What is the infection AIDS caused by?

Explanation

AIDS (Acquired Immune Deficiency Syndrome) is an infection first described in 1981. AIDS is caused by human immunodeficiency virus (HIV), which transmits through sexual contact, through blood and blood products and from mother to child during pregnancy and child birth. An estimated 33 million people are infected with AIDS worldwide. 90% of all cases are in developing countries. Ever year, around 2.1 million people die from AIDS. December 1 is the international AIDS day, recognised e.g. by the UN.