Bans on smoking in public and the workplace led to a 10 percent drop in premature births and in emergency asthma treatment for children, researchers said Friday.

The evidence, based on the records of more than two million children, comes from 11 published investigations into the impact of local or national smoking bans in the United States, Canada and four European countries.

An artificial heart may help patients survive while awaiting a heart transplant, although the devices remain risky 10 years after they were approved, according to a U.S. study Thursday.

Researchers followed 22 patients with end-stage heart failure over the course of two months, to see how they responded to implantation with a Syncardia total artificial heart, the only such device that is approved by the U.S. Food and Drug Administration.

People who are hospitalized in the United States risk acquiring healthcare-associated infections, which kill 75,000 patients per year, U.S. health authorities said Wednesday.

Many bacterial infections -- which can lead to serious complications from pneumonia and illnesses of the intestinal tract -- could be prevented if healthcare workers practiced common hygiene, said the Centers for Disease Control and Prevention.

The brains of children with autism contain a built-in patchwork of defects, suggesting that the developmental disorder begins while they are growing in the womb, said a U.S. study Wednesday.

Researchers described their findings in the New England Journal of Medicine as "direct evidence" of a prenatal origin for autism, which affects as many as one in 88 children in the United States and has no known cure.

Iraq's health ministry said Wednesday it had found its first suspected polio case in 14 years, which could have originated in neighboring Syria where confirmed cases have sparked a region-wide alert.

The suspected case was found in a young boy in Bab al-Sham near Baghdad, ministry spokesman Ziad Tariq told Agence France Presse.

Guinea battled Wednesday to contain an Ebola epidemic threatening neighboring countries as fear and confusion gripped communities under siege from one of the deadliest viruses known to mankind.

Global aid organisations have sent dozens of workers to help the poverty-hit west African nation combat the haemorrhagic fever, with health officials raising the death toll by two to 63.

Hundreds of dead pigs are being recovered every month from a Chinese reservoir, partly due to government efforts to stop carcasses making their way onto the dining table, state media said Wednesday.

The revelations about the reservoir in Qionglai, in the southwestern province of Sichuan, are the latest scandal relating to food safety to hit China.

The South Korean capital Seoul is to restrict the use of plastic surgery adverts on public transport, officials said Wednesday, after complaints that they were fueling an unhealthy obsession with body image.

South Korea, and particularly Seoul, has an international reputation for plastic surgery, and adverts featuring famous surgeons and giant before-and-after photos are omnipresent -- on street billboards, subway trains, bus stops and the backs of bus seats.

Youths who play video games are more likely to think and act in aggressive ways, suggested a study out Monday of more than 3,000 schoolchildren in Singapore.

The research, published in JAMA Pediatrics, a journal of the American Medical Association, was based on more than 3,034 children who were studied over the course of three years.

People who use electronic cigarettes do not report higher rates of quitting than regular cigarette smokers, according to a U.S. study out Monday.

The findings were based on survey answers from 949 smokers, reported in a research letter to the Journal of the American Medical Association (JAMA) Internal Medicine.