This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
Earlier this month, I posted a Q&A on the Ebola outbreak with a Stevens colleague, medical anthropologist Theresa MacPhail. MacPhail also put me in touch with someone who could provide more insight into the outbreak, Dr. Rohit Chitale of the Armed Forces Health Surveillance Center (AFHSC). Rohit is an infectious disease epidemiologist and had worked at the CDC and WHO before he came to the Department of Defense. Rohit generously agreed to answer some of my questions about the Ebola outbreak.
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Horgan: How much of a threat is Ebola to regions outside Africa?
Chitale: Given various factors including the nature of global travel today, the incubation period of Ebola, and the sheer number of cases in this outbreak, imported cases of Ebola into other regions are a significant possibility. The U.S. Centers for Disease Control and Prevention (CDC), the World Health Organization (WHO), and many nations have established guidance for entry and exit screening (e.g., thermal or fever screening at airports), and many nations had put them in place weeks or even months ago. Regardless, some cases will probably be imported into other nations. However, as many others have indicated including Dr. Paul Farmer as Theresa MacPhail quoted in your blog, if cases occur in nations with a strong medical and public health infrastructure, like the U.S., patients that are suspected for Ebola will be isolated, exposed patients will be quarantined, and we would expect little to no spread of cases locally. So this is really not a direct threat for nations with robust health systems. But where resources are lacking and health systems are inadequate (as in West Africa), and where initial cases are not quickly discovered and managed, there is a real threat of local spread in the community from imported cases.
Horgan: Are there any characteristics of Ebola that limit the threat it poses?
Chitale: Since this is presently not a disease transmitted through the air (i.e., via the respiratory route), this helps limit the number of secondary cases (secondary cases are those that are infected by an initial, or primary, case). Also, healthcare workers and family and friends in close contact with Ebola patients are in the highest risk group for getting sick; this is because they may come in contact with infected blood or body fluids. When healthcare workers get sick, they serve as sentinels, which serve to warn the rest of the community- so this may be seen as a limiting feature. And, given the nature of the symptoms, it’s not easy to hide one’s illness. Most patients that get sick should present for care, or die, and this also helps limit the overall threat it poses. All that said, you can see from the high and growing number of cases that these characteristics are not enough to stop transmission; as the world is well aware of now, the present outbreak is an epidemic, the largest Ebola epidemic we've ever seen. Key drivers behind the continuing transmission in the affected nations include local cultural beliefs, norms and practices, and a general mistrust of national and international authorities. Sadly, the disease is 'winning', in large part due to these anthropological factors.
Horgan: Can you give us the latest statistics on deaths, infections etc.?
Chitale: The statistics are tricky because of the uncertainty in the data due to lack of good surveillance in all areas, that many cases are being hidden from health workers, and that some families are shunning treatment for infected cases. Therefore many cases are not being officially counted and represented in the numbers that are being reported by WHO, CDC, and Ministries of Health. Citing what is being reported by the Ministries of Health of the affected nations, as of 19 September, there are about 5,946 cases and among those cases, 2,623 deaths; however, the actual numbers may be several times higher than what is being reported. There are five affected countries - Guinea-Conakry, Sierra Leone, Liberia, Nigeria, and Senegal. Of all the cases, about 45% have died (though the case-fatality proportion from Ebola virus is normally higher than that). CDC is working with national ministries of health to help make better sense of the numbers so that we can have better data to inform our decisions; though at this point, honestly, there is a significant focus on managing sick patients, finding potentially exposed people, and stopping further transmission. It should also be noted that there is an Ebola outbreak ongoing in the Democratic Republic of Congo, but this outbreak is unrelated to the large West Africa outbreak.
Horgan: What are health authorities doing to contain the Ebola epidemic?
Chitale: A whole host of things are being done. In a response like this, you can categorize the types of things that need to be addressed. For example, and these are not mutually exclusive, they include surveillance, diagnostics, clinical care, contact tracing, medical countermeasures, risk communication (for health care providers and the population at large), guidance (for clinicians, laboratory, and travel/airport), logistics, where to go for information (like trusted websites and portals or dashboards), and more. All of these are being addressed. The United States Agency for International Development (USAID), part of the U.S. Department of State, has activated a Disaster Assistance Response Team (DART) and is working closely with many partners and the governments of the affected nations. The CDC is leading the medical and public health response, and has deployed over 100 people, and more and more will be part of the response over the coming months of this marathon. The U.S. Department of Defense (DoD), where I work, has been directly supporting CDC in its response efforts. And last week, as a direct indication of the gravity of the situation, President Obama announced an enhanced, whole of government response providing a significant role for the Department of Defense. “Operation United Assistance” calls for, in part, the U.S. DoD to deploy an estimated 3,000 troops to provide command and control, medical, engineering, and logistics support to the Ebola control effort.
Horgan: Is a vaccine in the works? Experimental drug treatments?
Chitale: Medical countermeasures in terms of vaccines and treatments are being aggressively pursued. The drug, ZMapp, has been given to a handful of patients, including the two Americans who were repatriated to Emory University in Atlanta. Of these patients, at least two have died, and given this small sample size we don’t yet have adequate information on the effectiveness of this drug. But several efforts are underway. The U.S. Food and Drug Administration (FDA) issued an emergency authorization to use a Department of Defense developed test for diagnosing patients. The U.S. Department of Health and Human Services (HHS) announced a multi-million dollar effort to accelerate testing of ZMapp, an experimental Ebola virus treatment being developed by Mapp Biopharmaceutical. The U.S National Institutes of Health (NIH) plans to begin human safety trials on a vaccine it developed along with GlaxoSmithKline, and other vaccines will begin testing later this year. The U.S Department of Defense has a long standing and robust capability in material solutions, e.g., developing, producing, and transporting 'things', like diagnostics, treatments, protective equipment for health care workers, beds for patients, tents for temporary clinics, and the like. DoD was engaged before this outbreak in developing a number of candidate medical countermeasures for Ebola, and is now working more closely with NIH, HHS, and CDC on these efforts.
Horgan: Do you have any advice for journalists and other communicators reporting on outbreaks of diseases like Ebola?
Chitale: In short, I’d say that journalists should strive for accuracy, and seek to inform the audience without sensationalizing the outbreak. In an age where media often prioritize speed, accuracy in media reports may be sacrificed. But accuracy can help all of us. Part of my job when I was at CDC was to verify reports from media and other data sources (e.g., websites, blogs, email communications, official and unofficial posts, and others) and then use the information to determine if CDC wanted to or could respond to an outbreak. Accuracy in media reports serves to both educate the readers, and especially with respect to resource constrained areas, helps disease detectives shorten the time to detection of an event. The media have for decades been reporting on disease outbreaks- this is nothing new. In fact, in 2002, the media played a critical disease detection role by being among the first to report on an unknown severe acute respiratory syndrome in China that turned out to be SARS.
Horgan: What kind of job are the media doing reporting on Ebola?
Chitale: There is a great deal of coverage, and similar to the weeks and months following the start of the H1N1 2009 pandemic, there is a glut of channels and information on this outbreak. Early during this epidemic, some media outlets appeared to sensationalize rather than educate the public with accurate information. I think this has been improving with more articles containing information from CDC, U.S. government and international experts, which help disseminate the right messages. Over the last decade I’ve seen improvements among many media outlets across the world on how they report on outbreaks. Also, relatedly, electronic translation algorithms have improved, and many of us in the disease detection and response field are aware of global baselines of disease, and how to interpret media reports. In general, the media provide a clue or a lamppost in the location of a problem. I really think that they do a great job in helping us identify the presence of a problem.
Horgan: Besides Ebola, are there any other epidemics that you find alarming?
Chitale: Absolutely. There are many outbreaks that are ongoing throughout the world at any given time – with and without media or global attention- many of which are alarming. Regardless of whether CNN or other media are present, these outbreaks sicken and kill millions of people every year. These include dengue and chikungunya outbreaks, that tend to be explosive in nature and are increasingly global. Novel influenza strains always capture attention, but fortunately to date we have not seen an influenza virus with the transmissibility of seasonal influenza and the pathogenicity and virulence of H5N1 or H7N9. But seasonal influenza still kills tens of thousands, or more, every year. MERS-CoV cases are still occurring, though the outbreak has fortunately slowed; if we’re lucky, it will disappear like SARS- we’ve not seen a case of SARS since 2003. Yet it won’t be the last novel coronavirus that affects humans, so stay tuned. Let’s not forget the global HIV pandemic, and two top infectious disease killers- tuberculosis and malaria. We’ve made great strides with reducing malaria deaths in the last 15 years, but now malaria strains resistant to the best therapy we have for treating malaria (artemisinin) are poised to translocate from Southeast Asia, where they acquired the resistance, to Africa. Tuberculosis continues to be a daily scourge and its drug resistant strains make for an increasingly alarming epidemic. Most people don't know that a significantly large proportion of the world is infected with TB. Much of it is silent or what we call latent tuberculosis infection, but nonetheless, people are infected and the tuberculosis bacteria is just waiting for our immunity to wane to become an active infection. So while our attention often tends to be on viruses, bacteria (like TB) still cause major illness and death every day. But also alarming is the global epidemic of non-communicable diseases, like heart disease, obesity, diabetes, and metabolic syndrome. With our increasingly ‘flatter’ (and fatter) world, we’re only going to see more and more of this.
Interestingly, the current global focus on the Ebola outbreak (epidemic) in West Africa means that we might be potentially missing or ignoring other ongoing or new outbreaks. One silver lining in this West Africa Ebola epidemic and other high profile epidemics, is that they might help bring attention to things that people tend to forget during times when there are not scary outbreaks on the television every day- including the degree of our connectedness and fragility on this planet, the need for constant vigilance when it comes to surveillance for new and old diseases, and, the necessity of a trained and deployable public health workforce.
Dr. Rohit Chitale is the Director of the Integrated Biosurveillance division of the Armed Forces Health Surveillance Center, a U.S. Department of Defense agency that provides health surveillance information to promote, maintain and enhance the health of military and military-associated populations. The opinions expressed are those of the author and do not necessarily represent the positions of the U.S. Department of Defense or its military services.
Photo of Ebola virus particles courtesy Public Library of Science and Wikimedia Commons, http://commons.wikimedia.org/wiki/Ebola#mediaviewer/File:Ebola_virions.png.