Le HIV, or the human immunodeficiency virus, is a type of virus that can cause a disease called SIDA boat (acquired immune deficiency syndrome). HIV infection affects the immune system, which is the body’s natural defenses against disease. If left untreated, serious illnesses can develop. Normally harmless infections, such as the flu or bronchitis, can get worse, become very difficult to treat, or even lead to death. In addition, the risk of cancer is also increased.

What distinguishes HIV from other viruses is that it affects immune system by taking control of CD4 T cells. The latter’s role is to coordinate the immune response when a virus presents itself. When HIV uses CD4 cells to spread, it damages and destroys them. In doing so, HIV undermines the immune system from within, which has the role of fighting it (see diagram).

Transmission

HIV is transmitted through body fluids: blood, sperm, the vaginal secretions and breastmilk. These bodily fluids only transmit HIV if they come into contact with an area that allows it to enter the body, a mucous membrane. Healthy skin is impermeable to HIV.

Most often, the virus is acquired duringsexual activities unprotected or was in the past by exchanging syringes among people who inject drugs. The risk of transmission through kissing with exchange of saliva is zero.

In most industrialized countries, anal sex between men is the most important route of HIV transmission. However, heterosexual transmission has greatly increased since the start of the epidemic.

The epidemic

• In North America, the first signs ofepidemic emerged in the late 1970s. Men who have sex with men (MSM) were the first to be affected;
• The virus HIV was isolated in 1983;
• Le premier antiretroviral therapy, AZT, was discovered in 1987. The triple therapy, combining several drugs that is much more effective, became available in the mid-1990s, then increasingly powerful antiretroviral therapy (ART) suggests that a young HIV-positive adult starting treatment quickly could live to age 80 or more. These treatments often lead to an undetectable viral load, even though the virus is still not eradicated from the body.
• About 35 million people people around the world today are living with HIV. Two thirds of them reside in Africa Saharan¹.

• In North America, 1,3 million people are living with HIV, in Western and Central Europe, 840, and in Sub-Saharan Africa 000 million³⁵.
• In France, 150 people are living with HIV, so 00 are not monitored and therefore not treated.
• The number of people living with HIV is increasing worldwide, with 2,5 million new infections per year and 1,5 million deaths. This is due to the considerable improvement in the effectiveness of the treatments.

• About 7000 discoveries of seropositivity in France (2012 figures) of which almost half among MSM (men who have sex with men), and 3000 deaths from AIDS in the year.
• In Canada, 71 people were living with HIV in 300³⁶. The number of new infections is estimated at 3175 in 2011. However, this underestimates the actual number of cases, as an estimated 25% of Canadians infected with HIV are unaware they are infected.

Evolution of infection to AIDS

• 1^re phase – the first-infection. In the weeks following infection, about a third of those affected have symptoms similar to those of the flu or mononucleosis: fever, headache, sore throat, rash on the skin, fatigue, muscle pain, etc. . These symptoms go away on their own, even without treatment.

• 2^e phase – asymptomatic infection. The virus can live in the body for many years without causing symptoms. As a result, the person may not feel that they are sick, but they are susceptible to transmitting HIV. The seroconversion – the moment when a person who is HIV negative (no antibodies in the blood) becomes HIV positive (presence of antibodies in the blood) – occurs during this phase, 1 to 3 months after infection.
• 3^e phase AIDS phase (acquired immunodeficiency syndrome) or to symptomatic infections. If still untreated, the person experiences one or more symptoms of HIV infection (fatigue, diarrhea, swollen glands, weight loss, night sweats, fever, etc.).
• 4^e phase –  If the number of immune cells (CD4 T lymphocytes) becomes is very low and the body can no longer fight against other infections or diseases, the diagnosis of AIDS is made. Symptoms of infection become more noticeable and consistent. In addition, opportunistic infections can cause serious health problems. Opportunistic infections are infections that are usually not serious, but which become serious in people with very weak immune defenses. Among the opportunistic diseases, we find for example candidiasis, pneumonia, tuberculosis, herpes infections, and also cancers (in particular lymphomas and Kaposi’s sarcoma).

Remark. Research has shown that cardiovascular disease is more common in people with HIV because their bodies are subject to a higher degree of inflammation. It is known that inflammation participates in the formation of plaques in the lining of the arteries, which can interfere with the flow of blood. In addition, cases of cognitive degeneration (eg Alzheimer’s disease) related to HIV infection have also been reported.