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Acquired immunodeficiency syndrome, HIV, Human immunodeficiency virus
HIV has two major categories: HIV-1 and HIV-2. HIV-1, which currently has about 10 subtypes, is most common worldwide and the only form found in the US. HIV-2 is less virulent and though currently confined to West Africa—it's spreading.
The Human Immunodeficiency Virus (HIV) basically provokes an infection, which destroys the body's immune system. And AIDS or Acquired Immune Deficiency Syndrome is the advanced stage of this disease, when the immune system becomes irreparably damaged, engendering multiple infections and cancers. A person is considered HIV positive when s/he tests positive for any of the 26 diseases (Kaposi's sarcoma, lymphoma, pulmonary tuberculosis, recurrent pneumonia within a 12-month period, wasting syndrome and other indicators) that can easily invade the body during our immune system's nonfunctionality.
On invading the body, the virus specifically attacks T-cells. A core part of the human defence system, they mobilize other cells to seek and destroy contagious foreign elements besid es leading the immune system's fight against infections. T-cells are targeted because the AIDS virus parasitizes the CD4 molecules on their surface.
With a protective outer shell of proteins and glyco-proteins, the AIDS virus contains genetic information on the inside. Although substantially smaller than the host T-cells—the virus reproduces by sponging off the host's cellular resources! Our body fights back by producing up to two billion new T-cells to replace the infected ones, stabilizing the T-cell count temporarily. Yet from day one, the T-cells fight a losing battle.
The genetic information of the AIDS virus, which is encoded as RNA (ribonucleic acid), needs to be reverse transcripted—which the intruder accomplishes with the help of the host cell itself! The now legible DNA is thereafter randomly transferred into the nucleus. All this is accomplished barely a dozen hours following the infection. By this time, the aggressor begins to substantially weaken the host cell, which eventually dies, eroding the immune system and making the body vulnerable to diseases.
Although HIV targets T-cells and other cells in the body, it thrives mainly in the lymph nodes—another important part of the immune system. Each lymph node has a netlike structure inside it that acts as a protective filter by trapping virus and infected T-cells. But as healthy T-cells move through contaminated lymph nodes, they are infected by HIV. Particularly during the early stage of the disease, lymph nodes contain more infected cells than the blood.
Symptoms
In the early stages, a mild flu and swollen glands are typical. But the symptoms are often unmistakeable when full-blown AIDS develops. Loss of appetite, weight loss, constant fever, prolonged fatigue, diarrhea, constipation, changing bowel patterns, swollen glands, chills coupled with excessive sweating, especially at nights, lesions in the mouth, sore throat, persistent cough, shortness of breath, tumours, skin rashes, headaches, memory lapses, swelling in the joints, pain in various parts of the body, vision problems and a regular feeling of lethargy and ill health make up the litany of symptoms.
With immune systems out of kilter, HIV-positive persons are susceptible to several types of cancer, particularly Kaposi's sarcoma (KS), an uncommon form that occurs under the skin and in the mucus membranes of the eyes, nose and mouth. Affected persons have lesions that appear as dark-coloured raised blotches. Though the lesions are painless, once KS spreads to the lungs, lymph nodes and digestive tract, the victim experiences difficulty in breathing, gastrointestinal bleeding and painful swelling around the lymph nodes, especially in the legs.
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