محمد مهدی زاده خالسرایی

This paper proposed a new nonstandard finite difference scheme for a mathematical model of HIV infection. The technique of nonlocal approximation and renormalization of the denominator of the discrete derivative was employed. The new scheme where found to possess elementary stability property and also preserve the positivity property which is one of the essential requirements for epidemic disease models. Unlike the other conventional approaches that are routinely use for such problems, the solution of new scheme have positivity property for any time step-sizes.