Rabies

Rabies is a viral disease that can infect mammals (warm-blooded animals, including humans). It infects the nerves and causes sudden encephalitis (swelling/pain of the brain). Rabies used to be called hydrophobia because one of its symptoms was causing fear to an infected person when trying to drink a liquid such as water. This is also why dogs or wolves with rabies foam at the mouth.

The disease is almost always fatal (for both people and animals) when the symptoms start. Basically no one has survived having rabies without prior vaccination (only one case, of a 15 year old girl, is documented). There is no treatment and cure for it when the symptoms occur. However, people (and pets) who are treated with vaccines soon after becoming infected have a very good chance of survival.

The disease is transmitted when infected saliva, tears or brain/nerve tissue comes into contact with a wound or mucous membrane. Mucous membranes refer to the lining of body cavities (e.g. gums, eyes). From the entry point, the virus replicates and travels up the nerves to the brain. The usual form of getting it is a bite of a rabid mammal. Pets, like dogs need to be vaccinated against it, in most countries.

 Spread of rabies 

About 99% of human rabies cases come from dogs. In the Americas, it is more common to get rabies from wildlife (e.g. bats). People rarely get rabies from other wild mammals. Rodents do not spread rabies to people. Livestock (farm animals) can get rabies, and sometimes spread it to people.

Tens of thousands of people die from rabies every year. About 95% of these deaths are in Asia and Africa. Some regions have no rabies or almost no rabies, such as Western Europe, Canada, the United States, Australia, and Japan. The rates of rabies cases went down from 1990 to 2020. In 2018, the World Health Organization made a plan to end human rabies deaths by 2030.

Transmission
Most of the time, rabies comes from an animal bite or deep scratch. People can also get it if an animal licks their eyes, mouth, or an open wound. No known person has ever been infected directly by another person. A few people have been infected by organ transplants.

When an animal that may have rabies bites a person, a few things can be done. First, the animal may be killed and tested for rabies. Second, the animal may be kept alive and watched. If it does not show signs in the next few days, the person is probably safe. If it does show signs, it will be killed and tested. If the animal had rabies, the person should be treated as soon as possible.

 Signs and symptoms 

At first, a person with rabies will have no signs or symptoms. They may start from one week to one year after a bite. The amount of virus and place of the bite can affect this.

The first symptoms are fever, pain, and feelings of tingling, prickling, or burning at the wound. After that, two kinds of rabies can form.

 Furious rabies causes excited behavior, hallucinations, poor coordination, seizures, a fear of water, and a fear of blowing air. Furious rabies causes death in 5-7 days.
 Paralytic rabies makes people unable to move their muscles. This is called paralysis. It later causes a coma, and death in two weeks or less.
It is not possible to know if an animal has rabies by looking at it. Some rabid animals act aggressive: they will attack or threaten for no reason. Others may act very tame: they allow people to get near to them. Some may drool or "foam at the mouth". In later stages, they may have trouble moving, because of paralysis. If an animal has strange behavior, people should be very careful when coming near it.

Fear of water is the most distinctive sign of rabies. People may panic when they see water, and have sudden muscle contractions in their throat.

 Treatment 

There is no cure for rabies. There is a Rabies vaccine (medicine to try to prevent rabies) against it. The vaccine was first developed by Louis Pasteur and Pierre Paul Émile Roux in 1885. This vaccine used a live virus grown in rabbits, and weakened (through drying it). The first person to be vaccinated was Joseph Meister (a 9-year-old boy who had been bitten by a dog). Vaccines similar to this are still used today, but other vaccines (growing the virus using cell cultures) are more often used. Some vaccines are made with bird embryos.

There is also a form of treatment that can be done once a person has been bitten. It needs to be done within 6 days of being bitten. There is no way to know whether someone is infected, until it is too late. Treatment starts with washing the wound. This is done to reduce the number of virus particles that enter the body. Often patients are given one dose of immunoglobulin and a certain number of vaccines, over a determined period of time, usually a month. After the signs and symptoms of rabies appear, less than 20 people have survived. Only one person world-wide has survived rabies without vaccine treatment.

 Prevention 
To prevent (stop) rabies, animals should get vaccines. It is most important to vaccinate dogs and cats. Children should learn how to be safe around animals. Wild animals should be prevented from biting pets and livestock. To stop rabies outbreaks, some countries quarantine animals that enter the country.

 References 

 Other websites 

History of Rabies in Los Angeles
Rabies Information 
Rabies - A Comprehensive Guide 
Centers for Disease Control and Prevention
World Health Organization factsheet on Rabies
World Health Organization factsheet on Rabies vaccine
Rules for importing pets to the United Kingdom 
A Rabies-Free World, Inc.  - NPO dedicated to fighting rabies worldwide
Rules for importing pets to the European Union  
Rules for importing pets to the European Union Q&A 
Aspen Skunk Rabies Research 
"When Raccoons Attack" from Field & Stream Online 
“Only Known Unvaccinated Rabies Survivor Thrives” (USA Today) Progress report on the first known survivor of rabies


Category:Diseases caused by viruses
Category:Zoonoses
Category:Lyssaviruses