Moscow and at least two other cities shut all their elementary schools Saturday to help fight one of the worst flu outbreaks to hit central Russia in more than a decade, officials said.

The Moscow closure would affect more than 1,500 schools.

Venezuelan health authorities appealed Thursday to more than 400 people exposed to cholera at a wedding in the Dominican Republic to report for treatment in order to head off an epidemic.

So far, 37 people have been treated for cholera in Venezuela but authorities were still trying to locate the rest of the 452 people who traveled to the Dominican Republic for the January 22 wedding.

Eating foods high in trans-fats and saturated fats increases the risk of depression, according to a Spanish study published in the U.S. Wednesday, confirming previous studies that linked "junk food" with the disease.

Researchers also showed that some products, such as olive oil, which is high in healthy omega-9 fatty acids, can fight against the risk of mental illness.

Bill Gates' foundation and Abu Dhabi's crown prince are donating $50 million each to vaccinate children in Afghanistan and Pakistan against polio and other diseases.

Sheik Mohammed bin Zayed Al Nahyan and the Bill and Melinda Gates Foundation say two-thirds of the funds will go toward a pair of vaccines against pneumonia, diphtheria, whooping cough and other ailments afflicting young children in Afghanistan. The rest will be given to the World Health Organization and UNICEF to provide polio vaccines in Afghanistan and Pakistan.

Federal health officials said Wednesday they are investigating a possible link between breast implants and a very rare form of cancer, raising new questions about the safety of devices which have been scrutinized for decades.

The cancer, known as anaplastic large cell lymphoma, attacks lymph nodes and the skin and has been reported in the scar tissue which grows around an implant. The Food and Drug Administration is asking doctors to report all cases of the cancer so the agency can better understand the association.

Exposure to road traffic noise boosts the risk of stroke for those 65 or older, according to research published online Wednesday in the European Heart Journal.

In a survey of more than 50,000 people, every 10 additional decibels of road noise led to an increase of 14 percent in the probability of a stroke when averaged for all age groups.

When Neil Brown got high on dangerous chemicals sold as bath salts, he took his skinning knife and slit his face and stomach repeatedly. Brown survived, but authorities say others haven't been so lucky after snorting, injecting or smoking powders with such innocuous-sounding names as Ivory Wave, Red Dove and Vanilla Sky.

Some say the effects of the powders are as powerful as abusing methamphetamine. Increasingly, law enforcement agents and poison control centers say the advertised bath salts with complex chemical names are an emerging menace in several U.S. states where authorities talk of banning their sale.

The U.N. health agency says world leaders will discuss efforts to clamp down on junk food marketing to children when they meet in New York on Sept 19-20.

The World Health Organization says heads of state will use the U.N. General Assembly meeting to talk about limiting the number and type of ads that children are exposed to.

Attention, Walmart shoppers: The food in your cart, from fruit drinks to salad dressing, may soon get healthier.

The nation's largest grocer said Thursday it will reformulate thousands of store-brand products to reduce sodium and sugar and push its suppliers to do the same.

Bedbugs have terrorized homeowners and tourists around the world, but U.S. researchers say their genetic analysis of the beasts may lead to better ways to kill them off.

Entomologists at Ohio State University found genes that appear to be pesticide-resistant, according to their findings published Wednesday in the online Public Library of Science.