Ebola - Getting Better or Worse??

As we head into September, the wrath of Ebola continues to devastate West Africa. Now over five months since this deadly virus infected its first victim, one wonders where we are in terms of combating the disease. Are infection rates beginning to plateau or are they continuing to rise? And if they are rising, how quickly? This week I decided to answer this question by plotting WHO Ebola data dating back to late March, when the virus first popped up in Guinea. What I found was startling. Not only are infection rates continuing to rise, but they are rising near exponentially. As are the death rates. These exponential curves are depicted in the graph below, with total cases depicted in blue and total deaths depicted in red. Using the equations of the respective lines, I also predicted the total cases and deaths each week through the end of September, depicted as light green points.

At present, the cumulative death toll from Ebola in West Africa stands at 1,552 people, with 3,069 cases. It has become pointless to compare these numbers to anything previously seen from Ebola as this outbreak is so far off the charts. What’s more, it is thought that these numbers are underreported as many patients are dying before ever reaching hospitals, or are refusing to visit doctors due to harsh quarantine measures and stigma. According to my graph above, if this current rate of infection continues, the death toll will reach 2,250 by mid-September, infecting nearly 4,200 people. By the first of October, the death toll will increase further to 3,200, with over 6,100 cases! One can only hope that this trend deviates from its exponential trajectory sooner rather than later.
As of August 26, the Democratic Republic of Congo confirmed an outbreak of Ebola. At the moment, however, this is not believed to share any connection with the outbreak taking place in West Africa. I will keep you posted. In the U.S., there have fortunately been no confirmed Ebola cases, besides the two American healthcare workers who were transported to the U.S. from Africa. Both of these patients, though, have made successful recoveries and no longer carry the virus.

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                                                                                                  -Shahir Masri, MS


Ebola - The Death Toll Rises

The death toll in West Africa has recently exceeded an astonishing 1,000 dead. Official numbers, updated as of this morning, amount to 2,127 cases and 1,145 deaths from Ebola. In terms of infected people, this exceeds the previous worst Ebola outbreak by a factor of 5! To follow up on my last blog, a science/ethics panel which convened last week on the issue of administering experimental medication to infected Ebola patients has concluded that such medication is ethical to use given the severity of the current outbreak, provided that certain criteria are met, such as transparency about care, informed consent, freedom of choice, etc. Further details about the meeting are scheduled for release tomorrow.

When I look at the staggering disease statistics for Ebola and compare them with historic numbers, two things jump out at me. One, the frequency of major outbreaks has increased since the virus was first recognized in 1976. Maybe this is due to better reporting, or maybe not. That this phenomenon is real, however, supports the sensible hypothesis that we will see more and more infectious disease outbreaks as human populations encroach more and more into the native habits of disease-carrying animals. The second thing that popped out at me was the sheer scale of the current outbreak. For a given year, 2014 has already seen over three times more Ebola cases than any previous year, and five times more than any single outbreak, as mentioned. To better put things in perspective, I decided to compile WHO data into a graph, which I’ve shared with you below. I think the graph really elucidates things!

Different ideas are floating around as to what is causing the explosiveness of the present Ebola outbreak, one of which I discussed in my last blog; namely, airborne transmission. Though we put that hypothesis to rest, we have yet to answer the pressing question. That is, to what can we attribute the severity of this ongoing outbreak? To answer this, one must realize that West Africa has previously never been afflicted by Ebola. In fact, previously many West Africans went as far as to deny the existence of the deadly disease. That said, when the 2014 outbreak hit this previously unaffected region, many health workers were largely underprepared to deal with Ebola patients and were not taking the necessary measures to prevent transmission to themselves and others. Local residents too were unaware of the precautions necessary to prevent infection. Furthermore, as the outbreak worsened, the capacity of the local medical system to deal with the enormous influx of severely ill and contagious patients was such that the entire system became quickly overwhelmed; in turn exacerbating the problem and leading to even higher infection rates. These factors, in conjunction with the ease of modern day transport, made for a dreadful combination. In brief, the explosiveness of this outbreak is not due to mutation and aerosolization of Ebola, but simply and tragically to lack of preparedness and infrastructural capacity in a world of better transportation. At present, the WHO and others are working tirelessly to combat the problem. But from what I can tell from recent online interviews, such efforts have not translated to enough in terms of getting real resources to the ground in Africa.  In my next blog, I will create a graph of this outbreak’s infection and fatality rates in order to give us an idea as to whether this catastrophe is near stabilizing or whether things are only getting worse. See you then!

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                                                                                       -Shahir Masri, MS


Ebola: Has the Virus Gone Airborne?

Since my last blog, the World Health Organization (WHO) has reported 68 new cases and 29 new deaths from Ebola in West Africa, bringing the new total to 1,779 infected and 961 dead. These numbers include suspected, probable, and confirmed cases alike. Given the magnitude of this crisis, the recently formed WHO Emergency Committee met for two days via teleconference this past week and unanimously decided that the present outbreak constitutes a Public Health Emergency of International Concern. Importantly, no registered medicines or vaccines currently exist to combat Ebola. This Monday, however, a WHO-organized panel of medical ethics experts will meet to discuss the prospect of using experimental treatments to quell the outbreak.   

As for the title of this blog, while the ongoing Ebola outbreak continues to produce record-breaking numbers of infections, much talk has begun circulating as to the reasons for such a severe outbreak. Among the different hypotheses I’ve heard is the idea that this particular Ebola virus has mutated into an airborne form. Were this hypothesis true, it would of course spell catastrophe for the globe. For this reason, and as promised in my last blog, I’ve decided to dedicate the following paragraphs to addressing this concern.
In general, the assertion of airborne Ebola appears to be mostly conspiracy, although there is some merit to the argument which deserves mention. First, the Ebola virus responsible for the present outbreak is indeed of a strain we have not previously seen, though it may have existed in the region for quite some time. This new strain, however, shares 98% homology with Zaire ebolavirus, which we have seen numerous times over the last 38 years, and which would require no mutations for transmission to be viable through the air. Rather, experiments have already shown Zaire ebolavirus to be stable and infectious in small-particle aerosols. This was observed both intentionally and accidentally in laboratory monkeys at the United States Army Medical Research Institute in 1995, for instance.
When considering such evidence of airborne transmission in monkeys, it is important to keep in mind that a virus’s ability to infect through the air is largely dependent on the viral burden of an animal’s lungs and that animal’s efficiency at aerosolizing particles through exhalation (there are other factors as well). It may well be, in the case of monkeys, that their physiology is such that airborne transmission is an important pathway of exposure. In short, observing such transmission in monkeys does not necessarily mean this route is driving transmission in humans, although admittedly this should raise some eyebrows.
To better answer the question regarding humans, it is more informative to turn to epidemiological studies. Historically, such studies have shown Ebola to spread in close circles, usually to family members or nurses giving care to infected individuals, as well as those involved in the handling or funeral preparations of deceased Ebola victims. In fact, cases of Ebola in people who never had direct contact with other infected people are quite rare, even when infected individuals live in the same household. Where there is no direct contact, there is usually no spread of disease. Even among people who have limited direct contact with patients, transmission is still low, as was learned following the 1979 outbreak in Sudan.
To further consider the “airborne hypothesis,” it is useful to look at the rate of geographic spread of the current epidemic. Were Ebola truly an airborne killer, we would expect the virus to spread much like other airborne killers from the past, such as the SARS epidemic which spread internationally across 26 countries in 2003, or the swine flu which traveled the entire 3,000 mile length of the U.S., infecting all 48 states in a matter of 7 months. By contrast, we are now over five months into the present Ebola outbreak and the virus has remained confined to four nations of western Africa. While four nations is not insignificant, three of these nations happen to share close borders with the epicenter of the outbreak. In brief, the rate of spread of this outbreak, though of grave concern, does not follow the pattern we’d expect of an airborne killer.
In light of low evidence for airborne transmission of Ebola, can we completely rule out the air as a pathway of exposure? No. And this is largely what has aroused suspicion and criticism among the public regarding statements made by the Center for Disease Control and Prevention (CDC). Before hastening to criticism, however, one must note that direct contact (versus airborne) as defined by the CDC includes large airborne droplets, such as those generated from sneezing and coughing. So when they are denying airborne exposure, they are not necessarily denying airborne exposure as perceived by the public. Their acceptance of the virus’s ability to spread through airborne droplets is in fact reflected in their 2005 medical guidelines for managing Ebola which identify the importance of eye and mouth protection. Definitions aside, it would make little sense for the CDC to risk panicking the nation by uttering the word “airborne”, particularly when such transmission accounts for the fewest of Ebola cases and that the media is known for making mountains out of molehills when it suits their interests.
A likely reason for low airborne transmission of Ebola is that the infection does not cause coughing, meaning the generation of infectious airborne particles from the lung is relatively low. This is in stark contrast to SARS which caused incessant coughing and spread rapidly to many countries. So if the virus hasn’t gone airborne, to what can we attribute the explosiveness of the current Ebola outbreak? Are such epidemics likely in the future? In my next blog I will discuss this topic as well as present an informative graph I created that really puts this current epidemic in perspective. See you soon!  

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                                                                                     -Shahir Masri, MS


Ebola: Death Toll Rises in West Africa

Since the CDC hasn't updated their website, I thought I'd provide you with the latest statistics relating to the Ebola outbreak, according to the WHO Regional Office for Africa. 

Cases = 1,711
Deaths = 932
Case fatality rate = 54%

This is madness!
Check in soon for more updates.

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Ebola Virus Outbreak: Background & News

          To those unaware, a deadly Ebola outbreak of historic proportions is ripping its way through West Africa as of this writing. Further history was made last Saturday when an American infected with Ebola virus was flown in an isolation chamber from Liberia to Atlanta’s Emory University Hospital to receive emergency treatment. This represented the first known Ebola patient to ever be treated on U.S. soil, something that has alarmed many Americans. This Tuesday, a second patient is due to arrive to the same hospital for treatment. In this blog, I will briefly outline the latest as it relates to this deadly Ebola outbreak. Additionally, I’ll provide insight as to what Ebola virus is and shed light on its background to help put the current situation in perspective. I am intending to follow and report on this outbreak periodically through a series of blogs. So stay tuned  for updates on the issue.

About Ebola Virus

          Endemic to Africa, Ebola virus disease, as it is technically referred, was first recognized in 1976 in the equatorial region of the continent. Though the reservoir of this virus is not entirely known, it is increasingly thought to reside in non-human primates and bats. Frighteningly, Ebola is about as virulent a disease as we see on this planet, with a case fatality rate of up to 90%. In other words, Ebola kills up to 9 out of 10 people infected, with the least deadly outbreaks still killing over 50% of those infected. To compare, the highest case fatality rates for avian flu are around 60%. The average for West Nile is about 25%. Cholera, though not a virus, kills roughly 0 – 10% of those infected, depending on the country.
          Ebola infection is characterized by sudden onset of fever, extreme weakness and muscle pain, as well as headache and sore throat. Not too dissimilar from the symptoms of common illnesses we’ve all experienced. Later symptoms, however, include diarrhea, vomiting, rash, and impaired function of the kidneys, liver and other organs. In some cases, internal and external bleeding can occur. The current state of knowledge on Ebola transmission is that the virus can be contracted from person-to-person, but that such transmission can only occur through direct contact with bodily fluids of an infected person. I will discuss more on this last point and the possibility of airborne transmission in my next blog.

Situation in West Africa

          Outbreaks of Ebola are not very uncommon, however, most outbreaks are usually confined to small villages, fizzle out quickly, and produce no more than 100-200 fatalities. Among the largest Ebola epidemics was the 1995 outbreak in the Democratic Republic of Congo, which resulted in 315 cases and 244 deaths. By comparison, the present outbreak has already resulted in 1,603 cases and 877 deaths, according to the World Health Organization. These numbers are staggering to say the least!  Furthermore, since the first cases originated in Guinea around Feb/March, the epidemic has not remained confined, nor has it faded away. Instead, it has crossed borders into neighboring Sierra Leone and Liberia, and most recently into non-neighboring Nigeria.
          The present issue is certainly raising concern among health and government officials around the world, particularly given the rapidity with which people in the modern day can move from country to country. The incubation period for Ebola can be up to 21 days, meaning an infected person can easily board a flight and travel to another country before ever presenting symptoms of the deadly virus. Additionally, there has been some talk about the possibility that this Ebola virus is of a strain that can be spread via airborne transmission. Were this true, it would of course warrant enormous concern to nations around the world, far surpassing both the SARS and H1N1 scares. Having spent extensive time studying air pollution and the transport mechanisms of airborne particles, I have my own thoughts on this possibility. However, I will reserve this discussion for Part 2 of this Ebola blog series. Note, depending on how often I post on this topic, I may not link all posts through Facebook, so be sure to "join" or tune into the blog directly for updates. In the meantime, let’s send our prayers to the people of West Africa and all others affected by this terrible epidemic. 

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