People with Alzheimer's disease may start experiencing shrinking of parts of the brain as many as 10 years before the degenerative condition is diagnosed, a U.S. study suggested on Wednesday.

While the results are still preliminary, scientists said the findings could one day provide a way to identify by MRI scan which individuals are most likely to develop the disease, which can run in families and has no cure.

Genital herpes can be transmitted even if a person has no symptoms, suggesting a high risk of transmission from people with unrecognized infections of herpes simplex 2, researchers said on Tuesday.

The study published in the Journal of the American Medical Association followed about 500 people between March 1992 and April 2008. The subjects took daily swabs of their genital secretions for 30 to 60 days.

It's that time of year when the bugs emerge to bug us.

Some can pose real threats — Lyme disease from tiny ticks, West Nile virus from mosquitoes, or life-threatening allergic reactions to bee stings. But most bug bites in this country are an itchy nuisance.

Japan prepared on Tuesday to undertake its first organ transplant from the body of a child aged under 15, made possible by a legal amendment aiming to save the lives of many children.

The health ministry said that the child, identified only as a boy aged between 10 and 15, was declared brain-dead early on Tuesday after suffering serious head injuries in a traffic accident.

A new treatment for obesity that combines two existing drugs resulted in twice as much weight loss as the only approved long-term anti-obesity medication, according to a study released Monday.

A mix of Phentermine and topiramate, sold under the brand name of Topamax, was shown in clinical trials to be twice as effective as orlistat, which is commercialized in some countries as Xenical or Alli, it said.

About one in 10 cancers in men and one in 33 in women in western European countries are caused by current and past alcohol consumption, according to a study released Friday.

For some types of cancer, the rates are significantly higher, it said.

Being exposed to highway pollution can cause brain damage in mice akin to memory loss and Alzheimer's disease, U.S. researchers said Thursday.

Scientists recreated the airborne pollutants that come from the burning of fossil fuels and the weathering of car parts and pavement, and exposed mice to the harsh air for 15 hours per week over 10 weeks.

Urgent global action is needed to prevent the spread of a multi-drug-resistant "superbug" after it was found in water supplies in the Indian capital, doctors said in research published Thursday.

The study in The Lancet medical journal said that New Delhi metallo-beta-lactamase 1 (NDM-1) producing bacteria were found in 51 out of 171 samples taken from water pools and rivulets and two out of 50 tap water samples in the city.

The discovery of radiation in seafood has hit Japan right in its culinary heart, as the nation that brought sushi to the world contemplates having to change thousand-year-old eating habits.

For an archipelago that has lived off the ocean since prehistoric times, radioactive fish is a worst-case scenario with possibly economy-wide implications.

Meditation can deliver powerful pain-relieving effects to the brain with even just 80 minutes' training for a beginner in an exercise called focused attention, a study released Tuesday found.

"This is the first study to show that only a little over an hour of meditation training can dramatically reduce both the experience of pain and pain-related brain activation," said Fadel Zeidan, lead author of the study and a post-doctoral research fellow at Wake Forest Baptist Medical Center in North Carolina.