Most deaths from Legionnaires' disease are tied to hospital and nursing home showers, not outdoor cooling towers, new government figures released Thursday show.

Cooling towers are the focus of an investigation into a Legionnaires' outbreak in New York City this summer that is one of the largest in U.S. history. Twelve people have died.

The Ebola epidemic in West Africa could be completely over by the end of the year if efforts to root out new cases are kept up, the WHO chief said Thursday.

World Health Organization director Margaret Chan cautioned there could be setbacks in the coming months but said Guinea, Liberia and Sierra Leone could begin 2016 completely Ebola-free.

A team of U.S. scientists said Thursday they have taken an important step toward engineering painkillers from yeast, a process that has raised both hope and concern worldwide.

The report in the U.S. journal Science describes how researchers at Stanford University genetically engineered yeast to convert sugar into hydrocodone -- an opioid in the same chemical family as morphine -- in just three to five days.

The bars and cafes are full and lively in the northern Ethiopian town of Mekelle -- but they are no longer smoke-filled, with the strict implementation of a smoking ban in public places.

"It's a good thing," said Hiriti, the owner of a small bar in a busy street. "Of course, some customers are not happy, but it also depends on the way you tell them not to smoke.

Estonian authorities say they will cull about 3,700 pigs to prevent the spread of African swine fever.

Agriculture ministry spokeswoman Karin Volmer says two more cases of the disease have been found in domestic pigs in southern Estonia, the northernmost of the three Baltic countries.

Listening to music before, after and even during surgery reduces anxiety and the need for painkillers, according to a comprehensive study published Wednesday.

In a review of more than 70 clinical trials involving nearly 7,000 patients, researchers found music to be a powerful analgesic under almost all circumstances.

An Indian court on Thursday overturned a government ban on Nestle's hugely popular Maggi noodles brand, but ordered further tests before the product can go back on sale.

Nestle had gone to the court to challenge the nationwide ban ordered by India's food safety watchdog in June after tests by some states found lead levels exceeded statutory limits.

Africa has marked one year since the last case of recorded polio, with the United Nations celebrating Wednesday a key step towards eradicating the disease.

The last recorded case on the continent was in Somalia in August 11 2014, although health officials must wait two more years before declaring the continent free from the highly infectious, crippling virus.

Drugmaker GlaxoSmithKline shut down a plant in North Carolina Tuesday that produces inhaled medications after discovering the bacteria that causes Legionnaire's disease, a potentially fatal form of pneumonia.

The manufacturing plant in Zebulon, about 25 miles (40 kilometers) east of Raleigh, was closed after routine testing found the bacteria in a self-standing cooling tower. About 400 of the 850 employees who work in Zebulon were told to stay away until the towers are cleaned, officials for the London-based company said.

Amish chicken farmer Ura Gingerich begins each day by lantern light, but his simple life of tradition is threatened by a modern scourge that has devastated the U.S. poultry industry.

More than 48 million turkeys and chickens have either died by the bird flu virus or been killed to stop its spread since it emerged on the west coast in December and swept across the nation.