Rabies

Some animals carry a tiny germ.

This germ can make them very sick. It can spread if an animal bites or scratches you. Most cases come from dogs.

In some places, bats are the cause. The germ travels through the body to the brain. It can make people afraid of water. If you get a bite, wash it with soap. A doctor can give you medicine to help. This medicine can stop the germ from making you sick. It is important to get help fast.

Rabies is a serious disease caused by lyssaviruses. These are tiny germs that can make mammals sick.

Most human cases come from dog bites. In the Americas, bat bites are a common cause.

An animal spreads the virus through bites or scratches. Saliva can also spread it if it touches eyes or mouths. Once the virus enters the body, it travels along nerves. It moves toward the central nervous system, which includes the brain.

This can take one to three months.

Symptoms can include fever and confusion. Some people feel a fear of water. This is called hydrophobia. It happens because swallowing becomes very painful. In many cases, the disease leads to death.

We can prevent rabies with care. If an animal bites you, wash the area with soap and water for 15 minutes. Doctors can also give vaccines. These medicines work if you get them before symptoms start.

Many places, like Japan, have no rabies in dogs. Animal programs help keep these areas safe.

Rabies is a very serious disease caused by lyssaviruses. These tiny germs can make all kinds of warm-blooded mammals sick.

In many parts of the world, dogs are the most common animals to spread it. In those places, dog bites cause over 99% of human cases. However, in the Americas, bat bites are the most common source. Rabies is found in more than 150 countries across all continents except Antarctica. It is even called a neglected tropical disease.

The way the virus works is quite specific. It usually enters a body through a bite or a scratch. Saliva from an infected animal can also spread it if it touches eyes, a nose, or a mouth. Once inside, the virus first infects muscle cells near the site. It then travels along the nerves to reach the central nervous system. This journey to the brain can take one to three months. Sometimes, this period can be less than a week or more than a year.

When the virus reaches the brain, it causes severe inflammation. This leads to many different symptoms. Some people feel fever, headaches, or strange sensations. Others may experience confusion, anxiety, or even hallucinations. A famous symptom is hydrophobia, which means a fear of water. This happens because swallowing becomes very painful and causes spasms in the throat. This pain makes it hard for people to drink. Once these symptoms appear, the disease almost always leads to death.

Scientists have studied this disease for a long time. The name rabies comes from the Latin word for madness. The virus belongs to a group called lyssaviruses. Research shows that most people who die from rabies are in Africa and Asia. About 40% of the 59,000 annual deaths are children under age 15. Even though it is dangerous, some places stay safe. Countries like Japan and Australia do not have rabies in their dog populations.

We can take steps to stay safe from this virus. If an animal bites you, you should wash the wound with soap and water for 15 minutes. This can help reduce the number of virus particles. Doctors can also use vaccines to prevent the disease. These treatments work well if they are given before symptoms start. People who work with bats are often given these vaccines early. Vaccination programs for animals also help keep communities safe.

Rabies is a serious zoonotic disease caused by lyssaviruses. This term refers to diseases that spread from animals to humans. The virus causes acute and severe encephalitis, which is an inflammation of the brain and the protective membranes surrounding it. Historically, the disease was often called hydrophobia, or the fear of water. This name came from the intense panic victims feel when offered liquids. Once the physical symptoms of rabies appear, the disease is almost always fatal. It is currently classified as a neglected tropical disease.

The mechanism of the virus is a complex biological process. It begins when an infected animal bites or scratches a human. The virus can also enter through the eyes, nose, or mouth via infected saliva. It can even be transmitted through tears or nervous tissues. Once inside, the virus is neurotropic, meaning it specifically targets nerve cells. It usually starts by replicating in muscle cells near the site of the wound. This allows the virus to multiply without being noticed by the host's immune system.

To move through the body, the virus must travel to the central nervous system. It binds to specific receptors, likely the acetylcholine receptor, at the neuromuscular junction. The virus then uses a process called retrograde transport to move along the nerve cell axon. It achieves this by using a protein called P to interact with dynein, a protein in the cytoplasm. Once it reaches the cell body, it moves rapidly into the brain. After infecting the brain, the virus travels outward to the salivary glands. This prepares the virus to be transmitted to a new host through biting.

There are two main clinical forms of the disease. The first is the furious form, which affects about 80% of infected people. This version causes irrational aggression and can lead to a "foaming at the mouth" effect. This occurs because saliva accumulates in the mouth. The second is the paralytic form, which affects the remaining 20%. This form is marked by muscle weakness, loss of sensation, and paralysis. Unlike the furious form, the paralytic version does not usually cause hydrophobia.

The timeline of the disease is measured by the incubation period. This is the time between the initial infection and the first symptoms. This period usually lasts between one and three months. However, it can be as short as one week or as long as one year. The exact timing depends on how far the virus must travel along the nerves to reach the brain. Once symptoms like fever, headache, or confusion begin, death usually occurs within two to ten days.

Globally, the impact of rabies is significant and widespread. The virus is present in more than 150 countries on every continent except Antarctica. It causes approximately 59,000 deaths every year. About 40% of these deaths occur in children under the age of 15. More than 95% of these human deaths happen in Africa and Asia. Dogs are the most common source of infection globally. In areas where dogs carry the disease, they are responsible for more than 99% of human cases.

In different parts of the world, the primary source of rabies changes. In the Americas, bat bites are the most common cause of infection. In these regions, dog bites account for less than 5% of cases. While most mammals can be infected, some animals are rarely involved. Rodents, such as mice and squirrels, are almost never infected. This is often because larger rabid animals kill them before they can spread the virus. Some animals, like the Virginia opossum, are resistant due to their lower body temperatures.

Prevention and medical intervention are vital for managing the risk. If an exposure occurs, washing the wound with soap and water for 15 minutes can help. This may reduce the number of viral particles. Doctors can use the rabies vaccine and rabies immunoglobulin to prevent the disease. These treatments are effective only if they are administered before symptoms start. Vaccination programs for animals and people at high risk are also essential. These efforts have successfully removed rabies from dogs in places like Japan and Australia.