What are AIDS and HIV?

AIDS is an English acronym which stands for Autoimmune Deficiency Syndrome. It is an autoimmune disorder characterized by opportunistic infections (infections that occur when the immune system is weakened), neurological changes and a wide range of other pathological disorders.

HIV is the name of the virus responsible for AIDS. HIV is an English acronym that stands for Human Immunodeficiency Virus. Infection by HIV, in its later stages, becomes AIDS.

The term HIV designates two different viruses that are closely related one to each other: HIV-1 and HIV-2. Both HIV-1 and HIV-2 are retroviruses and both cause AIDS.

HIV-1 is the retrovirus that has had the greater medical and social impact. It was identified in 1984 and is responsible for the AIDS epidemic.

How is HIV transmitted?

The transmission of HIV calls for contact with plasma or bodily fluids that contain HIV infected cells. HIV can be present in any liquid or secretion that contains plasma or lymphocytes to include blood, semen, vaginal secretions, milk, saliva or secretions from injuries. However, infections through contact with saliva or mucous from sneezing or coughing is extremely rare. The most common forms of infection are by sharing contaminated needles and through sexual intercourse. Sexual relationships that do no involve any exposure to bodily fluids are considered to be safe.

HIV can be transmitted by a transfusion with HIV-infected blood, an accidental stick with a contaminated needle or exposure to mucous membranes (for example, in sexual intercourse). A person suffering from other diseases such as syphilis, trychomoniasis, herpes and other sexually transmitted diseases will be more prone to being infected with HIV than a healthy person.

HIV blood tests for blood to be used in transfusions clearly reduces the risk of infection although it is possible for the blood of somebody who has been recently infected with HIV to show a false negative result and thus transmit the disease. This lapse in which laboratory tests are negative yet the blood is already infected is known as a “window period”.

An HIV carrier is the person who has the virus in his body but does not present any symptoms of the disease. If symptoms are present, we say that this person suffers from AIDS or is an AIDS patient.

What does the disease transmitted by HIV consist of?

HIV, like all viruses, possesses an enzyme called reverse transcriptase, which turns viral RNA into a copy of proviral DNA. The proviral DNA integrates into the DNA of the host cell of the infected person. When the infected cell divides, these proviruses are duplicated by the normal genes of the cell and transmitted to every cell arising from the originally infected cell. The proviral DNA is transcribed into RNA which produces thousands of copies of the virus.

The cells infected by HIV are T4 lymphocytes and other non-lymphoid cells. Lymphocytes are a special type of white cells. The role of white cells is to destroy germs that typically come in contact with the body. As a result of HIV infection, the quantity of T4 lymphocytes circulating in the body is greatly reduced. Therefore, with the onset of AIDS, it becomes easier for the infected person to acquire infections.

Epidemiology of HIV infection

HIV-1 is the virus responsible for most AIDS cases in America, Europe, Asia and Central, Southern and Eastern Africa. HIV-2 is the main agent causing AIDS in Western Africa. The disease was identified for the first time in 1981 in California. By the end of 1999 there were some 34,300,000 persons in the world who were infected with HIV or suffering from AIDS, according to data from the World Health Organization.

95 % of HIV carriers live in developing countries.

Symptoms and signs of the disease.

HIV produces a wide range of symptoms which are similar to those for other diseases. After a month from the initial infection, some patients show the so-called acute retroviral syndrome or primary HIV infection which includes a temperature, general discomfort, skin rashes, pain in the joints and generalized lymphadenopathy (appearance of ganglia or lymph nodes in different parts of the body). The first stage of infection lasts from 3 to 14 days. During this period the patient is not yet a positive carrier, that is, blood tests will not detect an HIV infection. Within 3 days after the primary infection, HIV becomes detectable in the blood. This patient’s condition is often confused with a respiratory disease or else with mononucleosis. Some patients continue to present lymphadenopathy and, sometimes other non-specific symptoms such as fatigue, diarrhea and fever that do not lead to an HIV diagnosis.

Symptoms that are typical of AIDS can vary a lot:

  1. Neurological: are common and can be the first symptoms to appear. This can be due to the HIV virus itself or else due to opportunistic infections, tumors or vascular complications. These include meningitis, disorders of the peripheral nerves and of the brain, seizures, motor and sensory disorders. There may also be intellectual disorders leading to dementia.
  2. Hematological: certain patients show anemia and thrombocytopenia, which is a reduction in the numbers of platelets (needed for the normal clotting process) in the blood.
  3. Digestive symptoms: abdominal pain, nausea and vomiting, diarrhea, opportunistic infections and tumors. There may be fungal infections in the mouth and throat, a tumor known as Kaposi sarcoma, lymphoma, herpes and mouth ulcers. Vomiting and diarrhea contribute to weight-loss in AIDS patients. Kaposi sarcoma is a viral tumor (a virus different from HIV) that can settle in the skin, lymph nodes and internal organs. Kaposi sarcoma is a rare disease in people who do no suffer from HIV infection but is found very frequently in HIV infected persons.
  4. Dermatological symptoms: in all stages of the disease skin problems may occur. In the primary infection, skin rashes and genital ulcers are common. In more advanced stages, herpes zoster and Kaposi sarcoma might occur as well.
  5. Oral symptoms: in addition to those symptoms already mentioned, gum disease may also occur, with bleeding, tumefaction and tooth loss.
  6. Lung symptoms: the most frequent lung infection in AIDS patients is tuberculosis. Some opportunistic infections may also occur such as Kaposi sarcoma and lymphoma.
  7. Symptoms in women: vaginal fungal infections that are difficult to treat as well as an increased risk of cervical tumors.
  8. Encocarditis and myocardiopathy may occur (diseases of the cardiac muscle), together with congestive kidney failure.
  9. Kidneys: although rare, kidney failure might occur.

Laboratory diagnosis

  1. Tests: The ELISA test for HIV. If the initial test is negative, it should be repeated three months later in case the patient is in the “window period” discussed above.
  2. T4 leukocyte count: If it is low it can help show the immune system is being suppressed by the HIV virus.
  3. Leukocyte count and formula: May reveal abnormalities although these cannot positively establish the presence of an HIV infection by themselves.


There are treatments for the HIV infection under the care of a physician.

The physician will also need to treat the complications and opportunistic infections of the disease unique each case.