Rat-bite fever is an acute, febrile human illness caused by two bacteria Spirillum minus or Streptobacillus moniliformis and transmitted by rodents, rats or mice in most cases. The majority of cases are due to the animal's bite. It can also be transmitted throughout food or water that is contaminated with rat excreta. Rat bite fever is transmitted to people in around 10% of rat bites. The exact incidence is unknown. Many cases go unreported and underdiagnosed. It is diagnosed by isolating S. moniliformis from blood, synovial fluid, or other body fluids.