Dakar, Senegal — After Africa’s first suspected case of the Wuhan coronavirus emerged last month in the Ivory Coast, doctors sent a sample from the coughing college student to the closest equipped lab — 4,500 miles north, in Paris.

Officials said the wait for the results, which came back negative, highlighted the need to rapidly expand testing capacity on the continent, where health authorities are scrambling to prepare for a potential outbreak.

No cases have been confirmed so far in any of Africa’s 54 countries, but the risk of an outbreak is high, World Health Organization leaders say. Africa is home to 1.2 billion people, including an estimated 1 million Chinese nationals, who tend to work in business, construction, oil and mining — a testament to Beijing’s increasingly tight relationship with Senegal, Nigeria, Ethiopia and beyond.

Flights from the Asian power bring at least 1,000 travellers to the continent each day. But as of this week, only six labs could test for the coronavirus. (In the United States, all cases were tested at the headquarters of the Centers for Disease Control and Prevention in Atlanta until Wednesday, when test kits were sent to more than 100 state labs.)

“Our greatest concern is about the potential for spread in countries with weaker health systems,” which lack the capacity to detect the virus, WHO Director-General Tedros Adhanom Ghebreyesus said Wednesday.

To address that concern, medical teams from 15 African nations are convening in Dakar on Thursday for an emergency workshop on the first layer of readiness: diagnosing the new virus. WHO officials said 24 countries, encompassing most of Africa’s population, will receive the material needed to conduct the tests by the end of the week.

“We can do a test in four hours,” said Amadou Alpha Sall, general administrator of the Institut Pasteur in Dakar, the region’s top biomedical research facility, “and our goal is to spread that capability.”

The lab was one of only two on the continent that had testing capabilities before Nigeria, Ghana, Madagascar and Sierra Leone received the supplies this week, the WHO said. (The other one was in South Africa.)

The WHO has fielded dozens of alerts about possible infections from 20 African countries since late January. African governments are rushing to ramp up their preparedness, including by building isolation wards, but more specialized training is needed to address a new and fast-spreading problem.

How the new coronavirus compares to Ebola, Zika and SARS

Scientists have identified certain parts of the world as hot spots for emerging diseases. (Blair Guild, Luis Velarde/The Washington Post)

The number of people infected in China climbed sharply this week, with nearly 3,700 new cases reported on Wednesday alone, bringing the country’s total to more than 28,000. China has reported more than 560 deaths. More than 190 cases have been counted in 24 countries, including the United States, Canada and Australia.

As the United States denies entry to foreign nationals coming from China, and as European nations impose varying levels of travel restrictions, countries across Africa are deploying less stringent tactics.

Countries with large numbers of travellers arriving from China are screening at airports with thermal monitors and isolating anyone who shows symptoms.

Mozambique stopped issuing visas for Chinese nationals. South Africa’s postal service no longer accepts packages from China. Six African airlines halted flights they have deemed hazardous, but Ethiopian Airlines has maintained 17 weekly flights to four Chinese cities, not including Wuhan.

In a global ranking last October of 195 countries on their level of preparedness for a “biological threat” by experts at Johns Hopkins University, African nations ranked toward the bottom of the list — with Equatorial Guinea placing last.

“I still think there are places that are flat-out bald in parts of Africa where the coronavirus could just race through,” said J. Stephen Morrison, director of the Global Health Policy Center at the Center for Strategic and International Studies, a Washington think tank.

Sall, head of the Institut Pasteur in Dakar, disputed such characterizations.

“It’s not right to say Africa is the most vulnerable and least prepared,” he said. “That’s based on how they see Africa and not on what’s actually happening.”

Police stopped two Chinese businessmen at Senegal’s border with Gambia last week. No thermal cameras greeted the visitors, who had arrived days earlier from Beijing. No one quarantined them. And no one panicked.

“Police took their addresses and phone numbers,” said El Hadji Mamadou Ndiaye, head of prevention at Senegal’s Ministry of Health. “We’re checking in with them every day for 14 days, and if any sign of the virus arrives, we’re ready for it.”

Have you experienced racism, xenophobia or other discrimination connected to the coronavirus epidemic?

Thirty-eight others who have entered the West African country from China since Jan. 28 have received the same treatment of daily phone calls and doctor visits.

“We can’t afford quarantine,” Ndiaye said. “So we track their whereabouts. If they show even the slightest sign, we come and pick them up.”

A college student who returned to Dakar from China last week with a fever and a cough was tested and cleared, he said, in one afternoon.

Hanging over the response to the coronavirus is the memory of the Ebola epidemic that killed roughly 11,000 people in West Africa from 2014 to 2016.

Doctors know to report cases sooner, Sall said, and quickly share information across borders. Authorities are in regular contact with the WHO, the Africa CDC and Chinese worker associations.

Governments have launched campaigns to educate people about coronavirus symptoms and what to do if they manifest, but authorities have kept a tighter lid on medical data.

Senegalese health officials declined to say how many samples the Institut Pasteur has tested and from which countries.

Cities across sub-Saharan Africa — thought to be the fastest-growing region on Earth — are densely crowded, which elevates the risk for respiratory contagion, experts say.

Multiple outbreaks are ongoing in other parts of Africa, including simultaneous Ebola and measles outbreaks in eastern Congo. If the coronavirus were to arrive in Africa, some resources probably would have to be diverted away from the response in Congo, complicating already fraught efforts there.

Congo’s Health Ministry is generally regarded as competent at containing outbreaks, but health workers have been repeatedly targeted by Congo’s numerous militias, as well as locals suspicious of the motives behind the WHO’s large-scale intervention.

The Ebola outbreak has infected nearly 3,500 and killed 2,250.

Bearak reported from Addis Ababa, Ethi­o­pia, and Bernstein reported from Washington. Borso Tall in Dakar, Senegal, and Lena H. Sun in Washington contributed to this report.