RABIES

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What is it

Rabies is a viral infection caused by a virus of the Rhabdoviridae family1 that can infect any warm-blooded mammal (both domestic and wild) and is commonly seen in dogs, cats, foxes, raccoons, skunks, wolves and bats.1 Those infected mammals in close contact people may transmit the disease to humans (such as cattle, horses and domestic dogs).1 Once it enters the body, the virus attacks the central nervous system, eventually affecting the brain.1 Rabies is almost always fatal once symptoms occur.1
Due to strong prevention and control programs, human rabies is rare in Canada, with only four cases since 1985.1 However, rabies is a significant public health concern in many Asian and African countries.1

Who is at risk

Injury to the upper body or face (such as when the skin is compromised or broken), poses the greatest risk of rabies transmission.1 The risk is also greater in children than in adults, and greater in boys than in girls.1

What are the symptoms

Symptoms usually appear within 1 to 3 months, but may vary considerably from days to years, depending on various factors.1,2

The earliest symptoms tend to be flu-like, consisting of headache, generally feeling unwell, fever, and fatigue, and may also include pain or tingling at the site of exposure.2

Symptoms will continue to progress quickly as the virus spreads to and attacks the central nervous system. The illness can present itself in one of two ways:1,2

  • "Furious rabies": This is the more common form and is characterized by anxiety and psychological disturbances such as confusion, delirium, agitation, rage, hallucinations, seizures, and hydrophobia (fear of water).
  • "Dumb rabies": This form occurs in approximately 20-30% of patients and presents as weakness and paralysis.

In both forms of the illness, death usually occurs within 7 to 14 days due to paralysis of the muscles that help facilitate breathing.1

How is it spread

Rabies is caused by a Lyssavirus, which is most often transmitted from mammal-to-mammal (including humans) through saliva, most commonly by a bite or scratch, or by licks on broken skin or mucous membranes (such as the eyes, nose or mouth).1,2,3 While it is theoretically possible for rabies to be transmitted from human-to-human, no such case has been confirmed, and therefore occurs through animal-to-human contact.1 Humans most often contract the disease through domestic dogs, making dog vaccination important in preventing rabies in humans.2

How is it prevented

Rabies vaccines are available and can be used to prevent the virus from entering the central nervous system. It can be administered either before being exposed to rabies (pre-exposure prophylaxis) or after exposure to rabies (post-exposure prophylaxis) .1,3,4,5

Pre-exposure prophylaxis is indicated for vaccination of people who are at a high risk of contact with potentially rabid animals or the rabies virus (for example certain laboratory workers, veterinarians, animal control and wildlife workers, travellers to countries with rabies, etc.) .3,4,5

Post-exposure prophylaxis is a priority for anyone exposed to animals with confirmed or suspected rabies due to the fact that rabies is almost always fatal.1,4,5,6 It should be administered as soon as possible after exposure and should always be administered, regardless of the amount of time that has passed since exposure.1

If an individual has been bitten by an animal and they believe they may have been exposed to rabies, they should immediately and thoroughly wash and flush the wound with soap and water for a minimum of 15 minutes.2,3,4,5,6 They should then contact a healthcare provider immediately to assess their risks and the need for treatment.2

How is it treated

Current tools for diagnosis are not suitable for detecting rabies before the onset of symptoms, and unless certain symptoms are present, a diagnosis by a healthcare provider based on symptoms may be difficult as well.3

Once symptoms of rabies are present there is no treatment for the illness.2 Medical advice is recommended for the onset of symptoms. For further information regarding rabies and immunization, please speak with your healthcare provider.

REFERENCES

  1. Public Health Agency of Canada. Fact Sheet on Rabies. (2008) http://www.phac-aspc.gc.ca/im/rabies-faq-eng.php
  2. Government of Canada. Rabies (2016) https://travel.gc.ca/travelling/health-safety/diseases/rabies
  3. WHO. Rabies Fact Sheet. (2017) http://www.who.int/mediacentre/factsheets/fs099/en/
  4. GlaxoSmithKline RabAvert Product Monograph. (2017) https://pdf.hres.ca/dpd_pm/00038458.PDF
  5. Sanofi Pasteur Imovax Rabies Product Monograph. (2006) https://www.vaccineshoppecanada.com/document.cfm?file=IMOVAX_E.pdf
  6. Sanofi Pasteur Imogam Rabies Pasteurized Product Monograph. (2015) https://www.vaccineshoppecanada.com/document.cfm?file=imogam_rabies_e.pdf