September 28 is World Rabies DayPosted on by
It is one of the most feared diseases in the world, and for good reason. Rabies has a fatality rate of nearly 100%, and it causes the most human deaths of any zoonotic disease, that is, diseases which can be spread between animals and humans. Each year, an estimated 59,000 people die from rabies worldwide; that’s one death every 9 minutes. The loss of life to this preventable disease is staggering, but even more tragic is the reality that most of those who die are children.
If you were alive around 1,000 BC Babylonia, there was a popular curse that was often used to highlight the terrible things that would rain down on enemies, opponents and rivals. The prophet Marduk used it against an entire city. “I will send the gods of cattle and grain off to the heavens. The god of beer will make ill the heart of the land. The corpses of people will clog the gates. Brother will eat brother. Friend will kill friend with a weapon. Lions will cut off the roads. Dogs will become rabid and bite people. All the persons whom they bite will not survive but die,” he said in a taunt to Babylon. This is one of the earliest written reference to rabies.
Many of you reading this blog were not around to hear the Prophet Marduk. More of you are likely products of the 1970’s or 1980’s, and for you the word “rabies” might conjure an image of Cujo the bloodthirsty dog that wreaked havoc in a popular movie, or Old Yeller being put down after getting rabies while protecting his family from a wolf. If you are a millennial, you probably associate rabies with zombies rather than with dogs or other animals. The accepted truths about rabies also changes based on where you live. Readers in Wisconsin may think of bats and skunks, and people in New York will most likely be concerned about raccoons, whereas about 3 billion people on earth worry about getting rabies from their dogs.
While rabies may be one disease, it looks very different when viewed in terms of time and geography. As a veterinary epidemiologist at CDC, time and geography are some of the tools I use to track zoonotic diseases like rabies.
The domestic dog is the most successful terrestrial mammal in the history of the world. There are now an estimated 500 – 700 million dogs in the world. While dogs are truly man’s best friend, they are also the harbinger of this deadly disease, with more than 98% of human rabies deaths due to a bite from a rabid dog.
While dogs represent the greatest risk of rabies for people, any mammal can get rabies. In different parts of the world, wildlife species have been identified as maintaining the rabies virus even in places where it has been eliminated in dogs. In Eastern Europe, rabies is found in the fox and raccoon dog (neither a raccoon nor a domesticated dog, but a primitive canid found in Europe). In Asia, there are rabies viruses transmitted from a little-known creature called a ferret-badger. In Africa, the virus has been found in jackals, kudus, and shrews. Here in the United States, though we have eliminated rabies in dogs, we still have rabies viruses that circulate in skunks, raccoons, foxes, and mongooses. And these are just the terrestrial mammals. Rabies and rabies-like viruses are found in bats on every continent except Antarctica.
The acute phase of rabies infection is characterized by intermittent fever, paresthesia, and hallucinations. Other symptoms of rabies are behavioral changes and neurologic changes, often aggression and paralysis. Unfortunately, in many parts of the world these typical symptoms of the virus are not well understood or explained. A lack of education about this disease can lead to great misinterpretations of the underlying medical issues.
In 2014, in a small rural community in a developing country, two young men were bitten by a dog. They did not seek medical attention for the bite; it healed and was soon forgotten. However, a few weeks later, separated by only several days, both men started to speak in tongues and have unusual arm spasms. Instead of going to the local health center, their families took them to the local traditional healer. It was decided that the men had been cursed, and the men were given a potion. The symptoms became worse over the next several days and progressed to aggression, striking at people, and trying to bite. The healer was again consulted, and it was decided that someone had turned the two men into zombies. The families were told to tie the men to a tree to keep everyone safe. Unfortunately, both men died.
Rabies is invariably fatal, however a vaccine against rabies was invented more than 100 years ago, and this vaccine is nearly 100% protective when given appropriately, soon after exposure. But it is important to remember that this is not a disease that is easily spread between humans. Rather this is a disease of animals, particularly dogs. And numerous studies have shown that controlling the disease at its source, in the dog, can be up to 100 times more cost effective than continuing to vaccinate people after an exposure.
September 28 marks the day that the inventor of the rabies vaccine, Louis Pasteur, died in 1895. It is also the day that many countries in the world acknowledge the significance of this leading killer among zoonotic diseases, and organize events to raise awareness for its control. It is important to recognize that rabies is still a major concern for over half the world’s population, and is still a threat in the United States. On this day, rabies scientists, animal health professionals, human health professionals, animal care and control professionals, and many others involved in the fight against rabies, draw attention to the year round effort to control and eliminate canine rabies and its burden on humans. This should be a day for pet owners to remember to vaccinate their dogs and cats. It should be a day for outdoor enthusiasts to remember to stay away from wild animals. And this should be a day that we think about ways we can help prevent the unnecessary deaths of so many people around the world from a disease that has been vaccine preventable for the better part of a century.
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