Scientists Say: Rabies | Science News for Students

Scientists Say: Rabies

This virus infects mammals and causes drooling, confusion and death
Nov 6, 2017 — 6:30 am EST
rabid dog
This dog is drooling so much because it has rabies.
CDC/Wikimedia Commons

Rabies (noun, “RAY-bees”)

This is a disease caused by the rabies virus. The virus infects mammals such as bats, dogs and people. It can also infect birds. The virus is spread through the saliva of an infected animal. The infected animal may scratch or bite another. Or its saliva may get into a healthy animal’s nose or eyes. The virus then infects the brain and nerves of the host.

The first signs that a person is infected with rabies include a fever or headache. But as the virus spreads through the brain and spine, these tissues become inflamed. The person may become very anxious and confused, or they might be unable to move. People and animals that are infected with rabies can have trouble swallowing and become terrified of water. They also can start drooling or foaming at the mouth. When animals or people become confused and very active, they may end up dying of a heart attack. Eventually the virus kills cells in the brain, which leads to death.

Rabies vaccines are available for animals and people. Pets such as dogs and cats get vaccinated regularly so that their bodies can fight off the virus if they encounter it. But people generally only get the vaccine when they are bitten by a rabid animal. If someone infected with rabies does not get the vaccine within 10 days of exposure to the virus, they almost always die.

Very few people in the United States get infected with rabies. But in other countries, it’s often a different story. Rabies — usually transmitted by dogs — kills an estimated 59,000 people a year. Most of those deaths occur in countries such as India, Ethiopia and the Democratic Republic of Congo.

In a sentence

Rabies is usually a death sentence — except for one group of people in Peru who seem to survive rabid bat bites.

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Power Words

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bat     A type of winged mammal comprising more than 1,100 separate species — or one in every four known species of mammal.

birds     Warm-blooded animals with wings that first showed up during the time of the dinosaurs. Birds are jacketed in feathers and produce young from the eggs they deposit in some sort of nest. Most birds fly, but throughout history there have been the occasional species that don’t.

host      (in biology and medicine) The organism (or environment) in which some other thing resides. Humans may be a temporary host for food-poisoning germs or other infective agents.

infect     To spread a disease from one organism to another. This usually involves introducing some sort of disease-causing germ to an individual.

mammal     A warm-blooded animal distinguished by the possession of hair or fur, the secretion of milk by females for feeding their young, and (typically) the bearing of live young.

nerve     A long, delicate fiber that transmits signals across the body of an animal. An animal’s backbone contains many nerves, some of which control the movement of its legs or fins, and some of which convey sensations such as hot, cold or pain.

rabies     A virus that is transmitted from mammals such as bats, raccoons, skunks and dogs — sometimes to people. Rabies is found on every continent except Antarctica, and is spread by contact with the saliva of an infected host. A vaccine exists. Without a vaccination, nearly every infected person will die.

vaccine     (v. vaccinate) A biological mixture that resembles a disease-causing agent. It is given to help the body create immunity to a particular disease. The injections used to administer most vaccines are known as vaccinations.

virus     Tiny infectious particles consisting of RNA or DNA surrounded by protein. Viruses can reproduce only by injecting their genetic material into the cells of living creatures. Although scientists frequently refer to viruses as live or dead, in fact no virus is truly alive. It doesn’t eat like animals do, or make its own food the way plants do. It must hijack the cellular machinery of a living cell in order to survive.