ratbite

Ratbite, commonly referred to as rat bite fever (RBF), is an infectious illness caused by bacteria transmitted through rat bites or contact with rodents and their secretions. It is rare but occurs worldwide, often in settings with close human–rodent contact or poor sanitation. Two bacterial species are responsible for the disease, giving rise to distinct regional forms.

The most frequent cause is Streptobacillus moniliformis, which accounts for the Western form of rat bite fever. A second form is caused by Spirillum minus (also called S. minus) and is more commonly reported in parts of Asia. Transmission typically follows a rat bite or scratch, but can also occur through contact with rodent excreta or contaminated food or water. The incubation period varies, commonly about a week for S. moniliformis and up to several weeks for Spirillum minus.

Symptoms are variable but often include fever, malaise, muscle and joint pains, and a rash that may appear on the trunk and limbs. Headache, nausea, and swollen lymph nodes can occur, and arthritis may be a prominent feature in some cases. Some people experience only mild illness, while untreated infection can lead to complications such as septicemia, endocarditis, or meningitis, particularly in those with weakened immune systems.

Diagnosis relies on exposure history and clinical presentation. Laboratory confirmation can be challenging because the bacteria are fastidious; blood cultures may be negative, and specialized culture techniques, serology, or molecular methods can aid detection.

Treatment typically involves prompt antibiotic therapy. Penicillin or amoxicillin are commonly used for Streptobacillus moniliformis infections; doxycycline or other suitable antibiotics may be employed in penicillin-allergic patients or for Spirillum minus infections. Wound cleaning after exposure and supportive care are important. Prevention focuses on avoiding rodent bites, improving sanitation, rodent control, and thorough wound care if exposure occurs.