Why We Know Ebola Still Isn’t Easy to Contract (Commentary)

Just some quick math to set your mind at ease:

If Ebola were EASY to transmit, there would be a MUCH larger burden of cases in the world right now. Let me show you with math.

Let’s be conservative and say this outbreak started January 1st with one patient. Let’s say this person infected 10 other people, who then infected 10 other people, and so on. With an incubation period of 21 days, and assuming that people can’t transmit the disease until they are symptomatic, it’s pretty easy to calculate where we would be if the above were anywhere close to reality.  (Remember, I’m oversimplifying how this all works, but the answer will still be right enough to make my point).

On Day 21 there would be 10 cases. (1×10)
On Day 42 there would be 100 cases (1x10x10)
On Day 63 there would be 1000 cases (1x10x10x10)
and so on. You’ll notice that with every incubation period, we simply add another exponent to the pile. Period 3 is 1×103, period 4 is 1 x 104, etc.

So for an outbreak that started on January 1st, there have been 290 days (today is Oct 18th, 2014), or 13.8 incubation periods. Let’s round that to 14 to show that a perfectly transmissible virus under these idealized conditions would have caused:

1 x 1014 cases, or 100,000,000,000,000 cases. That’s ONE HUNDRED TRILLION (in American parlay, where a billion is known as a “thousand million” everywhere else) cases, or enough to wipe us all out several times over.

The reality:

Total Cases: 8997

Laboratory-Confirmed Cases: 5006

Total Deaths: 4493

(from cdc.gov)

Ok, this is the worst outbreak of Ebola in recorded history and we need to contain it, and learn how to treat it more effectively.   Every death is a tragedy, and every illness creates anxiety.   I really want you to pay attention to those numbers and understand them, though.  Despite everything, Ebola is hard to catch…this is why in the US (so far, tomorrow could prove me wrong) the only people who have contracted the disease on our soil were health care workers, basically immersed in the stuff.

What’s scary about Ebola is its mortality rate, and the WAY people die from the virus.  We may very soon have some good news on those fronts, too.  People have been discovered who have antibodies to the virus but never got sick.   These people may provide some very important insights into the inflammatory response of the body to the virus which wreaks such havoc.  In addition, there are labs all over the world with mouse-myeloma hybrid cells churning out monoclonal antibodies RIGHT NOW (more on this later if you’re interested) that may very soon give us an unending supply of antibodies to treat infected people.   A vaccine would set people’s minds at ease, particularly if it worked quickly so we don’t have to vaccinate the whole world and only people who have been exposed to the virus (similar to what was done with smallpox).  Ultimately tracking this piece of crap virus down to the animals that harbor it and vaccinating THEM would kick this virus’s ass once and for all.

Anyway, enjoy.  Follow the Ebola story with interest and watch how we defeat it (Nigeria did it, so can we), but don’t panic about it.  Ok?

 

your obt svt,

 

Dr Steve

 

PS: Here’s the CDC’s take on transmission of Ebola virus.  We discussed some of these issues in our podcast last week, and again on the Saturday, Oct 18 episode of “Weird Medicine” on SiriusXM (Sirius 206, XM 103, 10pm Eastern).

Weird Medicine Addendum with Doctor Steve

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