The Ebola Epidemic of 2014 - The Revenge of Die Fledermaus
"It may be that without a vaccine, we can't really stop this epidemic" … Peter Piot, a co-discoverer of the Ebola virus in 1976 and director of the London School of Hygiene and Tropical Medicine http://www.spiegel.de/international/world/interview-with-peter-piot-discoverer-of-the-ebola-virus-a-993111.html The people of Africa have suffered calamities both man-made (slavery, colonialism, tribalism, hunger, religious extremism and corruption) and natural (malaria, HIV, Yellow fever). However, in modern times, no affliction has had greater power to conjure fear than the current Ebola outbreak. Ebola, like so many lethal epidemics, is firmly rooted in the social chaos that pervades many African countries. While this bug has a potent biological toolkit to kill healthy humans, Ebola could not so readily wreak havoc were the social determinants of disease not in place. It appears that the virus resides in fruit bats, which are commonly eaten in West Africa. Ebola at some level is an example of politically unstable states resulting in poverty, leading to desperation (eating bats), culminating in disease. In addition, the WHO Ebola response team suggests that population density with substantial migration of people amongst the affected countries and inadequate early attention to case isolation let the situation, which likely started with a single infected toddler, become an international crisis. Health care workers have paid a heavy price: 318 infected including 151 dead. Ebola Virus Disease is caused by a virus of the family Filoviridae. The virus was named after the Ebola River, a landmark near where the virus was first isolated in 1976 that was arbitrarily selected by Dr. Piot and co-workers as a name people would remember (they were right). This particular species of Ebola virus kills ~70% of the people that it infects. By September 14, 2014, 4507 probable and confirmed cases had been reported from five countries in West Africa — Guinea, Liberia, Nigeria, Senegal, and Sierra Leone (2296 deaths) and the day before this blog the first case to be diagnosed in North America occurred. A recent summary of the epidemic in NEJM shows the magnitude of the problem: To see the growth of this epidemic in real-time visit: NEJM and click on the Ebola Times Series: http://www.nejm.org/doi/full/10.1056/NEJMoa1411100?query=featured_ebola Ebola is caused by the four strains of Ebolavirus, which appear to have a reservoir in fruit bats (http://www.cdc.gov/vhf/ebola/about.html). Interestingly the strain of Ebola causing the current epidemic appears to be the same as that which caused an earlier outbreak in the Congo. It is postulated that migrating colonies of fruit bats may have moved the virus to West Africa. (http://www.theguardian.com/society/2014/aug/23/ebola-outbreak-blamed-on-fruit-bats-africa) Like many diseases of Africa, cures come slowly and we are not quite as motivated to find a cure for a disease we perceive to be restricted to “others”. However, as the epidemic grows, and numbers like 1.4 million cases by 2015 with case mortality rates > 50% are thrown about, even the most isolationist North American is becoming concerned about Ebola. One of the many disconcerting aspects of the Ebola epidemic was the discovery that we had (or almost have) a vaccine. It raises questions of when and how fast this would have been rolled out had this epidemic not occurred. Indeed the huge death rate and slow response of the western world to the crisis raises questions about how we should roll out vaccines in epidemics. Is our route of testing and licensing new drugs and vaccines too plodding? Our rigorous testing procedures are designed to mitigate any risk and avoid litigation against manufacturers; this is perhaps an acceptable approach for therapeutics aimed at chronic illnesses but it does not feel like the right modus operandi for intervening in an epidemic. The Ebola outbreak suggests we may need to rethink how we test new drugs when we are confronted with a lethal, communicable illness. Several Pharma companies plan trials of Ebola vaccine, including GSK, Johnson & Johnson, NewLink, Inovio, Pharmaceuticals and Profectus Biosciences
Another therapeutic option is to prevent the virus from entering the cells and causing vascular collapse. This can be done using ZMapp a combination of 3 monoclonal antibodies (2 developed at the National Microbiology Laboratory in Winnipeg and 1 was developed at the U.S. Army Medical Research Institute of Infectious Diseases in Frederick, Md). ZMapp is produced by a small biotech company, Defyrus (http://www.cbc.ca/news/health/ebola-treatment-with-zmapp-cocktail-expected-in-2015-1.2781556). A third promising approach is a strategy akin to decloaking the viruses, removing its shields and depriving it of the tools it uses to damage our cells. Viruses encode miRNAs that regulate genes-both their own and the hosts. These miRNA are small non-coding transcripts that function as posttranscriptional regulators of gene expression and they help make the virus dangerous to the host. Tekmira is a Canadian biotech company that is attempting to cure Ebola by neutralizing the viral miRNAs expression using complementary single-stranded oligonucleotides or so-called anti-miRNAs (http://www.foxnews.com/health/2014/09/23/us-canada-allow-emergency-use-tekmira-ebola-treatment/). The Vancouver-based company said its treatment, TKM-Ebola, has been used in Ebola patients and noted that repeat infusions have been well tolerated. Canada feels confident (? too confident) that we are safe in our icy fortress (http://www.cbc.ca/news/canada/ebola-outbreak-how-canada-s-prep-has-led-the-world-1.2728188). True, we have the public health infrastructure to give better care than can be done in Africa; however, having watched Canadian hospitals struggle with seasonal influenza outbreaks and SARS, I can imagine it would not take too much of an outbreak to cause problems in the homeland. Between the writing of this blog and its publication the first confirmed North American case of Ebola has been diagnosed in a patient who arrived in Dallas Texas from Liberia. In the global village, air travel has the potential to “one up” the fruit bat…moving the disease across oceans. While there is no need to panic the call to action by the WHO and other agencies will now resonate more strongly in North America than it did when this was a West African problem.
So perhaps it is best that we engage in helping our fellow human beings in west Africa-for their good and for ours. Maybe we will develop new accelerated means of testing life saving drugs and vaccines. Perhaps we will harness the power of anti-miRNAs to treat lethal viral diseases. Sadly I suspect that we will not learn the more fundamental lesson (offered previously by the plague, typhoid fever) that good health remains more about adequate access of people to safe food, clean water and education. Throw in good government and freedom from war and viruses will really be nervous. If you are looking for reliable information about Ebola, I suggest you visit the Ebola site, created by Public Health Ontario (PHO), the Crown corporation dedicated to protecting and promoting the health of all Ontarians: http://www.publichealthontario.ca/en/BrowseByTopic/InfectiousDiseases/Pages/Viral-Hemorrhagic-Fevers.aspx#.VCwaBUsnOi9 Or the site created by the US Centres for Disease Control: (http://www.cdc.gov/vhf/ebola/pdf/west-africa-outbreak-infographic.pdf). Ebola Q&A
- How is Ebola spread? Through direct contact with infected bodily fluids during the infections phase of the illness. In African Ebola may also be spread by contact with bushmeat (wild animals hunted for food) and infected bats.
- Could KGH handle a patient with Ebola? According to PHO and CDC Yes. Any hospital that is following CDC’s infection control recommendations and can isolate a patient in their own room with a private bathroom is capable of safely managing a patient with Ebola.”
- What if you are in the epidemic area and return to North America? “Monitor your health for 21 days if you were in an area with an Ebola outbreak, especially if you were in contact with blood or body fluids, items that have come in contact with blood or body fluids”.
- Where not to visit (except to participate in humanitarian work)? Guinea, Liberia, and Sierra Leone.
- An interesting book about Ebola and other hemorrhagic fevers: The 1994 nonfiction thriller. The Hot Zone. It is guaranteed to keep you from exploring bat-filled caves:
I would like to acknowledge the editorial input of Dr. Gerald Evans, Chair of the Division of Infectious Disease at Queen’s University and Dr. Kathie Doliszny, Epidemiologist Specialist at Public Health Ontario (PHO).