Tim Fitzsimons

When Health and Human Services Secretary Margaret Heckler announced that scientists had discovered the virus that caused AIDS at a press conference in 1984, the disease was still mysterious and invariably fatal.

The world's annual death toll from AIDS has been falling in recent years — 1.5 million in 2013, a 35 percent drop from the peak of 2.4 million in 2005.

Now the number of deaths could soon drop even more.

The World Health Organization issued new guidelines Wednesday that recommend greatly increasing the number of people who take antiretroviral medications for the treatment and prevention of HIV infection.

In the aftermath of disasters like earthquakes, fires and severe weather events, the rush to both alert and check on family and friends can crash telecommunications networks. During the freak 2011 Virginia earthquake, which rattled the nation's capital and damaged the Washington Monument, panicked phone calls quickly overloaded the phone network.

Facebook's newest tool, known as Safety Check, aims to allow people to quickly alert friends and family that they are safe after a natural disaster.