Spirillum minus or streptobacillary is a specific type of spirillum species that is associated with rat-bite fever. It is a bacterium where the cells is twisted like a spiral and occurs in bacillus cells. They are not found in clusters or chains and are distinguished by their length, size of spirals, the number of spirals, and the direction of their coils. This particular bacterium is rare and is found most often in Asian countries. Spirillum disease is commonly known as sodoku in Japan. Infection is set through the transfer of the bacteria through contact with secretions or urine from the mouth, eye, or nose of an infected animal. It is most commonly transferred through a bite from an infected rat. Squirrels, gerbils, and weasels can also carry the disease and transfer the bacteria to humans. As long as treatment is administered at the first signs of symptom, a full recovery is expected.

Symptoms of spirillum bacteria include red or purple rash, muscle aches, chills, fever, and headache. In some cases swollen or painful joints can occur. Open sores where the bite occurred is inflamed and red in most cases. Blood antibody tests are used to diagnose the condition and spirillum bacteria is found in the skin, joint fluid, and in the lymph nodes. More serious complications from spirillum disease can occur and include inflamed tendons and partoid glands. The heart valves can become infected and absceses can occur in soft tissue or the brain. Endocarditis or an inflammation in the linings inside the heart chambers or valves is possible and can cause heart disease. Symptoms of these more serious conditions can also be seen in sings of fatigue, abnormal urine color, and swelling in the legs or feet.

Treatment for infections caused by this bacteria is penicillin. Persons that are allergic to this particular antibiotic can receive treatment with tetracyclines or erythromycin. Normal dose of antibiotics is one gram every eight hours for up to 14 days. Treatment should begin at the first sign of contamination or bite. Bleeding should be controlled immediately. Cleaning the wound with warm water and soap is necessary to kill bacteria quickly. Covering the wound with a dry dressing and the use of antibiotic ointment is recommended before seeking medical attention. Rat bites are deep and could possibly need stitching to seal the wound. With most bites, swelling will occur, so removing jewelry from the hand is recommended. Once oral antibiotics or shots are prescribed, it is important to keep the wound clean to reduce the risk for further infection.

Avoiding contact with rodents is the only prevention to this infection. After contact with a rodent, wash the hands and face immediately with warm water and soap. Scratches should be treated the same as bite marks and victim should be monitored for symptoms of spirillum minus.