Ebola – Time to Panic?

Colourised transmission electron micrograph of a Ebola Virus Virion. This media comes from the Centers for Disease Control and Prevention's Public Health Image Library (PHIL), with identification number #10816
Colourised transmission electron micrograph of a Ebola Virus Virion. This media comes from the Centers for Disease Control and Prevention’s Public Health Image Library (PHIL), with identification number #10816

Science and health blogs are going wild. An Ebola epidemic originating in Guédeckou in southern Guinea, West Africa, is causing concern even for those many thousands of miles away. Why is this outbreak any different to the 14 other outbreaks that have occurred since the beginning of the new millenium? Is it true that the outbreak has reached Italy? Should we be worried? I’d like to think that I can help shed some light on each of these questions.

Before I dive into any speculation, it’s worth spending a moment to bring everyone up to speed about Ebola. As the name suggests, Ebola virus disease (EVD) is caused by the Ebola virus (1). Advanced symptoms of infection include vomiting, diarrhoea, and in some individuals, internal and external bleeding. This usually results in organ failure and severe dehydration, and can be fatal in up to 90% of cases.

The fatality rate of a disease isn’t the only important consideration when thinking about infectious disease – pathogens have evolved to maximise their transmission, and understanding how this occurs is essential for controlling their spread. Unfortunately, the prediction and control of the spread of Ebola is complicated by a current lack of understanding about how Ebola spreads in non-human hosts. The natural reservoir (long-term host where most of the viral population can be found) is believed to be various species of fruit bat which could be responsible for introducing Ebola to the area, although no transmission event to humans has ever been proven (2). The virus has also been shown to be carried by macaque monkeys (Philippines), and asymptomatically in pigs (Philippines and People’s Republic of China).

With regard to human-to-human transmission, Ebola virus is incredibly contagious. The virus infects new hosts via mucous membranes (e.g. mouth, urogenital tracts), across broken skin, or via contact with infected blood. However, once an outbreak has been identified, the necessity for direct contact makes control of the disease considerably easier than airborne diseases, despite the fact that symptoms  may not appear for up to 21 days post-infection. Close monitoring must continue even after a patient appears to have recovered because they may remain infectious for up to 7 weeks after losing any symptoms. Unfortunately there is currently no vaccine or drug therapy available, making control of the outbreak incredibly difficult.

The current outbreak probably originated in Guinea many weeks prior to first World Health Organisation (WHO) notification on the 23rd of March which reported 49 cases and 29 deaths (3). Almost one month down the line, the WHO have reported 208 cases and 136 deaths in Guinea, including those of 16 healthworkers (4). This may seem alarming, but you only need to look back to 2007 to find a larger outbreak in the Democratic Republic of Congo (1). So why has this outbreak received so much attention?

An interview in the Independent suggests that the geographic spread of Ebola observed in Guinea is previously unprecedented, affecting a number of different towns, and even reaching across international borders into Liberia where there have been an additional 34 suspected cases (4, 5). This larger than normal coverage may be for a number of reasons. Firstly, there have never previously been any confirmed cases of the disease in Guinea, meaning that the local population are generally either unsure how to respond, or suspicious of the aid workers. Many believe that the health care workers actually harm their patients within their camps and have been blamed for bringing the disease to Guinea with them. Not only have the health workers been actively avoided by infected individuals, but violence has erupted in the Guniean city of Macenta against them (6).

However, the spread of cases into neighbouring Liberia is a far cry from recent rumours of cases in the southern Italian city of Pisa. Although by no means the source, the furthest back that I have been able to track the rumour is to Turner Radio Network, at which point I have been unable to find any further references (7). The website claimed that the virus was introduced to Italy by “40 illegal alien migrant workers“, and that “a statistical probability expert” has predicted that by the time we reach the 70th day of the outbreak the virus will have spread sufficiently that “nearly every place on the globe within 1000 miles of a commercial airport is fair game“. The article then goes on to describe how individuals should best prepare for a global pandemic.

Even if Ebola virus has reached Italy (which I doubt – see below), it is unlikely to spread in western culture. Many of the contributing factors to the spread of the disease in Guinea are irrelevant in more developed countries where healthcare workers are (generally!) respected, ill people seek help (and are more easily traced), and the dead are not touched.

To conclude this post, please allow me a small digression. While I can’t discount that the aforementioned article may be based on truth, I would argue that there are indicators that suggest that the article may not be entirely reliable, and could exhibit a degree of bias. Take from this carefully worded statement what you will, but I would always caution bloggers and readers from swallowing anything that isn’t supported by references or data, especially when something so newsworthy isn’t pounced on by other forms of media. Consider whether an author gains anything from spreading rumours (increased readership, support for a given cause, etc.) and generally consider the reputation of the author or publication. If we do not critically assess what we are reading, it is easy to disseminate false information as rumours that spread faster than the disease itself.

 

References

  1. WHO – Ebola Fact Sheet
  2. Vogel, G, Are Bats Spreading Ebola Across Sub-Saharan Africa? Science Vol. 344 no. 6180 p. 140 (2014)
  3. WHO, 23/03/14 – First notification of Ebola in Guinea
  4. WHO, outbreak as of 22/04/14
  5. The Independent, 13/04/14 – Exclusive A Medecins Sans Frontieres specialist on how the unprecedented spread of the ebola virus in west Africa makes the work of medics tougher than ever.
  6. The Independent, 06/04/14 – Panic as deadly Ebola virus spreads across West Africa
  7. Turner Radio Network, 17/04/14 – Ebola Containment lost…

 

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13 thoughts on “Ebola – Time to Panic?”

  1. I’ve had a few comments on other pages which can be summarised by Frederick Leatherman’s response(http://frederickleatherman.com/2014/04/22/ebola-deaths-exceed-140-and-may-have-spread-to-italy/#comment-277864):
    “this strain of the virus has been described as more deadly and, if ever there were an incubator perfectly suited to spread this disease, it would be the seaport capitol of Guinea with a substantial population living in close quarters without clean water, sewage disposal and access to adequate medical care.”
    My response is included below for interest!

    You are entirely correct to question my conclusion. For a start, it is indeed a new strain of the virus, albeit closely related to the previous Zaire strains seen in DRC (97% similarity, http://www.nejm.org/doi/full/10.1056/NEJMoa1404505#t=article). 3% is potentially a very large difference, although I am yet to read anything that conclusively shows that it is any more virulent than any previously observed strains.

    Regardless, you are also correct to highlight that Guinea provides an ideal environment for the virus to spread around and from, and this is a major concern for control efforts. In an ideal world I would have addressed this more in my post, but in an attempt to keep it short I had to choose between addressing the rumours of Ebola in Italy, or talking about the prospects of Ebola in Guinea. Given that I am not able to shed any more light than the next man on the Guinea situation, I thought it worthwhile to address the (in my opinion) false rumours that Ebola has reached Italy as a way to highlight the importance of critically assessing your sources.

    If I were to speculate on the situation in Guinea (although this is exactly that, speculation), I would argue that as awareness is increased, the spread will be controlled much more quickly. This will be enhanced as communities begin to see people recovering with the help of the healthworkers, and trust is built up. Individuals and families will spot the symptoms much more quickly, and they’ll know to keep the sick individuals away from others. In my opinion it is the lack of previous exposure to the disease, and the resulting unawareness, that has made this outbreak different to previous outbreaks. The infrastructure in the DRC is no better, and most probably worse than that in Guinea, for example.

    However, only time will tell. It’ll be interesting to keep an eye on this and see where it goes – hopefully I’m right (and not for reasons of personal satisfaction!).

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    1. Hello, Crane-Station here. I am married to Frederick Leatherman and blog with him at his site- that is how I got here. Very much appreciate this article on Ebola, and I am going to link it in the comments today at Over Easy on Firedoglake. Thank you so much. I became interested in Ebola years ago when, like many others, I suppose, I read The Coming Plague. My father and brother are pathologists (father retired) who trained at Emory so I sort of grew up with a fascination for all things related to pathogens, and I have come to the conclusion that there may be nothing more sophisticated on the planet, than a virus. Thank you so much for your excellent post, very much appreciated. I will be reading more, here.

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      1. Thank you very much for your kind comment, I am glad that you enjoyed my post. I aim to post on a variety of subjects, and as a virologist/immunologist myself there should be plenty of viruses to satisfy your fascination! I would also like to thank you for offering to link to it from your blog – as you will have noticed I’m just starting up, and so I will always appreciate any help spreading the word about my blog!

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      2. Thank you! You’ve inspired me to set up a Twitter account (@vectorofscience). It won’t be hugely active because it will mainly be a means to advertise my blog, but I’ll put things not worthy of a whole blog post up there. Any re-tweets of these or tweets just advertising my blog posts would be hugely appreciated! I’ll be making sure to keep an eye on your blogs/twitter too!

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  2. While the above article is very well put together in layman’s terms, I have a couple of concerns which I am afraid may affect the spread of this “novel” strain of evd, if it in fact is a novel strain.
    My primary concern is the adopted policy of secrecy by the WHO. “Who” do they think they are? How does the who simply assert the power to restrict knowledge of any kind under the “panic” justification. It only makes reasonable people more leery of an organization wielding self-grabbed powers it should legally not have.
    Secondly, features of this strain are not fully understood or rather, fully known owing to the who’s attitude that the name they have taken implies fitness or recognition by “the world” and reasonable people may have doubts about both the who and un’s ability or right to assert powers in the name of a disease and outbreak they will not be forthright about.
    If this strain is truly novel, with survivability and airborne vector, then any high school student would be right in speculating a “New flu” status with probability of the virus becoming endemic in more places.
    If that were so, we would all know within 30 days and all be at risk within about 6 months.
    There is a LOT more I would like to say, but simply must watch while the loose canon, often inept “who” exercises powers it should not have and says to the world “You’ll know when it hits your town and we take over in the name of health, destroying your food supplies and quarantining your people. But no need to worry, we are the who! Second rate on all fronts by American scientific and medical standards, yet allowed vast powers.”
    I do not like this, yankee doodle I am!
    Best wishes ~

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    1. I’m confused as to what makes you think that the WHO is being secretive. If it is the very vague statement made on Reuters (“A senior health ministry official told Reuters on Thursday the government planned to stop publicly releasing the death toll to avoid causing unnecessary panic”) which has subsequently been mindlessly requoted across the web, I’m afraid that they were actually referring to the Guinean Ministry of Health (link to the article below). I have not seen any evidence that suggests that the WHO have been anything except incredibly open with both their approach and the information that they receive.

      With regard to the WHO claiming powers that it ‘does not legally have’, I am no legal expert, but I expect that this statement is incorrect. The WHO is responsible for advising and cooperating with the government in the country of concern. If the government were adverse to the WHO’s involvement, I have no doubt that there would be little that the WHO could do. However, given that the WHO is made up of the world’s leading public health individuals, I doubt that many countries would shun such support.

      The outbreak has been shown to have been caused by a new strain of the virus (http://www.nejm.org/doi/full/10.1056/NEJMoa1404505#t=article). However, it is not airborne, and is thought to be transmitted in the same way as the main Ebola strains. It has not even been shown to be any more virulent yet.

      Let me know what you think. Equally, if you have any further thoughts or questions (your comment suggested that you would), or if I have managed to overlook one of your points in your previous comment, please feel free to get in touch again!

      Reuters article: http://uk.reuters.com/article/2014/04/17/us-guinea-ebola-idUKBREA3G11W20140417

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  3. Thank you ~ I think at this point we just have to give the standard double incubation periods? Not just allowing for new case possibility but also for science to complete final assessment of the event and release it’s findings.

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    1. Hey ~ well it’s been a bit and I was wondering if you are still thinking the same on this? Haha whew! So many opinions still has me in the “we’ll see” if cynical position.

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      1. My opinion remains the same – I don’t believe that the virus will be allowed to spread very far in developed countries, which is entirely different to reaching them in the first place. Of course, no one knows for sure what will happen. These next few weeks will tell us a lot. It will be interesting to see how Spain handles the situation.

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