The coronavirus is spreading fast beyond its China birthplace but sub-Saharan Africa, one of the world's most vulnerable regions, has so far been almost spared - and experts want to know why.
More than 3 000 people worldwide have died of Covid-19 and almost 90 000 infected in over 45 countries.
Most of these have been in China, but cases are now rising fast in parts of Europe and the Middle East, while the first infection in Latin America was recorded on Wednesday, in Brazil.
But across all of Africa, just a few cases have surfaced - a tally that has health specialists scratching their heads, given the continent's close economic ties with China.
"This is the question that everyone is asking, especially as other regions such as South America or Eastern Europe now have cases," said Amadou Alpha Sall, head of the Pasteur Institute in Dakar, the Senegalese capital.
"The current figures could be the reality, it's hard to know. Maybe it's because Africa is not that connected."
Thumbi Ndung’u, director of a Durban-based infectious disease research centre, SANTHE, said "I don’t think anybody knows" why Africa so far appeared to be unscathed. He also speculated that it could be "there isn't much travel to that particular part of China from Africa – back and forth".
Or "it could just be a coincidence," said Ndung’u.
Could it be a cover up, or cases that have gone undetected? Michel Yao, an emergency response expert at WHO Africa, based in the Congolese capital Brazzaville, said these scenarios were most unlikely.
To detect and hide cases would require an "exceptionally managed" response, he said.
And undetected cases would result in an outbreak that would be "surely detected, because it spreads faster," Yao said.
Could Africa's predominantly hot climate ward off or even kill the virus?
"There is no current evidence to indicate that climate affects transmission," said Rodney Adam, who heads the infection control task force at the Aga Khan University Hospital in Nairobi.
"While it is true that for certain infections there may be genetic differences in susceptibility... there is no current evidence to that effect for Covid-19.
"If the continent can count itself lucky so far, experts say it is just a question of time.
"We think Africa is going to be affected," said Yazdan Yazdanpanah, head of infectious diseases department at Paris's Bichat hospital.
On the plus said, the apparent delay has given African countries precious weeks in which to prepare. Yao said more than half of sub-Saharan countries are now equipped with laboratories that can test for the virus – up from just two a few weeks ago.
"In the beginning we had two, South Africa and Senegal... [now] we have 29 out of 47 countries that have laboratories that can perform the tests. So this is progress," he said.
"We were lucky to have a big window of opportunity," he said.
Another positive is that Ebola outbreaks that have struck parts of West Africa and the Democratic Republic of Congo have generated valuable skills for handling coronavirus.
There is currently no vaccine or cure for the novel virus – the response is to contain it by identifying and isolating patients and carrying out grassroots awareness campaigns.
"This experience may add value on ground," said Yao.
Question of time
Despite this, Africa's vulnerabilities are well known. A 2016 analysis by the Rand Corporation, a US think tank, found that of the 25 countries in the world that are most vulnerable to infectious outbreaks, 22 are in Africa – the others were Afghanistan, Yemen and Haiti. Africa's many conflict zones, poor health infrastructure and porous borders are among the factors that accentuate the risk, it said.
Last week a Lancet study found that only Egypt, Algeria and South Africa had "the most prepared health systems in the continent" to handle the virus.
South Africa announced that 151 of its citizens trapped in China's Wuhan city, would be evacuated and placed in quarantine for 21 days.
In many countries, a sudden surge in numbers of seriously ill patients could overwhelm intensive care units. "Africa is at high risk," said Yao.
On Thursday, Madagascar banned all travellers who recently visited Iran, Italy or South Korea – the latest countries suffering major outbreaks of the virus - from entering the island country, a popular tourist destination.
Several African airlines including Kenya Airways have suspended flights to China, although the continent's biggest carrier Ethiopian Airlines has kept its China routes open.
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