Originally published October 31, 2014
Ebola… this is the word on everyone’s lips over the past few months, and rightly so. Since its discovery in the late ‘70s, there have been five species of the Ebola virus in circulation, which up until recently caused a little over 2,300 total cases of human infections. With close to 9,000 cases of Ebola in West Africa just since March of this year, and a mortality rate of at least 50%, this is by far the most widespread Ebola outbreak in recorded history. The Zaire strain of Ebola (EBOV) has been the culprit behind the majority of major human outbreaks throughout the past four decades, and is the strain currently in circulation. However, two major questions remain: (1) What makes this Ebola outbreak so different than all the previous ones, and (2) What steps are currently and should be taken to combat this deadly virus?
So what is it that makes this particular outbreak so unique? Your first response may be to “blame the virus”. Some viruses, such as HIV, are known to have rapid mutation rates that alter the course of disease over time, which leads many to wonder if this is what underlies this particular outbreak. However, mutations do not appear to be responsible for the current spread of Ebola. The first Ebola case study, reported in the New England Journal of Medicine by Dr. Sylvain Baize et al., revealed that the virus is 97% identical to EBOV strains from the DRC and Gabon. With viral mutations not being the driving force behind the outbreak, we must turn our attention to something besides the virus. The unprecedented magnitude of this outbreak is mostly due to a host of social factors, including inadequate basic hygienic tools during treatment (such as private bathrooms), distrust of government due to continued civil unrest, as well as porous borders allowing for unchecked travel between affected areas. All of this has contributed to the formation of a “perfect storm” scenario for the spread of this virus.
Considering that the current Ebola species in circulation has been around since the discovery of the virus, one can’t help but wonder what advances have been made to contribute to treatment or prevention. Many people have now heard of the experimental drug ZMapp, which was used during treatment of the first two Ebola patients in the United States. Through research conducted in the lab of Dr. Gary Kobinger, this drug, consisting of a cocktail of antibodies against Ebola, was shown to be effective in primates when administered early (up to five days post-infection) during viral infection. While no studies have been published to determine the effectiveness of the drug further into disease progression, this is a significant step in the right direction for treatment of Ebola.
Measures are currently being taken to address prevention of Ebola. At the WHO Consultation on Ebola Vaccines on September 29-30 of this year, it was decided that the testing and production of the two most promising Ebola vaccines be expedited. Both vaccines are currently ready for phase I trials, meaning that they have already shown adequate safety and efficacy in at least two different animal models. One of these vaccines, now being produced by GSK in collaboration with the US National Institute of Allergy and Infectious Diseases, has had very promising results in initial studies with primates. In a publication from the NIH Vaccine Research Center lab of Dr. Nancy J. Sullivan this September, the ChAd3(Z) vaccine conferred 100% protection to animals challenged with a lethal dose of Ebola. These along with various other studies provide some hope for the future of Ebola treatment and prevention.
Here at Emory, much is already being done at the clinical level to fight Ebola. At the Emory University Public Health Sciences Grand Rounds on September 19th, the Emory community was given a peek into the treatment regimen of the first two United States citizens infected with Ebola treated here at Emory. Dr. Marshall Lyons explained the many considerations that had to be addressed in order to treat these patients here in the U.S. One can only imagine the logistics behind coordinating a team of over 120 people for the care of these two patients. While the experimental drug ZMapp was included in the patients’ treatment regimen, there was a host of supportive therapy that was critical for the survival of these two patients including but certainly not limited to administration and monitoring of fluids, electrolytes, ventilation, life support, and blood transfusions. The use of adequate sanitation, full isolation of the patients during treatment, and the work of professionals in proper personal protective equipment made it possible for both patients to walk out of the hospital completely healthy. Through the panel discussion at this event, we learned that collaborative efforts are now being made by the CDC along with other health groups around the world to bring some of the more basic medical standards, which we have in the US, to the West African countries most affected by the current epidemic. It is clear, however, that in order for there to truly be a long-term resolution to the issue of Ebola in this region, more efforts will need to be made both to restore public trust in government and to build an adequate infrastructure for health care in the countries affected.