By Anirudh Raghupathy Narendra Nath, Head of Veterinary
While on a pleasant walk outside, you see a rather cute-looking stray dog lying down on the roadside. Wanting to pet it, you venture closer with an outstretched hand. Before you know it, you are hastily pulled back and reprimanded for attempting something so dangerous. As you are being lectured about all the things that could have gone wrong – it bites you, parasites transfer to you, germs from it infect you, dirt and grime come into contact with you – one particularly odd-sounding disease catches your attention - Rabies.
One method of warning children is exaggerating the consequences of an action in an attempt to further dissuade them from doing so. Peers and parents would have undoubtedly told you of the horrors of this zoonotic disease – feral dogs frothing at the mouth, people losing their minds, hydrophobia, and worst of all - no known cure. Has this disease been exaggerated, similar to other things in our childhood, or does it truly live up to the horror that is associated with its name?
Rabies is a preventable viral disease often transmitted through the bite of a feral or rabid animal also infected with the rabies virus.
The transmission of rabies is most commonly attributed to dogs and bats (which are the leading cause of rabies-related deaths in the US), but other mammals such as foxes, raccoons, cats, monkeys, woodchucks, and skunks can also transfer rabies through their bites and saliva. Dogs are noted to be the main source of transmission and rabies-caused deaths. (Johnson, 17th September 2018)
Once the virus has been transferred through a bite or exposure to saliva, it travels through the body’s nerves, from the site of the bite to the brain. This period is known as the incubation period, and may last for weeks to months depending on factors such as the exposure site and the type of rabies virus. During this period the animal does not display any signs of illness. Bites from the animal will not transfer the virus, as it has not reached the salivary glands.
Now, onto the more horrific aspects of the disease – the symptoms which occur once the infection affects the central nervous system and causes inflammation in the brain. Animals and humans tend to have similar symptoms. Fever, agitation, hyperactivity, nausea, difficulty in swallowing, hydrophobia (caused by difficulty in swallowing), aerophobia (fear of air being blown on the face), excess salivation, hallucinations, insomnia, paralysis (which is known as paralytic rabies, and occurs more gradually) and more. A nightmarishly terrifying mix of symptoms, all from a bite and some spit. (Mayo Clinic Staff, 2nd November 2021)
Now that the virus, its transmission, and the symptoms have been discussed, the more positive aspects such as treatment and prevention can be addressed – especially a cure. If there were one, that is. An interesting fact – the rabies virus is bullet-shaped. Similar to a bullet, once this virus reaches the brain and symptoms show up, it’s usually game over for the unlucky victim. Less than 20 people have survived rabies after displaying symptoms of the disease.
“Prevention is better than cure” – in this case, since a cure does not exist, prevention is extremely necessary and must be carried out as effectively as possible. Taking precautionary measures could mean more than one life saved.
Pets are both at risk of getting rabies and could potentially transfer it. Vaccinating your pets is vital, and making sure they do not wander into spaces with wild animals could also help in preventing any contact with an infected animal. Naturally, this also applies to people. Furthermore, people travelling a lot should make sure they are up to date on their vaccinations. (WHO, 17th May 2021)
What would an animal with rabies look like, exactly? It should be simple – any rabid or feral animal acting extremely aggressive should have rabies. Well, it’s more complicated than that. Not every infected animal is a ravenous, drooling, crazed beast frothing at the mouth and snapping at the air. Some animals are tamer than usual, and some may even exhibit symptoms of paralysis. Aside from the aforementioned, more noticeable signs, things such as bats on the ground are also possible warnings. Unnatural behaviour is something to keep an eye out for. While these signs are helpful, the only real way to find out if an animal has rabies is to have it tested in a lab.
Aside from vaccinations and general awareness, there are some methods used to prevent the onset of the infection – yes, once the infection has affected the central nervous system nothing much can be done (apart from supportive treatment), but the infection can be prevented from taking hold. (CDC, 29th July 2020)
There are two notable procedures which have helped save people’s lives by preventing infection – Postexposure Prophylaxis (PEP) and Pre-Exposure Prophylaxis (PrEP).
Pre-exposure Prophylaxis is given to people who are at a higher risk of coming into contact with the rabies virus, for example: people who work with dogs, strays, people travelling to cave with bats, people working with the dead bodies of animals, and more. These people are given a series of rabies vaccine doses prior to the interaction, hence the term ‘pre-exposure’.
Postexposure Prophylaxis is a dose of human rabies immune globin (HRIG) and rabies vaccine, given on the day of the suspected rabies exposure (unless the animal responsible has been tested), and a dose of the vaccine again on the 3rd, 7th, and 14th days. The HRIG need not be given if the person is receiving PrEP or has been previously vaccinated, they should only be given the vaccine. For unvaccinated people, both should be administered. This combination is also highly recommended in cases of bite and non-bite (for example, contact with saliva) exposures. (CDC, 29th July 2020)
Rabies causes around 59000 deaths worldwide every year, but through preventive measures such as PEP and PrEP which millions of people take as a precaution, hundred of thousands of potential rabies deaths are prevented. The world knows how dangerous this virus can be – September 28th is known as World Rabies Day, and organizations such as the WHO are working to eliminate dog-mediated rabies deaths in people by 2030. This is an incredibly dangerous virus, but with the right precautions, both humans and our beloved animal companions can stay safe.
CITATIONS 1. “CDC - Rabies around the World - Rabies.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 29 July 2020, www.cdc.gov/rabies/location/world/index.html.
2. Johnson, Shannon. “Symptoms of Rabies in Humans, Risk Factors, How to Prevent IT & More.” Healthline, Healthline Media, 17 Sept. 2018, www.healthline.com/health/rabies#transmission. 3. Mayo Clinic Staff. “Rabies.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 2 Nov. 2021, www.mayoclinic.org/diseases-conditions/rabies/symptoms-causes/syc-20351821. 4.“Rabies.” World Health Organization, World Health Organization, 17 May 2021, www.who.int/news-room/fact-sheets/detail/rabies.
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