Streptobacillus moniliformis: Rat-Bite Fever Causes & Symptoms

Streptobacillus moniliformis is a Gram-negative, facultative anaerobic, motile rod that causes rat-bite fever (RBF). The most common presentation is Haverhill fever (from ingesting contaminated milk/water).

Transmission

• Rat bite or scratch (most common)
• Contact with rodent urine/saliva/feces
• Consuming contaminated food/water (Haverhill fever)

Symptoms (Typically 3–10 days post-exposure)

• Fever, chills, rigors
• Headache, muscle/joint pain (migratory polyarthralgia)
• Rash (maculopapular, petechial, or hemorrhagic) on extremities
• Vomiting, sore throat

Complications (Untreated)

• Endocarditis, meningitis, pneumonia, septic arthritis, abscesses
• Mortality up to 10–13% without antibiotics

Diagnosis & Treatment

Blood or joint fluid culture (fastidious, requires special media). Penicillin or doxycycline are first-line. Early treatment prevents complications.