Acquired immunodeficiency syndrome (AIDS) is a chronic, potentially life-threatening condition caused by the human immunodeficiency virus (HIV). By damaging your immune system, HIV interferes with your body’s ability to fight the organisms that cause disease.
HIV is a sexually transmitted infection. It can also be spread by contact with infected blood or from mother to child during pregnancy, childbirth or breast-feeding. Without medication, it may take years before HIV weakens your immune system to the point that you have AIDS.
There’s no cure for HIV/AIDS, but there are medications that can dramatically slow the progression of the disease. These drugs have reduced AIDS deaths in many developed nations. But HIV continues to decimate populations in Africa, Haiti and parts of Asia.
HIV is a virus. When someone becomes infected with HIV the virus weakens and damages their body’s defence system (the immune system) so that it cannot fight off infections.
Someone who has HIV is diagnosed as having AIDS only when their immune system cannot cope and they develop one or more particular illnesses.
Most people with HIV, who are taking treatment, will not go on to develop AIDS. The term AIDS is not used very often now. Late stage or advanced HIV infection is used instead.
HIV produces cellular immune deficiency characterized by the depletion of helper T lymphocytes (CD4+ cells). The loss of CD4+ cells results in the development of opportunistic infections and neoplastic processes.
Virology Of Hiv
HIV-1 and HIV-2 are retroviruses in the Retroviridae family, LENTIVIRUS genus. They are enveloped, diploid, single-stranded, positive-sense RNA viruses with a DNA intermediate, which is an integrated viral genome (a provirus) that persists within the host-cell DNA.
HIV contains 3 species-defining retroviral genes: GAG, POL, and ENV. The GAG gene encodes group-specific antigen; the inner structural proteins. The POL gene encodes polymerase; it also contains integrase and protease (the viral enzymes) and is produced as a C-terminal extension of the Gag protein). The ENV gene encodes the viral envelope—the outer structural proteins responsible for cell-type specificity. Glycoprotein 120, the viral-envelope protein, binds to the host CD4+ molecule.
HIV-1 has 6 additional accessory genes: TAT, REV, NEF, VIF, VPU, and VPR. HIV-2 does not have VPU but instead has the unique gene VPX. The only other virus known to contain the VPU gene is simian immunodeficiency virus in chimpanzees (SIVcpz), which is the simian equivalent of HIV. Interestingly, chimpanzees with active HIV-1 infection are resistant to disease.
The accessory proteins of HIV-1 and HIV-2 are involved in viral replication and may play a role in the disease process. The outer part of the genome consists of long terminal repeats (LTRs) that contain sequences necessary for gene transcription and splicing, viral packaging of genomic RNA, and dimerization sequences to ensure that 2 RNA genomes are packaged.
The symptoms of HIV and AIDS vary, depending on the phase of infection.
Primary Infection (Acute Hiv)
The majority of people infected by HIV develop a flu-like illness within a month or two after the virus enters the body. This illness, known as primary or acute HIV infection, may last for a few weeks. Possible signs and symptoms include:
- Muscle aches and joint pain
- Sore throat
- Swollen lymph glands, mainly on the neck
Although the symptoms of primary HIV infection may be mild enough to go unnoticed, the amount of virus in the bloodstream (viral load) is particularly high at this time. As a result, HIV infection spreads more efficiently during primary infection than during the next stage of infection.
Clinical Latent Infection (Chronic Hiv)
In some people, persistent swelling of lymph nodes occurs during clinical latent HIV. Otherwise, there are no specific signs and symptoms. HIV remains in the body, however, and in infected white blood cells.
Clinical latent infection generally lasts around 10 years if you’re not receiving antiretroviral therapy. This phase can last for decades in people taking antiretroviral medications. But some people progress to more severe disease much sooner.
Early Symptomatic Hiv Infection
As the virus continues to multiply and destroy immune cells, you may develop mild infections or chronic signs and symptoms such as:
- Swollen lymph nodes — often one of the first signs of HIV infection
- Weight loss
- Oral yeast infection (thrush)
- Shingles (herpes zoster)
Progression to aids
If you receive no treatment for your HIV infection, the disease typically progresses to AIDS in about 10 years. By the time AIDS develops, your immune system has been severely damaged, making you susceptible to opportunistic infections — diseases that wouldn’t usually trouble a person with a healthy immune system.
The signs and symptoms of some of these infections may include:
- Soaking night sweats
- Recurring fever
- Chronic diarrhea
- Persistent white spots or unusual lesions on your tongue or in your mouth
- Persistent, unexplained fatigue
- Weight loss
- Skin rashes or bumps
You can only be certain you are HIV positive if you have a test.
If you or a partner think you might have become HIV positive it is important that you don’t delay seeking advice and getting a test. Even if you don’t have symptoms an HIV test should be considered if:
- you have recently had unprotected sex (without a condom) with a new partner
- a sexual partner tells you they are HIV positive
- you have shared needles or injecting equipment or had a tattoo or piercing without a sterile needle
- you, or your partner, have had unprotected sex (without a condom) with other partners
- you, or your partner, have another sexually transmitted infection
- you are pregnant or planning a pregnancy.
There’s no cure for HIV/AIDS, but a variety of drugs can be used in combination to control the virus. Each class of anti-HIV drugs blocks the virus in different ways. It’s best to combine at least three drugs from two classes to avoid creating strains of HIV that are immune to single drugs.
The classes of anti-HIV drugs include:
- Non-nucleoside reverse transcriptase inhibitors (NNRTIs).NNRTIs disable a protein needed by HIV to make copies of itself. Examples include efavirenz (Sustiva), etravirine (Intelence) and nevirapine (Viramune).
- Nucleoside or nucleotide reverse transcriptase inhibitors (NRTIs). NRTIs are faulty versions of building blocks that HIV needs to make copies of itself. Examples include Abacavir (Ziagen), and the combination drugs emtricitabine-tenofovir (Truvada), and lamivudine-zidovudine (Combivir).
- Protease inhibitors (PIs). PIs disable protease, another protein that HIV needs to make copies of itself. Examples include atazanavir (Reyataz), darunavir (Prezista), fosamprenavir (Lexiva) and indinavir (Crixivan).
- Entry or fusion inhibitors. These drugs block HIV’s entry into CD4 cells. Examples include enfuvirtide (Fuzeon) and maraviroc (Selzentry).
- Integrase inhibitors. These drugs work by disabling integrase, a protein that HIV uses to insert its genetic material into CD4 cells. Examples include raltegravir (Isentress), elvitegravir (Vitekta) and dolutegravir (Tivicay).
When To Start Treatment
Everyone with HIV infection, regardless of CD4 count, should be offered antiviral medication.
HIV therapy is particularly important for the following situations:
- You have severe symptoms.
- You have an opportunistic infection.
- Your CD4 count is under 350.
- You’re pregnant.
- You have HIV-related kidney disease.
- You’re being treated for hepatitis B or C.
Treatment Can Be Difficult
HIV treatment regimens may involve taking multiple pills at specific times every day for the rest of your life. Side effects can include:
- Nausea, vomiting or diarrhea
- Heart disease
- Weakened bones or bone loss
- Breakdown of muscle tissue (rhabdomyolysis)
- Abnormal cholesterol levels
- Higher blood sugar levels
Other Diseases And Treatment
Some health issues that are a natural part of aging may be more difficult to manage if you have HIV. Some medications that are common for age-related cardiovascular, metabolic and bone conditions, for example, may not interact well with anti-HIV medications. Talk to your doctor about other conditions for which you’re taking medication.
Your doctor will monitor your viral load and CD4 counts to determine your response to treatment. Viral load should be tested at the start of treatment and then every three to four months during therapy. CD4 counts should be checked every three to six months.
HIV treatment should reduce your viral load to the point that it’s undetectable. That doesn’t mean your HIV is gone. It just means that the test isn’t sensitive enough to detect it. You can still transmit HIV to others when your viral load is undetectable.