This article focuses on modeling the spread of disinformation narratives on social media using the SEDPNR epidemiological model, an extension of the basic SEIR model that takes into account the specifics of digital communication. This includes the existence of a "doubt" phase and the division of active users according to their sentiment polarity. The analyzed data describe a specific disinformation narrative, “Biolabs Ukraine,” that spread in connection with the Russian invasion of Ukraine. The results demonstrate that the dissemination of the narrative exhibits characteristics of an infodemic wave: a rapid increase, a brief peak, and a subsequent decline. The analysis confirms the significant role of active users and shows that supportive and critical reactions both contribute to the further dissemination of content.