Rat-bite fever (RBF) is an infectious disease that can be caused by two different bacteria. Streptobacillary RBF is caused by Streptobacillus moniliformis while spirillary RBF or sodoku is caused by Spirillum minus. People usually get the disease from infected rodents or consumption of contaminated food or water. When the latter occurs, the disease is often known as Haverhill fever. If not treated, RBF can be a serious or even fatal disease.