We study a new model describing the dynamics of both Oseltamivir resistant and non- resistant Influenza virus. Incorporated in the model is oseltamivir drug for the non- resistant strain and nalidixic acid or dorzolomide drugs for the resistant strain. The basic reproduction ratios R0 are determined using the next generation matrix. The local and global asymptotic stability of the disease free equilibrium are determined and shown to only exist if R01ź1 and R02ź1. Local and global asymptotic stability of the endemic equilibria exist if R011 and R021. Lyapunov function was used to show the global stabilities.

The aim of this paper is to show how North Cyprus fought with Covid-19 by using R0 and Rt, as herd immunity. For that purpose, we used a SEIR model for basic reproduction number, R0, and calculated Rt values by using R0 values. North Cyprus is the first country in Europe to free from Covid-19 epidemic. One of the most important reasons for this is that the government decided to tackle Covid-19 pandemic by using R0 and Rt daily. For R0, we constructed a new SEIR model by using real data for North Cyprus. From March 11, 2020 to May 15, 2020, R0 varies from 0.65 to 2.38.