Rat bite fever A25.90

Place 1926

Rat bite fever, also known as streptobacillosis, spiral fever, bogger and epidemic arthritic erythema, is a notifiable (about 50% of all rats are affected), rare, bacterial infectious disease(zoonosis) transmitted to humans through bite wounds from rodents or animals that feed on rodents, also through contaminated food. The disease leads to a systemic syndrome characterized by fever, skin rash and migratory polyarthralgia. If left untreated, the mortality rate is 10%.

Streptobacillus moniliformis, Streptobacillusnotomytis or Spirillum minus (Spirillen-Rattenbissfever).

Most cases occur in Japan, but the disease has also been observed in the USA, Europe, Australia and Africa. It is usually transmitted through a rat bite. In some cases, however, contact with the urine or nasal, fecal or eye secretions of an infected rodent is sufficient. Rat bite fever can also be transmitted through food or water contaminated with feces or urine, or through pets such as dogs or cats that have been exposed to rodents.

General: Incubation period 1-5 days. Fever, chills, headache, myalgias, polyarthralgias.

Skin lesions: 2-3 days after clinical manifestation morbilliform, maculopapular, often hemorrhagic exanthema, especially on extremities, palmae and plantae.

Radiological data suggest that rat-bite fever can cause damage to the epiphyses and acroepiphyses of the bones, similar to frostbite.

If rat bite fever is suspected and cultures are negative, a biopsy of the bite site can be performed to isolate the organism. Streptobacillus moniliformis is a filamentous, highly pleomorphic, nonmotile gram-negative organism. Under the microscope, it may appear straight but have some irregular lateral tubercles. The bacteria may occur in aggregates or chains. The colonies appear like "cotton balls" in culture media.

Due to the relatively low incidence and low mortality rate, there is little information on the pathogenesis of S. moniliformis. The organism is capable of causing morphologic findings that are not associated with bacterial infections. Autopsy of rat bite fever victims revealed erythrophagocytosis, hepatosplenomegaly, interstitial pneumonia, lymph node sinus hyperplasia, endocarditis and myocarditis, and degenerative changes in the kidneys and liver. A leukocytoclastic vasculitis was detected in the biopsy of skin lesions in rat bite fever (see figure).

Clinic with evidence of bite injury (trilogy of: fever, polyarthritis, polymorphic hemorrhagic exanthema).

Blood culture

Systemic antibiotic therapy with benzylpenicillin (e.g. Penicillin Grünenthal 1 Mega) 2 times 0.6 million IU/day i.v. over 10-14 days, in case of complications such as endocarditis 5-20 million IU/day i.v. over 28 days.

Alternatively for penicillin allergy: Erythromycin (e.g. Erythrocin 500 Neo Filmtbl.) 2 g/day p.o. in 2-4 ED or Streptomycin 1 g/day i.m. (e.g. streptomycin fatol).

Rat bite fever, caused by Streptobacillus moniliformis, is a systemic disease classically characterized by fever, rigors and polyarthralgia. Unfortunately, the non-specific initial presentation combined with difficulties in culturing the causative organism leads to a significant risk of delayed or missed diagnosis. The increasing popularity of rats and other rodents as pets, as well as the risk of invasive or fatal disease, calls for increased attention to rat bite fever as a potential diagnosis.

Kasustik(Hayakawa Y et al. 2017): A case of rat bite fever diagnosed by positive cultures of Streptobacillus moniliformis from blood and joint fluid is reported. The patient, a 45-year-old man, presented with a history of a rat bite and alcoholic cirrhosis of the liver. He had been bitten on the middle finger by a rat caught in a mousetrap set in his home. About two weeks after the bite, the patient developed fever, rash and joint pain. The patient was admitted to our hospital and treated with a combination of ampicillin-sulbactam, vancomycin (VAN) and minocycline (MIN) antibiotics. The initial culture results of the anaerobic/F-resin blood culture were positive for Gram-negative bacilli after overnight incubation. Therefore, an infection with S. moniliformis was suspected and the administration of VAN and MIN was discontinued. On the eighth day in hospital, treatment was switched to oral amoxicillin-clavulanic acid and the patient was discharged from hospital. Subsequently, the pathogen was also detected in the synovial fluid and identified as S. moniliformis by 16S rRNA sequencing analysis.

1. Coessens M et al. (2022) Rat bite fever: a case report review. Acta Clin Belg 77:883-888.
2. Elliott SP (2007) Rat bite fever and Streptobacillus moniliformis. Clin Microbiol Rev. 20:13-22.
3. Hayakawa Y et al. (2017) A Case Study of Rat Bite Fever Caused by Streptobacillus moniliformis. Jpn J Infect Dis 70: 323-325.
4. Hryciw BN et al. (2018) Rat bite fever on Vancouver Island: 2010-2016. Can Commun Dis Rep 44:215-219.
5. Nakagomi D et al. (2008) Rat-bite fever identified by polymerase chain reaction detection of Streptobacillus moniliformis DNA. J Dermatol 35: 667-670.
6. Prouty M (1950) Periarteritis nodosa associated with ratbite fever due to streptobacillus moniliformis (erythema arthriticum epidemicum). J Pediatr 36:605-613.