Tuesday, December 28, 2010

Aids - Symptoms, Causes,Treatment, Prevention & More

Aids:- Aids is acronym of Acquired immune deficiency syndrome

Aids was identified in the early 1980s, an unprecedented number of people have been affected by the global AIDS epidemic. Today, there are an estimated 33.3 million people living with HIV and AIDS worldwide.

What is AIDS?
• Aids is a disease of the human immune system caused by the human immunodeficiency virus (HIV).

• AIDS is a medical condition. A person is diagnosed with AIDS when their immune system is too weak to fight off infections.

What are causes of AIDS?
AIDS is caused by HIV. AIDS is the ultimate clinical consequence of infection with HIV. HIV is a retrovirus that primarily infects vital organs of the human immune system such as CD4+ T cells, macrophages and dendritic cells. HIV is a virus that slowly attacks immune system cells. As HIV progressively damages these cells, the body becomes more vulnerable to infections, which it will have difficulty in fighting off. It is at the point of very advanced HIV infection that a person is said to have AIDS. It can be years before HIV has damaged the immune system enough for AIDS to develop.

Symptoms of AIDS
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.

A person is diagnosed with AIDS when they have developed an AIDS related condition or symptom, called an opportunistic infection, or an AIDS related cancer. The infections are called ‘opportunistic’ because they take advantage of the opportunity offered by a weakened immune system. Opportunistic infections are common in people with AIDS.These infections affect nearly every organ system.

It is possible for someone to be diagnosed with AIDS even if they have not developed an opportunistic infection. AIDS can be diagnosed when the number of immune system cells (CD4 cells) in the blood of an HIV positive person drops below a certain level.

Centers for Disease Control and Prevention (CDC)
United States federal agency is a Centers for Disease Control and Prevention (or CDC) under the Department of Health and Human Services based in Atlanta. It works to protect public health and safety by providing information to enhance health decisions, and it promotes health through partnerships with state health departments and other organizations. The CDC focuses national attention on developing and applying disease prevention and control (especially infectious diseases), environmental health, occupational safety and health, health promotion, injury prevention and education activities designed to improve the health of the people of the United States.

HIV test
The different types of HIV test:-

1. HIV antibody test
HIV antibody tests are the most appropriate test for routine diagnosis of HIV among adults. Antibody tests are inexpensive and very accurate. The ELISA antibody test (enzyme-linked immunoabsorbent) also known as EIA (enzyme immunoassay) was the first HIV test to be widely used.
How do antibody tests work?

When a person is infected with HIV, their body responds by producing special proteins that fight infection, called antibodies. An HIV antibody test looks for these antibodies in blood, saliva or urine. If antibodies to HIV are detected, it means a person has been infected with HIV. There are only two exceptions to this rule:

• Babies born to HIV infected mothers retain their mother's antibodies for up to 18 months, which means they may test positive on an HIV antibody test, even if they are actually HIV negative. Normally babies who are born to HIV positive mothers receive a PCR test (see below) after birth.

• Some people who have taken part in HIV vaccine trials may have HIV antibodies even if they are not infected with the virus.

2. Window period
The window period (the time between initial infection and the development of detectable antibodies against the infection) can vary since it can take 3–6 months to seroconvert and to test positive. Detection of the virus using polymerase chain reaction (PCR) during the window period is possible, and evidence suggests that an infection may often be detected earlier than when using a fourth generation EIA screening test.

3. Rapid HIV tests
Rapid HIV tests are tested by the same technology as ELISA tests, but instead of sending the sample to a laboratory to be analysed, the rapid test can produce results within 20 minutes. Rapid tests can use either a blood sample or oral fluids. It is easy to use and do not require laboratory facilities.

All positive results from a rapid test must be followed up with a confirmatory test, the results of which can take from a few days to a few weeks.

4. PCR test
Polymerase Chain Reaction test can detect the genetic material of HIV rather than the antibodies to the virus, and so can identify HIV in the blood within two or three weeks of infection. The test is also known as a viral load test and HIV NAAT (nucleic acid amplification testing).

Babies born to HIV positive mothers are usually tested using a PCR test because they retain their mother's antibodies for several months, making an antibody test inaccurate. Blood supplies in most developed countries are screened for HIV using PCR tests. However, they are not often used to test for HIV in individuals, as they are very expensive and more complicated to administer and interpret than a standard antibody test.

5. Antigen test (P24 test)
Antigens are the substances found on a foreign body or germ that trigger the production of antibodies in the body. The antigen on HIV that most commonly provokes an antibody response is the protein P24. Early in HIV infection, P24 is produced in excess and can be detected in the blood serum (although as HIV becomes fully established in the body it will fade to undetectable levels).

6. Fourth generation tests
During June 2010, the FDA approved the first fourth generation test in the United StatesIn the UK, fourth generation tests are the primary recommendation for HIV testing among individuals, but are not offered by all testing sites
Some of the most modern HIV tests combine P24 antigen tests with standard antibody tests to reduce the ‘diagnostic window’. Testing for antibodies and P24 antigen simultaneously has the advantage of enabling earlier and more accurate HIV detection.

6.HIV home sampling and HIV home testing

Home sampling
With a home sampling kit, a person can take a sample (usually a blood sample) and send it to a laboratory for testing. They can phone up for the results a few days later. If the result is positive then a professional counsellor will provide emotional support and referrals. The main advantages of home sampling are convenience, speed, privacy and anonymity.

There is one company in the USA that offers an FDA-approved home sampling kit for HIV.3 Many home sampling kits that have not been approved by the FDA are being marketed online.

There is also a company in the UK that offers home sampling services using oral fluid instead of blood.5 If a person’s test result is positive they will need a follow up blood-test at a clinic.

Home testing
A home self-test involves a person conducting a rapid antibody HIV test in their home. The person takes either a blood or saliva sample and can interpret the result within minutes. A positive result will require a further confirmatory blood-test in a clinic.

In many countries it is illegal to sell HIV test kits to the public. If a test is purchased over the internet, there is no guarantee that the test kit is genuine or will provide accurate results.

WHO - staging system of HIV
In 1990, the World Health Organization (WHO) grouped these infections and conditions together by introducing a staging system for patients infected with

HIV-1Stage I: HIV infection is asymptomatic and not categorized as AIDS.

• Stage II: includes minor mucocutaneous manifestations and recurrent upper respiratory tract infections

• Stage III: includes unexplained chronic diarrhea for longer than a month, severe bacterial infections and pulmonary tuberculosis.

• Stage IV: includes toxoplasmosis of the brain, candidiasis of the esophagus, trachea, bronchi or lungs and Kaposi's sarcoma; these diseases are indicators of AIDS.

The three main transmission routes of HIV are sexual contact, exposure to infected body fluids or tissues, and from mother to fetus or child during perinatal period.

1.Sexual contact
The majority of HIV infections are acquired through unprotected sexual relations between partners, one of whom has HIV. During a sexual act, only male or female condoms can reduce the risk of infection with HIV and other STDs.

2.Body fluid exposure
Frequent and thorough washing of the skin immediately after being contaminated with blood or other bodily fluids can reduce the chance of infection. Finally, sharp objects like needles, scalpels and glass, are carefully disposed of to prevent needlestick injuries with contaminated items.

3 Mother-to-child
HIV-infected mothers should avoid breast-feeding their infant. However, if this is not the case, exclusive breast-feeding is recommended during the first months of life and discontinued as soon as possible.

4 Education
One way to change risky behavior is health education. Several studies have shown the positive impact of education and health literacy on cautious sex behavior. Education works only if it leads to higher health literacy and general cognitive ability. This ability is relevant to understand the relationship between own risky behavior and possible outcomes like HIV-transmission .More research on the actual implementation of sex-education programmes (such as teacher training, access to related services through schools and the community, or parental attitudes to HIV and AIDS education) and more longitudinal studies on the deeper complexities of the relationship between education and HIV.

Infection rates are rising, indicating that HIV prevention is just as important now as it ever has been. Prevention efforts that have proved to be effective need to be scaled-up and treatment targets reached.

How is AIDS treated?
Antiretroviral treatment can prolong the time between HIV infection and the onset of AIDS. Modern combination therapy is highly effective and someone with HIV who is taking treatment could live for the rest of their life without developing AIDS.

An AIDS diagnosis does not necessarily equate to a death sentence. Many people can still benefit from starting antiretroviral therapy even once they have developed an AIDS defining illness. Better treatment and prevention for opportunistic infections have also helped to improve the quality and length of life for those diagnosed with AIDS.

Cure for AIDS
Prevention is better than cure.Many people think there is a 'cure' for AIDS - which makes them feel safer, and perhaps take risks that they otherwise wouldn't. However, there is still no cure for AIDS. The only way to stay safe is to be aware of how HIV is transmitted and how to prevent HIV infection.

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