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From: avg@navajo.STANFORD.EDU (Allen Van Gelder)
Newsgroups: net.puzzle,sci.math,sci.med
Subject: Re: Math of Diseases
Message-ID: <1057@navajo.STANFORD.EDU>
Date: Sun, 2-Nov-86 23:34:41 EST
Article-I.D.: navajo.1057
Posted: Sun Nov  2 23:34:41 1986
Date-Received: Tue, 4-Nov-86 04:14:33 EST
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Reply-To: avg@navajo.UUCP (Allen Van Gelder)
Organization: Stanford University
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In article <2188@mtuxo.UUCP> jasond@mtuxo.UUCP (j.demont) writes:
>...
>I would like to model the spread of the disease before it is apparent that
>anyone even has it.  Therefore I would like to add the constraints that it
>is chronically contagious, non-fatal and in no way can be known or guarded
>against.
>...
>Jason De Mont
>ihnp4!mtuxo!jasond
Think of each person in a population as a vertex in a graph, with edges
to the people he or she comes in contact with.  In each time step,
there is a probability that an infected person infects a neighbor in
the graph.  Assume one person is affected initially.  Measure distance
from that person in terms of path length in the graph.  The infection
will evidently tend to spread in a "sphere", but depending on the
assumed graph structure, the growth could be anything from linear
(the graph is a line) to quadratric (a grid) to exponential (a tree).

This model ignores the possibility that a person's set of neighbors
varies over time.  It is a Markov process.  Good luck on your analysis.