In this paper, we study the dynamic of a multi-strain SEIR model with both saturated incidence and treatment functions. Two basic reproduction numbers are extracted from the epidemic model, noted R0,1\documentclass[12pt]{minimal}
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\begin{document}$$R_{0,2}$$\end{document}. Using the Lyapunov method, we investigate the global stability of the disease free equilibrium and prove that it is globally asymptotically stable when R0,1\documentclass[12pt]{minimal}
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\begin{document}$$R_{0,2}$$\end{document} are less than one. Moreover, we formulate the optimal control problem, solve it, and perform some numerical simulations, to support the analytical results and test how well the proposed model may be applied in practice.