AIDS and HIV

AIDS(Acquired Immune Deficiency Syndrome) results from infection with the Human Immunodeficiency Virus (HIV (news - web sites)). HIV infects and destroys lymphocytes, a type of white blood cell involved in the body's immune (infection-fighting) response to invading germs.

The HIV virus attacks specific lymphocytes called T helper cells (CD4 cells, also known as T-cells), taking over the machinery of these cells to make more copies of itself. This process begins to destroy the CD4 cells. Over time, the total number of CD4 cells in the body drops off, lowering the body's resistance to invading germs and disease.

When the population of CD4 cells falls to a very low level, people with HIV get infections (known as opportunistic infections) that a healthy immune system would otherwise successfully fight off. This weakened immune system (or immune deficiency) is known as AIDS, and results in severe life-threatening infections, some forms of cancer, and the deterioration of the nervous system. Although AIDS is always the result of an HIV infection, not everyone with HIV has AIDS. In fact, adults who get infected with HIV will appear healthy for years before they get sick with AIDS.

HIV/AIDS Statistics
The first case of AIDS was reported in 1981 but the disease may have existed unrecognized for many years before that. HIV infection leading to AIDS has been a major cause of illness and death among children, teens, and young adults worldwide. Nationally, AIDS has been the sixth leading cause of death in the United States among 15- to 24-year-olds since 1991. Worldwide, AIDS-related illnesses have caused more than 20 million deaths, and millions more are living with the disease.

In recent years, AIDS infection rates have been increasing rapidly among teens and young adults. Half of all new HIV infections in the United States occur in people under 25 years of age; thousands of teens in the United States become infected each year. According to the Centers for Disease Control (CDC), the majority of new HIV cases in younger people are transmitted through unprotected sex; one third of these cases are from injection drug usage - the sharing of dirty, blood-contaminated needles.

In 2000, the CDC reported that more than 90% of current cases of AIDS in children - and almost all new HIV infections reported in young children in the United States - resulted from transmission of the HIV virus from the mother to her child during pregnancy, birth, or through breastfeeding. Fortunately, current medicines given to HIV-positive pregnant women have reduced perinatal (mother-to-child) HIV transmission by more than 60% in the United States; these are discussed in detail in the "Treatment" section of this article.

Causes
HIV is transmitted through direct contact with the blood or body fluid of someone who is infected with the virus.

The three main ways the HIV virus is passed to a very young child are:

• while the baby develops in the mother's uterus (intrauterine)
• at the time of birth
• during breastfeeding

Among teens, the virus is most commonly spread through high-risk behaviors including:

• unprotected sexual intercourse (oral, vaginal, or anal sex)
• sharing needles used to inject drugs (including contaminated needles used for injecting steroids and tattooing and body art)

HIV can also be transmitted by direct contact with an open wound of an infected person (the virus may be introduced through a small cut or tear on the body of the healthy person), but this is very rare. Blood transfusions can also transmit the virus, but again, this is rare. Since 1985, the U.S. blood supply has been carefully screened for HIV.

Signs and Symptoms
Although there are no immediate physical signs of HIV infection at birth, children born with HIV can develop opportunistic infections (infections that take advantage of a person's weakened immune system), such as Pneumocystis carinii pneumonia (PCP), in the first months of life. They also can have much more severe bouts of other common childhood infections, such as Epstein-Barr virus (EBV), which causes mild illness in most kids but can cause fatal pneumonia in children with HIV/AIDS.

A baby born with an HIV infection most likely will appear healthy. But sometimes, within 2 to 3 months after birth, an infected baby may begin to appear sick, with poor weight gain, repeated fungal mouth infections such as thrush, enlarged lymph nodes, enlarged liver or spleen, neurological problems, and multiple bacterial infections, including pneumonia.

Teens and young adults who contract HIV usually show no symptoms at the time of infection. In fact, it may take up to 10 years or more for symptoms to show. During this time, they can pass on the virus without even knowing they have it themselves. Once the symptoms of AIDS appear, they can include rapid weight loss, intense fatigue, swollen lymph nodes, persistent diarrhea, night sweats, or pneumonia. They, too, will be susceptible to life-threatening opportunistic infections.

Diagnosis
If a woman knows she is HIV-infected and already has children, then it is recommended that all of her children be tested for HIV. Even if she has older children and they seem healthy, they could still have an HIV infection if she was already HIV-positive at the time they were born. A blood test is needed to know for sure.

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