A candidate vaccine against the joint disease chikungunya, endemic to Africa and south Asia but moving north- and westward, showed promise by provoking an immune response in human trials, its developers said Friday.

The trial drug is made with nanoparticles that resemble a West African strain of the virus, which causes high fever and intensely painful arthritis, said a study in The Lancet medical journal.

U.S. President Barack Obama called his counterparts in Liberia and Sierra Leone Thursday to discuss the Ebola outbreak in West Africa, the White House said.

The calls to Presidents Ellen Johnson Sirleaf of Liberia and Ernest Bai Koroma of Sierra Leone came as the U.S. State Department ordered families of its diplomats in Sierra Leone to leave the country to avoid exposure to the disease.

People around the world eat twice as much salt as they should, and this behavior translates into 1.65 million heart-related deaths per year, researchers said Wednesday.

Excess salt can cause high blood pressure, which is leading factor in heart disease and stroke, according to the study in the New England Journal of Medicine.

Older people are likely to benefit from a high-dose flu vaccine to ward off the seasonal malaise, which can be particularly dangerous to those over 65, researchers said Wednesday.

The findings in the New England Journal of Medicine are from the first randomized, controlled trial to compare high and standard doses of flu vaccine in older people.

Being overweight boosts the risk of 10 common cancers, said a study of five million UK adults that prompted a call Thursday for tougher anti-obesity measures.

Researchers calculated that 12,000 cases of these 10 cancers every year in the UK were attributable to excess body weight.

Guinea declared an Ebola outbreak that has killed 377 in the nation a "health emergency" and more flights from hard-hit west African countries were cancelled as the region awaited shipments of experimental vaccine.

Guinean President Alpha Conde on Wednesday announced a series of measures including strict controls at border points, travel restrictions and a ban on moving bodies "from one town to another until the end of the epidemic".

The Ebola virus killed 56 people in just two days, bringing the global death toll to 1,069, the World Health Organization said Wednesday.

The death toll, which passed the 1,000-mark at the weekend, soared higher between August 10 and 11.

Several hundred mourners joined a funeral service on Wednesday for a Spanish priest who died from Ebola after being infected in Liberia, becoming the first European victim of the worst-ever outbreak of the virus.

A black hearse transported an urn containing missionary Miguel Pajares's ashes to the chapel of the San Rafael hospital in Madrid, which was decorated with floral arrangements, including one sent by Spain's royal family.

Representatives of the Gulf monarchies met in Riyadh on Wednesday to discuss precautions against the Ebola epidemic ahead of the annual hajj pilgrimage to Mecca in early October.

The executive bureau of the Gulf Cooperation Council's committee of health ministers met in the light of "preventive measures taken by some countries to protect against the Ebola virus... and the approach of the hajj," bureau director Taufik Khoja said.

Canada is sending up to 1,000 doses of an experimental Ebola vaccine to West Africa to help the WHO fight an epidemic, the health minister announced Wednesday.

Minister Rona Ambrose said between 800 to 1,000 doses would be distributed through the World Health Organization where it is needed.