A child has contracted polio for the first time in Pakistan's militant-infested tribal belt since the Taliban banned vaccinations a year ago, a U.N. official said Monday.

"The new case has been detected in North Waziristan where we had been denied access in June last year," the World Health Organization's senior coordinator for polio eradication in Pakistan, Elias Durry, told AFP.

The Man Nyon Pharmacy is lined with rows of colorful packages containing everything from dried bear bile and deer antler elixir to tiger bone paste and ginseng. But the ancient "Koryo" medicine provided at this popular dispensary isn't just for minor aches and pains.

It has been integrated into the health system from the smallest village clinic all the way up to the nicest showcase hospitals in the privileged capital of Pyongyang. Both modern and traditional styles of healing have long been uniquely intertwined nationwide with doctors from both schools working in tandem under one roof.

Immunologists expressed concern Friday about the "dangerous" work of scientists in China who created a hybrid bird flu virus that can spread in the air between guinea pigs, and now lives in a lab freezer.

The team from the Chinese Academy of Agricultural Sciences and Gansu Agricultural University wrote in the journal Science they had created a new virus by mixing genes from H5N1 "bird flu" and H1N1 "swine flu".

Five Saudis who died after contracting a new SARS-like virus last week had not travelled abroad, a health ministry doctor said on Saturday.

"After questioning relatives, it turned out that none of these people had been abroad before being infected," Dr Ziad Mimish, who heads the ministry's disease prevention unit, told Agence France Presse.

The U.S. food and drug regulator on Friday called the addition of caffeine to children's foods like chewing gum and jelly beans "dangerous" and warned of a possible crackdown.

Food and Drug Administration deputy commissioner Michael Taylor said the rise in such caffeine-added products outside the beverage industry was "very disturbing," after candy giant Mars Inc. announced a caffeinated version of its Wrigley gum.

Some of the most devastating forms of cancer have genetic similarities even though they strike different body parts, according to new studies out Thursday.

The new research -- one study focused on a form of leukemia, in the New England Journal of Medicine, and a second on endometrial cancer, in Nature -- could offer a pathway to new, more effective treatments.

Suicide rates are rising dramatically among middle-aged Americans, according to U.S. government statistics, which showed a 28 percent spike from a decade ago in the number of people taking their own lives.

The U.S. Centers for Disease Control and Prevention said the figures show more people taking their own lives than dying in car accidents, and attribute the increase to the sharp rise in suicides among adults aged aged 35 to 64.

China has detained 900 people for meat-related crimes including selling rat and fox meat as beef and mutton, the public security ministry said, in another blow to the nation's food safety.

News of the three-month operation added to a string of scandals that have galvanized public concern from recycled cooking oil to dangerous chemicals in baby milk powder.

Chinese police have arrested the head of a kindergarten and her associate over the deaths of two children from a rival school who ate yogurt injected with rat poison, state media said Friday.

The five- and six-year-old girls from northern Hebei province died after eating the yogurt which they had found in a bag on the side of the road while walking to school with their grandmother.

Playing videogames can prevent and even reverse deteriorating brain functions such as memory, reasoning and visual processing, according to a study released Wednesday.

The University of Iowa study of hundreds of people age 50 and older found that those who played a videogame were able to improve a range of cognitive skills, and reverse up to seven years of age-related declines.