Thursday, 17 April 2014

Update on Ebola virus disease (EVD) case accumulation chart with new WHO African Regional Office data for 16-Apr-2014.

Click on image to enlarge.
Since the last update [2] there looks to have been a big jump in cases, but that is mostly be because its been a while since that WHO update. 

You could draw a straight line between the dot from the update on 11-Apr and it would maintain the overall gradual slope. 

Total suspected/probable/confirmed cases: 227
Total suspected/probable/confirmed deaths: 135 (59.5%)
Total lab confirmations: 114 (50.2% of 227)

What I find encouraging in the latest numbers [1] is that the lab confirmations have jumped up by nearly 10% so we now have 50.2% of all the (227) cases listed having been confirmed up from 41.6%. Also, none of the Mali suspect cases tested positive for this variant of the Zaire ebolavirus species (by the way, you can tell I meant species because I called out the full species name and used italics - just fyi). And the proportion of fatal cases has dropped because the suspect/probable case numbers have gone up faster than the fatal case number. A good thing for now, but that may well change in the future for reason I've written about recently.[4]

Less encouraging is that I couldn't find the number of lab confirmations for Liberia so that number may shift a little. When the most recent case became ill was not listed. Also, healthcare worker (HCW) numbers have jumped from 15 suspect and confirmed with 11 fatalities to 24 and 13 fatalities but I'm not sure just how many are currently lab confirmed. HCWs suffer a lot to be at the forefront of these outbreaks. We should never forget that.

We also learned today, thanks to a very speedy and nicely laid out New England Journal of Medicine article [3] by Baize and colleagues from Europe and Africa, that the particular variant of this species that has ravaged Guinea is a virus distinct from those found in other African Ebola virus outbreaks. I wonder if it has evolved in the local bats of Guinea or the greater West African region? I'm ignorant of how wide-ranging bat travels are or how friendly different region's bat colonies are. More testing is needed to answer the virology underneath all that...as always. 

The Guinea Ebola virus variant is still a member of the species Zaire ebolavirus, genus Ebolavirus, family Filoviridae, but it has enough genetic variation across its genome to mark it as different from those found variants of Zaire ebolavirus identified in 1976, 1994-1995, 2002, 2007-2008.[3] How different? That will take more research to answer. What's its new name? We don't know yet but the Filoviridae Study Group can tells us that they would rather not use a country or patient name, prefer to avoid any "unusual" characters, choose easy to pronounce designations - and contact them for guidance! They'd like to see something that rolls off the tongue and includes...


<virus name> <isolation host-suffix>/<country of sampling>/<year of sampling>/<genetic variant designation>-<isolate designation> 

e.g. Ebola virus H.sapiens-tc/COD/1995/Kikwit-9510621

Source...

  1. Ebola virus disease, West Africa (Situation as of 16 April 2014)
    http://www.afro.who.int/en/clusters-a-programmes/dpc/epidemic-a-pandemic-alert-and-response/outbreak-news/4100-ebola-virus-disease-west-africa-16-april-2014.html
  2. Update on Ebola virus disease (EVD) case accumulation chart with new WHO African Regional Office data for 11-Apr-2014.
    http://virologydownunder.blogspot.com.au/2014/04/update-on-ebola-virus-disease-evd-case_15.html
  3. Emergence of Zaire Ebola Virus Disease in Guinea — Preliminary Report
    http://www.nejm.org/doi/pdf/10.1056/NEJMoa1404505
  4. Ebola virus disease and lab testing...
    http://virologydownunder.blogspot.com.au/2014/04/ebola-virus-disease-and-lab-testing.html