We start Chapter 4 by considering a
relatively simple complete but simple version of a model for two
competing SIR disease strains. In this formulation N_{AB}
refers to the proportion of the population who are A with respect to
disease 1 and B with respect to disease 2. The two diseases have
differing basic epidemiological characteristics, hence β and γ are
strain specific parameters. In addition, previous exposure to the one
strain leads to differential levels of susceptiblity (controlled by
α) and transmissibility (controlled by a) for the other strain. The
basic equations are:
Parameters
β_{i} 
is the basic transmission
rate for strain i.

γ_{i} 
is the
recovery rate for strain i.

ν

is
the birth rate, which is set equal to μ

μ

is the per capita death rate.

α_{i}

is
the modified susceptiblity to strain i
for those individuals recovered from the other strain.

a_{i}

is the modified
transmission
rate of strain i from those individuals that have recovered from the
other strain.

N_{AB}(0) 
is
the initial
proportion of the population in each group is set within the program.

All rates are
specified
in days.
Requirements.
All parameters must be positive.
Files
Python Program, MATLAB Code.
