Journal ArticleTrypanosomes (Kinetoplastea: Trypanosomatida: Trypanosomatidae), particularly salivarian trypanosome species as well as stercorarian Trypanosoma cruzi, are important parasites of humans and other animals that cause often fatal diseases. Stercorarian T. lewisi is known as a rat-specific species of the subgenus Herpetosoma. Rodent trypanosomes cause latent infections, and T. lewisi infection beyond the genus border, e.g. infection in mice, is considered to be virtually impossible. Nevertheless, nine human cases of T. lewisi infection have been reported in recent decades, with an increased incidence (five cases) in the last two decades. In the present review, we summarize the records of atypical human trypanosomiasis ascribed to T. lewisi infection and provide information on the background of disease incidences and possible PCR-based diagnostic approaches.