Rabies

• 1. Introduction

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  Rabies kills about 59,000 people around the world every year. About 40% of them are children under the age of 15. Once symptoms appear, the result is virtually always death, even with intensive care. The disease passes from animals to people, most often through a bite. It is present in more than 150 countries and on every continent except Antarctica. More than 3 billion people live where it occurs. The global cost is estimated at around US$8.6 billion per year, counting lost lives and livelihoods, medical care and psychological trauma that nobody has managed to calculate. This documentary follows rabies from the first spasm to the last survivor. Why would an illness of the brain make a thirsty person recoil from a glass of water? How can a virus enter through a small wound and take weeks or months to announce itself? And if the odds are so grim, why have some countries driven the disease almost out of existence?

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• 2. Fear of Water

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  The word rabies comes straight from Latin, where it meant madness. The Greek word lyssa carries the same meaning and gives the rabies virus its genus name, Lyssavirus. Lyssa itself traces either to lykos, the Greek word for wolf, or to an old Indo-European root meaning light.

  For centuries the illness was also known as hydrophobia, which means fear of water. In the late stages, swallowing becomes difficult and a offered drink can provoke panic. Even the thought or suggestion of drinking may set off agonizing spasms in the muscles of the throat and larynx. Saliva production rises sharply, yet the person cannot quench their thirst. The cruel logic favors the virus. Unable to swallow, the patient accumulates saliva, and the virus multiplies and gathers in the salivary glands, ready to pass on through a bite.

  Fever and headache are the usual first signs, sometimes with odd sensations where the exposure happened. As the brain and its membranes become inflamed, anxiety, insomnia, confusion, agitation, paranoia, terror and hallucinations can follow. Delirium and coma come next. Death usually arrives two to ten days after the first symptoms.

  About 80% of infected people develop furious rabies, the form most tied to hydrophobia. It brings irrational aggression, which helps the virus spread through bites. The foaming mouth of popular imagination is simply that excess saliva. The other 20% get a paralytic form, marked by muscle weakness, loss of sensation and paralysis. This form does not usually cause fear of water. The saliva that pools in the mouth is where the virus waits, and it gets there by a long trip through the body's wiring.

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• 3. A Virus Climbing Nerves

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  A rabies virus particle measures about 180 nanometres long and 75 across, wrapped in an envelope and built around a single strand of RNA. That genome carries just five genes. They code for a nucleoprotein, a phosphoprotein, a matrix protein, a glycoprotein and the viral polymerase. The rabies virus is the type species of the genus Lyssavirus, which belongs to the family Rhabdoviridae. Other lyssaviruses cause the disease too, including Australian bat lyssavirus, and Duvenhage lyssavirus may cause a rabies-like infection.

  The journey begins at the wound. The virus first infects muscle cells near the site, where it multiplies without being noticed by the immune system. Once there is enough of it, it binds to acetylcholine receptors at the junction between nerve and muscle. That receptor is also the most likely doorway into cells. Then the virus climbs. Its P protein interacts with dynein, a protein inside nerve cells, and this hauls the virus backward along the nerve fiber toward the cell body. From there it races into the central nervous system and multiplies in motor neurons until it reaches the brain. Finally it spreads outward again through the peripheral and autonomic nervous systems and into the salivary glands.

  This long climb explains the delay before symptoms. The wait is usually one to three months, but it can be under a week or more than a year, depending on how far the virus must travel along peripheral nerves. During the climb the virus is hard to detect, and a vaccine given in this window can still prevent symptoms. Once the virus reaches the brain it quickly causes encephalitis, and mortality is over 99%.

  Infected animals are often unusually aggressive and may attack without provocation. Biologists describe this as a pathogen changing the behavior of its host to help itself reach new hosts. Which animals deliver the virus to people turns out to be a surprisingly varied list.

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• 4. Carriers and Hosts

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  Dogs account for about 99% of human rabies cases worldwide. In countries where dogs commonly have the disease, more than 99% of human cases come from dog bites. The Americas are the exception. There, bat bites are the most common source, and dogs account for less than 5% of cases.

  Nearly any warm-blooded animal can be infected. People have caught rabies from monkeys, raccoons, foxes, skunks, cattle, wolves, coyotes, cats and mongooses, and exposure to bears, farm animals, groundhogs and weasels is also a risk. Saliva that reaches the eyes, nose or mouth of a person can carry the virus in.

  Rabbits, hares and small rodents such as mice, rats, squirrels, hamsters and guinea pigs are almost never found infected. A larger rabid animal usually kills them in any encounter, so they do not live long enough to become carriers. The Virginia opossum is a marsupial whose body temperature is lower than the virus prefers, which makes it resistant but not immune. Birds were first artificially infected in 1884, and they show largely no symptoms and recover. In 2024, rabies was found spreading among Cape fur seals in South Africa, possibly the first documented outbreak in marine mammals.

  In animals the disease runs through three stages. A prodromal stage of one to three days brings behavioral changes. The excitative stage lasts three to four days, and this is furious rabies, when an animal reacts wildly and bites anything nearby. Some animals skip that stage and move straight to the paralytic phase. Rear limb paralysis, drooling and trouble swallowing set in, and death is usually caused by respiratory arrest.

  Humans are poor carriers. In theory a person could pass on rabies by biting, but no such case has been documented. Patients are usually hospitalized by the time their saliva is infectious, and severe weakness makes biting difficult. The few recorded person-to-person cases all came through organ transplants, most often corneal transplants from infected donors. Touching an infected person, or contact with urine, blood or feces, does not count as an exposure and needs no emergency treatment.

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• 5. Old Remedies, Older Fear

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  Rabies has been known since around 2000 BC. The oldest written record is the Codex of Eshnunna, a Mesopotamian text from about 1930 BC. It told the owner of a dog showing signs of rabies to take precautions against bites. If that dog bit someone who later died, the owner faced a heavy fine.

  In ancient Greece, people blamed Lyssa, the spirit of mad rage. Remedies in the ancient medical literature were many and useless. The physician Scribonius Largus prescribed a poultice of cloth and hyena skin. Antaeus recommended a preparation made from the skull of a hanged man. Healers also cut away the lingual frenulum, the thin membrane that attaches the tongue, because they believed rabies began there. That practice stopped once the real cause was discovered.

  Rabies appears to have originated in the Old World. The first outbreak among animals in the New World struck Boston in 1768.

  By the 19th century rabies was considered a scourge. In France and Belgium, where Saint Hubert was venerated, people heated the St Hubert's Key and pressed it to a wound to cauterize it. Dogs were branded with the key in the hope of shielding them, an act of magical thinking. The fear has not faded in modern times. The agitation and rage of rabies have inspired zombie fiction, which often pictures a mutated, stronger virus that fills people with murderous rage and sets off a devastating pandemic.

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• 6. Vaccines and Emergency Treatment

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  In 1885, Louis Pasteur and Émile Roux developed the first rabies vaccine. Until then, almost every human exposure to rabies was fatal. They harvested the virus from infected rabbits and weakened the nerve tissue by letting it dry for five to ten days. The vaccine worked and was progressively improved to cut its often severe side effects. Nerve tissue vaccines of this kind are still used in some countries because they cost much less than modern cell culture vaccines.

  The human diploid cell rabies vaccine was started in 1967. Less expensive purified chicken embryo cell and purified vero cell vaccines are now available. The old series meant many painful injections into the abdomen with a large needle. In many countries the vaccine is now given as intramuscular injections in the upper arm, and World Health Organization intradermal regimens are replacing the nerve tissue version. Fear of that pain can be dangerous, since it may keep an exposed person from seeking care in time.

  Treatment after exposure can prevent the disease if it is given within 10 days. The vaccine is 100% effective if it is given before symptoms appear. Over 29 million people worldwide are vaccinated after a possible exposure every year. In the United States the recommendation is one dose of human rabies immunoglobulin and four doses of vaccine over 14 days. The immunoglobulin makes up most of the cost, which can reach several thousand dollars. In the United Kingdom, one dose costs the National Health Service £1,000, while a full vaccine course costs £120-180.

  People who were vaccinated in the past skip the immunoglobulin and need only vaccine doses on days 0 and 3. Thorough washing of the wound with soap and water as soon as possible reduces the number of viral particles. Povidone-iodine or alcohol is then recommended to reduce the virus further.

  Waking up to find a bat in the room is itself a reason for treatment, because a bite may go unnoticed. A 2002 study supported giving precautionary treatment when a child or a mentally compromised person has been alone with a bat, especially in a sleeping area. Vaccination before exposure is likewise recommended for people at high risk, such as those who work with bats.

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• 7. Baits and Borders

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  High in the Swiss Alps, scientists placed chicken heads laced with live weakened vaccine. Foxes, proven to be the main source of rabies in the country, ate them and became immunized. The disease was virtually eliminated in Switzerland. Oral vaccines in baits have since reduced rabies in rural areas of Canada, France and the United States. In Montreal, baits are used on raccoons in the Mount-Royal Park area. In Ontario, an aerial bait campaign brought a dramatic drop in rabies. A recombinant vaccine called V-RG has been used for wildlife in Belgium, France, Germany and the United States.

  In the United States, human deaths from rabies fell from 100 or more a year in the early 20th century to one or two a year. Vaccination of dogs and cats and the arrival of human vaccines and immunoglobulin explain the drop. From 1960 to 2018, 125 human cases were reported. Of those, 36, or 28%, came from dog bites suffered during international travel. Among the 89 infections acquired inside the country, 62, or 70%, were attributed to bats.

  Italy was declared rabies-free in 1997, but the disease returned to wild animals in the Triveneto regions in 2008, after an epidemic in the Balkans that also reached Austria. A large wildlife vaccination campaign cleared the virus again. The last reported case was in a red fox in early 2011, and Italy regained its rabies-free status in 2013. Sweden and mainland Norway have been free since 1886. The United Kingdom saw its last death from indigenous rabies in 1902 and its last infection in 1922.

  India has the highest rate of human rabies in the world, with an estimated 20,000 deaths a year, more than a third of the global total. Stray dogs are the main reason, and their numbers have greatly increased since a 2001 law forbade killing dogs. A form of mass hysteria called puppy pregnancy syndrome makes things worse. Dog bite victims, men as well as women, become convinced that puppies are growing inside them and often turn to faith healers instead of medical care.

  In 2013, Thailand had nearly eradicated human rabies by requiring vaccination of all domestic dogs. Infected animals kept crossing the border from Cambodia, Laos and Myanmar, which could not afford control measures. The result is roughly 100 cases a year in border zones known as Rabies Red areas. Even in Thailand, about 10 people a year die because they refuse treatment. Treating wild canines costs 10 times more than treating bite victims one at a time, which keeps many poorer countries from trying.

  In 2010, an estimated 26,000 people died of rabies, down from 54,000 in 1990. Every year the 28th of September is World Rabies Day. A 2015 partnership of the World Health Organization, the World Organization for Animal Health, the Food and Agriculture Organization and the Global Alliance for Rabies Control set a goal of ending deaths from rabies by 2030.

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• 8. Testing and Survival

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  Early rabies is easily mistaken for other diseases, or even for a simple aggressive temperament, and it can be diagnosed only after symptoms begin. The reference method recommended by the World Health Organization is the fluorescent antibody test. It uses a rabies-specific antibody linked to a fluorescent molecule, which makes rabies antigen visible under a microscope. Brain samples taken after death give the most reliable result. Negri bodies, clumps found in brain cells, are 100% diagnostic but turn up in only about 80% of cases. In 2018 the Centers for Disease Control and Prevention developed a test called LN34, which is easier to run on the brain of a dead animal and helps decide who needs treatment.

  Once rabies has developed, death almost certainly follows. The recommended care is palliative, in a hospital, with large doses of pain medication and sedatives in preference to physical restraint. Ice fragments can be given by mouth for thirst.

  In 2004, a teenage girl from Wisconsin named Jeanna Giese became the first human known to have survived rabies without post-exposure treatment before symptoms began. Doctors used what became known as the Milwaukee protocol. It places the patient in a chemically induced coma and uses antiviral medications to protect the brain while the body makes its own antibodies. Giese needed extensive rehabilitation, and her balance and neural function stayed impaired. The protocol has since been tried on many victims and judged a failure, and some who survived the acute phase later died of rabies. A report in 2025 suggested that some of the few survivors may never have had rabies progress far enough to develop antibodies, which would undermine some success stories.

  Research in 2010 among people in Peru with a history of vampire bat bites hints at a different story. Of 73 people who reported bat bites, seven had rabies virus-neutralizing antibodies, and only one reported being vaccinated. The authors read this as evidence of undocumented infections that began and then fizzled out. People may sometimes be exposed, develop natural antibodies and never need treatment. Meanwhile, the antiviral drug favipiravir has shown potential at inhibiting the development of encephalitis, and researchers have suggested combining it with immunotherapy and measures that protect the brain.

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