Rabies and lyssavirus

Disclaimer These guidelines have been produced to guide clinical decision making for the medical, nursing and allied health staff of Perth Children’s Hospital. They are not strict protocols, and they do not replace the judgement of a senior clinician. Clinical common-sense should be applied at all times. These clinical guidelines should never be relied on as a substitute for proper assessment with respect to the particular circumstances of each case and the needs of each patient. Clinicians should also consider the local skill level available and their local area policies before following any guideline.  Read the full CAHS clinical disclaimer

Aim 

To guide Emergency Department (ED) staff with the assessment and management of rabies and lyssaviruses.

Definition

Rabies virus, Australian bat lyssavirus (ABLV) and other lyssaviruses are members of the Rhabdoviridae family. These viruses cause the rabies disease.

Rabies and other lyssavirus infections are notifiable diseases and considered to be an urgent public health priority. 

Background^1,2

• Rabies virus is enzootic in some parts of the world, including Asia, Africa, North and South America and parts of Europe. Most cases are due to transmission by dogs but all mammals are susceptible to infection with rabies virus. Bat associated rabies occurs globally.
• Australian Bat Lyssavirus (ABLV) (first identified in 1996) has been found in several species of flying foxes and bats in Australia, and has been associated with 3 human deaths, one in 1996, one in 1998 and one in 2013.² It is assumed that all Australian bat species have the potential to carry and transmit ABLV.
• It is assumed that ABLV infection has the same clinical features as rabies. Hence, rabies post-exposure prophylaxis is recommended for patients with a potential exposure to ABLV, other lyssaviruses or rabies. 

Clinical features of Rabies^3,4

• Incubation period: 5 days to several years (usually 2-3 months)
• Risk highest in bites to head and neck (due to proximity to the central nervous system (CNS)) and fingers (richly innervated)
• Prodromal Phase (10 days) – nonspecific: anorexia, cough, fever, headache, myalgia, sore throat, nausea
• Paraesthesia / fasciculation near site of wound
• Acute encephalitis – aerophobia, hydrophobia, hyperactivity
• Autonomic instability – hypersalivation, hyperthermia, hyperventilation
• Neurological status deterioration to coma or cardiorespiratory arrest. Invariably fatal.

Pre-exposure Vaccination – Human Rabies Virus (HRV)

• Three doses on days 0, 7 and 21–28
• See Australian Immunisation Handbook – Rabies and other Lyssaviruses for recommendations and administration
• Recommendations for pre-exposure vaccination may differ in other countries based on the 2018 WHO position statement, however the current recommendation in Australia remains for three doses^7,8

Assessment

Potential exposure to Rabies

• Any bite or scratch from, or mucous membrane or broken skin contact with, the saliva or neural tissues of a wild or domestic terrestrial mammal (e.g. dogs, cats and monkeys) in rabies-enzootic countries (e.g. Asia, Africa, North, Central and South America and parts of Europe); includes Bali from August 2008.
• Any bite or scratch from, or mucous membrane or broken skin contact with the saliva or neural tissues of a bat anywhere in the world including Australia.
• Exposures due to direct contact with bats in situations where bites or scratches may not be apparent (as some bats have small teeth and claws).
• For potential exposures where the person is unaware or unable to communicate about the exposure, seek advice from public health or an Infectious Diseases consultant.
• Rabies can remain viable in dead animals. For contact with dead animals fitting the above criteria, seek advice from public health or an Infectious Diseases consultant. 

Management of Exposure³

• Post exposure management is recommended for any potential exposure and should start as soon as possible following the exposure.
• All exposures require wound care:
  • Wash all wounds with soap and water thoroughly for approximately 15 minutes as soon as possible after the exposure
  • Apply a virucidal antiseptic solution (e.g. povidone-iodine 10%)
  • Primary suture of wound is to be avoided where possible. If suturing is required, it should only occur after Human Rabies Immunoglobulin (HRIG) administration in the wound (if indicated)
• Consideration should be given to the possibility of tetanus and other wound infections. Refer to Tetanus Prone Wounds – ED Guideline and Skin and Soft Tissue (Paediatric Empiric Guidelines) – ChAMP.
• Post exposure prophylaxis (PEP) requires a course of rabies vaccine with or without HRIG.
  • The PEP schedule depends on the animal involved (mammal or bat), the exposure category (severity), the patient’s immune status and previous vaccination history. Refer to the detailed guidance algorithms in the Australian Immunisation Handbook.
  • PEP can be given even if there is a significant delay in seeking medical care after exposure. HRIG is not recommended if a person presents more than 12 months after exposure (note: vaccine should still be given). After 10 years it may be appropriate not to provide any PEP (discuss with Infectious Disease consultant or public health).
  • If the first rabies vaccine is given prior to HRIG, HRIG should be given within 7 days of receiving the first dose. Do not give HRIG if it has been more than 7 days (168 hours) since the 1st dose of rabies vaccine (this is because HRIG may interfere with the immune response to the vaccine).
  • It is not uncommon for patients who have been exposed overseas to have commenced PEP in that country. Refer to the Australian Immunisation Handbook for detailed guidance on how to align and complete the schedule, and to determine whether HRIG is required now. Note that ‘day 0’ of an overseas schedule refers to the day of the first vaccine, not the day of the exposure.
  • Discuss with public health or an Infectious Diseases Consultant if uncertain.

Access to post-exposure prophylaxis (PEP): Human Rabies Immunoglobulin (HRIG) and / or Human Rabies Vaccine (HRV)

Advice and approval to access PEP must be obtained via the public health (available 24/7), before using cache stock

• Refer to the flow chart how to access post-exposure prophylaxis. Rabies & other lyssavirus (including Australian bat lyssavirus) exposures. HOW TO ACCESS POST EXPOSURE PROPHYLAXIS (PEP): INFORMATION FOR HEALTHCARE PROVIDERS IN METROPOLITAN PERTH (internal WA Health only)

During office hours, contact the local public health unit.

• For PCH this is the Metropolitan Communicable Disease Control (MCDC). Phone: 9222 8588
• After hours, contact the public health on-call duty officer and request to speak with the on-call Public Health Physician. Phone: 1800 434 122.
• Inform the Public Health Physician that you have cache / on-site stock but are seeking public health advice / approval to use the stock.
• Use the online public health Rabies virus and other lyssaviruses exposure assessment form to document the details of the exposure.
  • This form is required for public health assessment and approval, and national data collection but also includes references to guide assessment.
  • Completing this form is required to trigger restock of government funded vaccine and HRIG to PCH ED.
    • Cache stock is held in the ED Pod C 3-cell ADM, with 2 doses of each vaccine and 8 vials of HRIG kept on imprest.
    • Non-urgent re-supply will be delivered to PCH Pharmacy next business day and the ADM will be restocked by Pharmacy.
• No stock is held by PCH Pharmacy. If urgent out-of-hours re-supply is required, the on-call Public Health Physician should be contacted and advised to organise delivery direct to PCH ED.
• Rabies PEP is funded by the WA Department of Health (regardless of Medicare eligibility).
• Stock must only be accessed from the ED ADM once the public health officer has approved the use of the products and the form has been completed.

Human Rabies Immunoglobin (HRIG)³ administration

• Dosage of HRIG is 20 units/kg (the same dose for infants, children, and adults).
• HRIG should be given at the same time as the first rabies vaccine dose, as soon after exposure as possible.
• Infiltrate as much of the calculated dose as possible in and around all wounds, the remainder is to be given intramuscularly (IM) at a site away from the rabies vaccine injection site. Depending on the volume, this could be in the alternative deltoid, lateral thigh or gluteal muscle. 
• Note potential for compartment syndrome if injected into the hand.
• Consider regional anaesthesia (e.g., ring block), analgesia and procedural sedation (nitrous oxide) for infiltration into painful areas.
• See Australian Immunisation Handbook - Rabies and other lyssaviruses for further administration information.

Human Rabies Vaccine (HRV)schedule and administration

• Please see the Australian Immunisation Handbook for recommendations and administration based on the patient’s exposure, vaccination history and immune status; there are differences between management of bat and terrestrial animal exposures.
• Note that some vaccine products contain egg so the appropriate product should be used in individuals that are allergic to eggs.
  
  Refer to Rabies post-exposure prophylaxis: bat exposures | The Australian Immunisation Handbook (health.gov.au)
  
  Refer to Rabies post-exposure prophylaxis: terrestrial animal exposures | The Australian Immunisation Handbook (health.gov.au)
  
  
• Recommendation for most immunocompetent patients:
  • No previous vaccination course received:
    • 4 doses of HRV on day 0, 3, 7 and 14 (in addition to HRIG, if indicated)
  • Previously immunised:
    • 2 doses HRV on day 0 and day 3
• Immunocompromised patients should be discussed with an Infectious Diseases consultant
• Do not give rabies vaccine in the buttock, as post-exposure prophylaxis can fail when vaccine is given in this area.⁶

Completing the PEP course

• Patients may complete their vaccination course with their usual GP or at a travel clinic.
• Advise public health (when known) where remaining doses should be sent.
• Selected Perth travel clinics have government funded rabies PEP on premises and often can see patients that day. See WA Health Protocol for Accessing Immunoglobulin Blood Products for Public Health Use in Western Australia

Confirmed or suspected rabies or other lyssavirus

Suspected or confirmed cases of rabies and other lyssaviruses must be notified urgently to the local public health unit via telephone, and using the communicable disease notification form⁵, following the submission details on that form.

• Phone: 9222 0255 (office hours) or 1800 434 122 (after hours)
• For cases residing in regional areas refer to the appropriate regional population/public health unit – WA Country Health Service (WACHS)

References

1. Rabies Virus and other Lyssavirus (including Australian Bat Lyssavirus) Exposures and Infections. CDNA National Guidelines for Public Health Units (SoNGs). Last updated: 24 Jun 2022. Cited: 31 Aug 2022. Available from: rabies-and-other-lyssavirus-cdna-national-guidelines-for-public-health-units.pdf
2. Francis, J.R., McCall, B.J., Hutchinson, P., Powell, J., Vaska, V.L., & Nourse, C. (2014, December 11). Australian bat lyssavirus: Implications for public health. The Medical journal of Australia, 201(11), 647-649. https://doi.org/10.5694/mja13.00261
3. Rabies and other lyssaviruses. Australian Immunisation Handbook Last updated: 6 Jun 2018. Cited 31 Aug 2022. Available from: Clinical features | Rabies and other lyssaviruses | The Australian Immunisation Handbook (health.gov.au)
4. Lyssavirus (ABLV) Healthdirect  Last updated April 2021. Cited 31 Aug 2022. Available from: Lyssavirus (ABLV) - vaccine, treatment and symptoms | healthdirect
5. Rabies and other Lyssavirus (including Australian Bat Lyssavirus) Statutory notification alert. Department of Health (WA) Last reviewed 18 July 2022. Cited: 31 Aug 2022. Available from: Rabies and other Lyssavirus (including Australian Bat Lyssavirus) (health.wa.gov.au)
6. Centers for Disease Control and Prevention (CDC), Manning SE, Rupprecht CE, et al. Human rabies prevention – United States, 2008: recommendations of the Advisory Committee on Immunization Practices. MMWR. Recommendations and Reports 2008;57(RR-3):1-28
7. Rabies Vaccines: WHO position paper – April 2018. Weekly epidemiological record, No 16, 2018, 93, 201–220 Available from: Rabies vaccines: WHO position paper – April 2018
8. Pre-exposure prophylaxis (PrEP) Centres for Disease Control and Prevention – Rabies Homepage. [Last reviewed May 4, 2022. Cited: Jan 10, 2023.] Available from:  Pre-exposure Prophylaxis (PrEP) | Prevention | CDC -

Endorsed by:	CAHS Drug and Therapeutics Committee	Date:	Jan 2024
		Review date:	Jan 2027

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