Genetic evidence from ancient humans and modern people suggests that travelers from northern Eurasia moved south several thousand years ago. They stuck around to have kids with early European farmers.
U.S. aid is beginning to flow into the countries fighting the deadly virus. But while protective equipment and food supplies are vital, what's really needed now are health workers.
Are you more an apple or a pear? If it's the former, you've got company. Americans' waistlines are growing, even though obesity rates have plateaued. And more belly fat increases health risks.
About 27 percent of respiratory tract infections in children are caused by bacteria, a study finds. But doctors prescribe antibiotics for 57 percent, leading to 11 million unneeded prescriptions.
Heating pads and other passive treatments don't do any good if the goal is gaining strength and mobility, according to the Choosing Wisely campaign. Instead, it's all about the exercise.
The number of deaths of children under 5 has dropped by 49 percent since 1990. There are many reasons why, from better vaccines and health workers to "kangaroo mother care."
The president announced a "major increase" in the U.S. response to the outbreak, including a new military command center in Liberia, and sending medical professionals from the U.S. to field hospitals.