Michaeleen Doucleff

There's fever. And unexplained bleeding. Like Ebola. But tests show that the 51 cases in South Sudan are definitely not Ebola.

The health agency is making changes so it can get boots on the ground if a pandemic strikes. But critics say it hasn't gone far enough.

Health officials have warned for years that the world is not ready for the next big pandemic. Leaders at the World Health Organization are meeting this week to try to change that.

Long-lasting hormone contraceptives are now the most recommended form of birth control for young women. And many women say the fact that they can reduce or eliminate periods is a big plus.

Mosquito season is just getting underway in the U.S., and some areas have the mosquitoes that transmit the Zika virus. Pregnant women in places like Florida and Texas are at greatest risk.

Experiments on mice have given scientists an understanding of how the virus causes severe brain malformations.

The money was part of the President's Emergency Plan for AIDS Relief. It went to sex ed classes and public health messages in Africa. Effective or not? A new study offers a clear verdict.

A country is declared Ebola-free. Then the virus flares up again. Doctors now know why.

A study finds that HIV infection — or the treatment for it — can have an impact on the way the body ages.

This week the world is attempting a first — the largest, quickest rollout of a vaccine in history. The goal is to make the polio vaccine safer, but it comes with a big risk.

Scientists estimated how contagious the virus is in Colombia — and that gives us some clues to how it might spread in the U.S.

Laughter turns out to be a universal language in more ways than we realize.

Scientists say research has establish a connection between Zika and microcephaly. More research is needed to establish how much danger a fetus is in if a pregnant woman becomes infected.

Using a battery of advance tests, doctors at Johns Hopkins were able to see signs of brain damage in a fetus that standard tests had missed.

Scientists now have evidence the Zika virus was spreading in South America long before health officials detected it. The findings suggest Zika could be hiding out in other corners of the world, and Southeast Asia may be the next region to see a big outbreak.

To figure out how the outbreak began, scientists decoded the genomes of Zika viruses in Brazil. The findings suggest Zika could be hiding out in other corners of the world.

In 1893, a German scientist made a striking discovery: Cells from a fetus hide out in a mother's body after birth. Scientists say these cells alter the risk of breast cancer and autoimmune diseases.

Kamala B.K. is tiny. She's barely 5 feet tall. A bright red ribbon sets off her dark hair.

As she walks past our guesthouse in the village of Tankut, we try to get her to come over and talk to us. But the 14-year-old won't come over to the porch.

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Renowned astronomer Geoffrey Marcy resigned this week after accusations that he sexually harassed students became public. Researchers are asking why so little is done to stop harassment in science.

Most hospitals around the country aren't doing a good job of helping new moms who want to breast-feed, researchers report Tuesday in the journal Morbidity and Mortality Weekly Report.

Several common practices at the institutions may actually prevent moms from sticking with breast-feeding for six months — the duration ...