Israel is to vaccinate all children against polio, after "thousands" of people in the south of the country were found to be carriers, Health Minister Yael German said on Saturday.

German said 98 percent of Israelis were already vaccinated but could pass the virus onto the remainder.

With her 1-day-old son propped against her in a hospital bed nursing, Qi Wenjuan says she has no desire to feed her child with infant formula.

"I don't trust baby formula," the first-time mother said, lying in the maternity ward of Beijing's Tiantan Hospital. "There are too many quality problems."

A plant extract used in Chinese herbal remedies for arthritis, gout and inflammation has been directly linked to cancer and causes a surprising number of genetic mutations, scientists said Wednesday.

The gene signature of aristolochic acid -- derived from a vine known as birthwort -- was found in tumors from 19 upper urinary tract cancer patients from Taiwan.

Researchers on Friday pointed to the Arabian camel as a possible host of the deadly human MERS virus plaguing the Middle East.

The exact origins of the virus is a riddle scientists have been working hard to solve in a bid to halt its spread, especially in the lead-up to the annual hajj pilgrimage to Saudi Arabia in October.

A new kind of malaria vaccine that mimics the effect of mosquito bites has shown early promise by offering 100 percent protection to a dozen human volunteers, researchers said Thursday.

The experimental vaccine, called PfSPZ and produced by the Maryland-based company Sanaria, contains live malaria parasites collected through a painstaking process of dissecting the salivary glands of mosquitoes.

The United States has seen a slight decline in obesity among low-income preschoolers for the first time in decades, according to government figures.

A report by the Centers for Disease Control and Prevention found a slight decline in 19 states from 2008-2011.

Chinese scientists on Wednesday reported the first likely case of direct person-to-person transmission of the H7N9 bird flu virus that has killed over 40 people since March.

The development was "worrying" and should be closely watched, the team wrote in the British online journal bmj.com, but stressed that the virus, believed to jump from birds to people, was still inadept at spreading among humans.

New Zealand dairy giant Fonterra moved to assure parents Wednesday that tainted baby formula which has sparked global safety recalls has all been removed from retailer's shelves.

No products containing a potentially deadly bug, which were distributed from China to Saudi Arabia, were in the shops, Fonterra chief executive Theo Spierings said.

Most Americans do not want to live beyond age 100, and a poll out Tuesday suggests many worry that anti-aging technologies may end up being a luxury for the rich.

The survey of more than 2,000 people by the Pew Research Center's Religion and Public Life Project sought to probe the nation's views on the prospect of living longer lives.

Scientists said Tuesday they had found evidence that a lack of sleep causes changes in brain activity that lead to people feeling hungrier and craving more fattening foods.

Researchers have long pointed to a correlation between a steep rise in obesity in industrialized nations and a decline in sleep duration.