HIV/AIDS RISK FACTORS
Anyone of any age, race, sex or sexual orientation can be infected with HIV, but you're at greatest risk of HIV/AIDS if you:
Have unprotected sex with multiple partners. You're at risk whether you're heterosexual, homosexual or bisexual. Unprotected sex means having sex without using a new latex or polyurethane condom every time.
Have unprotected sex with someone who is HIV-positive.
Have another sexually transmitted disease, such as syphilis, herpes, chlamydia, gonorrhea or bacterial vaginosis.
Share needles during intravenous drug use.
Received a blood transfusion or blood products before 1985.
Have fewer copies of a gene called CCL3L1 that helps fight HIV infection.
Newborns or nursing infants whose mothers tested positive for HIV but did not receive treatment also are at higher
Thursday, October 30, 2008
The HIV Life Cycle
The HIV Life Cycle
Introduction
In order for viruses to reproduce, they must infect a cell. Viruses are not technically alive: they are sort of like a brain with no body. In order to make new viruses, they must hi-jack a cell, and use it to make new viruses. Just as your body is constantly making new skin cells, or new blood cells, each cell often makes new proteins in order to stay alive and to reproduce itself. Viruses hide their own DNA in the DNA of the cell, and then, when the cell tries to make new proteins, it accidentally makes new viruses as well. HIV mostly infects cells in the immune system.
Infection: Several different kinds of cells have proteins on their surface that are called CD4 receptors. HIV searches for cells that have CD4 surface receptors, because this particular protein enables the virus to bind to the cell. Although HIV infects a variety of cells, its main target is the T4-lymphocyte (also called the "T-helper cell"), a kind of white blood cell that has lots of CD4 receptors. The T4-cell is responsible for warning your immune system that there are invaders in the system.
Replication: Once HIV binds to a cell, it hides HIV DNA inside the cell's DNA: this turns the cell into a sort of HIV factory.
Definitions
There are a few things you need to know in order to understand HIV infection.
DNA: DNA is like the "blueprint" for building living cells.
Enzymes: Enzymes are like the workers of a cell. They build new proteins, transport materials around the cell, and carry out other important cellular functions.
RNA: RNA is like the construction boss. Cells use RNA to tell enzymes how to build a specific part of a cell. To make a new protein, enzymes will copy a specific part of the DNA into a piece of RNA. This RNA is then used by other enzymes to build a new protein or enzyme.
Proteins: The building blocks that are used to make living things.
Nucleus: A small package inside the cell where the genetic material is kept.
A virus consists of an outer envelope of protein, fat and sugar wrapped around a set of genes (in the case of HIV, genetic information is carried as RNA instead of DNA) and special enzymes.
HIV has proteins on its envelope that are strongly attracted to the CD4+ surface receptor on the outside of the T4-cell. When HIV binds to a CD4+ surface receptor, it activates other proteins on the cell's surface, allowing the HIV envelope to fuse to the outside of the cell.
Entry can be blocked by entry inhibitors.
Introduction
In order for viruses to reproduce, they must infect a cell. Viruses are not technically alive: they are sort of like a brain with no body. In order to make new viruses, they must hi-jack a cell, and use it to make new viruses. Just as your body is constantly making new skin cells, or new blood cells, each cell often makes new proteins in order to stay alive and to reproduce itself. Viruses hide their own DNA in the DNA of the cell, and then, when the cell tries to make new proteins, it accidentally makes new viruses as well. HIV mostly infects cells in the immune system.
Infection: Several different kinds of cells have proteins on their surface that are called CD4 receptors. HIV searches for cells that have CD4 surface receptors, because this particular protein enables the virus to bind to the cell. Although HIV infects a variety of cells, its main target is the T4-lymphocyte (also called the "T-helper cell"), a kind of white blood cell that has lots of CD4 receptors. The T4-cell is responsible for warning your immune system that there are invaders in the system.
Replication: Once HIV binds to a cell, it hides HIV DNA inside the cell's DNA: this turns the cell into a sort of HIV factory.
Definitions
There are a few things you need to know in order to understand HIV infection.
DNA: DNA is like the "blueprint" for building living cells.
Enzymes: Enzymes are like the workers of a cell. They build new proteins, transport materials around the cell, and carry out other important cellular functions.
RNA: RNA is like the construction boss. Cells use RNA to tell enzymes how to build a specific part of a cell. To make a new protein, enzymes will copy a specific part of the DNA into a piece of RNA. This RNA is then used by other enzymes to build a new protein or enzyme.
Proteins: The building blocks that are used to make living things.
Nucleus: A small package inside the cell where the genetic material is kept.
A virus consists of an outer envelope of protein, fat and sugar wrapped around a set of genes (in the case of HIV, genetic information is carried as RNA instead of DNA) and special enzymes.
HIV has proteins on its envelope that are strongly attracted to the CD4+ surface receptor on the outside of the T4-cell. When HIV binds to a CD4+ surface receptor, it activates other proteins on the cell's surface, allowing the HIV envelope to fuse to the outside of the cell.
Entry can be blocked by entry inhibitors.
Wednesday, October 15, 2008
HIV/AIDS Transmission
HIV/AIDS Transmission
HIV is transmitted when the virus enters the body, usually by injecting infected cells or semen. There are several possible ways in which the virus can enter.
Most commonly, HIV infection is spread by having sex with an infected partner. The virus can enter the body through the lining of the vagina, vulva, penis, rectum, or mouth during sex.
HIV frequently spreads among injection-drug users who share needles or syringes that are contaminated with blood from an infected person.
Women can transmit HIV to their babies during pregnancy or birth, when infected maternal cells enter the baby's circulation.
HIV can be spread in health-care settings through accidental needle sticks or contact with contaminated fluids.
Very rarely, HIV spreads through transfusion of contaminated blood or blood components. Blood products are now tested to minimize this risk. If tissues or organs from an infected person are transplanted, the recipient may acquire HIV. Donors are now tested for HIV to minimize this risk.
People who already have a sexually transmitted disease, such as syphilis, genital herpes, chlamydial infection, gonorrhea, or bacterial vaginosis, are more likely to acquire HIV infection during sex with an infected partner.
The virus does not spread through casual contact such as preparing food, sharing towels and bedding, or via swimming pools, telephones, or toilet seats. The virus is also unlikely to be spread by contact with saliva, unless it is contaminated with blood.
HIV is transmitted when the virus enters the body, usually by injecting infected cells or semen. There are several possible ways in which the virus can enter.
Most commonly, HIV infection is spread by having sex with an infected partner. The virus can enter the body through the lining of the vagina, vulva, penis, rectum, or mouth during sex.
HIV frequently spreads among injection-drug users who share needles or syringes that are contaminated with blood from an infected person.
Women can transmit HIV to their babies during pregnancy or birth, when infected maternal cells enter the baby's circulation.
HIV can be spread in health-care settings through accidental needle sticks or contact with contaminated fluids.
Very rarely, HIV spreads through transfusion of contaminated blood or blood components. Blood products are now tested to minimize this risk. If tissues or organs from an infected person are transplanted, the recipient may acquire HIV. Donors are now tested for HIV to minimize this risk.
People who already have a sexually transmitted disease, such as syphilis, genital herpes, chlamydial infection, gonorrhea, or bacterial vaginosis, are more likely to acquire HIV infection during sex with an infected partner.
The virus does not spread through casual contact such as preparing food, sharing towels and bedding, or via swimming pools, telephones, or toilet seats. The virus is also unlikely to be spread by contact with saliva, unless it is contaminated with blood.
HIV/AIDS Overview
HIV/AIDS Overview
HIV (human immunodeficiency virus) infection has now spread to every country in the world. Approximately 40 million people are currently living with HIV infection, and an estimated 25 million have died from this disease. The scourge of HIV has been particularly devastating in sub-Saharan Africa, but infection rates in other countries remain high. In the United States, approximately 1 million people are currently infected. Here are a few key points about the disease:
Globally, 85% of HIV transmission is heterosexual.
In the United States, approximately one-third of new diagnoses appear to be related to heterosexual transmission. Male-to-male sexual contact still accounts for approximately half of new diagnoses in the U.S. Intravenous drug use contributes to the remaining cases. Because the diagnosis may occur years after infection, it is likely that a higher proportion of recent infections are due to heterosexual transmission.
Infections in women are increasing. Worldwide, 42% of people with HIV are women. In the United States, approximately 25% of new diagnoses are in women, and the proportion is rising.
There is good news on one front: New HIV infections in U.S. children have fallen dramatically, with only 38 cases reported in 2006. This is largely a result of testing and treating infected mothers, as well as establishing uniform testing guidelines for blood products.
In order to understand HIV and AIDS, it is important to understand the meanings behind these terms:
HIV stands for the human immunodeficiency virus. It is one of a group of viruses known as retroviruses. After getting into the body, the virus kills or damages cells of the body's immune system. The body tries to keep up by making new cells or trying to contain the virus, but eventually the HIV wins out and progressively destroys the body's ability to fight infections and certain cancers.
AIDS stands for the acquired immunodeficiency syndrome. It is caused by HIV and occurs when the virus has destroyed so much of the body's defenses that immune-cell counts fall to critical levels or certain life-threatening infections or cancers develop.
HIV (human immunodeficiency virus) infection has now spread to every country in the world. Approximately 40 million people are currently living with HIV infection, and an estimated 25 million have died from this disease. The scourge of HIV has been particularly devastating in sub-Saharan Africa, but infection rates in other countries remain high. In the United States, approximately 1 million people are currently infected. Here are a few key points about the disease:
Globally, 85% of HIV transmission is heterosexual.
In the United States, approximately one-third of new diagnoses appear to be related to heterosexual transmission. Male-to-male sexual contact still accounts for approximately half of new diagnoses in the U.S. Intravenous drug use contributes to the remaining cases. Because the diagnosis may occur years after infection, it is likely that a higher proportion of recent infections are due to heterosexual transmission.
Infections in women are increasing. Worldwide, 42% of people with HIV are women. In the United States, approximately 25% of new diagnoses are in women, and the proportion is rising.
There is good news on one front: New HIV infections in U.S. children have fallen dramatically, with only 38 cases reported in 2006. This is largely a result of testing and treating infected mothers, as well as establishing uniform testing guidelines for blood products.
In order to understand HIV and AIDS, it is important to understand the meanings behind these terms:
HIV stands for the human immunodeficiency virus. It is one of a group of viruses known as retroviruses. After getting into the body, the virus kills or damages cells of the body's immune system. The body tries to keep up by making new cells or trying to contain the virus, but eventually the HIV wins out and progressively destroys the body's ability to fight infections and certain cancers.
AIDS stands for the acquired immunodeficiency syndrome. It is caused by HIV and occurs when the virus has destroyed so much of the body's defenses that immune-cell counts fall to critical levels or certain life-threatening infections or cancers develop.
HIV/AIDS Symptoms
HIV/AIDS Symptoms
Many people with HIV do not know they are infected.
Many people do not develop symptoms after they first get infected with HIV. Others have a flu-like illness within several days to weeks after exposure to the virus. They complain of fever, headache, tiredness, and enlarged lymph nodes in the neck. These symptoms usually disappear on their own within a few weeks. After that, the person feels normal and has no symptoms. This asymptomatic phase often lasts for years.
The progression of disease varies widely among individuals. This state may last from a few months to more than 10 years.
During this period, the virus continues to multiply actively and infects and kills the cells of the immune system.
The virus destroys the cells that are the primary infection fighters, called CD4 cells.
Even though the person has no symptoms, he or she is contagious and can pass HIV to others through the routes listed above.
AIDS is the later stage of HIV infection, when the body begins losing its ability to fight infections. Once the CD4 cell count falls low enough, an infected person is said to have AIDS. Sometimes, the diagnosis of AIDS is made because the person has unusual infections or cancers that show how weak the immune system is:
The infections that happen with AIDS are called opportunistic infections because they take advantage of the opportunity to infect a weakened host. The infections include (but are not limited to)
pneumonia caused by Pneumocystis, which causes wheezing,
brain infection with toxoplasmosis which can cause trouble thinking or symptoms that mimic a stroke,
widespread infection with a bacteria called MAC (mycobacterium avium complex) which can cause fever and weight loss,
yeast infection of the swallowing tube (esophagus) which causes pain with swallowing, and
widespread diseases with certain fungi like histoplasmosis, which can cause fever, cough, anemia, and other problems.
A weakened immune system can also lead to other unusual conditions:
lymphoma in the brain, which can cause fever and trouble thinking; or
a cancer of the tissues called Kaposi's sarcoma, which causes brown, reddish, or purple spots that develop on the skin or in the mouth.
These are some of the symptoms of HIV/AIDS
Many people with HIV do not know they are infected.
Many people do not develop symptoms after they first get infected with HIV. Others have a flu-like illness within several days to weeks after exposure to the virus. They complain of fever, headache, tiredness, and enlarged lymph nodes in the neck. These symptoms usually disappear on their own within a few weeks. After that, the person feels normal and has no symptoms. This asymptomatic phase often lasts for years.
The progression of disease varies widely among individuals. This state may last from a few months to more than 10 years.
During this period, the virus continues to multiply actively and infects and kills the cells of the immune system.
The virus destroys the cells that are the primary infection fighters, called CD4 cells.
Even though the person has no symptoms, he or she is contagious and can pass HIV to others through the routes listed above.
AIDS is the later stage of HIV infection, when the body begins losing its ability to fight infections. Once the CD4 cell count falls low enough, an infected person is said to have AIDS. Sometimes, the diagnosis of AIDS is made because the person has unusual infections or cancers that show how weak the immune system is:
The infections that happen with AIDS are called opportunistic infections because they take advantage of the opportunity to infect a weakened host. The infections include (but are not limited to)
pneumonia caused by Pneumocystis, which causes wheezing,
brain infection with toxoplasmosis which can cause trouble thinking or symptoms that mimic a stroke,
widespread infection with a bacteria called MAC (mycobacterium avium complex) which can cause fever and weight loss,
yeast infection of the swallowing tube (esophagus) which causes pain with swallowing, and
widespread diseases with certain fungi like histoplasmosis, which can cause fever, cough, anemia, and other problems.
A weakened immune system can also lead to other unusual conditions:
lymphoma in the brain, which can cause fever and trouble thinking; or
a cancer of the tissues called Kaposi's sarcoma, which causes brown, reddish, or purple spots that develop on the skin or in the mouth.
These are some of the symptoms of HIV/AIDS
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