Lesson 22 — Activity 1: What Is a Communicable Disease?
Completion requirements
Lesson 22 — Activity 1: What Is a Communicable Disease?
Explore
You are probably quite familiar with some communicable diseases, even if that is not what you call them! Communicable diseases are sometimes called infectious diseases or contagious diseases. In this activity, you will learn what a communicable disease is.
Communicable diseases are usually spread by contact between a sick person and a healthy person. You may recall many examples of communicable diseases from your study of various epidemics occurring throughout history.
Because communicable diseases are spread by contact, some are very common. You have likely had a cold or the flu at least a few times and will probably experience it several more times in the future. In addition to the common cold and influenza, many other illnesses fit into the category of communicable diseases.
What causes communicable diseases?
Germs
are usually blamed for the spread of diseases. Remember that examples of
these disease-causing microscopic life forms are viruses, bacteria,
fungi, and parasites. A lot of communicable diseases are caused by
either viruses or bacteria. Below is a review of viruses and bacteria.
- A
virus is made of protein and genetic material and can reproduce only
when it infects humans, animals, insects, or plants. Various viruses
affect various groups.
- Bacteria are single cells that grow and reproduce in certain conditions.
Images courtesy of www.imagesgoogle.com