Bovine spongiform encephalopathy

Disease Description (Causes and Symptoms)

• Cause: Rabies is a viral infection of the central nervous system caused by the Rabies virus (family Rhabdoviridae), and is primarily transmitted to humans through the saliva of infected animals. The most common route of transmission is a bite; other routes include exposure of mucous membranes (eyes, nose, and mouth), contact between saliva and damaged tissue, and, rarely, corneal transplantation or laboratory exposure.
• Pathophysiology: The virus travels along the terminal and peripheral nerves at the wound site and ascends to the central nervous system, invading the brain and spinal cord (neurotropism). The incubation period varies from several days to several years depending on the wound location (shorter for the face and neck, longer for the limbs), wound depth, and viral load (generally 20–90 days). Once clinical symptoms appear, the disease progresses rapidly and has a very high mortality rate.
• Major symptoms: After initial nonspecific prodromal symptoms (fever, headache, fatigue, vomiting, etc.), symptoms are classified as acute neurological symptoms.
  • Furious rabies: hyperexcitability, anxiety and aggression, auditory hallucinations and delusions, fear (hydrophobia and aerophobia), etc.
  • Paralytic rabies: peripheral paralysis (beginning at the bite site and progressing), paralysis of the respiratory muscles
  • Common terminal symptoms: coma, seizures, difficulty breathing, muscle rigidity

Treatment

• Post-exposure prophylaxis (PEP) is essential — when administered appropriately and promptly, it can prevent the disease from developing.
  1. Initial treatment
     • Immediately wash the wound with soap and running water for a sufficient period of time (at least 15 minutes).
     • Disinfect the wound (e.g., with 70% alcohol or 1% benzalkonium).
     • If there is severe bleeding, control the bleeding and then visit a hospital.
  2. Passive immunization: Human Rabies Immune Globulin (HRIG)
     • Recommended dose: 20 IU/kg of body weight (some guidelines differ, recommending either 20 IU/kg or 40 IU/kg). Inject as much as possible directly around the wound (administer the remainder intramuscularly).
  3. Active immunization (vaccine): Standard adult schedule (Essen regimen)
     • Usually administered intramuscularly (IM) on days 0, 3, 7, 14, and 28 (5 doses in total). (WHO and some national guidelines use a 4-dose schedule or other alternatives depending on the circumstances.)
     • Even after vaccination, combined administration of HRIG and the vaccine is recommended when HRIG is indicated (depending on the severity of the exposure).
  4. Treatment after symptom onset
     • After symptoms develop, there is almost no effective established treatment, and the fatality rate is extremely high. Intensive care and supportive treatment (maintaining respiration and circulation, controlling seizures) are mainly provided. Experimental or specialized treatments (e.g., the Milwaukee protocol) have been attempted in a small number of cases, but are generally not recognized as reproducible treatments.
• Vaccination (pre-exposure prophylaxis)
  • Pre-exposure vaccination consisting of 3 doses (days 0, 7, and 21/28) is recommended for high-risk groups (veterinarians, laboratory workers, people staying in endemic areas for extended periods, etc.). If exposure occurs, the number of vaccine doses may be reduced or the use of HRIG may be simplified (however, additional post-exposure doses may still be necessary).
• Medication and interaction precautions
  • Immunosuppressants (such as steroids and anticancer treatment) may reduce the vaccine response, so consultation with the treating physician is necessary.
  • Post-exposure vaccination and HRIG are recommended during pregnancy and in children, as the benefits outweigh the risks.

Checklist Before an Outpatient Visit (Including Sample Questions)

• Items to prepare
  • Photographs of the wound, if possible, and a record of when and how the wound occurred
  • The type and condition of the animal that bit you (wild or domesticated), and whether the animal has been vaccinated
  • Recently received vaccines or passive immunization (including information about prior rabies immunity)
  • A list of medications currently being taken (including anticoagulants, antiplatelet agents, and immunosuppressants)
  • History of allergies (including allergies to medications and blood products)
  • Possibility of pregnancy (for women)
• Information to provide to the doctor during the visit
  • Location of the wound (face, neck, hand, limb, etc.), depth, and whether there was bleeding
  • When the wound was first discovered and whether initial treatment was provided (washing and disinfection)
  • Whether the animal can be observed (e.g., whether a domesticated dog can be observed at home for 10 days)
• Sample questions (to prepare in advance)
  • “Is HRIG definitely necessary for the wound I received?”
  • “What is the vaccination schedule, and what side effects may occur?”
  • “If the animal can be observed, can vaccination be omitted?”

General Sample Questions to Ask the Doctor

• “Do I need to receive HRIG for this wound right away?”
• “What are the side effects and common adverse reactions of the vaccine?”
• “I am pregnant. Is it safe for me to receive the vaccine and HRIG?”
• “Do I need a blood test to confirm whether immunity has developed after vaccination?”
• “What precautions should I take regarding future pet vaccinations and prevention at home?”

Disease-Specific Sample Questions

• “The wound is located on my face (or head and neck). How does this affect the incubation period and risk of disease, and what is the treatment priority in this case?”
• “Are there situations in which HRIG can be omitted if I arrive at the hospital within a few hours of exposure? (For example, if the animal can be observed and its vaccination history has been confirmed.)”

Additional guidance: Rabies can be prevented if appropriate treatment is received promptly after exposure, but the prognosis is extremely poor once symptoms develop. If you have been bitten, visit an emergency medical institution or the infectious diseases department or emergency room as soon as possible to determine whether PEP is needed.