Thursday, December 11, 2014

Number Crunching Reported Cases

Courtesy of Reddit and user c0mputar, here are the 4-day daily case totals of reported Ebola cases going back to late August:

  • Dec 4th-7th: 102/day
  • Nov 30th-3rd: 128/day
  • Nov 26th-29th: 129/day
  • Nov 22nd-25th: 129/day
  • Nov 18th-21st: 120/day
  • Nov 14th-17th: 122/day
  • Nov 10th-13th: 165/day
  • Nov 6th-9th: 185/day
  • Nov 2nd-5th: 115/day
  • Oct 29th-1st: 115/day
  • Oct 25th-28th: 146/day
  • Oct 21st-24th: 107/day
  • Oct 17th-20th: 168/day
  • Oct 13th-16th: 127/day
  • Oct 9th-12th: 130/day
  • Oct 5th-8th: 132/day
  • Oct 1st-4th: 124/day
  • Sept 27th-30th: 138/day
  • Sept 23rd-26th: 129/day
  • Sept 19th-22nd: 137/day
  • Sept 15th-18th: 130/day
  • Sept 11th-14th: 124/day
  • Sept 7th-10th: 127/day
  • Sept 3rd-6th: 105/day
  • Aug 30th-2nd: 104/day
  • Aug 26th-29th: 101/day
  • Aug 22nd-25th: 101/day

  • With all the caveats regarding "official" reported numbers vs. actual cases, and noting that this includes periods where nations added - and subtracted - thousand-plus numbers into short periods, what's notable is that since late August, this outbreak hasn't been below 100/new cases day. It's also never gotten as high as 200 cases/day.

    IMHO, that points to this range being the maximum number of tests that can be run in one day, and/or the maximum number of people who come forward for testing, versus any approximation of the actual number of people infected in any place or period.

    Which explains everything else about supposed flattening of the growth curve.
    The fact that it isn't going anywhere, up or down, is proof that there are always (for the last nearly 4 months) at least 100 people so sick with Ebola that they'll finally drag themselves to an ETU - or collapse in the street - for isolation and testing. (It's more than that, but a notable number of them die before testing, which opts them out of the process with some finality, while simultaneously letting those nations elect to not count them in the death stats, since the cause of death is thus "unknown". How convenient. Shovel, shut up, and keep the news cheerful. QED)

    So what this tells us is more like a tachometer than a speedometer of the infection: it tells us how fast the labs are cycling tests.
    It doesn't tell us what gear the infection is in, if you will.

    It might be fair to think things were winding down, except for recent note that burials are humming along everywhere, while stacks of unburied bodies are being discovered all over Sierra Leone, while in Guinea, the spread of the disease simply refuses to taper off. Liberia seems mainly to have mastered the use of pencil erasers to solve their statistical problems.


    1. How does a pcr test take?
      I tried to Wikipedia it but, well, you probably know better.
      Is it a fully automatic process or lots of manual intervention?

      I hit on the 'its not peak cases its peak testing' idea, just wondering how hard testing is?
      Are med techs measured in tests per minute, hour or day?

      1. My understanding is that the bottleneck with the testing is related more to transporting the samples than it is to the actual test. Roads are bad, vehicles are in short supply, and the whole thing is quite disorganized (leading to inefficient use of resources, e.g. transporting a single sample at a time to the lab). But to compare, when there's a possible case that turns up in the U.S., test results seem to come back about half a day later, usually. In Africa, the turnaround time is several days.

        Interestingly, there was an article back in mid-November that Sierra Leone had greatly increased its testing capacity with the opening of a newly-built British lab, reducing turnaround time for Ebola tests from nine days(!) to two. That corresponds with the time-frame of the case numbers in SL starting to go up suddenly. So the sudden surge of new cases in SL may just be a reflection of greater testing capacity rather than how fast the virus is spreading. That's... not good.

        Hey, here's an idea: if we shut down all the labs, we can officially declare the Ebola epidemic "over", with zero additional confirmed cases. I should get the Nobel Prize for Medicine for that, right?

      2. So its a distributed patients centralised lab problem.
        Makes sense

    2. Maybe not the Nobel Prize, but Asst. Minister of Public Health in any or all three of the primarily affected countries is well within the realm of possibility.

      Likely though they'd just steal the idea, and leave you with nothing, if they're not already working on it.