Saturday 11 October 2014

Ebola is highly contagious … plus seven other myths about the virus

Extract from The Guardian

The Ebola outbreak is serious, but the nature of the epidemic is often misunderstood – and inappropriate measures suggested
German Red Cross trains Ebola volunteers
A volunteer doctor travelling to west Africa to help care for Ebola patients takes off an isolation suit during during training offered by the German Red Cross. Photograph: Timm Schamberger/Getty Images
The Ebola outbreak has been claiming lives in Africa for many months now, but following the first Ebola death from a case diagnosed outside the continent, coverage – and concern – in the west has stepped up yet another notch.
The outbreak is certainly a grave issue for west Africa, a public health priority, and has been exacerbated by a slow response from international bodies and rich nations. It has already claimed more than 3,800 lives, and could claim far more without an appropriate international response.
But it is also not the species-ending disaster some fear it could be. Below are eight Ebola myths, and an attempt to set out the real position.

1. Ebola is highly contagious

Compared with most common diseases, Ebola is not particularly infectious. The primary risk of catching Ebola comes from the bodily fluids of people who are visibly infected – primarily their blood, saliva, vomit and (possibly) sweat. These can transmit the disease if they make contact with the mucus membranes (lining of your nose, mouth, and similar areas).
Each patient in the current Ebola outbreak is infecting on average two healthy people (this figure, known as the R0 value, can be reduced with appropriate precautions). The Sars outbreak of 2002-03 had an R0 of five, mumps 10 and measles a huge 18. Ebola could be much more infectious than it is.

2. You can catch Ebola from someone who looks perfectly healthy

You almost certainly can’t. Ebola has an incubation period of up to 21 days between infection and showing symptoms (though it’s generally shorter). This is part of the fuel behind fears people could travel from west Africa then spread the disease.
However, in general, people who display no Ebola symptoms are not yet infectious – and in any case, casual social contact (being nearby, or even shaking hands) generally doesn’t spread the virus.
The exception actually lies with those who have had Ebola and recovered: studies suggest the virus can linger in semen for up to three months after recovery – so you may wish to think twice before having sex. Or at the very least, use a condom.

3. If you catch Ebola, you’ll almost certainly die

The most widely cited figure about Ebola is that its death rate is “up to 90%”. The history of Ebola, prior to this year, is a series of short-lived and very isolated outbreaks of different strains of the disease, and it is true that one of these outbreaks had a fatality rate of 90%.
Thankfully, this outbreak has a lower death rate. At present, about 8,000 people have been confirmed as diagnosed with Ebola, and of those 3,865 have, sadly, died. This is a fatality rate of 48% (though it could increase as some of those still ill die) – tragically high, but not nearly as bad as it could be.
Given the rudimentary and overloaded conditions in many of the hospitals in affected areas, it is likely this rate could be lower still for patients with access to top-tier medical care.

4. We should quarantine anyone with ‘Ebola-like symptoms’

This would lead to a lot of people being quarantined: if you want an accurate list of symptoms for early-stage Ebola, simply imagine the last time you (or someone you know) had flu – the two are almost indistinguishable at first.
This set of symptoms, shared among many common ailments, is behind the flurry of incidents at airports of “possible Ebola cases” causing so much coverage and disruption. It’s likely to keep happening, though there should be many more false alarms than real cases.

5. We should screen everyone for Ebola at our airports

Airports take in a lot of people, the overwhelming majority of whom have travelled nowhere near west Africa. Using measures like temperature sensors or similar en masse in western airports would trigger a vast number of false alarms.
The most effective measure, public health officials have repeatedly stated, is to make sure there is effective and comprehensive screening in place for people exiting countries with Ebola outbreaks – though some nations (notably the US) have implemented screening for airports with particularly high numbers of travellers from west Africa.

6. We are not ready for Ebola in the west

We’re about as ready as we can be. The Sars outbreak and pandemic flu scares mean hospitals and public health officials in most countries are required to have contingency plans for both local, small-scale outbreaks and major events.
Rich countries have much more ability to track and isolate those who have been in contact with anyone diagnosed with Ebola, and much better abilities to treat those who have been affected in hospital.
That’s not to say the risk is zero, but generally speaking public health officials are confident of their ability to limit the direct harm Ebola could do to countries like the US or UK.

7. Ebola has brought Africa to its knees

It is important to stress the three nations currently most affected by Ebola – Guinea, Liberia and Sierra Leone – face a public health emergency, social unrest, and economic issues caused by the protracted outbreak. Dealing with this is a humanitarian priority, and more help is needed.
But it is an oversimplification to suggest Ebola is a disaster for “Africa”, a continent of more than 50 countries and a land mass more than twice the size of Europe. The countries currently battling Ebola make up less than 1% of the continent’s economy – for much of Africa, like the rest of the world, it is largely business as usual.
It’s also worth noting that Ebola is far from Africa’s number one infectious killer: malaria, tuberculosis and HIV have each claimed hundreds of thousands of lives – many, many times more than Ebola – already this year, with none of the horrified coverage of the latter.

8. Ebola is the biggest public health disaster imaginable

Ebola is a real issue for the world’s governments, and one they’ve been slow to respond to. But there are many things epidemiologists (and others) think we should worry about far more.
Top of the list is a repeat of a deadly pandemic flu. Despite a few near misses, we’ve yet to see a repeat of the Spanish flu outbreak of 1918, which devastated nations already barely recovered from war, killing the youngest and healthiest.
There are extensive measures in place for such a situation, but officials agree they all leave much to be desired. If you must fear a pandemic, it’s a much better candidate than Ebola.
Ebola is a serious problem, which anyone with a degree of compassion should be concerned about. But if you’re in the west, it is astonishingly unlikely it will affect you, or anyone you know, personally.
Perhaps, though, it’s only that fear that’s making us pay the virus any attention at all.

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