World Rabies Day: A Journey from Myths to Modern Medicine and Prevention

World Rabies Day: A Journey from Myths to Modern Medicine and Prevention

Sub: Science

Sec: Health

Why This is in News

World Rabies Day, observed on September 28, commemorates the death of Louis Pasteur and focuses on raising awareness about rabies. The tragic death of a nine-year-old boy in Alappuzha, Kerala, in May 2024 highlights the ongoing threat of rabies, despite medical advancements and available vaccines.

Rabies: A Global Health Threat

Rabies has a near 100% fatality rate once symptoms develop, making it a serious public health challenge.

Despite advancements in medical science and the availability of effective vaccines, rabies remains prevalent, particularly in countries like India.

Rabies is a zoonotic viral disease caused by viruses from the Lyssavirus family, which infect a wide range of mammals. The disease primarily targets the central nervous system, and once symptoms appear, rabies is almost 100% fatal.

Transmission of Rabies: Dogs are the most common source of rabies transmission to humans, followed by other animals like cats, bats, and wild carnivores. The virus is most commonly transmitted through the bite or scratch of an infected animal, as saliva carries the rabies virus.

Symptoms and Fatality: Rabies has an incubation period of 1 to 3 months, although this can vary based on factors like the distance of the bite from the brain. Once symptoms manifest, rabies is almost always fatal, with only a handful of survivors worldwide despite intensive medical intervention.

India accounts for about 36% of global rabies deaths, with dog bites being the leading cause.

Post-exposure prophylaxis (PEP): It is the most effective treatment for preventing rabies after potential exposure. PEP includes the immediate administration of rabies immunoglobulin (Rabies Ig) and a series of rabies vaccine doses.

How is the vaccine made?

The vaccine is made up of an inactivated virus that is expected to induce the body into producing antibodies that can neutralise the live virus in case of infection. There are also test vaccines that involve genetically modified viruses. There is no single-shot rabies vaccine or one that offers permanent immunity.

There are mainly two ways of administering the rabies vaccine. One, called post-exposure prophylaxis (PEP), is given to persons who have been exposed via a bite to an animal suspected to be infected. The vaccines are administered either into the muscles, or into the skin.

It can also be given ahead of time to persons who have a high risk of being infected, such as veterinarians, animal handlers, areas with a high number of rabies infection, by what is called Pre Exposure Prophylaxis (PrEP). The advantage of a PrEP is that if bitten, one doesn’t need a immunoglobulin injection, and two subsequent shots of the vaccine will suffice for full protection, unlike the four-course prescription in the case of PEP. However, the WHO doesn’t recommend PrEP as a general preventive.

Historical Context:

Susruta Samhita (Ancient Indian Text): This early medical text from India described symptoms of rabies, indicating an ancient awareness of the disease in the subcontinent.

Mesopotamian Records: Rabies is mentioned in records from Mesopotamia, where the disease was linked to dogs, which were often responsible for transmitting the virus to humans.

Hydrophobia: Hydrophobia (fear of water), a common symptom in rabies-infected patients, was identified and documented in ancient times, showing that the neurological effects of the disease were known even though effective treatments did not exist.

The 19th century marked a pivotal moment with the development of the germ theory and Louis Pasteur’s revolutionary work on rabies.

Pasteur developed a vaccine using attenuated rabies virus, although the concept of viruses was not yet fully understood. His vaccine was the second ever developed after the smallpox vaccine.

About Louis Pasteur

Louis Pasteur was born on December 27, 1822, in Dole, France. He is renowned as a French microbiologist and chemist.

Germ Theory of Disease: Pasteur is most famous for developing the germ theory of disease, which revolutionized medical science by proving that microorganisms cause diseases.

Pasteurization: He invented the process of pasteurization, which involves heating liquids like milk and wine to kill harmful bacteria, ensuring food safety. This process is still widely used today.

Rabies Vaccine: In 1885, Pasteur developed the world’s first rabies vaccine, using an “attenuated” (weakened) form of the rabies virus. His successful treatment of Joseph Meister, a young boy bitten by a rabid dog, marked a groundbreaking moment in medical history.