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Showing posts with label Democratic Republic of the Congo. Show all posts
Showing posts with label Democratic Republic of the Congo. Show all posts

Perhaps Bili|1956 was an Ebola virus disease outbreak...

I didn't blog this one earlier in April when it was mentioned in the literature, but have been reminded of it by Secret Squirrel D in relation to my last post.[1]

The main gist of the Letter to Lancet Infectious Diseases by Colebunders and Van den Ende [2] is that there was a clinically compatible outbreak of disease in Bili, Democratic Republic of Congo in 1956 - 20 years earlier than the first documented and laboratory-confirmed EVD outbreak there - when the DRC was called Zaire.

The 5-week disease outbreak manifested as a fever and rash followed after 10 or so days by bleeding from the mouth and nose and some times bloody diarrhoea. Vomiting blood was a precursor to death. Those without any bleeding survived and recovered after 3-weeks.

About 80 of at least 215 people died (37%), with cases clustering among family groups. A very good survival rate for some filovirus infections. Quarantine efforts and safe burials  seemed to halt the outbreak although some bodies were "recovered" by family for re-burial under more traditional circumstances. Its not clear if this process caused any new infections as it did in west Africa in 2014.

The authors of this letter conclude that the disease course, consumption of monkey meat (but not bats, despite the proximity of colonies) suggests the outbreak could have been due to a filovirus of some sort.[1]

Unfortunately we don't know which filovirus, if a filovirus at all, was responsible since there was no laboratory testing to confirm the specific agent. 

So this one remains a "could be" for now. If only there were stored samples.

References...

  1. Yes, there were signs that Ebola was in west Africa, perhaps as far back as 1973...
    http://newsmedicalnet.blogspot.com.au/2015/04/yes-there-were-signs-that-ebola-was-in.html
  2. Filovirus epidemic in 1956 in Bili, DRC
    http://www.thelancet.com/journals/laninf/article/PIIS1473-3099(15)70092-7/fulltext

The battle of Ebola gains a second front...the Democratic Republic of Congo (DRC; formerly Zaire) [UPDATE #3]

So there are three reasons for this post. 
  • It may be a little while before we get solid confirmed information from the DRC and I think maps are useful for those of us who are ignorant of where countries live! [See below for update from WHO]
  • I'm looking for a quick post so I can move the previous post's grisly pictures down the page!
  • Mike Reid (see comments below; many thanks) brought to my attention that the range of the hammer-headed bat (Hypsignathus monstrosus; [5]) overlays the current ebolavirus outbreak areas strikingly well. I lifted that range graphic and (imperfectly, in pink) overlaid it onto my map - et voila!
Data for the hammer head bat's (Hypsignathus monstrosus) range come from The International Union for Conservation of Nature (IUCN) Red List of Threatened Species. I adapted the graphic for VDU from Wikipedia [3]
An 24-Aug report quoted the Minster for Heath, Felix Kabange Numbi.[2] This latest outbreak occurs in a country that was the site of the first (known) outbreak of a virus of species Zaire ebolavirus (called Ebola virus [1] or EBOV), and which has had six other battles with Ebola virus disease (EVD).

One of the two viruses was reported to have been genotyped as a member of the species Sudan ebolavirus (SUDV) and the second was a "mixed" infection of SUDV and an EBOV.[2] A mixed natural infection of a human would be very...unheard of. Can't really say much more though, until we get this all clarified. 

A 26-Aug WHO-AFRO update noted that the index case, a woman from Ikanamongo village, died 11-Aug sometime after butchering a bush animal.[6] 24 suspected cases of haemorrhagic fever occurred between 28-Jul and 18-Aug. 

The latest updates define that the outbreak is solely due to viruses from the species Zaire ebolavirus.[7,8,9] The EBOV viral variants share 99% nucleotide identity with the Kikwit lineage of viruses from this same species (not "strain"). Put simply, this is the evidence needed to be able to state that the two concurrent EVD outbreaks (indicated in the map above as distinct events), are indeed due to genetically distinct viral variants of Zaire ebolavirus and are not related outbreaks. 

For more on naming ebolaviruses - check out my earlier post "Behind the naming of ebolaviruses".[10]

This latest outbreak was previously and relatively quickly (too quickly? Perhaps a message in there for all of us) described by the World Health Organization as being due to gastroenteritis with haemorrhaging...

...but subsequently we learn today that...

The outbreaks share at least one common potential animal vector range. This is one of three bat species often pointed to as a possible natural host for ebolaviruses.

Since this is not the first time concurrent outbreaks of ebolaviruses have occurred, I was wondering about seasonal factors and whether they attract or affect bats. This new information adds another piece of of the puzzle.

References
  1. http://newsmedicalnet.blogspot.com.au/2014/08/behind-naming-of-ebola-virusesnot-yet.html
  2. http://www.aljazeera.com/news/africa/2014/08/congo-ebola-outbreak-2014824183430461469.html
  3. http://en.wikipedia.org/wiki/File:Hammer-headed_Bat_area.png
  4. http://www.iucnredlist.org
  5. http://en.wikipedia.org/wiki/Hammer-headed_bat
  6. http://www.afro.who.int/en/clusters-a-programmes/dpc/epidemic-a-pandemic-alert-and-response/outbreak-news/4263-ebola-virus-disease-drc.html
  7. http://reliefweb.int/report/democratic-republic-congo/update-ebola-virus-disease-drc-no-5-30-august-2014
  8. http://www.who.int/mediacentre/news/ebola/2-september-2014/en/
  9. http://reliefweb.int/report/democratic-republic-congo/virological-analysis-no-link-between-ebola-outbreaks-west-africa
  10. http://newsmedicalnet.blogspot.com.au/2014/08/behind-naming-of-ebola-virusesnot-yet.html

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