Teaching About Infectious Diseases Using the 5E Model

If you’re like me and want to teach about infectious diseases from an environmental science perspective, BioInteractive has the resources for you. I teach AP Environmental Science to third- and fourth-year students in Marshfield, Wisconsin, a rural community with approximately 1,300 students. My students come to AP Environmental Science with two years of previous lab science at any level, but with diverse experiences and successes in the science classroom. 

As an AP Environmental Science teacher, I strive to develop lessons that meet three basic criteria:

• Does the lesson provide the content and knowledge my students need to understand broader environmental issues and solutions in a robust way?
• Are they doing the work of real environmental scientists, which includes using multiple science practices throughout the learning cycle?  
• Is the lesson driven by student inquiry?

Using BioInteractive resources with the 5E instructional model checks all the boxes!

The 5E Model
Rather than teaching AP Environmental Science as a checklist of topics, I try to use pedagogical strategies that link the concepts, spiraling back to important topics to present them in different contexts throughout the year. To do this, I use the 5E model, which has five phases: 

1. Engage
2. Explore
3. Explain
4. Elaborate
5. Evaluate

As Rodger Bybee, the architect behind the 5E model, notes, this method of instruction provides a sequence of instructional activities that helps students construct an understanding of scientific concepts. Using this approach makes the challenges of an AP science class accessible to students who have traditionally been underserved in upper-level science courses.

Throughout the year, I build on inquiry-driven activities using the 5E model of instruction, taking students through a series of activities that create a cohesive picture of how science works. This practice allows students to ask driving questions and continue to build on their knowledge; they move from identifying and describing phenomena to rich explanations of the processes involved.

Below, I describe how I used the 5E model with BioInteractive resources to develop a lesson sequence on infectious disease.

Engage
The Engage phase of the 5E model has students focus on a specific phenomenon or problem. I engage students with the concept of infectious disease using the first part of the Stopping Mosquito-Borne Disease Click & Learn (Slides 1–11). The Click & Learn introduces students to vector-borne diseases with a focus on dengue fever, a disease spread by a mosquito vector. Students create a chart listing three things they know about infectious disease, work through Slides 1–11 of the Click & Learn, and record three new things they learned about infectious disease and one question they have based on new knowledge. It is a non-intimidating way to engage students with a difficult concept because there are no right or wrong answers! Below is an example:

The majority of students identify that understanding the mosquito life cycle is important in reducing the spread of disease. The animation The Mosquito Life Cycle is a great supplement that ties in reproductive strategies and variables that impact population growth, which is the key information we will carry forward in the Explore and Explain phases of instruction. In the engage phase of instruction, students are immersed in AP Environmental Science Practice 1: Concept Explanation—describing and explaining environmental problems in applied contexts. 

Explore
The Explore phase gives students time to explore their ideas in preparation for developing more formal explanations. I begin with the Scientists at Work Video Genetically Modified Mosquitoes and the complementary activity “Tracking Genetically Modified Mosquitoes.” These resources introduce students to the Zika virus, which causes a medical condition called microcephaly. The objective is for students to explore a strategy for reducing mosquito populations, and thus the spread of Zika virus. Students analyze data from an experiment in which genetically modified male mosquitoes were released to breed with wild females, passing on a lethality gene that caused their offspring to die.

Students apply what they learned during the Engage phase, expanding their knowledge, getting answers to some of their questions, and forming new questions. Because students have a clear understanding of the design of this real-life research project, the calculations they perform to determine the change in mosquito density make more sense to them.

Explain
During the Explain phase, students construct evidence-based models and explanations. I use the Data Point activity “Using Wolbachia to Suppress Mosquito Fertility” to guide students through the analysis of a published figure from a study that tested whether releasing mosquitoes infected with Wolbachia bacteria can reduce mosquito populations. Students expand on previous knowledge and apply it to a new situation to make an evidence-based claim about the effectiveness of the strategy.

The figure from the Data Point activity. Source: Figure 2b from Mains et al. (2016), used under CC BY 4.0.

The “Educator Materials” for the Data Point provide a step-by-step process to guide students through data analysis. The discussion questions included in the “Educator Materials” are an essential part of my toolbox for stimulating class discussion about the data. The questions are sequenced in such a way that I can guide students through the inquiry process and make sense of a challenging data set.

Students start by identifying what the bars of the graph represent: the percentages of eggs that hatched in areas where male mosquitoes were released versus the percentages that hatched in untreated areas. Next, I prompt students to describe the essential components of the experiment using discussion questions, such as:

• Why were only male mosquitoes released? 
• Why were eggs counted in areas where no mosquitoes were released? 
• If the treated sites were left untreated the following year, predict what this same graph might look like. 
• What concerns might scientists or the public have with the release of male mosquitoes treated with a laboratory strain of Wolbachia?  

One of the great things about this activity is the ability of students to dig into AP Environmental Science Practice 7: Environmental Solutions. They can conceptually move through the skills from describing environmental problems to describing advantages and disadvantages of solutions, and finally using evidence to support a solution.

Elaborate
During the Elaborate phase, students make conceptual connections between new and previous experiences. In this case, I have them examine Ebola, a disease transmitted from person to person rather than by mosquitoes.

The Scientists at Work video Think Like a Scientist: Natural Selection in an Outbreak focuses on the 2013–2016 Ebola outbreak in West Africa by highlighting the work of disease ecologists who study the genome of the Ebola virus. Students learn factors that contribute to the spread of diseases that are transmitted from human to human, such as high population density. 

The “Ebola: Disease Detectives” activity that accompanies the video is one of my favorite BioInteractive resources and works so well in the lesson on infectious disease. Students model the spread of the Ebola virus by analyzing strips of DNA sequences from the virus, placing them in groups based on similarities. They learn that the Ebola virus mutates as it replicates in people and that advantageous mutations increase in frequency in the population.

It is so rewarding to see the students take concepts they learned in earlier units and apply them to understanding a new situation. For example, they can take their understanding of natural selection to a new level by applying it to understanding disease spread. While the activity is challenging for many of my students, they are less intimidated and more willing to dig in because they have been building their understanding of infectious disease through a series of well-planned activities.

Evaluate
The Evaluate phase of my infectious disease lesson asks students to reflect on how climate change will impact:

1. the spread of mosquito-borne diseases
2. the spread of diseases transmitted from person to person 

This is the most rewarding part of the learning cycle! By going through a sequence of engaging activities, my students have built a complex explanation for how infectious diseases are spread. By the end, they are able to cycle directly back to our study of environmental science with a deeper understanding of how human-induced climate change is impacting human health.

The 5E strategy models how to sequence a series of instructional activities, and BioInteractive provides activities that are engaging to students. Student feedback has validated that using 5E with BioInteractive resources provides a clearer path for forming complex explanations.