HIV infection is transmitted exclusively by parenteral route, i.e. through the biological body fluids: blood, sexual secretions. Hence, the most frequent way of HIV infection is through sexual contact. In semen contains a large number of infectious agents and, during unprotected intercourse, in violation of the vaginal mucosa to the virus with a 90% probability enters the body. More than half of the HIV-infected catch the virus precisely this way. Especially dangerous in these cases anal sex as listed semen infection almost instantly absorbed through the intestinal mucosa into the blood.
HIV and blood transfusion, while not always the main role is played by the negligence of the medical staff. A blood transfusion stations is a multi-stage validation, before reaching the patient. However, the virus in the process of the incubation period, perfectly capable not manifest itself. But the risk to get an infection thus, according to the statistics, is extremely low. Much more likely to become HIV-infected injecting drug users using a single syringe for a big friendly company. However, the hospital did not want to see that prick was made with a sterile syringe from the package.
HIV children get the disease in utero from an infected mother. This mode of transmission is called vertical. Infection acquired by a woman during pregnancy can not touch the baby. Whereas a woman is infected before pregnancy, can give birth to a dead child or to miscarry. Often children with HIV diagnosis die within a few days after birth. Poorly developed immune system of a newborn cannot withstand such infection load.
In the media repeatedly flashed the cases that illustrate the intolerance of society towards HIV patients. Parents threatened to withdraw their kids from school or kindergarten, colleagues, submit a letter of resignation. As experts say, this phenomenon is connected with the usual ignorance, but not with the public danger that an HIV-positive man allegedly poses to others. And I remind you that you can't get HIV when sharing household utensils, coughing and sneezing, even kissing. The concentration of virus required for infection, contains only in blood and sexual secretions. In saliva the amount of virus is extremely low.
Public danger is people who do not know about their disease. Or those who deliberately seek to infect as a lot of others. Compliance with the rules of sexual health and hygiene, lack of addiction to drugs, will allow to reduce the figure of HIV infection to a minimum.