Hi All,

I've followed the subject of bees and viruses closely for some years.
There are similarities of interest regarding humans and covid.

My brother recently asked me how many virions it would take to contract
covid.  This issue generally does not appear to be "contracting" the virus,
but rather the dose received, balanced against the ability of the body to
mount an innate immune response while the adaptive immune response develops
antibodies.

The "minimal infective dose" for covid appears to be in the thousands to
tens of thousands of virions, largely dependent upon your immunocompetence
(and perhaps previous exposure to other coronaviruses)  But the question is
whether contracting the virus results in your getting sick, or in the worst
case, dying.

Anyone with a compromised immune system is of course at considerable risk.


But for a healthy person, the body's initial response to exposure to
virions is to minimize viral replication via our "innate" immune response
system -- using inflammation, a number of types of white blood cells, and
cellular apoptosis (self sacrifice).  The innate immune response attempts
to keep virus replication in check until our "adaptive" immune system, in
which our body creates antibodies, allowing targeting of the virus by T and
B cells.  But this process takes days or weeks to develop.  However, if
your innate response can hold virus replication in check until you've
developed your adaptive response, you may not get "sick" (although you may
still be able to infect others).

So the key issue with covid is to avoid getting a massive exposure of
virions -- catching a full faceful of infected sputum from a cough can be a
death sentence.  This appears to be why previously fit health care workers
are dying.  And it is criminal to ask them to care for us without providing
them with adequate protective gear.

For the rest of us, having EVERYONE wear masks *if they are around other
humans*, and washing their hands after touching any potentially-exposed
surface would be the wisest course of action.  Luckily, we beekeepers often
work alone, out in the open, away from other humans.

The informed opinions on this page pretty much summarize our current
knowledge:
https://www.sciencemediacentre.org/expert-reaction-to-questions-about-covid-19-and-viral-load/

-- 
Randy Oliver
Grass Valley, CA
www.ScientificBeekeeping.com

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