Tuesday, January 16, 2007

What is HIV?


HIV stands for human immuno deficiency virus. It is the virus that causes AIDS. A member of a group of viruses called retroviruses, HIV infects human cells and uses the energy and nutrients provided by those cells to grow and reproduce.

What is AIDS?

AIDS stands for acquired immunodeficiency syndrome. It is a disease in which the body's immune system breaks down and is unable to fight off infections, known as "opportunistic infections," and other illnesses that take advantage of a weakened immune system.
When a person is infected with HIV, the virus enters the body and lives and multiplies primarily in the white blood cells. These are immune cells that normally protect us from disease. The hallmark of HIV infection is the progressive loss of a specific type of immune cell called T-helper, or CD4, cells. As the virus grows, it damages or kills these and other cells, weakening the immune system and leaving the person vulnerable to various opportunistic infections and other illnesses ranging from pneumonia to cancer. A person can receive a clinical diagnosis of AIDS, as defined by the U.S. Centers for Disease Control and Prevention (CDC), if he or she has tested positive for HIV and meets one or both of theses conditions:
The presence of one or more AIDS-related infections or illnesses;
A CD4 count that has reached or fallen below 200 cells per cubic millimeter of blood. Also called the T-cell count, the CD4 count ranges from 450 to 1200 in healthy individuals.

What are the early Symptoms of HIV infection?

Many people do not develop any symptoms when they first become infected with HIV. Some people, however, get a flu-like illness within three to six weeks after exposure to the virus. This illness, called Acute HIV Syndrome, may include fever, headache, tiredness, nausea, diarrhoea and enlarged lymph nodes (organs of the immune system that can be felt in the neck, armpits and groin). These symptoms usually disappear within a week to a month and are often mistaken for another viral infection.

During this period, the quantity of the virus in the body will be high and it spreads to different parts, particularly the lymphoid tissue. At this stage, the infected person is more likely to pass on the infection to others. The viral quantity then drops as the body's immune system launches an orchestrated fight.

More persistent or severe symptoms may not surface for several years, even a decade or more, after HIV first enters the body in adults, or within two years in children born with the virus. This period of "asymptomatic" infection varies from individual to individual. Some people may begin to have symptoms as soon as a few months, while others may be symptom-free for more than 10 years. However, during the "asymptomatic" period, the virus will be actively multiplying, infecting, and killing cells of the immune system.

CURE/SOLUTION

Treatment
When HIV was first identified in the early 1980s, there were few drugs to treat the virus and the opportunistic infections associated with it. Since then, a number of medications have been developed to treat both HIV/AIDS and opportunistic infections. For many people, including children, these treatments have extended and improved the quality of life. Scientists at the National Institutes of Health estimate that since 1989, anti-retroviral medications have provided HIV-positive Americans with 3 million years of extended life. But none of these drugs can cure HIV/AIDS, many have side effects that can be severe, and most are expensive. What's more, after 20 years on AIDS drugs, some people — about 40,000 in the United States alone — develop resistance to the drugs and no longer respond to treatment. The new protease inhibitor darunavir is intended to help this group of people.
Treatment guidelines
A panel of leading AIDS specialists has developed recommendations for the use of anti-retroviral medications in people with HIV. These recommendations are based on the best information available at the time they were developed. AIDSinfo, a program of the U.S. Department of Health and Human Services, has a program in place to regularly refine and update the recommendations as knowledge about HIV infection evolves.
According to current guidelines, treatment should focus on achieving the maximum suppression of symptoms for as long as possible. This aggressive approach is known as highly active antiretroviral therapy (HAART). The aim of HAART is to reduce the amount of virus in your blood to very low, or even nondetectable, levels, although this doesn't mean the virus is gone. This is usually accomplished with a combination of three or more drugs.
But the treatment guidelines also emphasize the importance of quality of life. Thus the goal of AIDS treatment is to find the strongest possible regimen that is also simple and has the fewest side effects. If you have HIV/AIDS, it's important that you take an active role in every treatment decision. You and your doctor should discuss the risks and benefits of all therapies so that you can make an informed decision about what will likely be a complex and long-term treatment.
Antiretroviral drugs
Antiretroviral drugs inhibit the growth and replication of HIV at various stages of its life cycle. Six classes of these drugs are available:
 Nucleoside analogue reverse transcriptase inhibitors (NRTIs). NRTIs were the first antiretroviral drugs to be developed. They inhibit the replication of an HIV enzyme called reverse transcriptase. They include zidovudine (Retrovir), lamivudine (Epivir) didanosine (Videx), zalcitabine (Hivid), stavudine (Zerit) and abacavir (Ziagen). A newer drug, emtricitabine (Emtriva), which must be used in combination with at least two other AIDS medications, treats both HIV and hepatitis B.
The major side effect of zidovudine is bone marrow suppression, which causes a decrease in the number of red and white blood cells. Approximately 5 percent of people treated with abacavir experience hypersensitivity reactions such as a rash along with fever, fatigue, nausea, vomiting, diarrhea and abdominal pain. Hypersensitivity reactions can also occur without a rash. In either case, symptoms usually appear within the first six weeks of treatment and generally disappear when the drug is discontinued. If you've had a hypersensitivity reaction to abacavir, avoid taking the drug again. Side effects of emtricitabine include nausea, vomiting, abdominal pain, difficulty breathing and fatigue.
 Protease inhibitors (PIs). PIs interrupt HIV replication at a later stage in its life cycle by interfering with an enzyme known as HIV protease. This causes HIV particles in your body to become structurally disorganized and noninfectious. Among these drugs are saquinavir (Invirase), ritonavir (Norvir), indinavir (Crixivan), nelfinavir (Viracept), amprenavir (Agenerase), lopinavir, atazanavir (Reyataz) and tipranavir (Aptivus). Darunavir (Prezista), a protease inhibitor approved in 2006, is intended for people who haven't responded to treatment with other drugs. Darunavir is used in conjunction with ritonavir and other anti-HIV medications.
The most common side effects of protease inhibitors include nausea, diarrhea and other digestive tract problems. PIs can also cause a significant number of side effects when they interact with certain other medications you may be taking. That's because all PIs, to one degree or another, affect an enzyme system in your liver that is responsible for metabolizing a large number of drugs. Newer side effects have also appeared with the continuing and widespread use of protease inhibitors. These include elevated triglyceride levels and problems with sugar metabolism that may sometimes progress to diabetes.
There may also be abnormalities in the way fat is metabolized and deposited in your body. Some people lose much of their total body fat; others gain excess fat on the back between their shoulders (buffalo hump) or in the stomach (protease paunch). No one knows exactly why these abnormalities occur. In fact, it's not even certain whether these problems are a direct result of treatment with protease inhibitors or due to some other cause that has yet to be identified. Similar metabolic abnormalities have occurred in people on anti-retroviral therapy that doesn't include PIs. Although these body changes can be distressing, the possibility they may occur should not stop you from obtaining treatment for HIV/AIDS.
 Non-nucleoside reverse transcriptase inhibitors (NNRTIs). These drugs bind directly to the enzyme reverse transcriptase. Four NNRTIs are approved for clinical use: nevirapine (Viramune), delavirdine (Rescriptor), efavirenz (Sustiva) and etravirine (Intelence). A major side effect of all NNRTIs is a rash. In addition, people taking efavirenz may have side effects such as abnormal dreams, sleeplessness, dizziness and difficulty concentrating.
 Nucleotide reverse transcriptase inhibitors (NtRTIs). NtRTIs work much like nucleoside analogs: They interfere with the replication of reverse transcriptase and prevent the virus from inserting its genetic material into cells. But NtRTIs act more quickly than NRTIs do. The only approved drug in this class, tenofovir (Viread), inhibits both HIV and hepatitis B and appears to be effective in people who are resistant to NRTIs. The most common side effects of tenofovir, when used in combination with other antiretrovirals, are nausea, vomiting, diarrhea and gas. As with all reverse transcriptase inhibitors, the possibility of severe, and even fatal, liver damage exists.
 Fusion inhibitors. One of the most alarming developments in the AIDS epidemic is the emergence of drug-resistant strains of HIV. Worldwide, a majority of people receiving treatment for HIV are resistant to at least one drug, and many don't respond to a typical three-drug combination. But a drug called enfuvirtide (Fuzeon), the first in a new class of drugs called fusion inhibitors, appears to suppress resistant strains of HIV. Fusion inhibitors stop the virus from replicating by preventing its membrane from fusing with the membrane surrounding healthy cells. Fuzeon is used in combination with other HIV drugs for people who have advanced infection and who have developed resistance to other drugs. Doctors administer Fuzeon by injection.
 Integrase inhibitors. The FDA approved the first drug in this new class of drugs — aimed at treating those who become resistant to other treatments — in October 2007. The drug is raltegravir (Isentress) and is intended to be used in combination with other antiretroviral drugs rather than alone. This is the first class of drugs that blocks replication of the HIV integrase enzyme, which keeps HIV DNA from inserting itself into human DNA. Common side effects include diarrhea, nausea, headache and fever.
CCR5 antagonists
CCR5 antagonists is a new class of drugs used to treat a particular type of HIV infection called CCR5-tropic HIV-1. The first drug in this class — maraviroc (Selzentry) — was approved by the FDA in August 2007 for treatment of CCR5-tropic HIV-1 in adults. Maraviroc is the first drug that targets a human protein rather than components of the HIV virus itself.
Maraviroc is used in combination with other antiretroviral drugs for the treatment of adults with CCR5-tropic HIV-1 who have elevated levels of HIV (high viral load) in their blood despite treatment with other HIV medications. Maraviroc reduces viral load by preventing HIV from entering uninfected white blood cells. It does this by blocking CCR5, a major route of entry into the cells. CCR5 is a protein found on the surface of some immune cells, and maraviroc blocks the CCR5 co-receptor from accepting HIV.
During two large clinical trials, approximately twice as many people with CCR5-tropic HIV-1 infection who received maraviroc had undetectable viral loads after 24 weeks as did those who received more standard therapy in the control groups.
Side effects of maraviroc may include liver and cardiovascular problems, as well as cough, fever, upper respiratory tract infections, rash and abdominal pain.
Treatment response
Your response to any treatment is measured by viral load. Viral load should be tested at the start of treatment and then every three to four months while you're on therapy. In some cases you may be tested even more often.
New treatments
Many new drugs for HIV- or AIDS-related infections are in development or being tested in clinical trials. Among them is a drug that attacks the virus in the last stage of its life cycle. Although these medications are not yet licensed, some may be available by compassionate exception to people who need them.
Experts predict that an AIDS vaccine probably won't be found soon. More promising is the search for a microbicide to protect women from HIV infection during sex. Although microbicides may never be as effective as condoms, which offer nearly 100 percent protection when used properly, a microbicide could still save millions of lives.
For more information on new therapies, call AIDSinfo at 800-TRIALS-A, or 800-874-2572.

WATCH NEXT FOR MORE UBDATE ON THE HIV/AIDS DISEASE, AND DONT FOR GET TO CLICK ON THE GOOGLE ADS ON THE OTHER SIDE OF THIS PAGE FOR EXTRA INFO.