The first case of human-to-human transmission of the Ebola virus in the US has brought this exotic illness close to home and amplified an already concerned and sometimes fearful public. This is understandable, given the grim facts of this disease: the current outbreak in West Africa is the largest in history and almost half of the nearly 8400 cases have resulted in death. In addition, Ebola is now spreading out of Guinea, Liberia, and Sierra Leone as travel-related cases have been reported in Senegal, Spain, and the United States. To make matters worse, 2 US health care workers have contracted Ebola after caring for an infected patient.How worried should we be? What are the odds that we will catch Ebola? Hopefully the information presented here will help put this disease in perspective. For starters, Ebola is not a "new" disease. It was first recognized in 1976 when approximately 300 cases occurred in Zaire, an African country that is now known as the Democratic Republic of the Congo. The 22 outbreaks that have been recorded since that first event and through 2012 resulted in about 2400 cases and 1600 deaths.
Why is the current outbreak so much larger in scope than previous ones? There are probably many explanations, including the likelihood that diseases today are more rigorously diagnosed and reported. In addition, the world is much more mobile now, with people traveling easily and more frequently around the globe. This phenomenon helps diseases spread farther and faster than they did in the past. Finally, this outbreak is centered in 3 very poor countries with limited means of treating and containing Ebola. Their health care and public health systems are unfortunately not equipped to handle an outbreak of this magnitude.
There is a lot of evidence to support the assertion that it is difficult to catch Ebola through casual contact. For starters, none of the individuals who lived with Thomas Duncan, the only Ebola patient to die in the US, contracted the disease. These people emerged from their 21 day quarantine symptom-free. Secondly, only 2 out of the dozens (or perhaps even more) of US health care workers who have treated the 7 patients hospitalized in the US have become ill with Ebola. These workers are required to handle bodily fluids which have very high viral concentrations (blood, vomit, and feces). This group is therefore very vulnerable to infection if they are not following strict protocols, including the use of protective gear. Finally, the disease is spreading relatively much more slowly than diseases which are highly contagious via the air, (think influenza). This phenomenon is probably due to the fact that the Ebola virus is much larger than other viruses and doesn't appear to be able to stay suspended in air the way that other air-borne viruses can.
Effective management of Ebola requires a comprehensive approach which is familiar to those of us in the safety amd industrial hygiene fields. Adequate resources must be allocated to those governments and groups who are fighting this disease. Policies that will help stem Ebola need to be established. Information that helps us understand the disease and manage our risk needs to be shared. Procedures and practices which specify safe handling and treatment of Ebola patients need to be standardized, effectively implemented, and periodically audited.
Detailed training sessions and drills need to be conducted at a frequency that keeps skills sharp. PPE (personal protective equipment) that effectively isolates workers from the virus must be available and used properly. And finally, each of these elements must be periodically evaluated and potentially modified as best practices and continuous improvement opportunities are identified.
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