[Taxacom] Coronavirus spread speed

Richard Zander Richard.Zander at mobot.org
Sun Mar 15 13:12:17 CDT 2020

I just read a pundit item on the Web that said the novel coronavirus spread was exponential. The writer submitted the analogy of a pond with pond-lily spreading exponentially. At first you hardly notice the spread but then it speeds up until when the pond is half covered with pond-lilies, then the next step is complete coverage to reflect doubling.

I think this scenario is wrong and dangerously complacent.

Coronavirus spreads, it is said, at the rate of 2.4 new cases per old case. Assume the old cases survive and are infective. Thus, 1000 cases creates 2400 new cases plus the old cases, and we get 3400 cases. 100,000 cases will generate a total of 340.000 cases in the next step, assuming sparse distributi9on and no fast recovery. So, in the case of an analogy with a lily pond, after the pond gets covered only one-third of the way with pond lilies, then the next step is full coverage.

It may well be that rapid spread of the coronavirus will go on faster than recovery and loss of infectiveness of old cases (two weeks?).

If this is right, old taxonomists should retire to a fortress and hole up until the tsunami passes. It will be like a wall falling on you.

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