Learning About Viruses, Epidemics, and Ebola for Middle School
The purpose of these six lessons is to provide middle school students with a basic understanding of how viruses cause disease, how infectious diseases spread to become epidemics, and the challenges of bringing an epidemic under control, all from the perspective of the Ebola virus and the most recent Ebola epidemic that occurred in West Africa in 2014. Besides learning about the Ebola virus and how it caused an epidemic, students will be able to apply their understanding of the general principles of infectiousness and disease spread to other emerging epidemics, and will appreciate the importance of vaccines in preventing disease spread. Each lesson has been designed to take 45 minutes, but it is perfectly possible to spread them out more to maximize student learning.
How does our body keep us healthy?
The goal of this lesson is to introduce the notion that the immune system acts to defend the body from infection. The teacher introduces the concept using the analogy of a city with its different constituent parts (buildings, transportation, libraries and grocery stores). Likewise the body has similar constituent systems (skeletal, circulatory, nervous, and digestive) that all must function together in order for the body to work. Cities also have systems that defend them from harm and heal citizens (the police force and hospitals). The analogous body system is the immune system. Like the police force, the immune system patrols the body making sure that infections don’t enter. Like hospitals, the immune system is able to heal a body that has been damaged. The key concept – that the body is a collection of systems and society is a collection of people, and both must work together to defend against infections and epidemics – will be revisited throughout this unit.
What does our immune system defend us against?
In the previous lesson, students learned that the body has a system whose function is analogous to the police force and to a hospital: to defend and protect the body from harmful invaders. But what are these invading ‘pathogens’? In this lesson, students begin by trying to identify what causes a number of familiar infectious diseases (bacteria, viruses or parasites). They then work together to learn the different types of microbes, and why viruses are not true microbes. The second part of the lesson focuses more specifically on viruses. Students follow their readings to learn in groups how viruses are built so they can infect their host cells. The lesson ends by introducing the idea that viruses cause disease because they either kill or damage their host cells. This will set the stage for the next lesson, in which students learn how the immune system protects us from viruses and other pathogens.
How does our body defend us against pathogens?
The goal of this lesson is to show students how the immune system responds to a virus infection. In the first part of the lesson students learn the important concept of the inside and the outside of the body and how the body has developed physical and chemical barriers to prevent infection getting to the inside. Then students learn that even intact barriers won’t necessarily deter viruses. As long as viruses can contact their host cells they can infect them, so viruses commonly infect barrier cells – in the nose and throat, for example. This sets the stage for the next lesson when students will learn about how viral infections can spread.
How do infectious diseases spread?
The goal of this lesson is to consider what happens when a viral infectious disease spreads through the population to cause an epidemic in the whole population. Students are introduced to the concept that different viruses spread infections differently (through person/person contact, through the air, etc). and that how infections are spread will affect the number of people infected. Students will use an ‘infection map’ to calculate how different kinds of infections spread and the effect of vaccination on preventing spread. While the concepts aren’t difficult, students will need time to work through the questions systematically. Students can work alone or in pairs.
All about Ebola!
This lesson focuses on the Ebola virus. The homework reading from Lesson 4 introduced the Ebola virus in its natural habitat in West Africa and explained how it is transmitted from animals (fruit bats) to humans. Students may have many questions about Ebola and the 2014 Ebola epidemic, and you may want to encourage discussion rather than sticking very closely to the reading and the questions (although the questions do state the important learning goals from the reading). Students then work together in a jigsaw activity to learn about Ebola infection and disease. Finally they share out what they have learned. It is very important to connect what students have learned in general about viruses and infections to the specific case of Ebola.
Working together to prevent Ebola spreading
In the final lesson of this unit students are asked to bring everything they have learned to a discussion about how different African stakeholders might have responded to the 2014 Ebola epidemic. The key goal of this lesson is for students to realize that (a) no-one was anticipating an Ebola outbreak; (b) the change in demographics in the area allowed a previously less threatening form of Ebola to infect many people rapidly; (c) the health care infrastructure was essentially absent, preventing Ebola being identified and treated; and (d) cultural practices, particularly burial washing, inadvertently hastened spread. Another of the key elements of the discussion is for students to understand that it is often not effective for outsiders to come into a close community and try to change behaviors and practices. It is important to get buy-in from the senior community members, and they may not be the ‘officials’. That is to say, the most respected member of the community may not be the person with the title. Students will wrestle with giving advice that people cannot follow, because of lack of resources, or will not follow, because the advice conflicts with their cultural beliefs. Your job is to think through all of the scenarios and to be able to challenge students when they come up with a solution.