What is the recommended treatment after exposure to a bat, potentially infected with rabies?

Post-Exposure Prophylaxis for Bat Exposure

Any direct contact between a human and a bat should be evaluated for rabies exposure and treated with post-exposure prophylaxis (PEP) unless the bat tests negative for rabies or it can be reasonably certain that no bite, scratch, or mucous membrane exposure occurred. 1

Assessment of Bat Exposure

Types of Exposures Requiring PEP

• Direct contact exposures:

  • Confirmed bites or scratches from a bat
  • Mucous membrane contact with bat saliva
  • Any physical contact where a bite or scratch cannot be excluded 1

• Potential unrecognized exposures:

  • Finding a bat in the same room as:
    • A sleeping person
    • An unattended child
    • A mentally disabled person
    • An intoxicated person 1, 2

Exposures NOT Requiring PEP

• When it can be reasonably certain no bite, scratch, or mucous membrane exposure occurred
• When the person was awake and aware in the same room as the bat
• When the bat is available for testing and tests negative for rabies 1
• Indirect contact such as petting an animal, contact with blood, urine or feces, or contact of saliva with intact skin 3

Immediate Management

1. Wound Care (Critical First Step)

• Thoroughly wash and flush all wounds immediately with soap and water for about 15 minutes 3, 4
• Apply an iodine-containing or similarly virucidal topical preparation to the wound 3
• Administer tetanus prophylaxis if indicated 3

2. Bat Testing

• If possible, safely capture the bat and submit it for rabies testing 1
• If the bat tests negative, PEP is not necessary 1
• If the bat cannot be captured or tests positive, proceed with PEP 1

Post-Exposure Prophylaxis Protocol

For Previously Unvaccinated Individuals

1. Human Rabies Immune Globulin (HRIG):

   • Administer 20 IU/kg body weight 1
   • Infiltrate the full dose around and into the wound area if anatomically feasible
   • Inject any remaining volume intramuscularly at a site distant from vaccine administration 1

2. Rabies Vaccine:

   • Administer a 5-dose regimen on days 0,3,7,14, and 28 1
   • HRIG should be given with the first dose of vaccine or up to day 7 of the vaccination series 1

For Previously Vaccinated Individuals

• Administer only 2 doses of vaccine (days 0 and 3)
• No HRIG is required 1

Important Considerations

Timing of PEP

• PEP should be administered as soon as possible after exposure
• There is no absolute time limit for starting prophylaxis - even delayed administration can be beneficial 1
• The sooner treatment begins after exposure, the better the outcome 1

Bat-Specific Concerns

• Bat rabies virus variants are the most common cause of human rabies in the United States 1
• Bat bites may be minor and difficult to recognize, yet still transmit rabies 2
• During 1990-2007,34 naturally acquired bat-associated human rabies cases were reported in the US, with only 6 cases reporting a definite bite 2

Consultation

• Consult local or state public health officials for guidance in complex exposure situations 1, 2
• Because of the complexity of some bat exposure situations, consultation with state and local health departments should always be sought 2

Pitfalls to Avoid

• Underestimating nonbite exposures: Even minor or unrecognized wounds from bats warrant prophylaxis 1
• Delaying treatment: Prompt administration of PEP is crucial for effectiveness 1
• Inadequate wound care: Proper wound cleansing alone can significantly reduce rabies infection risk 1
• Incomplete HRIG administration: Ensure proper infiltration around wounds when anatomically feasible 1
• Assuming a healthy-appearing bat is not rabid: Clinical signs of rabies cannot be reliably interpreted in wildlife 3

Remember that rabies is virtually always fatal once clinical disease develops 5, making proper post-exposure prophylaxis essential for preventing death after bat exposure.