  A Caputo-type fractional-order mathematical model for "metapopulation cholera
transmission" was recently proposed in [Chaos Solitons Fractals 117 (2018),
37--49]. A sensitivity analysis of that model is done here to show the accuracy
relevance of parameter estimation. Then, a fractional optimal control (FOC)
problem is formulated and numerically solved. A cost-effectiveness analysis is
performed to assess the relevance of studied control measures. Moreover, such
analysis allows us to assess the cost and effectiveness of the control measures
during intervention. We conclude that the FOC system is more effective only in
part of the time interval. For this reason, we propose a system where the
derivative order varies along the time interval, being fractional or classical
when more advantageous. Such variable-order fractional model, that we call a
'FractInt' system, shows to be the most effective in the control of the
disease.
