A25.1 Streptobacillosis

Name of the Condition

• Streptobacillosis (ICD-10-CM Code: A25.1)

Summary

Streptobacillosis is a bacterial infection caused by Streptobacillus moniliformis, typically transmitted through rodent bites or contact with contaminated rodent secretions. The condition is characterized by systemic symptoms, including fever, rash, and localized inflammation at the site of exposure. Onset usually occurs 3–10 days after contact, though timing may vary.

Causes

Streptobacillosis is caused by Streptobacillus moniliformis, a bacterium carried by rodents such as rats and mice. Infection occurs when the bacteria enter the body through a bite, scratch, or contact with rodent urine, droppings, or nesting materials. The bacteria can also spread through handling of contaminated objects or surfaces.

Risk Factors

• Close contact with rodents (e.g., pet rats, wild mice)
• Occupational exposure (e.g., laboratory workers, pest control)
• Living in or traveling to areas with high rodent infestation
• Handling rodents without protective measures (e.g., gloves)
• Poor sanitation or storage of food that attracts rodents

Symptoms

• Sudden onset of fever (often with chills)
• Headache and muscle pain
• Rash (may be maculopapular or ulcerative)
• Swelling or redness at the site of rodent contact
• Lymph node enlargement near the exposure site
• Joint pain or stiffness

Diagnosis

Diagnosis is based on clinical presentation, exposure history, and laboratory testing. Blood or tissue cultures may identify Streptobacillus moniliformis. Serologic tests or molecular methods (e.g., PCR) can also confirm infection. Imaging or other tests may be used to assess complications.

Treatment Options

• Antibiotics: Penicillin or doxycycline are first-line treatments. Alternative antibiotics (e.g., ceftriaxone) may be used for severe cases or allergies.
• Supportive care: Rest, hydration, and pain management address systemic symptoms.
• Wound care: Clean and treat bite or scratch sites to prevent secondary infection.

Prognosis and Follow-Up

With prompt treatment, most patients recover fully. Untreated cases may lead to severe complications, including sepsis or endocarditis. Follow-up may involve monitoring for recurrence or complications, especially in high-risk individuals.

Complications

• Septic arthritis
• Endocarditis
• Sepsis
• Meningitis
• Pneumonia

Lifestyle & Prevention

• Avoid contact with rodents or their habitats.
• Use protective gear (e.g., gloves) when handling rodents.
• Maintain clean living spaces to reduce rodent infestation.
• Practice good hygiene after potential exposure.

When to Seek Professional Help

Seek care if you experience fever, rash, or other symptoms after rodent contact, or if symptoms worsen despite home care. Prompt evaluation is critical for severe cases or high-risk individuals.

Tips for Medical Coders

Document the clinical diagnosis of streptobacillosis and confirm exposure history (e.g., rodent bite or contact). Ensure the code A25.1 is used for Streptobacillus moniliformis infections, distinguishing it from other rodent-borne illnesses. Include details supporting the diagnosis for accurate coding and reimbursement.