Models H 1 . As discussed earlier, our purpose here is to measure the influence of some factors on the rate at which the virus spreads within or between populations. Two types of risk factors are tested here. The first ones concern the impact of demographic parameters (such as the number of cats within the population) on the virus transmission rate between cats of the same population. The second ones are not really risk factors. Behavioral observations suggest networks of connectivity between the different populations. The objective is to estimate whether introducing this information on the probability of disease reintroductions within populations produces significant predictive improvements, compared to models where external reintroduction rates are simply constants.