A drug developed by Swiss giant Roche to treat an aggressive form of breast cancer has been shown to extend patients' lives by almost 16 months, researchers said Sunday.

Patients who took the new Perjeta drug in combination with chemotherapy and Roche's older anti-cancer drug Herceptin lived a median of 56.5 months, compared to 40.8 months for people in the trial who weren't on Perjeta, Roche said in a statement.

An American doctor who was exposed to the Ebola virus in Sierra Leone was admitted Sunday to a clinic of the National Institutes of Health outside Washington.

The patient, whose identity was not revealed, was volunteering as a physician in a unit treating those suffering from the tropical fever that has already killed more than 3,000 people in west Africa since the end of last year..

Australia on Monday ruled out sending doctors to West Africa to help fight the Ebola outbreak there because of logistical problems in repatriating any Australian who became infected with the deadly virus.

Medecins Sans Frontieres, also known as Doctors Without Borders, as well as the Australian opposition party have called on the government to send a medical team to assist in a worsening doctor shortage in West Africa where the worst-ever outbreak of Ebola has killed more than 3,000 people.

Liberia's chief medical authority has placed herself in quarantine following the Ebola death of her deputy, health officials and humanitarian sources said on Sunday.

Dr Bernice Dahn, who is also a deputy health minister, opted to put herself in isolation after her assistant died of the infectious disease on Thursday.

Dr. Rick Sacra knew what he was getting into when he went to Liberia in early August to treat very ill pregnant women and deliver babies at a time when the West African nation was dealing with an outbreak of Ebola.

But Sacra, who contracted Ebola and was treated successfully in an isolation unit at the Nebraska Medical Center before returning home to Massachusetts, shrugged off any suggestion that he was a hero. He said there are many people, including firefighters, police officers and military personnel, who head toward dangerous situations instead of steering away.

An excruciating mosquito-borne illness that arrived less than a year ago in the Americas is raging across the region, leaping from the Caribbean to the Central and South American mainland, and infecting more than 1 million people. Some cases have already emerged in the United States.

While the disease, called chikungunya, is usually not fatal, the epidemic has overwhelmed hospitals, cut economic productivity and caused its sufferers days of pain and misery. And the count of victims is soaring.

The International Monetary Fund fast-tracked $130 million (102.5 million euros) in aid Friday to fight the Ebola epidemic after the governments of the worst-hit countries in west Africa said they were desperately counting on promises of global aid to be backed up with cash.

The IMF's executive board said it wanted to help Guinea, Liberia and Sierra Leone respond to the rapidly spreading outbreak that has killed some 3,000 people since December.

An Egyptian man reportedly cured of Ebola has been quarantined in Cairo as a precaution after returning from Sierra Leone, state media reported Friday.

The 35-year-old had received treatment in Sierra Leone and tested negative for the virus before landing in Cairo on Thursday, the state-owned al-Ahram newspaper reported on its website.

Thousands of experimental Ebola vaccine doses from British GSK and U.S. NewLink should be ready for use by early 2015 in countries affected by the epidemic, the World Health Organization said Friday.

"If everything goes well, we may be able to begin using some of these vaccines in some of the affected countries at the very beginning of next year," said WHO assistant director general Marie-Paule Kieny.

The European Union banned Thursday the party drug nicknamed "bath salts" and other so-called legal highs that have been linked to nearly 150 deaths.

The synthetic stimulant MPDV can spark a psychotic experience for users and was linked to a grisly attack in the United States in which a man chewed off another's face.