Saturday, 11 June 2016

More microcephaly to come..?

The Brazilian Ministry of Health presented some information around Zika virus (ZIKV), June 10. Specifically some good news about its recent steady decline ahead of the Olympics. Good timing, huh?

Its always good to see some data - it's unclear if these are clinically suspected (most probably) or laboratory confirmed cases (highly unlikely given the numbers being so high and lab capacity being reportedly so low) from this graph, but if we look further down at Figure 2, the Pan American Health Organization data, which lists slightly fewer cases each week that Brazil (PAHO figures may need updating?), does not list any confirmed cases, only "suspected". I assume that means rashy febrile people. 

If we add up the weeks listed by the Ministry, there have been 159,914 cases in 2016.

Figure 1. From Brazil Ministry of Health slideset, June 10.
Slides No.12 and No. 13 [1]
Click on image to enlarge.
So, if these are ZIKV and not Dengue virus, Chikungunya virus, an enterovirus or some other acute cause of rash [2], then should we expect to see a new wave microcephaly and central nervous system disorders starting from around July? I've said July because that is about 184 days pr 6 months after the rise starts - 184 being the magic number between when ZIKV was first identified in Brazil (although we are pretty sure it was there much earlier[3]) and when the first 141 microcephaly diagnoses were announced.[4]

Meanwhile, Colombia - the elephant that won't leave the room - reports just 6 ZIKV-linked microcephaly diagnoses despite nearly eight months having passed since they first identified local spread of ZIKV and there already being nearly 5,000 pregnant women confirmed as ZIKV infected.[5] 

Brazil reports just 3,598 pregnant women clinically, epidemiologically or laboratory (presumably a much smaller number) confirmed as infected with ZIKV yet its population is a quarter of Brazil's (48 versus 200 million according to 2013 data via Google). It's a strange one that could be explained by ZIKV alone not being the cause of microcephaly or else by those extra years during which ZIKV was in Brazil but not yet Colombia being somehow key to the occurrence of microcephaly. 

First we need a little more genome sequencing to understand whether ZIKV was also present in Colombia for longer than dictated by its first laboratory confirmed case report. Perhaps a ZiCRA project is required?[5]

Meanwhile, it would be great if Brazil published its national numbers in a weekly report - along with confirmed numbers. The promise of the "Boletins Epidemiol√≥gicos de Dengue, Chikungunya e Zika" has not been realised with only two reports over the past 10 epidemiological weeks and no specific listing of laboratory confirmed numbers.[6] 

I can't help but recall that some were very upset at The Kingdom of Saudi Arabia for what was, in hindsight, relatively better epidemiology data for MERS-CoV. Strange why this has not been an issue here. One of the many mysteries of Zikasteria? I have no answer. 

References...

  1. http://portalsaude.saude.gov.br/images/pdf/2016/junho/10/saude-nos-jogos-olimpicos-e-paralimpicos.pdf
  2. http://virologydownunder.blogspot.com.au/2016/01/zika-virus-briefly.html
  3. http://science.sciencemag.org/content/early/2016/03/23/science.aaf5036.full
  4. http://virologydownunder.blogspot.com.au/search?q=184
  5. http://zibraproject.github.io/about/
  6. http://combateaedes.saude.gov.br/situacao-epidemiologica#boletins