Senegal is a poverty-stricken nation that borders Guinea, one of the three countries hit hardest by the Ebola epidemic in West Africa. More than 1,500 people in Guinea have been infected with the Ebola virus since last December, and more than 900 of them have died.
In Senegal, however, there has been just one case and no deaths.
In Nigeria—Africa's most populous country, with about 174 million people, roughly 21 million of them in Lagos, the continent's largest city—Ebola was carried in by a Liberian American, Patrick Sawyer, who landed at the Lagos airport in July and passed the disease to everyone who helped him, from the officer who escorted him to the hospital to nine of the doctors and nurses who treated him.
At the time, public health specialists worried that an apocalyptic outbreak would sweep through the vast slums of Lagos. The U.S. Consul General in Nigeria, Jeffrey Hawkins, captured the sentiment: "The last thing anyone in the world wants to hear is the two words 'Ebola' and 'Lagos' in the same sentence."
Yet this week the World Health Organization declared that Nigeria's spread had been halted, having infected just 20 people, seven of whom died. The organization also declared both Nigeria and Senegal free of Ebola, because those nations had not had any new cases in 42 days—twice as long as the incubation period for the virus.
Health officials say the Ebola containment efforts in Senegal and Nigeria offer lessons to other nations—including the U.S., where government officials are working to contain the virus in New York and to recover from missteps that allowed the disease to spread from an infected patient in Dallas to two health care workers and raised concerns that dozens more people might have been infected.
"If a country like Nigeria, hampered by serious security problems, can do this," said World Health Organization Director-General Margaret Chan, alluding to recent kidnappings by the Islamist extremist group Boko Haram, "any country in the world experiencing an imported case [of Ebola] can hold onward transmission to just a handful of cases."
Guinea, along with its West African neighbors Liberia and Sierra Leone, crossed that threshold long ago, with more than 4,800 confirmed dead and more than 9,900 infected. Now those countries are trying to head off the worst-case scenario predicted by the World Health Organization: that the three nations at the center of the worst Ebola outbreak in history could see up to 10,000 cases a week before year's end.
In the U.S. the story of Ebola in Dallas—where a Liberian named Thomas Eric Duncan passed the virus to two nurses who treated him—appears to be winding down. One of the nurses, Nina Pham, was declared Ebola free by the National Institutes of Health on Friday. However, in New York City a new chapter in America's experience with Ebola is just beginning—a reminder that the U.S. doesn't have Ebola under control yet.
A doctor, Craig Spencer, who'd recently treated Ebola patients in Guinea, was diagnosed with the disease late Thursday at New York's Bellevue Hospital Center, after his temperature jumped earlier in the day.
At a news conference Thursday night, public officials—including New York Governor Andrew Cuomo, Mayor Bill de Blasio, and Thomas Frieden, director of the U.S. Centers for Disease Control and Prevention—said they would handle the newest case the way all Ebola cases worldwide should be handled: by isolating and treating the patient, tracking down all the people who've come into close contact with him so that they can monitor themselves for any symptoms, and keeping health care workers safe. On Friday, New York and New Jersey officials went a step further, saying they would quarantine health workers returning from the three West African nations plagued by Ebola.
For health officials, the immediate concern on Friday was tracking down people who might have come in contact with Spencer as he rode the city's subway system, visited a Brooklyn bowling alley, and got a ride in an Uber car in the hours before he got sick.
According to officials, Spencer's fiancée and two friends were being placed in isolation, and his apartment in Harlem had been sealed off.
New York officials said they were well prepared for Ebola cases. But the diagnosis of Spencer—who'd returned to the U.S. from Guinea about a week and a half before he got sick—is likely to raise questions about whether, as a precaution, he should have been put in isolation for Ebola's maximum incubation period of three weeks.
Frieden announced this week that all air passengers arriving in the U.S. from Liberia, Guinea, and Sierra Leone—including international aid workers such Spencer—would be tracked by health officials for 21 days after their arrival in the U.S. This means that health officials are in regular contact with the passengers, checking for high temperatures and other signs of illness. Such passengers are not necessarily in isolation, however.
Frieden also made changes to his agency's safety protocols for health care workers to provide "an extra margin of safety" for hospital staffs, including the kind of hands-on training that the Bellevue staff has received.
Frieden said this plan is modeled after a similar program in Nigeria that carefully tracked up to 18,000 people: "We are doing exactly what was done in Lagos."
As the New York City case unfolds, here are four key lessons that health officials say other nations could learn from the successful Ebola responses in Senegal and Nigeria.
1. Trace, isolate, and treat.
American public health officials have been saying it for months: Ebola can be stopped by tracing all the people who could have caught the disease, isolating them so they can't pass it on to others, and treating them quickly if they do develop symptoms.
It sounds simple enough. Nigeria and Senegal have followed the same drill in every outbreak since Ebola was first identified in 1976 near the banks of the Ebola River, in what is now the Democratic Republic of the Congo: Identify and isolate the victims' close contacts and educate them about symptoms. After a few early lapses, proper medical protocol kept health care workers from getting sick.
The same three-step plan has been implemented in the U.S., though the execution was imperfect at first. It now seems to be working in Dallas, where there have been no new cases in ten days.
In New York the process began anew Thursday, as Spencer, feverish and suffering gastrointestinal distress, detailed to public health officials how he'd spent the previous days.
Because he wasn't feverish until shortly before he notified authorities of his illness—Ebola patients are not contagious until they exhibit symptoms such as fever—it's unlikely that Spencer passed on the disease, Mary Bassett, commissioner of the New York City Department of Health and Mental Hygiene, stressed in Thursday night's news conference.
Spencer had traveled about the city on Wednesday even though he'd begun to feel fatigued on Tuesday, officials said, but his fever didn't spike until late Wednesday or early Thursday. The situation was reminiscent of the case involving Amber Vinson, the other Dallas nurse who'd become infected while treating Duncan. Vinson flew to and from Cleveland—apparently with the blessing of public health officials—even though she was feeling the first ill effects of the virus.
Thirteen passengers who were seated within three feet of Vinson during her flights are being monitored for symptoms and have agreed to voluntary isolation. Health officials said that as a precaution they have shut and are cleaning the bowling alley where Spencer went Wednesday and have interviewed the Uber driver who drove Spencer home, even though the health risks are low.
Pham potentially exposed just one person—her boyfriend—before she was diagnosed, which Frieden heralded as an example of successful containment.
U.S. health officials appeared to do a better job of isolating both infected nurses as they were transported to hospitals renowned for their treatment of infectious diseases. Spencer was taken to Bellevue by workers in full protective equipment and is expected to remain there for his treatment.
Meanwhile, in Guinea, Liberia, and Sierra Leone, it's been pretty much impossible to trace and isolate Ebola victims' contacts, because so many people are infected and there still isn't enough medical care. Crowded Ebola treatment units have been forced to turn away patients, and family members often are infected when they care for loved ones.
To compensate, officials have started to provide Ebola treatment kits with instructions and protective gear, allowing families to care for loved ones at home or in community settings—a last-ditch, do-it-yourself version of trace, isolate, and treat.
Health officials are also quickly rolling out a plan to try to contain an outbreak in Mali, which borders Guinea, where a two-year-old sick with the virus apparently traveled by public bus through several cities. "Multiple opportunities for exposure occurred when the child was visibly symptomatic," the WHO said Friday, adding that it is treating the situation as an emergency.
2. Detect early, before lots of people can be exposed.
Anyone with Ebola typically will infect about two more people, according to Frieden, unless something is done to intervene. The bottom line: The sooner Ebola is detected and the faster the victim can be isolated, the smaller the number of people who will become infected.
In Senegal a young man who arrived by car from Guinea was quickly identified as an Ebola patient. Because Guinea is next door, Senegal had been on the lookout for Ebola, with help from its world-class diagnostic laboratory, which can rapidly identify the disease.
With the WHO's help, Senegalese officials spent three weeks tracking 74 people with whom the young man had come into contact. None contracted Ebola.
In Nigeria the virus passed from Sawyer through the hospital that treated him. A scared patient who fled to Port Harcourt seeking better medical care spread the virus to a well-known doctor. But after tracking down hundreds of contacts in Lagos and in Port Harcourt, officials brought the outbreak under control.
"The few contacts who attempted to escape the monitoring system were all diligently tracked, using special intervention teams, and returned to medical observation to complete the requisite monitoring period of 21 days," the WHO said.
WHO officials say they are fairly confident that large numbers of victims are not escaping their notice in Nigeria, Senegal, or other nations near the three most affected countries. "Ebola is really hard to cover up," Keiji Fukuda, WHO's assistant director-general for health security, said during a news conference Thursday in Geneva. "There is reasonable confidence now that we are not seeing widespread transmission of Ebola into the neighboring countries. We think it would be very difficult to miss."
The doctor who initially diagnosed Sawyer, Stella Ameyo Adadevoh, has been praised for quickly identifying the disease and for preventing Sawyer from leaving the hospital, despite pressure from the Liberian ambassador to Nigeria. Apparently, Sawyer wanted to attend a popular Pentecostal church where the pastor claimed to have a miracle cure for Ebola. Adadevoh, who was widely credited with preventing a disaster that could have ensued if she'd allowed the patient to leave isolation, later died of Ebola.
In Dallas early detection initially failed. Texas Health Presbyterian Hospital has apologized for misdiagnosing Duncan when he first came in on September 25, complaining of abdominal pain so severe he rated it an 8 out of 10, fever that spiked to 103 while he was in the emergency room, and vomiting and diarrhea.
For reasons that still aren't entirely clear, the doctors and nurses glossed over the fact that he'd recently flown in from Liberia, where Ebola was running rampant.
Since then, the CDC has ramped up its training, trying to make sure that no doctor or nurse in America will again miss the signs of Ebola. In New York, Spencer contacted authorities when he woke up Thursday with symptoms and told them that he'd recently taken care of Ebola patients.
The CDC has been contacted about 400 times in recent weeks by individuals, doctors, and hospitals about possible Ebola cases. It has been able to rule out roughly 90 percent of them just by asking basic questions such as, Was the person in Liberia, Sierra Leone, or Guinea in the past 21 days?
The CDC also has opened 14 regional labs that can screen blood samples for Ebola, so that every sample no longer needs to go to the CDC's Atlanta headquarters.
A new requirement to screen every air passenger from Liberia, Sierra Leone, or Guinea is also intended to detect cases early. Yet even if the new requirements had been in place, it's not clear whether Spencer would have been required to stay in his apartment for three weeks after his return from Guinea.
In West Africa the lack of early detection aided an explosion in cases. The outbreak began last December when a two-year-old Guinean boy died from a mysterious illness near the border with Sierra Leone and Liberia. The illness spread quickly, but it wasn't until late March that the disease was identified as Ebola, which had never been seen before in that part of Africa.
Many sick Guineans traveled to Sierra Leone to see a renowned healer. When that healer died of the still-mysterious illness in May, hundreds attended her funeral. As many as 365 Ebola deaths have been linked to that funeral. Within a few weeks, the epidemic had spiraled out of control.
3. Strong leadership is essential.
The WHO credited Senegal and Nigeria with beating Ebola because of strong leaders who made the effort a top national priority.
In Nigeria the country's self-interest was clear. Its oil industry makes up half the national economy. If the country were to be shut down by Ebola, it would be devastated. The government also was hungry for a national success story and wanted to show its effectiveness, after the criticism it received when Boko Haram kidnapped hundreds of schoolgirls.
"The most critical factor is leadership and engagement from the head of state and the Minister of Health," the WHO wrote in its summary report about beating Ebola in Nigeria, released this week.
In the United States, critics have faulted the U.S. government for initially expressing confidence in its safety protocols and procedures for health care workers, then suddenly revising them after the nurses became infected. The new measures include hands-on training, complete skin coverage for those dealing with Ebola patients, and enlisting observers to watch workers as they put on and remove protective gear.
The leaders of Liberia, Sierra Leone, and Guinea generally have been praised for recognizing that Ebola was too much for them to handle and asking for global assistance.
But within Liberia, President Ellen Johnson Sirleaf was rebuked by her own parliament when she requested extra powers to respond to the epidemic and to delay upcoming elections. Sierra Leone President Ernest Bai Koroma reconfigured his country's response to the outbreak last week, establishing a new response team that reports to the defense minister rather than the health minister.
4. The public needs to be part of the solution.
Ebola has become a global problem in part because West Africans don't trust their leaders, often with good reason.
After years of civil war, violence, and government corruption, mistrust of government runs deep in Liberia, Sierra Leone, and Guinea. When government officials talked about the need for isolation, tracing of those who'd had contact with infected people, and protective equipment, many people didn't trust them enough to listen, and the disease spread further. Some thought hospital workers dressed in protective gear were devils sent to make people sick.
Gaining public trust is also key to ending the epidemic worldwide. In Nigeria, where government corruption also has been a problem, information campaigns were crucial to stopping the disease, the WHO has said. Efforts there included house-by-house leafleting, messages on local radio stations, and enlisting "Nollywood" stars to deliver health messages.
In the U.S., growing public concerns about Ebola led the federal government to take increasingly aggressive actions, although Frieden continues to reject the idea of banning travelers from Sierra Leone, Guinea, and Liberia, a plan pushed by some critics of President Barack Obama's administration.
When asked what Americans can do to help the global anti-Ebola effort, the WHO's Fukuda suggested that they contain their anxiety.
"Certainly one should have a very healthy respect for this infection, and there are instances where fear makes sense," he said. But "disproportionate fear can really cloud the judgment of people both in the general public and decision-makers ... It's not something which is all that helpful."