HIV stands for Human Immunodeficiency Virus. Viruses infect the cells of living organisms and replicate within those cells damaging the cells it replicates. By damaging the cells it replicates in, it is one of the things that can make an infected creature become ill. People can become infected with HIV from other people who already have it, and when they are infected they can then go on to infect other people. This is how HIV is spread. Someone who is infected with HIV is said to be HIV+ or HIV positive.
What makes HIV so dangerous? The immune system is a group of cells & organs that protect the body by fighting viruses & infections….(short extract)