Crisis in West Africa

In the six months since the current Ebola outbreak was first identified, it has killed upward of 2,400 people, making it far and away the deadliest episode of the disease to date. In August, the World Health Organization declared a global public health emergency, only the third time it has ever done so. And in early September, its chief, Margaret Chan warned the outbreak is "racing ahead of the control efforts," with an accelerating number of new infections.

The crisis has led Mailman School epidemiologists and infectious disease experts to examine the scope of the outbreak and what’s causing it, how Ebola in West Africa can be contained, and the broader lessons for global health in resource-limited settings. 

While the WHO has said that Ebola infections could top out at 20,000 in six to nine months, Jeffrey Shaman, assistant professor of Environmental Health Sciences, has reason to believe the toll could be far worse. A computer model he created with colleagues as part of the National Institute of Health-funded Models of Infectious Disease Agent Study (MIDAS) program predicts that the WHO number could be surpassed as soon as October. (Findings are posted online.)

"Over the last four or five weeks, the number of Ebola cases has grown exponentially," Shaman says. "Where it will peak is very difficult to know and will depend on the international response to the crisis," but it could climb much higher. Exactly how high is unknown, but Shaman concurs with MIDAS colleague Byran Lewis, a Virginia Tech epidemiologist, that hundreds of thousands could be infected before the outbreak is extinguished.

Urban Outbreak, Overtaxed Health Systems

Already, the number of people killed in the ongoing outbreak exceeds all previous Ebola outbreaks combined. One crucial factor: in the past, Ebola was confined to rural areas, making it much easier to manage. In busy cities, "there isn't enough manpower to track all these cases and make certain we educate people," Ian Lipkin, director of the School’s Center for Infection and Immunity, told National Geographic.

Guinea, Sierra Leone, and Liberia, which have borne the brunt of the outbreak, are among the poorest countries in the world. Each has about the same number of doctors you’d find in a single, medium-sized New York hospital, and many medical centers there lack protective equipment, even running water.

HIV has played a role in exacerbating the outbreak, according to the Mailman School’s Wafaa El-Sadr, although not as you’d expect. Countries in West Africa were largely spared the worst of HIV, but this has meant far less international investment in health systems compared with other parts of the continent that have enormous HIV burdens. "While they’ve been fortunate to not have the rates of HIV that East Africa, Central Africa, and South Africa," says El-Sadr, who is director of ICAP, "they didn’t get the investments that HIV mobilized elsewhere"—a fact that may explain why they have been particularly susceptible to Ebola.

"Ebola shows a lot of our vulnerabilities," says Mailman School epidemiologist Stephen Morse. When the area’s resources pour into fighting the outbreak, countries have a hard time tending to everyday health issues like heart attacks and car accidents, explains Morse. "The reality is that in many of these places, they’re not able to do either to a satisfactory degree."

An unstable political situation adds fuel to the fire. "People don’t trust the government, and they’re suspicious of medical care," says Morse. And when infected people stay away from the hospital, they are more likely to spread the disease to others.

Women and Health Workers at Risk

Whether patients go to the hospital or stay at home, women are more likely to get infected because they are more likely to be exposed to virus. In Liberia, they account for three-quarters of the dead, according to one report. "All around the world, women are the caretakers," explains El-Sadr. "The vast majority of healthcare workers are women, especially nurses."

Recruiting and training additional health workers will be a challenge going forward since many fear getting infected. So far, at least 250 health workers have contracted the virus; and more than half of them have died. "This is the first time I’ve seen international healthcare workers actually avoiding an outbreak," says Morse. "The risk is real," adds El-Sadr. It’s imperative to give health workers what they need to protect themselves, such as adequate training, supplies, and diagnostics, she says. "Without that, it’s hard to ask someone to take the risk."

Opportunity in Health Systems

While better treatments and a vaccine are needed, strong health systems are the lynchpin. "Even if we had a vaccine or treatment ready tomorrow, we need a systematic way of getting it to people," says El-Sadr. "It’s not just the clinics, that are important. It’s also the public health infrastructure."

Strengthening health systems would do much more than fight the current outbreak; it would help the region to fortify itself against any number of future outbreaks, observes Morse. "You would prevent a SARS just as well as you would prevent an Ebola."