Spirillum minus is a bacterium that can cause disease in animals and humans. Synonyms for Spirillum minus include Sodoku, rat-bite fever, streptobacillary fever, and Haverhill fever. The term Sodoku is derived from the Japanese words "so" meaning rat and "doku" meaning poison, reflecting the association of the bacterium with rodents. Rat-bite fever and Haverhill fever are both named after the modes of transmission of the bacterium, through bites or ingestion of contaminated food respectively. Streptobacillary fever describes the bacterial morphology of spirally coiled cells forming chains. Understanding these synonyms can aid in the diagnosis and treatment of Spirillum minus infections.