How do you get HIV, how can you get AIDS
Immunodeficiency virus, which causes the AIDS, can be contracted in several ways:

Ø     Sexually. Homosexual transmission of the virus HIV is the most dangerous in terms of   infection. The heterosexual, traditional mode of transmission is far safe. The safest in terms of statistics of HIV transmission is oral sex.

Ø     Through the blood. How do you get HIV through the blood? The virus can be contracted through blood in several different cases. 
1. Example, through a blood transfusion. It is known that the blood taken from a donor is stored for six months in order to avoid "the serological window" or "HIV window period", i.e. the situation where no symptoms of HIV are present, although the virus is already present  in the blood. The tests, however, show that it is not present. If a virus-infected individual has a strong immunity, the "HIV window period" may last longer than 6 months, and dangerous blood may end up being transfused to a patient. There will be an infection. 
2. Any surgical procedures starting from dental fillings and ending with transplantation of donated organs. Sterilization of instruments, of course, is carried out, but anything can happen ... especially in poor and developing countries. 
3. Needle stick injury in which the blood of a HIV positive person is contracted. Often this happens among drug addicts. When all the human aspiration is focused on the upcoming pleasure, hands simply do not reach out to take a new syringe and so they just get on with it. Still worse if there is a need to run to the drugstore for this syringe... 
4. Criminals can sometimes also cause pricks with an infected needle (medical needle with blood containing the immunodeficiency virus). Read "Crimes committed by people with symptoms of HIV".

Ø        Vertical transmission refers to the mode of infection upon transmission of the HIV virus from mother to child. Let us consider how can you get AIDS, and how the HIV gets transmitted: before, during, and after childbirth. 
1. At the time of pregnancy, the baby's blood and that of the mother do not mix; this is prevented by the placental barrier. However, events that can weaken or block this mechanism for a short time may occur (various pathologies, unexpected infections, accidents etc.). The virus gets into the baby's bloodstream. Antibodies produced by the body will begin no earlier than 1.5 years of age. Therefore, all pregnant women should be tested for HIV in the body and certainly, if necessary, anti-retroviral therapy must be prescribed. 
2. During labor, the baby comes in close contact with the mother's birth canal. Through defects in the mucus membranes, tears, microtraumas etc., the immunodeficiency virus passes from the mother's blood into the baby's blood. Likelihood of infection at birth is about 13-18%. 
3. A child can get HIV through breastfeeding - the child's body is still small, and does not know how to deactivate the virus that is present in breast milk. It is necessary to switch to bottle-feeding.

The clinical picture of the process of AIDS, or the localization of the signs and symptoms of HIV infection in men and women are very much connected with the mode of infection. Of course, the highest concentration of HIV is in the place from where it has been introduced into the human body.
If the virus entered into the oral cavity (through different ways), then you might have problems with teeth, gums, nasal sinuses. HIV can reach the central nervous system (brain), or down into the lungs and the digestive system. 
If the infection originates "from the bottom", the most affected parts are the reproductive organs, urinary tract, kidneys etc.
However, if you contract HIV infection during intravenous injection, the process of infection of the entire body progresses very rapidly and the immune cells of blood (CD4 + T lymphocytes) get affected. With the weakening of the immunity, a lot of secondary diseases and opportunistic infections may develop. 
If the infection has occurred in utero, the prognosis of the disease depends on genetic indicators of the immune system of the fetus. With strong immunity, there are chances of usual (as in adults) development of symptoms of HIV, and with low immunity, the child may get infected in the womb itself (which will lead to deformity). Pregnancies in such cases end either with the death of the child or with a miscarriage.