THE Acquired immunodeficiency syndrome (Aids) is caused by the Human Immunodeficiency Virus (HIV), which was recognized in mid-1981. O virus cause of the syndrome is broadcast sexually, through contact with contaminated blood and can also be transmitted from mother to child during pregnancy, childbirth or during the breast-feeding.
HIV affects the individual's immune system, weakening it and leaving the person more vulnerable to the development of opportunistic diseases. In the 1980s, when it was discovered, AIDS was considered an acute disease that quickly led to the individual's death. Today, antiretroviral therapy, which is distributed free of charge in Brazil, provides a better quality of life for people infected with HIV, ensuring a practically normal life.
According to the HIV/AIDS Epidemiological Bulletin 2019, from 1980 to June 2019, they were identified 966,058 AIDS cases in Brazil. Also according to the bulletin, the country has registered, annually, an average of 39 thousand new AIDS cases in the last five years, but the annual number of cases has been decreasing since 2013.
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What is AIDS?
AIDS is a syndrome characterized by weakening of the immune system as a consequence of HIV infection. Discovered in the 1980s, AIDS was considered a death sentence, since it was not known how the syndrome developed and there was no treatments suitable.
HIV infection alone is not enough to say that a person has AIDS. We say that a person has the syndrome when their immune system is severely weakened, not being able to adequately fight off disease-causing agents. At this point, the person is extremely fragile and opportunistic diseases begin to emerge.
HIV is the virus that causes AIDS. An HIV positive person does not necessarily have AIDS, as this is an advanced stage of the infection.
How does HIV act in the body?
As we know, AIDS is caused by a virus called HIV. This virus, belonging to the family Retroviridae, gender lentivirs, affects the cells of the immune system, in CD4+ T lymphocytes. The virus, however, can also target other cells, such as macrophages and monocytes.
HIV, little by little, destroys the body's defense cells, making it incapable of resisting other infections, which leads to the development of AIDS. According to UNAIDS, when the number of CD4 cells falls below 200 cells per cubic millimeter of blood (200 cells/mm3), it is considered that one has progressed from HIV to AIDS. In a normal individual, the CD4 cell count is between 500 and 1600 cells/mm3.
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Stages of HIV infection
HIV infection follows a series of stages until the development of AIDS. In some cases, the time between infection and development of the disease can be up to 10 years, however, in some people, this time can be reduced.
acute infection
Acute infection comprises the first few weeks of HIV infection. At this stage, a large amount of virus is produced and, consequently, there is a reduction of CD4 cells in the patient's body. At this stage, the person may have clinical manifestations, which are known as Acute Retroviral Syndrome (MRS).
Some of the manifestations noticed at this stage are high fever, sweating, enlarged lymph nodes, nausea, vomiting and weight loss. These symptoms disappear in approximately four weeks and are often confused with other viral illnesses. At the end of this phase, there is an increase in CD4 cells, but these will never have the same amount as before the infection.
latency phase
In the latency phase, the person has no visible clinical manifestations, with the exception of enlarged lymph nodes, which may persist. Anemia and leukopenia (low number of lymphocytes) may be present on laboratory tests. At this stage, HIV levels are low. The latency phase can remain for years.
Symptomatic phase
As the infection progresses, some symptoms develop. In the symptomatic phase, we can observe symptoms such as low-grade fever, night sweats, chronic diarrhea, bacterial infections and oral candidiasis.
Acquired immunodeficiency syndrome
AIDS sets in when the individual starts to present opportunistic infections and neoplasms, and the immune system is seriously compromised. These are opportunistic infections that deserve to be highlighted. tuberculosis and meningitis. With regard to neoplasms, we can mention the Kaposi's sarcoma, which is characterized by the formation of lesions on the skin and mucous membranes, and the non-Hodgkin's lymphoma, which is a type of cancer that affects cells in the lymphatic system.
HIV transmission
HIV can be transmitted in the following ways:
- sexual intercourse, without using a condom, with an infected person;
- Contact with blood from an infected person (This contact can occur, for example, when sharing sharp objects with infected people and through blood transfusion using contaminated blood. It is noteworthy that the rules for blood donation adopted nowadays and the tests available to test the blood received make cases of infection by transfusion rare.);
- From mother to child, it can occur during pregnancy, at the time of childbirth or even during breastfeeding.
It is noteworthy that HIV is not transmitted through kissing, sweating, tears, towels, sheets, soap, swimming pool, handshakes or hugs. Therefore, close contact with an HIV-positive person or with AIDS is not responsible for the transmission of the virus.
HIV/AIDS Diagnosis
The diagnosis of HIV infection is made through laboratory tests using blood or oral fluid from the patient. The tests aim at detecting antibodies against the virus or even at identifying the virus and its particles. Routinely, the most used techniques are based on the detection of antibodies against the virus.
It is noteworthy that, sometimes, the exam may show negative result, even in infected patients, due to the call immune window. We call immunological window the interval between the infection and the moment when it is possible to identify the antibodies against the disease. When we talk about HIV infection, this window can vary up to 30 days. This means that if the person has unprotected sex with an HIV positive person today and is tested for check the disease after 15 days, the result may be negative, due to the inability to identify the antibodies in this time course.
HIV/AIDS treatment
The treatment of HIV/AIDS does not guarantee the cure of the infection and is based on the use of drugs that inhibit virus replications. The use of these medications is important to control the infection and also to delay the progression to AIDS.
The first antiretroviral drugs appeared in the 1980s, the same decade in which AIDS became known. The emergence of these drugs was essential to ensure a better quality of life for HIV-positive people, controlling the disease and preventing the rapid weakening of the immune system.
According to the Department of Chronic Diseases and Sexually Transmitted Infections, since 2013, the SUS guarantees treatment for all people living with HIV (PLHIV), regardless of viral load. Also according to the department, currently there are 21 drugs, in 37 pharmaceutical presentations.
People cured of HIV infection
Currently, it is considered that two people have been cured of HIV infection. The first case, reported in 2007, is from Timothy Ray Brown, which became known as the Berlin patient. He was cured of HIV after having a bone marrow transplant. His donor had a gene that reduced the chances of contracting HIV.
The second case is from a patient who became known as London patient. This patient is still treated as a long-term remission, due to the fact that its treatment was carried out in 2016, being a relatively recent case. The patient no longer had HIV after undergoing a stem cell transplant.
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HIV/AIDS prevention
To prevent HIV infection, some measures should be taken, such as:
Condom use in all sexual relations;
Reduction in the number of sexual partners;
Use of disposable syringes and needles;
Blood testing before transfusions;
Pregnant women must have prenatal care to avoid vertical transmission (from mother to baby);
Health professionals must always be aware of biosafety regulations.
By Vanessa Sardinha dos Santos
Biology teacher
