Ebola: What You Need to Know Now
The 2014 West African outbreak of Ebola virus disease (EVD) is the largest in history. EVD is one of the world’s most virulent diseases, with a fatality rate of up to 90 percent, although in the present epidemic, the rate of death is about 70 percent. The Ebola virus is transmitted to people from wild animals, and fruit bats of the Pteropodidae family are considered to be the natural host. EVD spreads in the human population via direct contact with blood, body fluids and tissues of the infected. Outbreaks occur primarily in remote villages in Central and West Africa, near tropical rainforests. As of late September, there were nearly 6,600 probable and confirmed cases in the four countries of Guinea, Liberia, Nigeria and Sierra Leone and 3,000-plus deaths. The epidemic is of major public health concern worldwide, as it overwhelms the containment, control and medical systems in West Africa.
To answer essential questions about the outbreak, Public Health Quarterly talked to Mark A. James, PhD, professor and chair, Department of Biostatistics, Environmental Health Sciences and Epidemiology, and Christopher J. Woolverton, PhD, professor, Environmental Health Sciences, and director of the Center for Public Health Preparedness. They are experts in tropical diseases and biorisk preparedness and containment, respectively.
Q: How should our readers, largely working in Northeastern Ohio, put the outbreak in West Africa in proper perspective?
Mark James: EVD does not currently present a significant risk in the United States. The public needs to make a clear distinction between imagined fear and real risk. These are terms often used in the public health community. It’s important for the public and news media to appreciate the difference. Our readers are typically more aware of the nature of public health. Still, our populace needs to be continually educated – a taxi driver recently expressed concern and asked me about it. The Centers for Disease Control and Preventionhave an excellent website with information for all levels of understanding about EVD. The World Health Organization has outstanding resources regarding response for public health professionals.
Chris Woolverton: Public health has prided itself in years past on doing true risk analysis in the face of emergency. There is a very strong epidemic in West Africa, and it’s drifting out into more eastern countries. But today, there’s no evidence to suggest that the virulent virus itself has left West Africa in an epidemic fashion. There are no data to suggest that’s happening.
James: It’s important to consider that EVD isn’t contagious unless it’s in the symptomatic stage, two to 21 days post-infection. Those who may have been infected need to be isolated. After that period, those who don’t show symptoms can be determined to be free of the virus.
Q: How did the epidemic reach its current proportions?
Woolverton: There still is not a lot of great data to understand how the virus is transmitted outside of an infected person, nor how long virus particles remain viable after they leave a body. Once the virus digests endothelial cells, there is leakage of blood through skin, so even a dead body can be a source of viral transmission, and contact with a dead body can result in contagion.
James: There are a number of reasons the virus has spread so extensively. According to the New England Journal of Medicine, patient zero is suspected to have been a two-year-old male in southern Guinea, in a village bordering Liberia and Sierra Leone. He died December 6, 2013. His three-year-old sister, his mother and his grandmother all became infected and died. Mourners from three countries came to the grandmother’s funeral, and the virus spread from there. Also, the outbreak is a coincidence between the ecology and poverty in the region. Looking for ways to expand agriculture, people have been cutting down trees after the rainy season. They encounter dead monkeys and fruit bats, which are natural hosts for the virus, become infected and go back to their original communities. Fruit bats can migrate long distances, so it’s thought that this is how the virus got from Central Africa, where there was an outbreak several years ago, to West Africa. In addition, health care facilities are underequipped with personal protective equipment, so workers get infected and spread it to their families. There are traditions regarding preparation of the dead for burial and touching of the dead that also caused things to get out of hand.
Woolverton: The definitive host has not been found. In one particular species of bat, the virus infects, but doesn’t kill, the host. That’s how the virus gets from one population to another. There’s an old adage in microbiology that a good parasite is one that doesn’t kill its host prematurely; if it kills its host before it can get to a new host, it can’t continue its own existence. With human immunodeficiency virus (HIV), for example, a person can spread the virus for 10 to 15 years without knowledge of being infected. With this particular strain of Ebola, the time from onset of symptoms to death in some cases is less than a day, while the person can have been infected for up to three weeks. While we have great immune systems that can compensate for a while, eventual virus damage to the cells that line the bloodstream can overwhelm a patient in an hour.
A large number of citizens in West Africa fear western medicine and rely instead on local tradition and providers, rather than evidence-based practices. And these countries lack adequate access to medicine and containment techniques. It’s important to understand that proper containment and practices like rehydration will prevent EVD spread and return victims to health.
Q: How will the current epidemic in West Africa be stopped?
James: It will be difficult, in the short term. Additional volunteers are severely needed. Doctors Without Borders/Médecins Sans Frontières (MSF) and other aid organizations are overwhelmed. More volunteer physicians and epidemiologists really are crucial. That’s how best to fight the epidemic.
Woolverton: Of great concern is meeting the medical needs of West Africa, whether that is MSF or activating other medically based humanitarian groups that can be trained on containment and control issues to relieve the stress on doctors and nurses so that they can treat the stricken, rather than deal simultaneously with screening, containment and misinformation. Organizations in the United States are often tapped because of larger purses. This is not just an African problem, it’s a world problem. Like during the swine flu pandemic of 2009, we need to mobilize efforts globally to extinguish this epidemic before it takes an even greater toll.
Q: Are U.S. health system workers adequately trained and our facilities prepared for such an epidemic?
Woolverton: Because universities accept students from across the world, as a matter of course we consider how our public health and health care systems would be prepared if EVD showed up at our doorstep. In this region, we have really well-trained medical response resources who are already prepared for any epidemic contingency regardless of its origin. When joined by the public health practitioners with whom they serve, we would have really good diagnostic and containment should something ever begin to erupt.
James: We’re fortunate to be near Akron and Cleveland, where we would have access to health care in a quick fashion, rather than a largely remote, rural area like West Africa. We also have strong expertise in tropical medicine in this region, including the treatment of disease at the Center for Global Health and Diseases within the School of Medicine at Case Western Reserve University (CWRU), and tropical disease research there and here at Kent State’s College of Public Health.
Woolverton: Within our college, we have the Center for Public Health Preparedness, which trains first responders and lab professionals to work with agents like Ebola and other Biosafety Level 3 and 4 select agents. Kent State is a National Institutes of Health (NIH) designated training facility for biosafety and biocontainment. We have the materials and equipment to help folks understand and practice how to prevent transmission of these highly infectious diseases. We typically teach about a dozen folks from around the world annually. It’s a cold training lab, where we use surrogates for the real infectious agents. The trainees are not at risk, but we teach them all the specific duties to use with real agents. Our lab is one of only two officially designated National Biosafety and Biocontainment Training Program facilities. So we’re very fortunate in this area to have research scientists and policy makers at CWRU, the NIH training facility at Kent State, and Cleveland State University’s excellent first-responder training program. Also, we’re not far from Chicago, which boasts the Great Lakes Regional Center of Excellence for Biodefence and Emerging Infectious Diseases Research. So our region is well-prepared.
Q: What should public health students take away from the current epidemic?
Woolverton: It’s a cliché, but we do live in a global village, a global community. It’s important to recognize and share the burdens of others. EVD is in one location today; the very next day, it could be in another location if we are not careful and don’t watch containment. Epidemics spread across borders and know no boundaries in their early stages. Students should take away that we’re in an age in which infectious disease is still a killer of people. We’ve learned about containment and control, but sometimes we’re still at the mercy of these diseases. We also must recognize that as we mess up the environment – as we alter the ecology in which other species live – natural and native viruses and other organisms have nowhere else to go but other populations. Disease spreading more readily is an unintended consequence of this ecological interference.
James: Early on, public health students take an Introduction to Global Health course that covers a lot about these issues. These are not just diseases of developing countries, they’re relevant to us in Ohio given the right conditions. Global health is local health.
Woolverton: I say bravo to students for being in the College of Public Health. If our world is really going to respond effectively to issues like these, we need people who are trained well. That’s the purpose and mission of our college, to do a wonderful job of educating students to go out and deal with these issues.