We explain HIV and AIDS. The human immune system defends the body against illnesses all the time. It uses guards in the blood called T cells to recognize any intruders and destroy them. But instead of attacking the body, the human immunodeficiency virus or HIV attacks those T cells themselves. It turns them into copy machines to make more copies of itself. Then, the eventually kills the infected T cells. Without treatment, it takes 8 years on average for a person with HIV to develop AIDS or acquired immunodeficiency syndrome. By then, there aren't enough T cells to fight off various infections and diseases. So, it's not the virus directly, but the diseases that are eventually fatal. Humans first acquired HIV from blood contact with apes and gradually transmitted it to humans. It transmitted it to more people through unprotected sex, used syringes and childbirth. AIDS remained undiscovered until a sudden outbreak among gay men in New York and San Francisco in 1981. Very quickly, people began developing the same unusual symptoms around the world. The patients suffered from rare forms of skin cancer, pneumonia or thrush. And few survived. Pregidous against homosexuality made research funding hard to go. And more and more people were getting sick. What could be done? Keep the virus from spreading. It became clear that the best preventive measure was safe sex. As condoms kept the virus from infecting others, additionally blood banks started testing blood. And new programs even distributed clean needles to drug users. Finally, in 1987, the first treatment against the virus was released. The ancestor of combination therapy. The medication still isn't a cure. But it keeps the virus from multiplying and destroying the host immune system. By starting treatment early, people with HIV can now live long healthy lives. Unfortunately, many people still lack access to medication, especially in sub-Saharan Africa. Over the last 30 years, about 36 million people have died, while 2 million more are infected each year. Scientists have made a lot of progress, but are still looking for the cure. You too can help end the AIDS crisis. Play safe? Get tested? Donate to support research, prevention and care. And spread the word.