Predict some ways these infectious agents may move from one organism to another.
Overview
Using a model to determine different ways diseases are transmitted
Standards
Next Generation Science Standards
- Life Science
- [HS-LS1] From Molecules to Organisms: Structures and Processes
Activities
- 1. Initial Ideas about Transmission
- 2. Transmission Model
- 3. Investigating Transmission types
- 4. Direct vs Indirect Transmission
Student Directions and Resources
In this lesson you will use a model to determine different ways diseases are transmitted.
1. Initial Ideas about Transmission
In the previous lesson you looked at types of infectious agents. Bacteria, viruses, parasites, fungi, and prions all must be transmitted to infect new organisms.
Question 1.1
Question 1.2
What ways do you think are most effective for the disease to move to the most organisms?
2. Transmission Model
Use the model below to explore transmission type.
Question 2.1
Turn vector-infection and indirect-infection to "Off." Change "transmission type" to touch. You may need to slow down the time using the slider at the top.
What happens to the population during this transmission type? Who is getting infected?
Question 2.2
Using the same set up in question 1.
How long until the majority of the population is infected?
Question 2.3
Turn vector-infection and indirect-infection to "Off." Change "transmission type" to airborne. You may need to slow down the time using the slider at the top.
What happens to the population during this transmission type? Who is getting infected?
Question 2.4
Using the same parameters in question 2.
How long until the majority of the population has been infected?
Question 2.5
Turn off the transmission type, so organisms are no longer transmitting the disease to each other. Turn on "vector-infection." A vector is something that carries the infection, like how mosquitos can carry malaria and other diseases.
For the vector organism, yellow is uninfected, blue is carrier for infection.
What do you notice happen to the population of vector insects over time?
Question 2.6
Turn off "vector-infection," leave "transmission-type" set for "none" and turn on "indirect-infection."
What do you notice about this type of transmission, compared to the others you looked at?
3. Investigating Transmission types
Sometimes transmission of a disease can happen in multiple ways. Set up the model to test transmission using 2 of the factors.
Question 3.1
Which 2 transmission factors did you choose?
Question 3.2
How did having 2 transmission factors change the simulation? Did you notice anything different about the speed of disease transmission or how many organisms were infected?
Question 3.3
Which 2 transmission factors would be riskiest to have together? Provide evidence from the simulation to support your answer.
4. Direct vs Indirect Transmission
There are many ways infectious diseases may be transmitted from one organism to another. We typically group them as direct contact and indirect contact.
Direct Contact Transmission Types:
1. Contact Between Individuals: Transmission occurs when an infected person touches or exchanges body fluids, like saliva, with someone else.
2. Specific Contact Between Individuals: Is carried in blood and other specific bodily fluids, but not saliva. Pregnant women can also transmit infectious diseases to their unborn children via the placenta.
2. Droplet spread: The spray of droplets during coughing, sneezing and speaking can spread an infectious disease.
Indirect Contact Transmission Types:
1. Airborne transmission: Some infectious agents can travel long distances and remain suspended in the air for an extended period of time.
2. Contaminated objects: Some organisms can live on objects for a short time.
3. Food and drinking water: Infectious diseases can be transmitted via contaminated food and water.
4. Animal-to-person contact: infected animal bites or scratches you or when you handle animal waste.
5. Animal reservoirs
6. Insect bites (vector-borne disease)
7. Environmental reservoirs: Soil, water, and vegetation containing infectious organisms can also be transferred to people.
Question 4.1
Choose one of the transmission types present in the model. Explain what happened in the model for this transmission type.
Question 4.2
Choose one of the transmission types not in the model. How do you think you could change the model to show this transmission type? What features would you want to add? What would the model do to show this transmission type?
