What Makes a Disease Contagious?

You could get a cold if:
Your dog sneezes on you.
You clean the kitchen for a sick friend.
You could get a cold if:
People don’t normally catch colds from an animal, even your beloved dog or cat. Be careful when cleaning up after a sick friend, since viruses can live on countertops for a while.

"Infectious" and "contagious" mean the same thing.
True
False
"Infectious" and "contagious" mean the same thing.
A disease is infectious if it’s caused by a bacteria, virus, or other bug that gets inside you. It’s only contagious if people can pass it to each other. Not all infectious illnesses are contagious. For instance, malaria is spread by mosquitoes. But it can't jump from person to person. So it’s infectious, but not contagious.

Vaccines fight contagious diseases by causing your body to develop:
Antibodies
Antihistamines
Antibiotics
Vaccines fight contagious diseases by causing your body to develop:
When you are vaccinated, the shot mimics the disease and your body creates a natural defense to it. This gives you immunity. If you are exposed to the disease later in life, your body remembers and protects you.

Once a contagious disease has disappeared from a country, we no longer need the vaccine.
True
False
Once a contagious disease has disappeared from a country, we no longer need the vaccine.
Polio is a good example. The last time there was a natural outbreak that started in the U.S. was in 1979. But some countries still have it. So if a traveler brought it home and people stopped getting polio shots, it could spread.

Which of the following is NOT contagious?
Tetanus
The common cold
Hepatitis B
Which of the following is NOT contagious?
You can find it in almost everywhere, including soil and dust. But you get the infection from things, not people. Hepatitis B and colds pass from person to person.

You should avoid anyone who has a contagious disease.
True
False
You should avoid anyone who has a contagious disease.
It depends how easily the illness spreads. Some illnesses can easily pass from person to person if they use the same things, like remote controls or phones. But you won't catch other diseases, like HIV, unless you come into contact with their blood or other bodily fluids.

You don’t have to worry about catching this contagious disease:
Marburg hemorrhagic fever
Diphtheria
Smallpox
You don’t have to worry about catching this contagious disease:
No one has caught smallpox since 1977. Once one of the world’s most feared illnesses, it officially ended in 1979 thanks to a vaccine used worldwide. Samples of the smallpox virus still exist in only two labs in the world, just in case.

“Contagious” also means the disease is especially dangerous.
True
False
“Contagious” also means the disease is especially dangerous.
Although some, like Ebola, are life-threatening, others are mild. Take pinkeye, for example. It's a hassle and it will spread through a daycare center quickly. But it's very rare for it to become a major problem. "Contagious" is all about how a disease spreads, not how bad it is.