Rat bite fever may be caused by -a) Leptospira canicolab) Streptobacillus moniliformisc) Borrelia recurrentisd) Spirillum minus

**Core Concept**
Rat bite fever is a zoonotic infection caused by specific bacteria transmitted through bites or scratches from infected rodents. It's characterized by fever, rash, and lymphadenopathy.

**Why the Correct Answer is Right**
The correct answer is **D. Spirillum minus**. Spirillum minus is a gram-negative, spiral-shaped bacterium that causes rat bite fever. It's transmitted through the bites or scratches of infected rodents, such as rats and mice. The bacteria enter the body through the wound and cause an infection. Spirillum minus produces endotoxins that lead to the characteristic symptoms of rat bite fever, including fever, headache, and a distinctive rash.

**Why Each Wrong Option is Incorrect**
**Option A:** Leptospira canicola is a bacterium that causes leptospirosis, a different zoonotic disease transmitted through contact with infected urine or water. While it's also found in rodents, it's not the cause of rat bite fever.

**Option B:** Streptobacillus moniliformis is another bacterium that can cause rat bite fever, but it's not the most common cause. Spirillum minus is more commonly associated with this disease.

**Option C:** Borrelia recurrentis is the bacterium that causes louse-borne relapsing fever, a different vector-borne disease.

**Clinical Pearl / High-Yield Fact**
Rat bite fever can be treated with antibiotics, such as penicillin or doxycycline, if promptly diagnosed. However, if left untreated, it can lead to complications like endocarditis and osteomyelitis.

**Correct Answer:** D. Spirillum minus