Published on 1 Oct 2014

Are we heading for Ebola outbreak in the US?

The US is now dealing with the first case of Ebola to spread outside of Africa. As the size of the epidemic continues to grow exponentially there is a very high chance it won’t be the last.

So how likely is it that the US or other western nation sees a sustained Ebola outbreak? In short: not very.

The biology of the Ebola virus makes it quite capable of international travel. Depending on the route of infection it can take between five and 10 days for someone to become sick with the virus.

During that period a person can feel perfectly well and, with the help of air travel, be capable of moving large distances.

But the rest of the virus’ biology makes it less good at spreading fast into a new area.

Read more: UK volunteers step forward in the desperate battle against Ebola

Even when a person notices initial symptoms like a sore throat and fever they are not outwardly infectious to others.

Only when the disease progresses to fever and fluid loss do they become a lethal danger. Direct contact with their body fluids: blood, sweat, diarrhoea and vomit can pass the infection on.

But because the virus is not airborne, and dies quickly once exposed to sunlight or drying-out on a surface, nearly all cases of infection are linked to direct contact with a person who is very ill or has died from the disease.

The best example of this is an American-Liberian man who travelled from Liberia to Lagos in Nigeria in July. Though he was vomiting on the plane no other passengers were infected.

People who touched him later, including a group who helped him into a taxi at the airport and medical staff who treated him did contract the virus.

However, once authorities in Nigeria knew they were dealing with Ebola they were eventually able to trace all his contacts, and isolate and treat all of them.

Nearly all contacts have now died, survived, or passed the 21-day maximum incubation period of the virus and are assumed to be Ebola-free.
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“I have no doubt that we’ll stop this in its tracks in the US,” said Thomas Friedman the director of the US Centres for Disease Control in Atlanta, which has overall responsibility for Ebola containment.

The CDC will be concerned that this latest case, a man returning to the US from Liberia, sought medical help for a fever but was initially sent home. Doctors in the US and in the UK have been put on alert to treat any cases of fever in people returning from Liberia, Sierra Leone and Guinea as potential Ebola cases.

But now his infection has been confirmed it is almost certain that all his contacts will be traced and monitored for the disease. The US, like many developed countries has the resources to rapidly isolate infected cases and the necessary training and equipment to protect medical staff.

Read more: The terrifying mathematics of Ebola

“Whilst the risk of imported Ebola virus remains small, it’s still a very real risk, and one that won’t go away until this outbreak is stopped. It’s a reminder to the global community that Ebola virus isn’t just an African problem,” said Prof Jonathan Ball, a virologist at the University of Nottingham.

That’s why US authorities won’t be taking any chances. Though with the right procedures Ebola is easily contained, west Africa shows that despite its biological limitations the virus can, and does, present a major threat.

Even a country like the US faced with the thousands of cases seen in west Africa would struggle to contain and control an outbreak. And the only way of preventing that from happening is one new case leading to another.

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2 reader comments

  1. H Statton says:

    I was amazed at the negative response by some people in the United States on finding out that the first of two US aid workers was returning home from Liberia because they had contracted the Ebola virus.

    They were treated at the Atlanta Hospital in a high security containment unit, but despite this it evoked fear enough to ensure the hospital began receiving hate mail.

    Considering the nature of the virus and its fragility on exposure to air, unless there was a case of gross negligence the chances of the virus spreading were infinitesimally small.

    It goes to show the level of ignorance and the power of scaremongering. Although enormous care is needed, to which the epidemic in Sierra Leone and Liberia pays testament to prevent exposure and infection, the US probably has the best facilities worldwide to cope with the virus. Ebola may not be an endemic problem in the US but I’m sure infection ‘units’ could be readily set up in the event of an outbreak.

    After all, if rough and ready huts in Africa are exposing aid workers to the virus on a daily basis, and few have been infected, think how much easier it would be for a state of the art hospital to cope.

    Between 1994 and 2003, 61 cases of Plague were reported in the US. Leprosy (150 to 250 cases p.a.) is still prevalent in Texas and California carried by all things the armadillo, but these ‘mediaeval’ diseases fail to hit the headlines, at least globally.

    Plague is mainly contracted by coming into contact with infected wildlife such as squirrels, wild cats and dogs typically while on hunting expeditions, and although no longer considered an absolute death sentence as it very treatable, the disease still persists.

    A recent article in Scientific American (Sept. 16th 2014) Michael Osterholm of the University of Minnesota suggests that the Ebola virus could become airborne. However, this theory relies upon a large concentration of the virus within its host and a genetic mutation allowing it to cross the respiratory barrier within the lungs.

    At the moment it seems to be a waiting game. No-one appears to know for sure the full potential of the virus, but I find the idea of a US epidemic, moreover a pandemic difficult to imagine at this stage.

  2. Philip Edwards says:

    Tom,

    Odd how the West can mobilise for war so quickly…….but not for a deadly outbreak like this.

    If the same level of scientific intent was applied I am quite sure this horror could be contained.

    No wonder a nurse was in helpless tears today if this is the best Western governments can do. It’s a safe bet they would act like a shot from a gun if it was their family and friends being struck down.

    It is utterly heartbreaking to see such needless carnage amongst helpless human beings.

    It shames us all.

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