Pathogens and Transmission (Joshua Junkermeier)

Hook Videos:

NGSS Standards

• HS-LS4-5

• HS-LS2-2

• HS_ETS1-1

• Learn More

Scientific Problems

1. How can we protect population from "germs" or pathogens?

2. What variables impact the size of our population?

3. Is there an "arms-race" between humans and pathogens?

4. How can we improve the designs of hygiene equipment to

reduce the transmission of pathogens?

Activity 1: cleaning produce

1. Students attempt to clean a potato.

2. .

1. Background: the potato is "dusted" with a UV-reactive powder that may or may not be removed from cleaning. The powder simulates a pathogen present on the food (food-borne illness).

2. Students take their food-potato and examine their effectiven

1. ess to remove pathogens from their food using a UV-flashlight.Equipment List: potatoes, "UV powder", and available sinks for washing.

Activity 2: Washing Hands to reduce transmission of Pathogens

1. Participants apply a "clear", UV-reactant paint to their hands.

2. UV-reactant paint simulates pathogens

3. Participants proceed to wash their hands as they usually do.

4. Following their hand rinse, students use the UV-flashlight to determine how effectively they washed their hands.

5. Followup Video: "best methods for hand washing"

Extensions 1: engineering an effective "air dryer"

1. Students can develop a design for minimizing the dispersion of pathogens.

2. Students can run tests with UV-paints (simulation of pathogens) to collect data on dispersion of pathogens.

3. Incubate cultures from swabbed hand samples.

Extensions 2: transmission of pathogens in the classroom

1. Video Link: classroom activity

2. Student volunteer(secretly) to act as a vector for pathogen transfer.

3. UV-flashlight can track their surface contacts and "infections" during a class period.

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Principles Illustrated:

• Organisms interact within an ecosystem

• Pathogen populations may increase when a vector population has a high-density distribution (density dependent variables).

• Pathogens (bacteria, fungus, and virus) may experience natural selection as a response from human hygiene products and equipment.

• Products can be improved in order to solve problems.

• Organisms within a rapidly changing environment (pathogens) are likely to exhibit high reproductive rates as an adaptation for survival.

• Bacteria may exhibit high mutation rates as an adaptation to selective pressures in the environment (hygiene products)

Prior Knowledge & Experience

• This lesson may function as a "hook" into population ecology and density-dependent variables.

• This lesson may function as an exploration with a cell biology unit. Students can investigate the relevance of cell-scale organisms sharing their habitat or community.

• Students don't require prior knowledge to engage in the content or perform inquiry of the lesson.

Common Misconceptions:

• Students may not know how effectively the wash their hands.

• Students may not understand how effective the hygiene equipment and products are in restrooms.

• Students may not understand the challenges of reducing food-borne illness and cross-contamination due to pathogens from hands and produce.