The main difference between our approach and the classical one comes from the model used to describe the data. It is quite obvious that for transmissible diseases the probability of one individual being infected is not independent of the infection status of the other individuals [1, 14, 15] . Here we consider the probability of individuals becoming infected as the result of a dynamic process of between-host virus transmission (described in the next section). These types of models are widely recognized as common tools for representing infectious disease data.