Doctors at some public hospitals in South Africa have allegedly coerced dozens of HIV-positive women to undergo sterilization over the past three decades, rights groups said Thursday.

The Women's Legal Center, an independent local group, and the international Her Rights Initiative say they have received 48 complaints over coerced sterilization that occurred between 1986 and last year.

A much-hailed law that restricted the opening of new stand-alone fast-food restaurants in one of the poorest sections of Los Angeles did not curb obesity or improve diets, a new study found.

City lawmakers passed the zoning ordinance in 2008 that limited the opening or expansion of fast-food outlets in a 32-square-mile area south of Interstate 10 that struggles with high obesity rates and other health problems.

In a delay that some say may have cost lives, the World Health Organization resisted calling the Ebola outbreak in West Africa a public health emergency until last summer, two months after staff raised the possibility and long after a senior manager called for a drastic change in strategy, The Associated Press has learned.

Among the reasons the United Nations agency cited in internal deliberations: worries that declaring such an emergency — akin to an international SOS — could anger the African countries involved, hurt their economies or interfere with the Muslim pilgrimage to Mecca.

A large-scale trial of a new drug shows it boosts survival chances for Hodgkin's lymphoma, a cancer of the blood that mostly strikes younger people, a study said Thursday.

Known by the lab name of brentuximab vedotin (BV), the drug is the first new treatment for Hodgkin's in more than three decades.

World Health Organization chief Margaret Chan urged global action Wednesday to drive tobacco companies "out of business" and hailed progress in tackling smoking in many countries.

Speaking at the World Conference on Tobacco or Health in Abu Dhabi, she welcomed steps taken by several countries, led by Australia, to introduce plain packaging for cigarettes.

Sierra Leone is planning another three-day, countrywide shutdown later this month to ferret out Ebola cases, remind people how to protect themselves from the disease and control its transmission.

The West Africa Ebola outbreak that has killed more than 10,000 people is declining but the disease has remained stubbornly entrenched in parts of Guinea and Sierra Leone. Liberia, the third country severely affected, currently has no Ebola cases.

Bill Gates opened a mock Ebola field hospital at the prestigious TED Conference on Wednesday as part of a call to be battle-ready for a deadly global epidemic.

The Microsoft software mogul and philanthropist called for "germ games not war games" to train response forces and reveal holes in defenses.

Taking aspirin or ibuprofen tends to reduce the risk of getting colon cancer for most people, but it does not work in a minority of people with certain genes, researchers said Tuesday.

The findings in the Journal of the American Medical Association (JAMA) are based on an analysis of 10 large studies in Australia, Canada, Germany and the United States. More than 16,000 people -- all of European descent -- were included.

About a thousand people still contract tuberculosis daily in Europe and Central Asia, despite an overall decline of the disease, a report by the Europe Centre for Disease Prevention and Control(ECDC) revealed Tuesday.

The report, co-authored with the World Health Organization (WHO), said the continent would not be free of the disease until the next century at the current low rate of eradication, particularly due to prevalence in countries to the east of the region.

France's national cancer institute said on Tuesday there was a "clearly established link" between a rare form of cancer and a certain type of breast implant, as the health minister sought to allay fears.

The national cancer institute (INCa) said there had been 18 cases of the rare disease -- anaplastic large cell lymphoma -- since 2011, linked to silicone breast implants.