Ebola – Epidemics and Academics……

19 Nov

‘Epidemics have the potential to spread around the world killing millions. In 1918 a Flu pandemic infected 500 million people, killing 100 million. Cholera still infects 3 to 5 million people every year. So how much of a threat is Ebola to western nations and how many of us could die…..?’

Ebola is a cruel disease on many levels. Due to the highly infectiousEbola_Virus nature of Ebola the dying are denied the comfort of human contact in their final hours. With affected areas only 24 hours travel from almost anywhere in the world, what are the chances that Ebola could become a pandemic and kill thousands or possibly millions…..?

Estimates of the eventual death toll vary hugely and they are not just ‘stab in the dark’ best guesses. They come from well established models by Epidemiologists but how accurate are they and why do the figures quoted differ so much? Like all predictive models they rely on many variables and the more variables, the more room for errors. For an example; weather forecasts rely on thousands of measurements ranging from hi tech satellite data to simple daily rainfall and temperature measurements; some collected automatically, some by a dedicated army of volunteers. All of the data is then input into one of the most powerful computers in the UK and a forecast is produced. So why do they always seem to get it wrong? Despite the computing power and the accuracy of the models, the shear number of variables make the algorithms extremely complicated, leading to errors.

Ebola_Victim_01Fortunately, modeling the potential spread of Ebola has fewer variables which should mean the predictions are more accurate, so why do the experts opinions vary widely? Epidemiology is well studied and founded on past and current models built upon data collected during and after outbreaks of infectious diseases. In theory having fewer variables requires a less complicated algorithm, so what is having such a major effect on the predicted outcomes? The answer is the degree and urgency of the intervention.

Estimates of the death toll caused by Ebola vary from 700,000 in 2016 as the outbreak ends (confined to Liberia, Guinea and Sierra Leone), to as many as 12 million (unconfined and on an unknown timescale). This is where the speed and scale of the response matters so much. If the action taken by charities, governments and is rapid and proportionate, there could be a reasonably swift resolution. If, however, the response is too slow, the outbreak will spread to neighboring countries as fear increases and has the potential to reach previously unaffected areas, requiring a much greater effort to contain and eradicate it.

The current situation is beginning to stablize but unless the promises of help don’t arrive soon, we could be facing a very different outcome.

To end on a political note, in comparison, when wars begin we seem able to arrange huge logistical operations at the drop of a hat. In West Africa the body count started to mount months ago but the response has only just begun. Only time will tell if it is too little, too late……

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