Mali authorities on Saturday scrambled to calm fears over Ebola after the disease claimed its first victim in the African country, a contagious toddler who took a 1,000-kilometre journey on public buses before seeking treatment.

The World Health Organization warned the situation in Mali was an “emergency,” and said in its latest Ebola situation report that the biggest outbreak on record has now killed 4,922 people, the vast majority of them in Guinea, Liberia and Sierra Leone, with 10,141 cases reported.

The US states of New York and New Jersey ordered mandatory quarantine for medics who had treated victims of the disease in west Africa, after a doctor who had returned from the region became the first Ebola case in New York City.

President Barack Obama sought to calm a jittery public by hugging one of the two nurses who became the first to contract Ebola on American soil after treating a patient, but has now been declared free of the disease.

Mali President Ibrahim Boubacar Keita aimed to ease fears after the death of a two-year-old girl, the first Ebola case in the landlocked country, who travelled from neighbouring Guinea.

– Mali ’emergency’ –

But WHO said it was treating the situation in Mali as an “emergency” because the toddler had travelled for hundreds of kilometres on public transport with her grandmother while showing symptoms of the disease — meaning that she was contagious.

She was said to be secreting bodily fluids — contact with which is how the virus is passed on.

The girl and her grandmother travelled by public transport from Keweni in Guinea through the towns of Kankan, Sigouri and Kouremale to the Malian capital, Bamako.

The route made for a journey of around 1,000 kilometres (620 miles) that would likely take the better part of 24 hours.

An Ebola victim is contagious when showing symptoms of the virus, such as a high fever.

The Malian authorities were tracing everyone who had contact with the girl and her grandmother and 43 people had been placed under observation, the WHO said.

– Mandatory US quarantines –

New York City’s first Ebola case, 33-year-old doctor Craig Spencer who fell ill one week after returning from treating patients in Guinea, was said to be in a stable condition in isolation at the city’s Bellevue Hospital Center.

His fiancee and two of his friends are in quarantine but appear healthy, officials said.

In the wake of his diagnosis in the country’s largest city, the US states of New York and New Jersey ordered mandatory quarantines of 21 days — the maximum gestation period for Ebola — for any individuals who have had direct contact with an Ebola patient while in the worst affected countries.

Dallas-based nurse Nina Pham, who became the first person to contract Ebola in the US after treating an Ebola patient who eventually died at a Dallas hospital, was declared free of the disease.

Her nursing colleague Amber Vinson, who had also caught the disease, has also been given the all-clear.

– Vaccine doses by 2015 –

The search for an effective vaccine to fight the disease for which there is currently no licensed cure took on fresh urgency as the WHO said several hundred thousand doses could be available in the “first half” of 2015.

Experts are pinning their hopes on the experimental vaccine rVSV, with doses arriving in Geneva for a new round of trials, and ChAd3, made by Britain’s GlaxoSmithKline.

Five other potential vaccines are in the pipeline.

Whichever proves effective in trials, WHO hopes to send huge numbers of doses to Africa for “real-world” tests.