Rabies

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Rabies is a zoonotic disease (a disease that is transmitted to humans from animals) that is caused  by a virus. Rabies infects domestic and wild animals, and is spread to people through close contact  with  infected  saliva  (via  bites  or  scratches)  The  rabies  virus  infects  the  central  nervous  system,  causing  disease  in  the  brain  and,  eventually,  death.  Early  symptoms  in  people  include:  fever,  headache,  and  general  weakness  or  discomfort.  As  the  disease  progresses,  symptoms  include;  insomnia, anxiety, confusion, slight or partial paralysis, excitable behaviour, hallucinations, increase  in saliva, difficulty swallowing, and fear of water (hydrophobia). 

In  unvaccinated  humans,  rabies  is  almost  always  fatal  if  post-exposure  prophylaxis  is  not  administered before the onset of severe symptoms. Death usually occurs within days of the onset  of neurological symptoms. Dogs are the main carrier of rabies in Africa and are responsible for  most (approximately 97%) of the human rabies deaths worldwide. WHO estimates approximately  55,000 human deaths worldwide due to rabies each year; in Africa the annual death toll is 24,000. 

Case Definition 

Suspected: A person with one or more of the following: headache, neck pain, nausea, fever, fear of water, anxiety, agitation, abnormal tingling sensations or pain at the wound site, when contact with  a rabid animal is suspected. 

Confirmed: A suspected case that is laboratory confirmed.

Laboratory Investigation  

Human rabies is confirmed by intra-vitam and post-mortem diagnostic techniques that detect whole viruses, viral  antigens,  or  nucleic  acids  in  infected  tissues  (brain,  skin  or  saliva).  E.g.  Direct  fluorescent antibody (DFA) test, which targets rabies virus antigens in brain tissue, identification of  viral nucleic acid by reverse transcriptase PCR on fixed tissue collected post-mortem or in a clinical  specimen (brain tissue or skin, cornea or saliva) or detectable rabies-neutralizing antibody titre in  the CSF of an unvaccinated person. 

Pharmacological Treatment

Post-exposure prophylaxis (PEP) is the immediate treatment of a bite victim after rabies exposure by:

  • Extensive washing and local treatment of the bite wound or scratch as soon as possible after a suspected exposure; 
  • Providing effective rabies vaccine that meets WHO standards; 
  • Administration of rabies immunoglobulin (RIG), if indicated. 

Local  wound  therapy: wash  wound  thoroughly  with  running  water  and  soap  for  10  minutes,  and  repeat process with:  

A: 10% Povidone iodine; to prevent secondary bacterial infection

If patient presents with anxiety, agitation, seizures: 

A: diazepam Adults 10mg IV slowly in 3–5minutes (0.1–0.3 mg/kg in 3–5 min) 10mg in 3–5minutes, repeated 1–4 hourly Paediatrics 0.1–0.3 mg/kg in 3–5min, repeated 1–4 hourly to provide total 2.4–12 mg/kg IV for 24h

OR  

A: diazepam (IV) slowly in 3–5minutes, repeated 1–4hourly for 24hours 

OR 

A:  diazepam (IM) 20mg 2hourly for 24hours 

OR 

A:  diazepam (intrarectally) 10mg 1–4 hourly for 24 hours 

OR 

A: lorazepam 25–50mcg/kg 6 hourly for 24 hours  

OR

C: midazolam 0.08 – 0.2mg/kg (IV) repeated 1–4 hourly for 24 to 48 hours 

OR 

C: midazolam (intrarectally) 10–30mg over 24 hours by pump for 24 to 48 hours 

If patient presents with anxiety:

A: Haloperidol 5mg (IM or SC) hourly until calm, then 4 or 6 hourly and when necessary

OR 

A: haloperidol 5 mg (IV) 5–15mg/24 hours 

OR  

A: chlorpromazine (IM) 25–50mg/6–8 hourly for 48hours 

Table 4.3: Support for Patient with Fever, Hypersecretion and Pain Indication

Indication Drug Route of Administration Dose: Adult Dose: Paediatric
Fever A: paracetamol IV infusion over 15 minutes

1g every 8h, maximum 3-4g/24 h

  
intrarectal

1g every 4-6h, maximum 3-4g/24 h

 10-15mg/kg (PO) every 8 hours for 5 days
A: ibuprofen intrarectal 300–400mg 8 hourly  
A: aspirin intrarectal 450–900mg 4hourly,
maximum 3.6g/day		  
Hypersecretion A: Hyoscine (scopolamine) hydrobromide  sc or IV injection 400 mcg 4 hourly 10 mcg/kg 4-8 hourly
sc infusion 1.2–2mg/24 h 40-60 mcg/kg/24h
Pain  C: morphine  slow IV, SC, or IM 10mg 4 hourly  
intrarectal 15–30 mg 4 hourly 100 mcg/kg
S: fentanyl transdermal patch 12–25 mcg/h every 72 h 12 mcg/h every 72h

PreventionRabies can be prevented by:

  • Vaccinating pets 
  • Staying away from wildlife 
  • Seeking medical care after potential exposures before symptoms start 
  • Immunization  

Immunization

Active Immunization  

Pre-exposure  immunization  is  recommended  for  people  in  certain  high-risk  occupations  such  as  laboratory workers handling live rabies and rabies-related (lyssavirus) viruses; and people (such as  animal disease control staff and wildlife rangers)  

Active immunization: Human Diploid Cell Vaccine (HDCV) –either ID or IM 

A: anti-rabies vaccines (2- 3 IU/dose)  

  • IM: 1ml on days 0, 3, 7, 14, 28 (5 doses)     
  • ID: 0.2ml by dividing 0.1 ml on left shoulder and 0.1ml on right shoulder, on days 0, 3, 7 and 28 (4 doses). Intradermal (ID) is mostly advised. 

In addition, patients should receive rabies immune globulin with the 1st dose (day 0). 

Passive Immunization   

B: anti-rabies human immunoglobulin 20 IU/kg half the dose given parenterally and the other half injected into and around the wound for victims suspected to be infected  

AND 

A: tetanus toxoid vaccine, please refer to the section on Tetanus 

Note: 

  • Treat the person immediately after the animal bite, before onset of symptoms.   
  • Corticosteroid therapy generally is not considered for the management of brain edema in rabies. 

Public Health Control Measures 

  • Post exposure prophylaxis to prevent rabies 
  • Isolate patient and immunize contacts to prevent infection of others 
  • Vaccinate local dogs and cats to prevent outbreaks 
  • Promote public awareness of rabies 
  • Target immunization campaign for domestic or wild animals in high-risk areas 
  • Maintain active surveillance of rabies in animals