1 Visa - Digits two through six are the bank number, digits seven through 12 or seven through 15 are the account number and digit 13 or 16 is a check digit.  MasterCard - Digits two and three, two through four, two through five or two through six are the bank number (depending on whether digit two is a 1, 2, 3 or other). The digits after the bank number up through digit 15 are the account number, and digit 16 is a check digit.
AIDS is the acronym for acquired immunodeficiency syndrome. 1  It is the stage of HIV infection where a person's immune system is fully compromised, leaving the body open to a wide range of potentially deadly diseases known as opportunistic infections.
HIV: Early signs and symptoms. HIV is a virus that attacks a person's immune system. It can weaken the immune system to the point where a person's body struggles to fight infections and disease. If left untreated, HIV can lead to the disease AIDS. AIDS stands for acquired immunodeficiency syndrome. AIDS is the final stage of HIV infection.