3 Viruses Go "Viral"

Activity 1

Infectious or Contagious?


The purpose of this activity is to determine students’ prior understandings about the differences between an infectious and noninfectious disease (also explored in greater depth in Module 1 – About Infectious Disease) and between an infectious and contagious disease. Using the Disease Chart students identify a specific disease as infectious (I), noninfectious (NI) or contagious (C).

During the discussion students will determine that an infectious disease is a biological disorder caused by microorganisms such as viruses, bacteria and parasites.

A contagious disease is a subset of infectious diseases that are spread from human to human by direct contact or contact with respiratory droplets from infected individuals. Infectious diseases transmitted by food, water, animal or insect vectors are not considered contagious. This distinction becomes important when students explore reproductive rates (R0) as a factor in the spread of disease.


One copy of the Disease Chart for each pair or team of students, downloadable below.


  1. Provide each pair or team of students with one copy of the Disease Chart
  2. Have students label the various diseases as infectious (I), noninfectious (N) and/or contagious (C). Inform them that some diseases will have more than one designation. As they sort they should discuss why they designated a disease in one category or another. Suggest that they record their reasoning for each disease in preparation for class discussion.
  3. After they have completed the task have them look for commonalities in the diseases they labeled as contagious.
  4. Gather the class together to share their decisions about the category or categories of each disease and the reasoning for identifying a disease as infectious, genetic, or environmental.
  5. You may want to write the project the chart and record an “I,” “N,” or “C” next to each disease as groups voice their decisions.
  6. Examples of student responses include “Down syndrome is caused by an abnormality in a chromosome and is not caused by an infectious agent so it’s noninfectious”; “measles can be spread when someone coughs and another person breathes in the saliva droplets in the air, so it’s infectious and contagious”; “Polio is caused by viruses in water but can’t be caught from contact with people so it is infectious but not contagious”.
  7. For further review, have students complete the online version of this activity using the Interactive Table.

Disease Chart

Click the button below to toggle the answers in the table.

Show Answers

Disease Causative agent Transmission Mode Infectious/Contagious?
Ebola Ebola virus Direct contact I, C
Rabies Rabies virus Animal bite I
Type 2 Diabetes Poor diet N/A N
Malaria Plasmodium Mosquito I
Chicken pox Varicella zoster virus Direct contact/aerosol I, C
Warts Human papilloma virus Direct contact/sexual contact I, C
Food poisoning Salmonella Food borne I
Skin Cancer Radiation from sun N/A N
Poliomyelitis Polio virus Water borne I
Mononucleosis Epstein-Barr
Direct contact I, C
Down Syndrome Change in chromosome number N/A N
Lyme Disease Borrelia burgdorferi Tick I
Flu Influenza virus Direct contact/aerosol I, C
Common Cold rhinoviruses, adenoviruses and others Direct contact/aerosol I, C
Guillain-Barre Syndrome Zika virus Mosquito I
Typhoid fever Salmonella typhi Food borne I
Cholera Vibrio cholera Water borne I
Rubeola Measles virus Direct contact/aerosol I, C
Cystic fibrosis Gene mutation N/A N

Do you know whether a disease is noninfectious, infectious and/or contagious? In this activity you are challenged to identify different diseases as noninfectious, infectious and/or contagious. Some diseases may have more than one category. Be prepared to explain your decisions.