Gwynne Dyer: Ebola's exponential growth

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      Here are two good things about the Ebola virus.

      It is unlikely to mutate into a version that can spread through the air, as some other viruses have done. And people who have been infected by Ebola cannot pass it on to others during the incubation period (between two and 21 days). Only when they develop detectable symptoms, notably fever, do they become infectious to others, and only by the transfer of bodily fluids.

      Here are three bad things about Ebola.

      The “bodily fluids” that can transmit it include even the tiniest droplet of sweat: just the slightest touch can pass the virus on. The death rate for those who become infected is 70 percent. And the U.S. government’s Centers for Disease Control warned recently that we could have 1.4 million cases of Ebola by January.

      Since the number of known cases so far is only around 7,500, that suggests that the number of new cases is doubling approximately every two weeks. This is called exponential growth: not 1, 2, 3, 4, 5, 6... but 1, 2, 4, 8, 16, 32.... If you put one grain of wheat on the first square of a chess-board, two on the second, and keep doubling the grains every square, there are not enough grains of wheat in the world to get you to the 64th square.

      Exponential growth always slows down eventually, but the question is when? A vaccine would slow it down, and the British pharmaceutical giant GlaxoSmithKline already has one under development, but it is still in an early stage of testing. Human volunteers are now being given the vaccine to check for unforeseen side effects.

      If no serious side-effects are found, the vaccine will then be given to health workers in West Africa. A process that normally takes years is being compressed into mere months, and 10,000 doses of the vaccine are already being produced (for the health workers).

      But it will be the end of the year before we know if it actually gives a useful degree of protection from the virus.

      If it does, then millions of doses would have to be produced and injected into the people of Liberia, Sierra Leone, and Guinea, where Ebola is already an epidemic— or tens of millions of doses if the disease has spread by then to more populous countries like Ivory Coast, Ghana or, worst of all, Nigeria, which has 175 million people.

      Until and unless a vaccine becomes available in very large quantities, the only way to stop the exponential spread of Ebola in the affected countries is to isolate the victims, a task that is very difficult in mostly rural countries with minimal medical facilities. Liberia with 4.2 millioni people, had only 51 doctors and 978 nurses and midwives at the start of the crisis, and some of those have already died or fled.

      You don’t need to find and isolate everybody who gets the disease to break the exponential pattern. Just isolating 75 percent of them as soon as they become infectious would drastically slow the spread. But at the moment, in the three most affected countries, only an estimated 18 percent of the victims are being taken to treatment centres (where, of course, most of them will die).

      This is why the most important intervention so far has been the dispatch of 3,000 U.S. troops to Liberia, with the primary job of creating 17 large tent hospitals and training 500 nurses to work in them. Britain is providing 200 new hospital beds in its former colony of Sierra Leone, with 500 more in the next few months. Cuba has sent 165 health workers, China has sent 60, and France has sent various teams to help its former colony, Guinea.

      But with the exception of the American aid to Liberia, it is all woefully inadequate. Nine months after the first case of Ebola was confirmed in Guinea, we are still playing catch-up, and playing it badly. Why is that? Aren’t the developed countries also at risk if the virus continues to spread?

      Well, no, or at least their governments don’t think so. Even without a vaccine, they are confident that their health services can find and isolate any infected people quickly and prevent Ebola from becoming an epidemic in their countries. They are probably right, and so they see the limited help they are sending to West Africa as charity rather than a vital self-interest. But they may be wrong.

      As Professor Peter Piot, who first identified the Ebola virus in 1976, said in a recent interview with Der Spiegel, “I am more worried about the many people from India who work in trade or industry in West Africa. It would only take one of them to become infected, travel to India during the virus’s incubation period to visit relatives, and then, once he becomes sick, go to a public hospital.

      “Doctors and nurses in India often don’t wear protective gloves. They would immediately become infected and spread the virus.” Then you would have Ebola on the loose in a country of more than a billion people, millions of whom travel abroad each year. All hope of confining the disease to Africa and driving it back down to almost nothing, as was done in previous outbreaks, would be gone.

      Comments

      13 Comments

      Shane McTarrington

      Oct 8, 2014 at 3:27pm

      People forget that the plague was actually pretty good for your average working stiff.

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      RUK

      Oct 8, 2014 at 4:39pm

      If you care about this at all, please send money right now to Medicines Sans Frontieres. They will take a donation by credit card or cheque, and that money is needed immediately to get supplies to the front line workers so that they can do their job of containment.

      If you care even more than that, please contact your MP and Stephen Harper. We're sending some gloves and stuff but MSF really needs people and so far only the US is responding to their call for military and civilian support.

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      Proper Solution

      Oct 8, 2014 at 9:08pm

      The proper solution is military quarantine in infected areas. Ebola runs hot and fast, so if people are confined to their homes for a month, then the disease will burn itself out. It's too bad the USA is in Iraq instead of doing something useful like enforcing a quarantine in africa.

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      World War Z

      Oct 9, 2014 at 9:53am

      "Train is in the station!"

      Janice Vian

      Oct 9, 2014 at 12:01pm

      And the pilgrimage to Mecca is occurring now, with large numbers of African Muslims mixing in overcrowded conditions, with other Muslims from all over the world. After Ramadan, they all go home. I will be very surprised if this situation does not create a world-wide dispersal of Ebola.

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      Paul Wolf

      Oct 9, 2014 at 12:57pm

      Great article. Gwynne Dyer is always ahead of the pack journalists. Do the math - if it keeps doubling every few weeks it wont take long to get to millions of infected people. That means orders of magnitude more people getting on airplanes to rich western countries. And of course if Ebola took hold in India, it would be a catastrophe like we have never seen in our lifetimes. Lets send as many troops as needed, if this will help control the outbreak.

      shoegazer

      Oct 9, 2014 at 2:24pm

      @Shane McTarrington...with the emphasis on "stiff." Wake up,it may be later than you think.

      Math Man

      Oct 9, 2014 at 7:07pm

      If a vaccination is not developed in the next 41 weeks then n 41 more weeks there will be 7,864,320,000 infected (which is most of the world's population) and after about 2,359,296,000 will survive. The good news? Vancouver real estate will be much cheaper in 2015.