What is the prevention and management of rabies (Rabies Virus Disease)?

Prevention and Management of Rabies

Rabies is a fatal viral zoonosis that can be effectively prevented through a combination of animal vaccination, public education, and prompt post-exposure prophylaxis including wound cleansing, rabies immune globulin, and vaccination. 1

Understanding Rabies Transmission

Rabies is transmitted when the virus is introduced into:

• Bite wounds
• Open cuts in skin
• Mucous membranes

The virus is typically transmitted through saliva or neural tissue from infected animals 1. The incubation period is highly variable, averaging 2-3 months but can range from 2 weeks to 6 years 2.

Prevention Strategies

Animal Rabies Control

1. Domestic Animal Vaccination

   • Mandatory vaccination of all dogs, cats, and ferrets 1
   • Vaccination has reduced laboratory-confirmed rabies cases in dogs from 6,949 in 1947 to 71 in 2006 1
   • Cats should be specifically targeted for vaccination as they account for more rabies cases annually than dogs (247 vs 71 in 2006) 1

2. Wildlife Management

   • Control of rabies in wildlife reservoirs is challenging 1
   • Selective vaccination of free-ranging wildlife or population reduction may be useful in certain outbreak situations 1
   • Prohibition of importation, distribution, and relocation of wild animals (especially raccoons, skunks, coyotes, foxes, and bats) 1

3. Public Health Education

   • Essential component focusing on:
     • Rabies transmission routes
     • Avoiding contact with wildlife
     • Following appropriate veterinary care
     • Prompt recognition and reporting of exposures 1

Human Rabies Prevention

Pre-exposure Prophylaxis

Recommended for high-risk individuals:

• Laboratory workers handling infected specimens
• Diagnosticians
• Veterinarians
• Animal control workers
• Rabies researchers
• Cave explorers 3

Pre-exposure vaccination involves a three-dose series that:

• Confers protection against the virus
• Simplifies post-exposure prophylaxis if exposure occurs 3

Post-exposure Prophylaxis (PEP)

Post-exposure prophylaxis must begin immediately after potential exposure and includes:

1. Wound Management

   • Immediate and thorough washing of all bite wounds and scratches with soap and water
   • This simple measure markedly reduces the likelihood of rabies 4
   • Tetanus prophylaxis and bacterial infection control as indicated

2. Passive Immunization

   • Rabies Immune Globulin (Human) at 20 IU/kg body weight 4
   • Should be infiltrated around the wound site when possible
   • Can be administered through the seventh day after the first vaccine dose 4

3. Active Immunization

   • Initiate rabies vaccine as soon as possible after exposure (within 24 hours)
   • Follow manufacturer's recommended schedule 4
   • Previously vaccinated individuals with documented adequate antibody titers require only vaccine (no immune globulin) 4

Post-exposure Management Algorithm

Assessment of Exposure Risk

1. Animal Species Involved:

   • Dog/Cat:

     • Healthy and available for 10-day observation: No PEP unless animal develops rabies
     • Rabid or suspected rabid: Full PEP (RIGH + vaccine)
     • Unknown/escaped: Consult public health officials

   • Wild carnivores (skunk, bat, fox, coyote, raccoon, bobcat) and woodchucks:

     • Regard as rabid unless proven negative by laboratory tests
     • Full PEP (RIGH + vaccine)

   • Livestock, rodents, rabbits and hares:

     • Consider individually
     • Consult local public health officials 4

2. Circumstances of Bite:

   • Unprovoked attacks more likely indicate rabid animal
   • Provoked bites (during feeding or handling) generally lower risk 4

3. Type of Exposure:

   • Bite exposure: Any penetration of skin by teeth
   • Non-bite exposure: Scratches, abrasions, open wounds contaminated with saliva or neural tissue
   • Special consideration for bats: PEP should be considered for any physical contact with bats when bite cannot be excluded 4

Important Caveats and Pitfalls

1. Bat Exposures: Bat bites may go undetected due to their small size. Consider PEP for any physical contact with bats when bite cannot be excluded 4.

2. Delayed Treatment: Never delay initiating PEP when indicated. PEP is nearly 100% effective when administered promptly but useless once clinical symptoms develop 3.

3. Vaccine Failures: Rabies in vaccinated animals is rare but possible. Such cases should be reported to public health officials and thoroughly investigated 1.

4. Wildlife and Hybrid Animals: No rabies vaccines are licensed for wildlife or hybrid animals (offspring of wild animals crossbred to domestic animals) 1.

5. Human-to-Human Transmission: Only documented through corneal transplants from undiagnosed rabies victims. Stringent donor guidelines have reduced this risk 4.

6. Once Symptomatic: After clinical manifestations develop, treatment options are extremely limited with nearly 100% mortality 3.

Remember that rabies is invariably fatal once symptoms develop, making prevention through vaccination and proper post-exposure management the only effective approach to this disease 5.