The article discusses the phenomenon of diffusion of internal armed conflicts that occurs through the dissemination of organized violence and is similar to the process described by the model in the classic work of V.O. Kermack and A.G. Mackendrick in 1927. Along with the metaphors ''Domino effect'' and ''forest fire'', metaphors ''conflict - disease'' and ''spread - infection'' are images, which are most widely used to demonstrate the horizontal escalation of the dynamics of organized violence (its distribution from armed conflict of a state to its neighbors and to the potential distribution in the entire region). The author raises the question of the conceptual and analytical validity of the analogy between physiological contagion and the diffusion of armed conflict. The analysis shows that these phenomena exhibit considerable external similarity, in particular the similar character of influence on the object of infection, dependence on the type of conflict, propensity for ''contamination'' and intensity of contacts between the source and the object. However, a number of important differences in subjectivity of actions, knowledge of the channels and mechanisms of contagion and mediation process of the spatial-geographical factors indicate the conceptual limitations of the analogy from the point of view of its explanatory power. As a result of analysis, the author concludes that the scientific use of this analogy is justified only in descriptive, but not explicative purposes.