At least 2.6 billion people, over a third of the global population, live in parts of Africa, Asia and the Pacific where Zika could gain a new foothold, researchers warned Friday, with 1.2 billion at risk in India alone.

These are people who reside in as-yet unaffected parts of the world with the right climate and abundant mosquitoes for the virus to settle, spread and propagate an epidemic like the one besetting the Americas and Caribbean, they said.

Run-down roads, reckless driving and poor vehicle maintenance are all being blamed for a spike in deadly traffic accidents in Tunisia that has safety experts worried.

At least 16 people were killed and 85 injured on Wednesday when a lorry's brakes failed and it crashed into a bus in the center of the country.

Singapore urged all pregnant women showing symptoms of fever or rashes to have themselves tested for the Zika virus Wednesday after the number of cases in the city-state soared to 82.

The United States and Britain joined Australia and Taiwan in advising pregnant women to avoid non-essential travel to the city-state.

Singapore clinics Monday reported more Zika infections, bringing the suspected total to 50, as mosquito-fighting teams saturated the scene of the outbreak.

Afghanistan launched a polio vaccination campaign on Monday aimed at reaching children in areas previously controlled by Islamic State group militants, officials said.

Afghanistan and Pakistan are the only two countries in the world where polio remains endemic -- a fact blamed on opposition to immunisation by Islamist groups, who claim the vaccines are a conspiracy to sterilise Muslims or a cover for spying.

Singapore on Sunday reported 40 more cases of locally transmitted Zika virus infections, most of them foreign workers at a construction site.

Donated blood should be tested for the Zika virus, which can cause birth defects, US regulators warned amid a mounting outbreak of the mosquito-borne disease in the United States.

All donated blood should undergo tests for the Zika virus, which can cause birth defects, U.S. regulators said Friday amid a mounting outbreak of the mosquito-borne virus in the United States.

"There is still much uncertainty regarding the nature and extent of Zika virus transmission," said Peter Marks, director of the Food and Drug Administration's Center for Biologics Evaluation and Research.

Asia's population is ageing faster than anywhere in the world, a study said Thursday, warning the swelling ranks of the elderly will cost the region $20 trillion in healthcare by 2030.

Israeli scientists have uncovered how the most severe form of skin cancer spreads to other organs in a discovery that could revolutionize treatment of the disease, they said Tuesday.