Ebola, the emerging threat from Africa, is without doubt a lethal killer. This serious threat has a grossly high mortality rate; the fatality rate for Ebola’s haemorrhagic fever (now known as Ebola Virus Disease, EVD) is roughly 50%, although it can be as high as 90%1.
Although it is currently headline news, Ebola has struck before on a smaller, but no less devastating, scale. Previous cases originating again from Central Africa during the ’70s2 have killed hundreds in rural villages and near tropical rainforests1, but these have always died down after ravaging the local human and animal population. This may have been largely due to the isolated nature of these environments, however this outbreak is different in that it has erupted in crowded urban areas where hygiene awareness is a bit poor, allowing it to flourish in these cramped conditions.
With its notoriously rapid spread – a result of making its victims expel infectious bodily fluids, all fluids, combined with its deadliness it has been difficult to study this virus for the creation of a cure/vaccine. Research on this virus must be done under huge containment protocols (think biohazard suits, sterilisation showers and, literally, an air tight room housed inside another room) and this concoction of factors makes Ebola the perfect candidate for a 28-Days Later wipeout of humanity…right? Panic is gripping the world…But is there anything to worry about? It’s time to face the fear.
Visually Ebola is a filamentous, almost squiggly, enveloped virus2 that like Rabies and the common cold is highly contagious. But how is it so contagious? Ebola is carried within the bodily fluids of its victims; including the blood, vomit, sweat, diarrhoea, mucus, semen and water vapour from the victims’ lungs1, 2. So let’s think about it…If you were in a room with a person suffering from EVD just breathing in the same air as the victim, let alone the vomit and fluids being expelled, would be enough to infect you yourself. Scary!
On top of this, most pathogens have a reservoir to which they ‘retreat’ when an outbreak has dwindled. This can be something like stagnant pools, a lake or an animal, plant or insect that allows the replication of the pathogen without the host being affected detrimentally. It is highly suspected that the reservoir for the Ebola virus is the fruit bat1. Fruit bats can travel far distances and can roost in the eaves and roofs of dwelling places, increasing the risk of transmission to humans. In countries such as Guinea fruit bats are also a delicacy; perhaps then it is no wonder that Ebola outbreaks are common in these places.
Once Ebola has been contracted it takes two days to three weeks for symptoms to appear. At first they are inconspicuous symptoms such as a high fever, sore throat, aches and pains. Vomiting, diarrhoea and a rash can also occur1 with more serious symptoms such as decreases in liver and kidney function and internal and external bleeding. At this point the disease has severely progressed. But why are there so many symptoms to this disease? Why are there so many areas of the body affected? This is because the virus affects pretty much every cell type in the human body, especially the liver and endothelium cells. Endothelium cells are the cells making up and lining the blood vessels and as no area of the body is starved of blood this means that the entire body is open to the devastating effects of the virus. This also explains the internal and external bleeding; as the endothelium cells are destroyed blood is free to leak into the vital organs and out of the body.
Early detection of the disease can mean rehydration therapy can be given to relieve the symptoms of the disease but as yet there is no approved cure or vaccine for the diease1. With these terrifying things in mind the UK government has started to implement airport controls to reduce the chances of the disease entering the country- these include checking passengers from high-risk areas for high temperatures and giving them a self-assessing questionnaire about their state of health. But is this enough? For one it’s hard to track airplane passengers’ intermediate flights and destinations and as there are no direct flights from Sierra Leone to the UK, one of the worst hit areas of the outbreak, will that mean infected passengers could slip by undetected? And the questionnaire… I mean, really? People lie about having nothing to declare and only carrying one pack of cigarettes; are they really going to put their hands up to being a walking health risk? In my own opinion I believe tighter controls will be needed to fully ensure that this outbreak doesn’t run wild but this is an international responsibility and it will take us all pulling together to blunt the advance of this dreadful pathogen.
So keep calm and carry on, people. But stay vigilant.
- 1) WHO Fact Sheets; Ebola http://www.who.int/mediacentre/factsheets/fs103/en/ (Accessed on 16/10/14, at 8:05)
- 2) Wikipedia; Ebola http://en.wikipedia.org/wiki/Ebola_virus_disease (Acessed on 16/10/14, at 8:40)