The Ebola Epidemic – Simple and Not So Simple
Tyler A. Kokjohn, Ph.D.
Some aspects of the Ebola epidemic are simple. Hemorrhagic fevers caused by agents like the Ebola viruses are some of the deadliest infectious disease agents known and there is a substantial risk this expanding epidemic will spread across the world. Because vaccines remain in the testing stage and there are no reliable treatment options, the outbreak will be brought under control only if and when the chain of person-to-person virus transmission is broken. Achieving that critical goal will require substantial help from the international community.
Some issues are less clear cut, although it is still possible to get a sense of the situation. The current outbreak began about a year ago in Africa and has already taken a terrible toll in human lives. This is the largest Ebola virus disease epidemic ever seen and it is growing rapidly. However, the experts have only approximate counts of infections and deaths, making it difficult to project what may come next. Epidemiologists, scientists and futurists have warned for decades that viral hemorrhagic fevers and air travel could be a deadly combination. We are now watching that nightmare scenario unfold.
Regrettably, the lack of medical resources has facilitated the spread of Ebola virus disease. Perhaps some looking at those desperate conditions reached an erroneous conclusion: that if a traveler brought Ebola out of Africa, the superior capabilities of the medical care systems in the developed world would suffice to keep disaster at bay. Author and emerging disease expert Laurie Garrett (@Laurie_Garrett) summed up the situation succinctly: a significant impediment to the US public health system response to the Ebola epidemic challenge may have been simple overconfidence.
The arrival in the US of the first Ebola case in a traveler promptly exploded the myth of public health system preparedness. Knowing how to control Ebola infections is one thing, reducing that knowledge to actual practice is something else. Watching the situation in Africa grow worse, Centers for Disease Control and Prevention (CDC) authorities seem never to have asked some simple questions regarding how the US system might respond to the real thing. How long would it take to recognize an Ebola-infected patient had arrived unannounced at a medical center emergency department, an urgent care facility or a private practitioner’s office and what would happen after that? How many medical facilities across the nation were realistically ready to rapidly diagnose, isolate and treat such challenging patients? Perhaps confident that the Ebola infections in the US would be contained quickly, the CDC seems never to have anticipated that some simple errors compounded by a lack of preparedness could end up manufacturing secondary cases in medical personnel with the potential to spark additional, entirely home-grown, outbreaks. The tragic debacle surrounding events in Dallas exposed weaknesses and dramatically heightened public concern over the Ebola threat to the US.
This Ebola epidemic will pose a global public health menace for many months or perhaps even years and we are all simply going have to learn to live with that threat. But it is not going to be easy. One problem is the enhanced surveillance system has a gaping hole. Taking the body temperature of airline passengers may prevent some infectious Ebola carriers from boarding planes or enable them to be recognized on arrival in the US. But had the enhanced screening procedures been in place a month earlier, the late Thomas Eric Duncan, the first traveler to reach the US while incubating an unrecognized Ebola infection, would probably have breezed right through them. In addition, it is unclear if an infected person who takes ibuprofen or other fever-lowering drugs could then pass body temperature screening without being recognized. Influenza season is just beginning and travelers with fever will increase, will the comparatively rare Ebola-infected person get lost when screeners must contend with a large crowd of false alarms?
If air travel poses the greatest danger to spread Ebola to the US, isn’t banning all flights to areas involved in the epidemic a simple solution to the problem? Because the virus is a global threat, ensuring public security involves more than simply locking US borders to air traffic from a few countries. Some actions, although imperfect, have been taken. The CDC has issued advisories to discourage nonessential travel to Ebola epidemic areas and most (but not all) air passengers arriving in the US from those locations are now subject to enhanced screening. Authorities resist imposing outright air travel bans arguing such actions might impede arrival of aid and do more harm than good. In addition, suggesting people will evade any ban by travelling overland to other airports, they argue it could become even harder to detect Ebola-infected passengers if potentially exposed individuals start coming from many origination points. The fact that the control measures have some obvious holes makes it difficult to argue that the public safety is assured. Meeting this particular challenge may ultimately necessitate greatly increased reliance on military resources and we will probably soon see measures that fall somewhere in between a total ban and unfettered free travel.
Ultimately our security hinges on achieving success in two activities: controlling the Ebola outbreak at its source and preventing its spread. The US must participate in a global effort to ensure sufficient essential goods and services necessary to suppress the epidemic reach the affected localities and air travelers departing from outbreak areas are screened thoroughly and advised of their situation appropriately. It may be both cost effective and efficacious to abandon a strictly US-centric perspective as soon as possible and bolster the capabilities of the neighboring African countries not yet involved in the epidemic to screen air passengers prior to departure and deal effectively with any infected individuals. Travel ban or not, travelers incubating Ebola could literally show up anywhere at anytime.
Perhaps 20,000 cases of Ebola virus disease have appeared in Africa to date, yet only one traveler incubating an infection has reached the US. The good news is that the frequency of infected travelers has been low and the US may have sufficient time to improve its response measures before any more arrive in the future. The bad news is that the epidemic is expanding which suggests the risk of spread to new areas is likewise increasing. It is not clear how many simultaneously appearing Ebola cases the US medical system could accommodate and it may not take too many poorly handled situations to simply overwhelm the American public health system. Perhaps the appointment of an Ebola Czar will hasten the adoption of practical and proactive measures to avert that crisis. If any additional infected travelers reach the US and spark more outbreaks in medical personnel or the general public, the demands to impose simple, possibly counterproductive political solutions on the long-term and complicated challenges we face may become irresistible.
The Ebola epidemic is growing and the threat it poses to global public health is expanding. This situation will remain a hazard to global public health for many months or years into the future. Neither a miracle cure nor a vaccine is going to appear and get the world out of this situation, we will simply have to do this one the old fashioned way and break the chain of virus transmission. This will require fostering an international effort with resources sufficient to eradicate the Ebola epidemic in Africa while in the interim working to prevent it from sparking any new outbreaks in the US or other parts of the world.
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Ebola facts – http://www.nytimes.com/interactive/2014/07/31/world/africa/ebola-virus-outbreak-qa.html?_r=0
JayVay 