Here are some of the latest health and medical news developments, compiled by the editors of HealthDay:
U.S. Astronaut to Spend Year in Space
American astronaut Scott Kelly will leave Friday to spend a year on the International Space Station in order to learn how the human body responds to a prolonged stay in space.
No American astronaut has spent more than six months beyond Earth's atmosphere, ABC News reported.
Scott Kelly has a twin brother Mark, who is also an astronaut. While Scott is in space, Mark will provide an Earth-bound comparison to help assess the changes to his brother's body over the next year. The twins are 51 years old.
"There are risks and I am willing to accept that for what we are going to learn from it," Scott told ABC News.
"We need to figure out how people are going to live in space for really long periods of time, especially if we want to send somebody to Mars [and] build a base on the Moon," Mark said.
A roundtrip to Mars takes 18 months, ABC News reported.
Ebola Outbreak Could Be Over by Summer: U.N. Official
The Ebola outbreak in West Africa could be "gone" by the summer, a United Nations' official said on the one-year anniversary of the World Health Organization's announcement of the start of the outbreak.
It was on March 23, 2014 that the WHO said there was an Ebola outbreak in Guinea. It spread to Liberia and Sierra Leone and more than 10,000 people in West Africa have since died of Ebola, the Washington Post reported.
The U.N.'s initial efforts to fight Ebola in West Africa were hampered by a combination of "arrogance" and a "lack of knowledge," but the agency has learned lessons from the experience, according to Ismail Ould Cheikh Ahmed, head of the U.N.'s Ebola mission.
"We have been running away from giving any specific date, but I am pretty sure myself that it will be gone by the summer," he told BBC News, the Post reported.
However, there was recent disappointing news from Liberia. The country had not had an active Ebola case since March 5, but diagnosed a new patient on Friday. It's not clear how the patient contracted the disease.
In related news, a report released Monday by Doctors Without Borders criticized the world's response to the Ebola outbreak in West Africa, the Post reported.
"The world at first ignored the calls for help and then belatedly decided to act," the group said. "Meanwhile, months were wasted and lives were lost."
The actual death toll associated with the outbreak is unknown, because "the resulting collapse of health services means that untreated malaria, complicated deliveries and car crashes will have multiplied the direct Ebola deaths many times over," Doctors Without Borders said.
Baseball Players' Hitting Drops After Concussion: Study
Professional baseball players' hitting abilities decline after a concussion, a new study finds.
Researchers looked at 66 Major League Baseball players who suffered concussions between 2007 and 2013, including some who did not go on the disabled list after their head injury, The New York Times reported.
Over the two weeks before their concussion, the players hit .249 with a .315 on base percentage and a .393 slugging average. During the two weeks after their head injury, those statistics were .227/.287/.347, according to the study in the American Journal of Sports Medicine.
Major League Baseball allows concussed players to return to action if they pass a series of interview and tests of physical and mental functioning. But the players in this study passed those tests and still showed a decline in batting ability when they resumed playing, The Times reported.
"I would say that what they're doing now is a good start," study senior author Dr. Jeffrey Bazarian, a professor of emergency medicine at the University of Rochester, said of MLB's concussion protocol."But if they integrated some kind of analysis about how the player is swinging the bat, then you could see if they're really back to where they were."
He said while a 90 percent recovery may be adequate for most normal activities, it's not enough for a major league baseball player. "You really need to be fully recovered to swing a bat at a 95-mile-an-hour fastball," Bazarian told The Times.
CDC Team to Help Fight Indiana HIV Outbreak
A team from the U.S. Centers for Disease Control and Prevention will arrive Monday to help fight an HIV outbreak in southern Indiana.
So far, there have been 55 confirmed cases and 13 other preliminary positive cases of HIV in the outbreak, according to the state health department. Most of the infections have occurred in people who shared needles while injecting the painkiller Opana, and some other cases have been linked to unprotected sex, the Associated Press reported.
After their arrival, the CDC team will help state health workers with follow-up contacts of HIV-positive people and with data analysis. The outbreak is limited to Clark, Jackson, Perry, Scott and Washington counties.
"We are engaging local, state, and national partners to determine where we can most effectively focus our efforts," Health Commissioner Dr. Jerome Adams said in a news release, the AP reported.
"Extra care is being taken to invest resources in getting people off drugs and into treatment, since drug abuse is the clear driving force behind this outbreak," he added.
The state health department has launched a three-month public awareness campaign that provides information on drug abuse, needle disposal, safe sex, and HIV testing and treatment, the AP reported.
Roundup a 'Probable Carcinogen,' Report Says
An ingredient found in a number of herbicides, including the weed killer Roundup, is a "probable carcinogen," says a report from the International Agency for Research on Cancer (IARC).
Specifically, it's an ingredient called glyphosate that poses the threat, according to the report in the journal The Lancet Oncology, USA Today reported.
IARC is the cancer research arm of the World Health Organization.
"This latest finding, which links Monsanto's Roundup to non-Hodgkin's lymphoma and lung cancer is not the first to make these links, but it is one of the strongest indictments of glyphosate, the key ingredient in Monsanto's Roundup," said Ronnie Cummins, international director for the Organic Consumers Association, USA Today reported.
Monstanto disputed the finding, saying that all "labeled uses of glyphosate are safe for human health."
In 2013, the U.S. Environmental Protection Agency raised the allowed limits of glyphosate residues on fruits and vegetables. The agency plans to review glyphosate this year, USA Today reported.
Most genetically modified crops are designed to be resistant to Roundup.
"The widespread adoption of GMO corn and soybeans has led to an explosion in the use of glyphosate -- a main ingredient in Monsanto's Roundup and Dow's Enlist Duo," said Ken Cook, president of the Environmental Working Group, USA Today reported.
"Consumers have the right to know how their food is grown and whether their food dollars are driving up the use of a probable carcinogen," he added.
The group wants the U.S Food and Drug Administration to require GMO foods to be labeled, USA Today reported.