Rat bite fever is casued by spirillum minus and streptobacillus moniliformis bacteria. It is transmitter to humans through contact with secretions or blood of an infected rodent. Rats are the most common carrier of the bacteria. Squirrels, gerbils, and other carnivores that prey on rodents can also carry the disease. The bacteria is transferred in approximately 10% of bites to humans. Both forms of bacteria primarily affect urban dwellers that live in crowded conditions. In the United States and Europe, most cases are caused by streptobacillus moniliformis and can be known as Haverhill fever or epidemic arthritic erythema. In Asia it is commonly caused by spirillum minus and is known as sodoku or spirillosis. These bacteria are spiral shaped and are not found in clusters. They are characterized by their shape, size of spirals, number of spirals and the direction of the spirals.
Diagnosis is confirmed by culturing blood or fluid joint and locating the bacteria. It can also be visually diagnosed or blood tests can be performed. Rat bite treatment should be administered quickly after contact. After bleeding is controlled, the wound should be washed inside and out with warm water and soap to kill the bacteria. After the wound is dry, applying antibiotic ointment under a dressing is recommended. Most rodent bites are deep and could require stitching to help close the wound and keep the risk of infection down. Physicians will prescribed oral penicillin for rat bite treatment. A penicillin injection is given by the physician and oral tablets or suspension are prescribed for at home use over a course of 10 to 14 days. Persons that are allergic to this medication can use other antibiotics in its place. Other medicines can be prescribed to reduce the symptoms associated with the bite.
Rat bite symptoms are visually seen in most cases and include inflammation around the open sore. A rash can also spread around the area and appear red or purple. Other rat bite symptoms can include nausea, joint pain, and muscle pain. Symptoms of spirillosis can take up to a month after exposure to the organism to develop. The wound will exhibit slow healing and inflammation. It is possible for the fever to be recurring and last for months at a time. With streptobacillosis, the incubation period is approximately two weeks and begins with high fever, rigors, severe headaches, and joint pain. If not treated quickly enough or if the disease goes untreated, it can be fatal.
Avoiding contact with rodents is the most effective prevention for these conditions. Depending on geographical location, one of two types of spirillum bacteria can cause the infection. Treating an open sore or bite quickly and seeking medical attention for immediate treatment is necessary to reduce the risk of death due to rat bite fever.