An approach to estimate the influence of the treatment-type controls on the
basic reproduction number, R 0 , is proposed and elaborated. The presented
approach allows one to estimate the effect of a given treatment strategy or to
compare a number of different treatment strategies on the basic reproduction
number. All our results are valid for sufficiently small values of the control.
However, in many cases it is possible to extend this analysis to larger values
of the control as was illustrated by examples