterial (Salmonella, Shigella, Listeria or Campylobacter) and parasitic infections; and uncommon opportunistic infections such as cryptosporidiosis, microsporidiosis, Mycobacterium avium complex (MAC) and viruses,[16] astrovirus, adenovirus, rotavirus and cytomegalovirus, (the latter as a course of colitis). In some cases, diarrhea may be a side effect of several drugs used to treat HIV, or it may simply accompany HIV infection, particularly during primary HIV infection. It may also be a side effect of antibiotics used to treat bacterial causes of diarrhea (common for Clostridium difficile). In the later stages of HIV infection, diarrhea is thought to be a reflection of changes in the way the intestinal tract absorbs nutrients, and may be an important component of HIV-related wasting.[17]Neurological and psychiatric involvementHIV infection may lead to a variety of neuropsychiatric sequelae, either by infection of the now susceptible nervous system by organisms, or as a direct consequence of the illness is a disease caused by the single-celled parasite called Toxoplasma gondii; it usually infects the brain, causing toxoplasma encephalitis, but it can also infect and cause disease in the eyes and lungs.[18] Cryptococcal meningitis is an infection of the meninx (the membrane covering the brain and spinal cord) by the fungus Cryptococcus neoformans. It can cause fevers, headache, fatigue, nausea, and vomiting. Patients may also develop seizures and confusion; left untreated, it can be multifocal leukoencephalopathy (PML) is a demyelinating disease, in which the gradual destruction of the myelin sheath covering the axons of nerve cells impairs the transmission of nerve impulses. It is caused by a virus called JC virus which occurs in 70% of the population in latent form, causing disease only when the immune system has been severely weakened, as is the case for AIDS patients. It progresses rapidly, usually causing death within months of diagnosis.[19]AIDS dementia complex (ADC) is a metabolic encephalopathy induced by HIV infection and fueled by immune activation of HIV infected brain macrophages and microglia. These cells are productively infected by HIV and secrete neurotoxins of both host and viral origin.[20] Specific neurological impairments are manifested by cognitive, behavioral, and motor abnormalities that occur after years of HIV infection and are associated with low CD4+ T cell levels and high plasma viral loads. Prevalence is 10–20% in Western countries[21] but only 1–2% of HIV infections in India.[22][23] This difference is possibly due to the HIV subtype in India. AIDS related mania is sometimes seen in patients with advanced HIV illness; it presents with more irritability and cognitive impairment and less euphoria than a manic episode associated with true bipolar disorder. Unlike the latter condition, it may have a more chronic course. This syndrome is less often seen with the advent of multi-drug and malignancies Kaposi's sarcomaPatients with HIV infection have substantially increased incidence of several cancers. This is primarily due to co-infection with an oncogenic DNA virus, especially Epstein-Barr virus (EBV), Kaposi's sarcoma-associated herpesvirus (KSHV), and human papillomavirus (HPV).[24][25]Kaposi's sarcoma (KS) is the most common tumor in HIV-infected patients. The appearance of this tumor in young homosexual men in 1981 was one of the first signals of the AIDS epidemic. Caused by a gammaherpes virus called Kaposi's sarcoma-associated herpes virus (KSHV), it often appears as purplish nodules on the skin, but can affect other organs, especially the mouth, gastrointestinal tract, and B cell lymphomas such as Burkitt's lymphoma, Burkitt's-like lymphoma, diffuse large B-cell lymphoma (DLBCL), and primary central nervous system lymphoma present more often in HIV-infected patients. These particular cancers often foreshadow a poor prognosis. In some cases these lymphomas are AIDS-defining. Epstein-Barr virus (EBV) or KSHV cause many of these cancer in HIV-infected women is considered AIDS-defining. It is caused by human papillomavirus (HPV).[26]In addition to the AIDS-defining tumors listed above, HIV-infected patients are at increased risk of certain other tumors, such as Hodgkin's disease and anal and rectal carcinomas. However, the incidence of many common tumors, such as breast cancer or colon cancer, does not increase in HIV-infected patients. In areas where HAART is extensively used to treat AIDS, the incidence of many AIDS-related malignancies has decreased, but at the same time malignant cancers overall have become the most common cause of death of HIV-infected patients.[27]Other opportunistic infectionsAIDS patients often develop opportunistic infections that present with non-specific symptoms, especially low-grade fevers and weight loss. These include infection with Mycobacterium avium-intracellulare and cytomegalovirus (CMV). CMV can cause colitis, as described above, and CMV retinitis can cause blindness. Penicilliosis due to Penicillium marneffei is now the third most common opportunistic infection (after extrapulmonary tuberculosis and cryptococcosis) in HIV-positive individuals within the endemic area of Southeast Asia.[28]

AIDS is the abbreviation1） of ACQUIRED IMMUNE DEFICIENCY is a complicated illness that may involve several is caused by a virus that can be passed from person to impairs the human body's immune system，the system responsible for keeping off disease，and leaves the victim easily affected by various virus enters the bloodstream and destroys certain white blood cells，called T lymphocytes2），which play a key role in the functioning of the immune virus can also infect other types of cells in the body，including the immune－system cells knows as macrophages3）。Unlike T lymphocytes，however，macrophages are not killed by the people recently infected by the AIDS virus look and feel some people the virus may remain inactive，and these people act as carriers，remaining apparently healthy but still able to infect a few years，some people may develop AIDS－related complex，or symptoms may include fever，fatigue4），weight loss，skin rashes，a fungal5） infection of the mouth known as thrush，lack of resistance to infection，and swollen lymph is spread by direct infection of the bloodstream with body fluids that contain the AIDS virus，particular blood and semen from an HIV－infected virus is usually spread through various forms of sexual intercourse，the transfusion of virus－infected blood，or the sharing of HIV－contaminated intravenous6） need （艾滋病）是Acquired Immune Deficiency Syndrome （获得性免疫缺损综合症）的缩写。它是一种复杂的疾病，分好几个阶段，由一种通过人体密切接触而传播的病毒引起。艾滋病损伤人体抵御疾病的免疫系统，使患者易于受到各种感染。艾滋病病毒进入血液并损坏一种在免疫系统中起着关键作用的白细胞-T淋巴细胞。这种病毒也会感染人体的其他类型的细胞，包括免疫系统中的巨噬细胞。然而，不像T淋巴细胞，巨噬细胞不会被病毒杀死。刚感染艾滋病病毒的大多数人看上去仍然健康，而且自我也感觉身体还好。在一些人身上，这种病毒可呈非活跃状态。但这些人是病毒的携带者，他们虽然自己健康，却能把病毒传染给别人。几年之后，有些人会得与艾滋病有关的综合症（ARC），其症状包括有发烧、疲劳、体重减轻、皮疹、蛾口疮（口腔真菌感染）、缺乏对感染的抵抗力以及淋巴肿瘤。艾滋病是通过含有艾滋病病毒的体液，尤其是HIV（人类免疫缺损病毒）感染者的血液和精液，直接感染血液而传播的。通常，艾滋病的传播途径有性交、输入感染病毒的血液和使用被HIV污染的静脉注射针头等。abbreviation n. 缩写， 缩写词lymphocyte n. 淋巴球， 淋巴细胞macrophage n. 巨噬细胞fatigue n. 疲乏， 疲劳fungal adj. 真菌的intravenous adj. 静脉内的还有一些资料是可以参考的: