  In this paper we introduce a discrete time competing virus model and the
assumptions necessary for the model to be well posed. We analyze the system
exploring its different equilibria. We provide necessary and sufficient
conditions for the estimation of the model parameters from time series data and
introduce an online estimation algorithm. We employ a dataset of two competing
subsidy programs from the US Department of Agriculture to validate the model by
employing the identification techniques. To the best of our knowledge, this
work is the first to study competing virus models in discrete-time, online
identification of spread parameters from time series data, and validation of
said models using real data. These new contributions are important for
applications since real data is naturally sampled.
