AIDS was first time spotted in 1981, causing confusion and speculation. Medics in Europe and North America detected patients whose organism did not fight germs.
They died of various infections, like pneumonia.
The disease was clearly infectious and was characterized by a series of symptoms, due mainly to the ruin of the immune system. It was a syndrome, named AIDS (acquired immune deficiency syndrome). By 1983 American and French researchers detected independently the virus causing the disease. It was called human immunodeficiency virus (HIV). Today, it is the most investigated virus. Its detailed structure has been investigated and a map of its genes has been made. In fact, there are several types of HIV, which modifies continuously, turning difficult the development of a vaccine.
HIV is a retrovirus. It contains a central RNA molecule (not DNA), which is wrapped in a mosaic of various proteins. Inside the human host cells, RNA passes into DNA which is used as a mold for multiplying the virus.
Unlike other viruses, HIV is difficult to transmit. It cannot survive out of the body and its warmth and liquids. That's why it cannot be transmitted through air. Normally, HIV cannot be transmitted through coughing, sneezing, insects (like flies or mosquitoes), or collective use of towels, cutlery, or other objects.
HIV is transmitted through three ways, all involving blood or liquid exchange. People can get HIV when blood or a liquid (like semen) from the infected person enters into contact with the blood or inner liquids of another person. HIV is transmitted through sex, heterosexual and homosexual, and also oral or anal. It goes from one partner to another through the body fluids.
A second way is from the mother to the child found in her womb. The virus can enter the child's blood before birth or during the birth. Breastfeeding too can transmit the virus. The third way is through injections involving blood or body fluids. Before the rule of testing the blood (the test was developed in 1985) was active, many persons got infected through blood transfusions. The virus can be also transmitted by an unsterilized hypodermic needle or a not sterile syringe already used by an infected person.
High risk behaviors for getting HIV are drug use with not sterile needles, frequent change of sexual partners and unprotected sex. HIV is encountered in the saliva, but it is believed it cannot be transmitted through kissing.
Inside the body, HIV attacks certain types of immune white cells of the blood. As the immune system gets gradually weakened, white cells lose ability to fight germs. Microbes usually easy to neutralize stay in the body and multiply. AIDS is not caused by the HIV itself, but by the impairment of the immune system it causes.
The first symptoms of the HIV infection appear in 5-10 years. When the person gets infected, the virus rapidly multiplies and can be detected in the fluids around the brain and spine. The person may not be affected during this stage or it can have flue-like symptoms, like nose flow and fever, skin eruption, swelling of the axillary glands or frequent headaches.
These symptoms and the high levels of the virus disappear after a few weeks, when the infected person feels good again. The virus is present, but inactive, and the person can transmit unconsciously the virus to others. Later, sometimes including several years, the virus reactivates and starts multiplying again. This time AIDS installs.
It is still not very clearly known how HIV destroys the immune system. The virus attacks lymphocytes and other immune cells. Usually, when a germ enters the body, the immune system synthesizes special molecules called antibodies that fight with it. Antibodies float in the blood and body fluids sticking to microbes, destroying them or turning them inoffensive. The same happens when HIV enters the body, and a blood analysis detects anti-HIV antibodies. But, meanwhile, the "sleeping" viruses hide and constantly modify inside the cells, untouched by the antibodies.
Then, they start multiplying again, causing the first symptoms of AIDS. The axillary, neck and inguinal lymph glands swell and turn painful. This stage is called PGL (Persistent Generalized Lymphadenopathy), indicating that the immune system starts the fight, and the number of white cells from the blood is dropping.
The conditions caused by AIDS can develop gradually or in just a few weeks: infections of the skin, mouth, tongue and mucosae, like herpes, leucoplakia (white sores) and aphthae (white infectious spots) (the last two caused by fungi), while the organism can be defeated by diseases like tuberculosis or pneumonia, or infections and inflammations of the brain (meningitis and encephalitis). The brain inflammations cause confusion and mental issues. Sight impairment appears, as well as diarrhea and digestive conditions, and wounds with excessive bleeding. Other conditions that can emerge are: various cancer types and Kaposi's sarcoma, which causes severe skin wounds. In a few weeks or months, the patient enters the last state, as various conditions overwhelm the body.
Experience has improved patients' care and the treatment of the diseases and infections caused by AIDS. Some AIDS connected pneumonias can be treated with antibiotics and antivirals. Kaposi's sarcoma can be treated though radiotherapy (involving X rays). But currently there's no cure against AIDS and no effective treatment on long term. Also, there is no anti-HIV vaccine for impeding the evolution and spreading of the virus. Progresses in the anti-HIV fight are slow and difficult.
The difficulty comes from the fact that the virus breeds inside the host cells, hard-to-get targets. Zidovudine slows down AIDS evolution in some persons, but it can have severe secondary effects: vomits, nausea, weakness, and it can attack the bone marrow. Researchers focus on impeding the HIV to stick on the cells' surface.
By now, the condom and information are the main protections against HIV.
Where did the virus come? There are similar viruses in monkeys, called SIV (simian immunodeficiency virus). Now, it is believed that people got the virus through hunting apes (gorillas and chimps) for bushmeat, when the hunters got in contact with the blood and fluids of these species. In humans, the virus has an age of up to 100 years, but no less than 30 years. It spread from Africa due to the intensification of humans' movement around the globe. A new research showed HIV entered US Haiti, brought by just one person around 1969, much earlier than previously thought! That was the HIV-1 type, and it entered the U.S., from where it spread worldwide. Haiti was the stepping stone the virus took when it left central Africa.
The strain reaching U.S. in 1969, HIV-1 group M subtype B, is the HIV type found, and it is the culprit of HIV epidemics in most countries outside sub-Saharan Africa and south of Equator Africa, while HIV-2 is limited to West Africa.
About 4 million people got infected with HIV in 2006 and another 3 million died of it. Till now, about 25 million people have died of AIDS and other 40 million people are infected with HIV worldwide, most of them in the Sub-Saharan Africa.