What are the clinical signs and diagnostic methods to identify a rabid greater bandicoot rat?

Identifying a Rabid Greater Bandicoot Rat

Clinical identification of rabies in a greater bandicoot rat is unreliable, and the animal should be immediately euthanized and its brain tissue submitted for laboratory testing if it has bitten or exposed a person. 1

Critical Context: Rodents and Rabies Risk

Small rodents, including rats, are extremely low-risk species for rabies transmission and have not been documented to transmit rabies to humans. 1, 2 The CDC explicitly states that rodents such as rats, mice, squirrels, and chipmunks are rarely infected with rabies. 1 However, if a greater bandicoot rat is suspected of being rabid or has exposed a person, the following approach applies:

Clinical Signs (Unreliable for Field Diagnosis)

Suggestive clinical signs of rabies among wildlife cannot be interpreted reliably and should never be used as the sole basis for determining rabies risk. 1 While rabid animals may exhibit:

• Abnormal aggression or unusual tameness 3, 4
• Excessive salivation or difficulty swallowing 3, 4
• Paralysis or incoordination 3, 4
• Unprovoked attacks on humans or other animals 1

These signs are non-specific and can occur with other neurological conditions. 1

Definitive Diagnostic Method

The only reliable method to confirm rabies is laboratory testing of brain tissue using direct immunofluorescence (dFAT), which is the gold standard test recommended by both WHO and OIE. 1, 4

Proper Specimen Collection and Submission:

• Euthanize the animal immediately without unnecessary damage to the head 1
• Submit only the head or intact brain (including brain stem) under refrigeration, not frozen 1
• Avoid chemical fixation of tissues, as this prevents reliable testing 1
• Send to a qualified laboratory designated by local or state health department 1

Management Algorithm for Human Exposure

If the Greater Bandicoot Rat Has Bitten or Exposed a Person:

1. Immediately wash the wound thoroughly with soap and water for at least 15 minutes, then apply povidone-iodine solution 5, 3

2. Consult the state or local health department before deciding on postexposure prophylaxis 1

3. If the animal is available for testing:

   • Euthanize and submit brain tissue immediately 1
   • Consider initiating prophylaxis while awaiting results if the animal showed abnormal behavior 5
   • Discontinue prophylaxis if testing is negative 1

4. If the animal is unavailable or cannot be tested:

   • Health department consultation is mandatory to assess local epidemiology 1
   • Given that rats have not been documented to transmit rabies to humans, prophylaxis is typically not indicated 1, 2

Critical Distinctions to Avoid Errors

Do not confuse management of rat bites with high-risk species like bats, raccoons, skunks, or foxes, which require immediate rabies prophylaxis. 1, 2

• Bats are documented rabies reservoirs in 49 continental U.S. states and require different management 1, 2
• Wild terrestrial carnivores (raccoons, skunks, foxes) are high-risk and typically require immediate prophylaxis after bites 1, 2
• Rats and other small rodents are in a completely different risk category 1, 2

Additional Wound Management Considerations

Assess tetanus immunization status and administer booster if indicated. 5

Consider antibiotic prophylaxis if presentation is delayed >8-12 hours, as rat bites carry significant bacterial infection risk. 6, 5

Report the incident to local health authorities for epidemiological surveillance. 5