Saturday 20 July 2013

World War Z: a study in extreme epidemiology.

I saw this at the movies Thursday night. I really enjoyed the movie - really delivers on its zombie promise and adds the story of a father trying to look after his family.

It struck me though that it's also a great story of what would happen if, instead of anthropomorphising viruses into beings that wish to do gave them a pair of legs and let them decide what to do...which it turns out is to transmit, transmit, transmit! So, some irreverent thoughts on how a Z virus might fit in the current context of virus outbreaks..

  1. Diagnosis would be a doddle. No need to painfully design, optimise and validate a catch-all PCR for the virus based on one sequence you got from the internet, or to keep that assay ahead of mutation-defeating viral evolution. There would be pathognomonic signs of disease - eyes rolling back into the patient's head and turning white, a strange web-like pattern of blood vessels under a pallid skin tone, very bad teeth, spasmodic limb and jaw movements, disregard for personal safety when colliding with objects at speed, an ability to rapidly accelerate, disregard for heights, a hideous squeally noise on inhalation (which also prevents the virus from spreading stealthily) and the very urgent need to bite any piece of you that it can. Any 3 of these should be a diagnostic triad.
  2. Molecular epidemiology won't be necessary to track viral change. Nor will it be possible in the time you have left. No need to find the best and most diverse gene segments to sequence, no reason to use next generation/high throughput sequencing to characterize the entire genome, create phylogenetic trees and look for the impact of a multitude of tiny amino acid changes....because, you know, who cares how much worse could the virus get!?
  3. Monitoring virus transmission will be much easier. Turn on the TV or radio and follow how many countries have not yet been over-run. Oh, and that banging on your door is probably not someone asking you to switch your power company or coming to talk to you about religion.
  4. Calculation of the basic reproduction number (R0) should be made much simpler. It would be any number >1, rising continually until someone can successfully enact sufficient cranial damage upon the infected case. Definition of a super-spreader becomes much more obvious. Oh, and there are no asymptomatic cases.
  5. The need to argue about and decide upon the best way to calculate a Case Fatality Rate\Ratio would be relaxed. Every case dies...unless they already have a fatal disease. There is no time for hospitalisation...and anyone left in the hospitals wants to bite you.
  6. No need for arguments about, and delays due to, Material Transfer Agreements. Every country has its own cases, no-one wants to claim sovereign rights over the virus and there is no longer a biotechnology or manufacturing industry left to profit from diagnostic kit or antiviral developments down the track. The track has been eaten.
  7. Some of the variables needed to grow the virus for in vitro study are well defined: inoculation period-12 seconds to 10 minutes; favoured temperature-your body's; preferred cell type: does it really matter at this point?!
  8. Animal models are no longer needed for disease studies. Human models are plentiful. Unfortunately there won't be time for ethical approvals and no way to get informed consent. Additionally, your lab will need a large plexiglass-enclosed holding chamber in the middle of it. No real need to study transmission methods through. Generalising to "transmission occurs via a bite" is probably enough - the number or bites or whether a small bite is as effective a transmitter as a big one may be a study for another day.
  9. Treatment options are limited to removal of the bitten area along with 10cm of the neighbouring tissue. Do so within 5 seconds of infection or else look for a source of acute cranial trauma.
  10. Prevention is also limited to inoculation with a deadly micro-organism...or having a pre-existing terminal condition. The former will be easy to find in any WHO research facility apparently, just look for a cold room vault. Any vial of serum-coloured, non-frozen liquid, adjacent to a drawer of syringes, should do the trick. Probably best if you can find an antibiotic or functioning antiviral somewhere first.
  11. Detailed date data on illness onset and death are unnecessary - they will likely be the same day and probably today, or perhaps yesterday. This also removes frustration that your only information on new infections comes from cases being published through the scientific journals...rather than mainstream or social media.
Make you wonder?

1 comment:

  1. Love it.. I would be looking at parasitoidal fungus and others. I.E Glyptapanteles, Hymenoepimecis argyraphaga, Emerald cockroach wasp and the Zombie Ant (Ophiocordyceps unilateralis)... :) Now off to build my bunker lol



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