Hiv can also be passed from mother to child during pregnancy, labor or delivery, or breastfeeding through breast milk. There are two main types of human immunodeficiency virus hiv 1 and hiv 2. On the basis of genetic characteristics and differences in the viral antigens, hiv is classified into the types 1 and 2 hiv 1, hiv 2. Aids definition is a disease of the human immune system that is characterized cytologically especially by reduction in the numbers of cd4bearing helper t cells to 20 percent or less of normal thereby rendering the subject highly vulnerable to lifethreatening conditions such as pneumocystis carinii pneumonia and to some such as kaposis sarcoma that become lifethreatening and that is. Hiv cases diagnosed and not previously reported in each country should be reported according to a standard national case definition. Hiv human immunodeficiency virus is a virus that attacks cells that help the body fight infection, making a person more vulnerable to other infections and diseases. Definitions for hiv epidemiology data epidemiology of. Aids stands for acquired immune deficiency syndrome. Introduction to hiv, aids and sexually transmitted infection surveillance. Surveillance of hiv risk behaviours world health organization. After a latent periodduring which hiv progresses to aids hiv aids, the viruss. Hiv 1 aidsrelated virusarv, human immunodeficiency virus, human tcell lymphotrophic virus, type iiihtlviii, lymphadenopathyassociated viruslav the retrovirus intimately linked to aids skin in hiv see hiv dermatopathy diagnosis pcr, elisa to screen for anti hiv igm antibodies. Despite the rapid spread of hiv, several countries have achieved important success in curbing its transmission. Hiv is spread mainly by having sex or sharing injection drug equipment such as needles with someone who has hiv.
An infection that can be transferred from one person to another through sexual contact. Who case definition for hiv infection to facilitate the reporting of hiv infection, who recommends the following. Hiv positive having a positive reaction on a test for the human immunodeficiency virus. Acquired immunodeficiency syndrome, a syndrome caused by infection with the human immunodeficiency virus, with ensuing compromise of the bodys immune system. Glossary aidsinfo information on hivaids treatment.
Since 1982, many different definitions have been used for national and international reporting. The transfer spread of a disease or infection from person to person. Hiv 1 abbreviation for human immunodeficiency virus 1. Both types are transmitted through direct contact with hiv infected body fluids, such as blood, semen, and vaginal fluids, or from a mother who has hiv to her child during pregnancy, labor and delivery, or breastfeeding through breast milk. Aids definition, a disease of the immune system characterized by increased susceptibility to opportunistic infections, as pneumocystis carinii pneumonia and candidiasis, to certain cancers, as kaposis sarcoma, and to neurological disorders. Acute hiv infection, which causes very high plasma viral loads in the. The human immunodeficiency virus hiv is grouped to the genus lentivirus within the family of retroviridae, subfamily orthoretrovirinae. Typically, this is followed by a prolonged period with no symptoms.
In hiv positive people, the virus can be found in the blood, sex fluids such as sperm and vaginal fluids and breast milk. Terms, definitions, and calculations used in cdc hiv. The abbreviation hiv can refer to the virus or to hiv infection. It harms your immune system by destroying the white blood cells that fight infection. That means you cant catch hiv or aids by hugging, kissing, dancing or shaking hands with someone who has the infection. Human immunodeficiency virus hiv definition aidsinfo. Acquired immunodeficiency syndrome aids definition. The 7th edition of the aidsinfo glossary of hivaids related terms provides people living with hiv, their families and their friends, health care professionals, and students a guide to understanding this complex disease. The virus destroys a type of white blood cell in the immune system called a thelper cell, and makes copies of itself inside these cells. Acquired immunodeficiency syndrome aids is a chronic, potentially lifethreatening condition caused by the human immunodeficiency virus hiv. The terms included in the glossary represent the vocabulary of hiv used in a variety of federal resources, including federally approved hiv aids medical practice guidelines and published results from hiv related research studies.
A test for the human immunodeficiency virus, the cause of aids. Hiv is transmitted via blood, semen, and vaginal fluids and causes a range of symptoms that present soon after infection, including fever and mouth ulcers. Features include deficiency of certain types of leukocytes, especially t cells. Hiv tests are designed to detect antibodies to the hiv virus or the hiv virus itself the antibody tests are. Human immunodeficiency virus hiv is the virus that causes acquired immunodeficiency syndrome aids. Hiv2, discovered in 1986, appears to be less virulent than hiv1 and may also have a longer latency period.
Acquired immunodeficiency syndrome aids is the most advanced stage of hiv infection. A disease of the immune system due to infection with hiv. Hiv stands for human immunodeficiency virus, which is the virus that causes hiv infection. Fact sheets about hivaids treatment information, the prevention of motherto child transmission, and hiv treatment side effects. In hiv positive people, the virus can be found in the blood, sex fluids such as sperm and vaginal fluids. Lentiviruses are transmitted as singlestranded, positivesense, enveloped rna viruses. A person is said to have aids when their immune system is too weak to fight off infection, and they develop certain defining symptoms and. Since the first cases of acquired immunodeficiency syndrome. Hiv1, which causes most cases of aids in europe, north and south america, and most parts of africa.
Regional office for the eastern mediterranean, joint united nations programme on hiv aids p. Hiv diagnoses and stage 3 aids classifications hiv infection is classified as stage 3 aids when the immune system of a person infected with hiv becomes severely compromised measured by cd4 cell count and. Hiv destroys the cd4 t lymphocytes cd4 cells of the immune system, leaving the body vulnerable to lifethreatening infections and cancers. The hivaids impacts on the health workforce and health systems are an added insult to the already fragile health systems in developing countries which are characterized by poor infrastructure, insufficient numbers of service providers, lack of drugs and commodities and frequently poor. Aids stands for acquired immunodeficiency syndrome. Hiv human immunodeficiency virus is a virus that attacks cells that help the body fight infection, making a person more vulnerable to other. But access to effective prevention and treatment varies widely. Hiv is a member of the genus lentivirus, part of the family retroviridae. The virus that causes aids, which is the most advanced stage of hiv infection. By damaging your immune system, hiv interferes with your bodys ability to fight the organisms that cause disease. Hiv is a virus that attacks cells in the immune system, which is our bodys natural defence against illness. Human immunodeficiency virus infection and acquired immune deficiency syndrome hivaids is a spectrum of conditions caused by infection with the human immunodeficiency virus hiv. No single hiv prevention strategy will be sufficient to control the hiv pandemic.
Over time, hiv can destroy so many of these cells that the body cant fight off infections and disease. The hiv epidemic has shifted over the past 30 years, from the first reported cases in the early 1980s, to an estimated high of 3. Lentiviruses have many morphologies and biological properties in common. Recent scientific advances have shown that antiretroviral therapy art not only preserves the health, quality of life, and life expectancy of people living with hiv, but people living with hiv who take hiv medicine as prescribed and get and keep an undetectable viral load have. One of the retrovirus is the human immunodeficiency virus that causes aids retroviruses are so named because they carry their genetic information in the form of rna rather than dna so that the information must be transcribed in reverse direction from rna into dna.
Persons who are hiv positive require sensitive counseling, information regarding transmission of the virus, and. The following list of documents, mostly in pdf format, gives an overview of the most commonly used definitions. In this context, sexual contact is more than just sexual intercourse vaginal and anal and also includes kissing, and the use of sexual toys, such as vibrators. The 7th edition of the glossary includes concise definitions for. Many species are infected by lentiviruses, which are characteristically responsible for longduration illnesses with a long incubation period. However, a growing number of interventions have shown promise in partially protecting against hiv transmission and acquisition, including knowledge of hiv serostatus, behavioral risk reduction, condoms, male circumcision, needle exchange, treatment of curable sexually transmitted infections, and use of. It is spread by contact with certain bodily fluids of a person with hiv, most commonly during unprotected sex sex without a condom or hiv medicine to prevent or treat hiv, or through sharing injection drug equipment. Many may not know the difference between hiv and aids. The extraordinary potential of hiv prevention is exemplified by such diverse efforts as thailands 100 percent condom program, ugandas remarkable decrease in hiv prevalence, and the communitybased syndromic management of sexually. Aids and hiv case definitions overview of internationally used hivaids case definitions.
Introduction to hiv, aids and sexually transmitted. Aids were reported in the united states in 1981, surveillance case definitions for. Following initial infection a person may not notice any symptoms, or may experience a brief period of influenzalike illness. A case of hiv infection is defined as an individual with hiv. Human immunodeficiency virus hiv the virus that causes aids, which is the most advanced stage of hiv infection. Hiv case definitions are defined and harmonized with the clinical staging and immunological classifications to facilitate improved hivrelated surveillance, to better. A positive result means that they have detected hiv antibody in the bloodstream. Revised surveillance case definition for hiv infection cdc. Hiv human immuno deficiency virus is a virus that enters blood.
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