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Ebola virus disease: Lessons learned
In early May 2014, it looked like the epidemic in West Africa was under control, and I among others felt that it would follow the path of previous epidemics and just fade away. We were proven wrong by the subsequent explosion of cases. At that time there were about 230 cumulative cases of Ebola virus disease in West Africa. The situations in Guinea and Liberia were stable, and there were no documented cases in Sierra Leone. The epidemic was perceived to be close to over. As of January, there have been more than 20,000 reported cumulative cases in these three countries. Only about 13,500 of these cases were laboratory confirmed. The true total numbers may be either lower than the 20,000 reported due to erroneous inclusion of cases of Lassa fever, malaria and other diseases, or much higher because of false death certificates, clandestine burials and missing cases due to the hiding of patients.
There were a number of reasons for the misguided optimism about early success. First, the importance of the sociological construct of the populations and the impact of a lack of previous experience with Ebola virus disease (EVD) in West Africa were not adequately appreciated. There was great fear, suspicion and overt hostility toward EVD treatment centers and the doctors staffing them, as well as toward those in charge of case finding and contact identification. This led to the hiding of family members with EVD and a lack of identification of cases. As a result, case identification and isolation and contact tracing were much worse than perceived. There was little success in persuading the population to abandon unsafe burial practices. The porous borders of the involved countries resulted in spread over distances, and the occurrence of cases in big cities with crowded conditions was unanticipated. All of these factors led to spread of disease both numerically and geographically. The problem with not identifying cases and contacts may be illustrated by the fact that every confirmed EVD case has about 12 to 20 possible contacts that must be monitored.
The lesson learned and the resulting conclusion must be that, as long as there are cases of unrecognized EVD, there is the potential for spread of disease. The situation is much like an ember restarting a forest fire, or in the words of that famous philosopher Yogi Berra: “It ain’t over ‘til it’s over.”
Donald Kaye
It was assumed that all United States hospitals, because of their experience and expertise in infection control, would be able to safely handle EVD cases. This turned out to be a fallacy due to lack of experience in dealing with EVD on U.S. soil. The lesson is that it is foolish to believe that dealing with a new transmissible infectious disease is as simple as the traditional simplistic medical approach, “see one, do one, teach one.” The complexity and rigor required to safely treat EVD patients was only available at centers that had intensively prepared for the care of such patients. Even with intensive planning there were surprises; for example, Emory University Hospital, one of these few centers prepared to admit EVD patients, had problems dealing with disposal of the unprecedented amount of infectious waste generated by a patient with EVD. Another lesson is that even with our advanced public health system, mistakes due to poor communication will be made, such as the clearance of an exposed nurse to fly even after reporting feeling ill with an elevated temperature.
A lesson that should have been but was doubtfully learned was that medical experts, as well as political and other lay pundits who have had no experience with a new epidemic disease, should be circumspect in their pronouncements. While there is no way to counsel restraint on social media, the press, radio and TV should avoid highlighting the ill-advised statements that stirred the pot when we had the “huge epidemic” of two cases in the U.S. The lesson is that politics and the frenzy to provide continuous news will often trump scientific evidence and can lead to misguided decisions (ie, the New Jersey and New York quarantines on returning EVD workers).
One positive lesson learned was that EVD disease is curable, with a mortality rate well below 50% and approaching 10% when managed in a modern hospital that is prepared to handle EVD cases. Another positive lesson learned was that the capabilities of industrialized countries with resources such as the CDC — once mobilized and added to the resources of WHO and organizations like Doctors Without Borders — were extraordinary. It was unfortunate that it took so long for these assets to be mobilized.
And perhaps more of a caveat than a lesson, we learned that when people analyzed faulty data, they reached drastically high and incorrect predictions for the cost and global economic impact of the epidemic.
Perhaps the most important lesson learned is that there is a need to improve our research funding of “foreign diseases” now that globalization is here. As clearly demonstrated by the EVD epidemic, diseases such as malaria, dengue, avian influenza, Lassa fever and others are relevant to the public health of the U.S., especially with climate change. We need vaccines and effective drug therapy for the broad array of infectious diseases we will have to deal with in the future. We also need more basic science funding to reach a much better understanding of existing zoonotic diseases, such as EVD, as well as potential zoonotic diseases. As emphasized by the One Health concept, the onslaught of many of the recent new diseases we have seen, as well as yet unrecognized diseases we will see in the future, have their origin in the animal kingdom. An example of such an effort is the PREDICT project of the U.S. Agency for International Development. PREDICT seeks to identify new emerging infectious diseases that could become a threat to human health with a focus on wildlife that are most likely to carry zoonotic diseases — animals such as bats, rodents and nonhuman primates. Since 2009, PREDICT has detected 820 unique, new viruses in wild animals and humans in regions where diseases are most likely to emerge.
*Data cited in this article are derived from ProMED-mail.
Reference:
USAID. Excerpted from the PREDICT report. Reducing Pandemic Risk, Promoting Global Health. 2014.
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Donald Kaye, MD, is a professor of medicine at Drexel University College of Medicine, associate editor of ProMED-mail, section editor of news for Clinical Infectious Diseases and an Infectious Disease News Editorial Board member.
Disclosure: Kaye reports no relevant financial disclosures.