What is the treatment for a patient bitten by an animal suspected of having rabies, considering the patient's potential previous vaccination history?

Treatment for Animal Bite with Suspected Rabies

For a previously unvaccinated patient bitten by an animal suspected of having rabies, immediately initiate full post-exposure prophylaxis (PEP) consisting of thorough wound washing, rabies immune globulin (RIG) infiltrated into and around the wound, and a 4-dose rabies vaccine series (days 0,3,7,14) administered intramuscularly in the deltoid area. 1, 2, 3

Immediate Wound Management (Critical First Step)

• Thoroughly wash and flush the wound with soap and water for approximately 15 minutes immediately - this single intervention markedly reduces rabies transmission risk even without other prophylaxis 2, 3, 4
• Apply povidone-iodine solution or other virucidal agent to the wound after cleansing 2, 3
• Avoid suturing puncture wounds when possible to prevent trapping virus in deeper tissues 2
• Administer tetanus prophylaxis based on vaccination history 2, 3
• Consider antibiotic prophylaxis given contamination risk 2

Post-Exposure Prophylaxis Protocol

For Previously UNVACCINATED Patients (Most Common Scenario)

Passive Immunization - Rabies Immune Globulin (RIG):

• Administer 20 IU/kg body weight on day 0 2, 3
• Infiltrate the full dose thoroughly into and around the wound site - inadequate wound infiltration has been associated with prophylaxis failures 2, 3
• Any remaining volume after wound infiltration should be injected intramuscularly at a site distant from vaccine administration 2, 3
• RIG can be administered up to day 7 if not given initially, but should ideally be given immediately 2, 3
• Do not exceed the recommended dose (20 IU/kg) as this can suppress active antibody production 2

Active Immunization - Rabies Vaccine:

• Administer 4 doses intramuscularly on days 0,3,7, and 14 1
• Give vaccine in the deltoid area for adults (anterolateral thigh for children) - never use the gluteal area as this has been associated with PEP failures 1, 2, 5
• Administer vaccine at a different anatomical site than the RIG 2, 3
• Do not administer RIG and vaccine in the same syringe or anatomical site 2

For Previously VACCINATED Patients

• Administer only 2 doses of vaccine on days 0 and 3, without RIG 1, 3
• Previously vaccinated persons are those who have completed a pre-exposure or post-exposure prophylaxis series with cell culture vaccine and have documented rabies virus neutralizing antibody 3

For Immunocompromised Patients

• Use a 5-dose vaccine regimen (days 0,3,7,14,28) plus RIG 1

Critical Timing Considerations

• PEP is a medical urgency - initiate as soon as possible after exposure 2, 3, 4
• Begin treatment regardless of the interval from exposure, even if many months have passed, as long as clinical rabies symptoms have not yet appeared 1, 2
• Rabies incubation periods can range from days to over 1 year in humans, making delayed treatment still potentially life-saving 1, 6
• Treatment can be discontinued if the animal is later proven negative by laboratory testing 2, 5

Animal-Specific Management Decisions

Dogs, Cats, and Ferrets

• If the animal is healthy and available: confine and observe daily for 10 days 7, 3, 5
• Do not administer rabies vaccine to the animal during observation to avoid confusing rabies signs with vaccine side effects 7
• Begin PEP at the first sign of illness in the confined animal 3, 5
• If the animal is stray, unwanted, or escapes: euthanize immediately and test the brain, or begin immediate prophylaxis if unavailable 7, 2
• Rabies virus may be excreted in saliva only a few days before illness or death in these species 7

Wild Animals (Bats, Raccoons, Skunks, Foxes)

• Regard as rabid unless proven negative by laboratory testing 3, 5
• Initiate PEP immediately unless the animal is available for testing and public health authorities are facilitating expeditious laboratory testing 3, 5
• Bats are particularly concerning - transmission can occur from minor, seemingly unrecognized bites 3
• Consider PEP for any physical contact with bats when bite, scratch, or mucous membrane contact cannot be excluded 3

Small Rodents and Lagomorphs

• Small rodents (squirrels, chipmunks, rats, mice, hamsters, guinea pigs, gerbils) and lagomorphs (rabbits, hares) are rarely infected with rabies 3, 5
• Consult state or local health department before initiating PEP 3
• Bites from these animals almost never require post-exposure prophylaxis 5

Common Pitfalls to Avoid

• Do not delay prophylaxis while attempting to locate an escaped animal - begin treatment immediately 2
• Do not rely on the animal's healthy appearance - rabid animals may appear normal early in infection 2
• Do not fail to infiltrate RIG directly into the wound - this is associated with prophylaxis failures 2, 3
• Do not administer vaccine in the gluteal area - use deltoid muscle in adults 1, 2
• Do not withhold treatment based on time elapsed since exposure if clinical rabies has not developed 1, 2

Prognosis

• Once clinical manifestations of rabies develop, the disease is nearly 100% fatal 4, 8
• If PEP is used in a timely and accurate fashion, it is nearly 100% effective 4, 6
• To date, only seven individuals have survived rabies virus infection after clinical symptoms developed 4