The Ebola Epidemic

It’s been a while since my last blog and this time I’m going to write about something topical – Ebola.  Viruses are incredibly interesting biological specimens.  Not “living” until it’s hijacked a host’s cellular machinery where it can have devastating effects.  Heard enough about it already? Well here’s more about Zaire ebolavirus.

photo credit: CDC/ Frederick A. Murphy
Picture of the ebola virus (photo credit: CDC/ Frederick A. Murphy)

What is the Ebola Virus?

Essentially, Ebola suppresses the immune system and attacks the vascular system.  Scientists have struggled to keep pace with its progression as they pin down its sequence of events.  That is why it is still fairly mysterious, yet the effects of ebola have become increasingly apparent.

Specifically, Zaire ebolavirus infects dendritic cells, which display signals of infection to activate T-cells.  Ebola prevents dendritic cells from producing the right signal on their cell surface by inhibiting interferon, meaning T-cells cannot help to clear the infection.  This enables the virus to replicate and spread without delay.

The virus then uses the bloodstream to travel to new sites around the body.  At these new sites, macrophages eat up the virus, becoming themselves infected.  Consequently, they release proteins which trigger blood coagulation and cause blood clots.  Blood clots reduce the supply of oxygen to organs.  Additionally, these macrophages also release other inflammatory proteins and nitric oxide which damage blood vessels and cause haemorrhaging.

The bloodstream can transport the virus anywhere, but its most potent effect is in the liver.  Here it wipes out cells required for coagulation and other plasma components.  In the gastrointestinal tract it causes diarrhoea which can result in dehydration, especially where water is in limited supply like Africa.  In the adrenal gland, the virus damages cells that make steroids which regulate blood pressure.  The ultimate cause of death from Zaire ebolavirus is the resulting drop in blood pressure where patients die from shock and multiple organ failure.

Where Did Ebola Originate?

Now for a little history of the origin of Ebola virus. The epicentre of the outbreak and its first introduction is the region of Guéckédou, which is in Guinea’s remote forest region.

Where the virus first appeared.
Where the virus first appeared.

The outbreak spilled into neighbouring regions of Guinea as well as Liberia and Sierra Leone.  It is likely that the outbreak happened in these states of almost retrograde development because of inefficient and corrupt governments.  These governments are poorly resourced which means they are unable to respond fast enough to contain the spread, not to mention the unsanitary conditions.  This is compounded by infected individuals travelling across the rather porous borders of neighbouring regions of poor infrastructure and notable language barriers.

Zaire ebolavirus is one of the most lethal species of ebolavirus however it is native to Central Africa!  How did it appear in Guinea – a minimum 12 hour drive along rough roads?  Various genetic and serologic experiments point the finger at the fruit bat whose intestinal tract served as a reservoir for ebolavirus.  They are thought to migrate long distances.  The suspects are these adorable fellas:

The little collared fruit bat (Myonycteris torquata).
The little collared fruit bat (Myonycteris torquata).
The hammer-headed fruit bat (Hypsignathus monstrosus).
The hammer-headed fruit bat (Hypsignathus monstrosus).
Franquet's epauletted fruit bat (Epomops franqueti).
Franquet’s epauletted fruit bat (Epomops franqueti).

The first case was in December 2013 at the beginning of West Africa’s dry season.  It is this transition from the rainy to the dry season that is often associated with outbreaks.  Exposure to the virus is thought to be from the hunting and consumption of these fruit bats by humans, which has led to a call to ban the consumption of these animals.

Patient zero has been identified as a Guinean two-year-old, who eventually transmitted the virus to family members, including the grandmother who died as a result.  At the funeral the virus really began to gain traction as mourners who came into contact with the body brought the virus back to their villages.  Remember – it can still spread through the bodily fluids of the deceased!

Should You Panic? Is Ebola Contagious?

If you take sensationalistic journalism too seriously then you might warrant this a cause for panic.  However, it is important to remember that the reason Zaire ebolavirus spread so far and so fast is because of where it hit.  As I have mentioned, Guinea and its surrounding regions lack sufficient healthcare facilities and have unsanitary conditions.  With this in mind, the CDC have issued a Level 3 Travel Warning to Guinea to cull the spread.

A number survive the virus without treatment through rehydration which buys the body some time to fight off the infection.

GlaxoSmithKline (GSK) appear to be leading the charge on the vaccine front.  Unsurprising considering their dominant position in the pharmaceuticals market.  Efficacy trials could start as early as January in Africa, involving 12,000 people.  They estimate to have 24,000 doses available by that time and 230,000 by April provided all goes smoothly and 1 million by December.

Leaked documents from a recent WHO conference explained that a shortage of facilities that can fill vaccine trials under sterile conditions could be a problem.  As a result, it has been suggested that biosafety agencies relax their standards.  A worrying but perhaps necessary procedure.  Usually, it takes many years of human trials for a completely new vaccine to be approved.  This incredible fast track reflects the urgency to control this epidemic.

The danger is that if GSK are left to do this alone, it will affect their ability to make other vaccines.  The good news is that a number of smaller therapeutic companies are coming forward with surprising results.  For example, NewLink Genetics, in Iowa, have synthesised a vaccine which uses livestock pathogen Vesicular stoats virus (VSV) with an ebola gene inserted.

With the USA and other countries following suit on their health measures, I think it unlikely that this epidemic will continue to spread with the strength it has shown so far.  Cleaner and better resourced health facilities in developed countries along with focussed research efforts will undoubtedly reign in this threat.

Final Thoughts – A Conspiracy?

Why did the U.S. Government patent ebola back in 2009 (number CA2741523A1) around the time they prepared mass graves for U.S. citizens?  Is the astonishing rate at which the vaccine is being prepared a reflection of urgency or scripted pre-preparedness?  How will any harmful effects from this highly experimental vaccine be explained? As “mass hysteria” like the paralysis associated with the HPV vaccine in Colombia?

To read more about this check this out.  I agree it sounds a bit crazy but I believe there is at least an element of truth in there…readImage

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