Here's a look at what you need to know about AIDS and HIV globally, with a special focus on Africa.
AIDS stands for acquired immunodeficiency syndrome, and is also called acquired immune deficiency syndrome.
HIV stands for human immunodeficiency virus.
HIV/AIDS is spread through sexual contact with an infected person, sharing needles with an infected person, through transfusions of infected blood or through an infected mother.
People infected with HIV go through three stages of infection:
1) Acute infection, or acute retroviral syndrome, which can produce flu-like symptoms in the first month after infection.
2) Clinical latency, or asymptomatic HIV infection, in which HIV reproduces at lower levels.
3) AIDS, in which the amount of CD4 cells fall below 200 cells per cubic millimeter of blood (as opposed to the normal level of 500-1,500).
HIV-1 and HIV-2 can both cause AIDS. HIV-1 is the most common human immunodeficiency virus; HIV-2 is found mostly in western Africa.
34 million - Number of people living with AIDS/HIV worldwide in 2011. 23.5 million live in sub-Saharan Africa.
2.5 million - New infections worldwide in 2011
330,000 - New Infections in children worldwide
1.7 million - AIDS-related deaths worldwide in 2011
69 percent of the world's people living with HIV/AIDS live in Sub-Saharan Africa; an estimated 1.8 million people are newly infected with HIV/AIDS.
Sub-Saharan Africa is comprised of: Angola, Benin, Botswana, Burkina Faso, Burundi , Cameroon, Cape Verde, Central African Republic, Chad, Comoros, Democratic Republic of the Congo, Republic of the Congo, Cote d'Ivoire, Djibouti, Equatorial Guinea, Eritrea, Ethiopia, Gabon, The Gambia, Ghana, Guinea, Guinea-Bissau, Kenya, Lesotho, Liberia, Madagascar, Malawi, Mali, Mauritania, Mauritius, Mozambique, Namibia, Niger, Nigeria, Rwanda, Sao Tome and Principe, Senegal, Seychelles, Sierra Leone, Somalia, Republic of South Africa, Sudan, Swaziland, Tanzania, Togo, Uganda, Zambia and Zimbabwe.
1981 - CDC publishes reports of men in Los Angeles, New York and San Francisco who were previously healthy and are suffering from rare forms of cancer and pneumonia, and accompanied by "opportunistic infections."
1982 - Disease adopts the name AIDS.
1983 - French and American researchers determine that the HIV virus is caused by AIDS.
1985 - Blood tests to detect HIV are developed.
December 1, 1988 - First World AIDS Day.
1999 - Researchers in the U.S. find evidence that HIV-1 most likely originated in a population of chimpanzees in West Africa. The virus appears to have been transmitted to people who hunted, butchered and consumed the chimpanzees for food.
2011 - The UN announces that the overall number of new HIV infections has decreased by 20 percent in the past decade.
2011 - The use of antiretroviral drugs has increased the life expectancy of those with HIV/AIDS.
June 5, 2011 - The 30th anniversary of the first five reported CDC cases of AIDS.
October 2011 - In his book The Origins of AIDS, Dr. Jacques Pepin traces the emergence and subsequent development of HIV/AIDS to suggest that initial AIDS outbreaks began earlier than previously believed.
March 3, 2013 - Researchers announce that a baby born infected with HIV has been "functionally cured." The child, born in Mississippi, was given high doses of antiretroviral drugs within 30 hours of being born. Two years later, doctors were unable to detect evidence of HIV in the child's blood.
The U.S. President's Emergency Plan for AIDS Relief (PEPFAR):
January 29, 2003 - In his State of the Union speech, President Bush promises to dramatically increase funding to fight HIV/AIDS in Africa.
May 27, 2003 - President Bush signs H.R. 1298, the U.S. Leadership Against HIV/AIDS, Tuberculosis and Malaria Act of 2003, also known as PEPFAR, that provides $15 billion over the next five years to fight HIV/AIDS, tuberculosis, and malaria abroad, particularly in Africa.
July 30, 2008 - H.R. 5501, The Tom Lantos and Henry J. Hyde United States Global Leadership Against HIV/AIDS, Tuberculosis, and Malaria Reauthorization Act of 2008, becomes law and authorizes up to $48 billion to combat global HIV/AIDS, tuberculosis and malaria. Through 2013, PEPFAR plans to work in partnership with host nations to support treatment for at least 4 million people, prevention of 12 million new infections, and care for 12 million people.
September 30, 2012 - PEPFAR has supported life-saving antiretroviral treatment for approximately 5.1 million men, women and children since 2003.
July 2012 - PEPFAR announces its latest results. The program is supporting 4.5 million people on treatment and has donated more than $7.1 billion to the Global Fund to Fight HIV/AIDS, Tuberculosis and Malaria.
July 24, 2012 - Doctors announce during the 19th International AIDS Conference that Timothy Ray Brown, the Berlin patient, has been "cured" of HIV. Brown, diagnosed with leukemia, underwent a bone marrow transplant in 2007 using marrow from a donor with an HIV-resistant mutation. He no longer has detectable HIV.
2013 - Under PEPFAR, the U.S. Government has committed approximately $46 billion to HIV/AIDS programs, the Global Fund to Fight HIV/AIDS, Tuberculosis and Malaria, and tuberculosis programs through 2010.
June 18, 2013 - Marking the 10th anniversary of PEPFAR, Secretary Kerry announces that the millionth child has been born HIV-free due to prevention of mother-to-child transmission programs (PMTCT).
2013 - President Obama's PEPFAR budget request for 2014 fiscal year includes $6 billion for global aids prevention, $1.65 billion for the Global Fund to Fight HIV/AIDS, Tuberculosis and Malaria, and $1.1 billion for the Department of Veterans Affairs.