Show the Students a Video Describing What a Virus Is and How We Become Infected

Virus Spread in population
Learning Objectives:
-Understand what a virus is.
-Understand how a virus is maintained in the human population.
-Understand how viruses spread from one person to another.
-Understand what preventive measures can protect from becoming infected.
Materials:
Computer
Projector
Speakers
Board
markers
Styrofoam cups
Water
Lime juice / Sodium carbonate
pH indicator
Popsicle sticks
Glue
Scissors
Play-do of different colors
Foam balls
Paint
Paint brushes
glitter
10 min / Engage
Purpose: Make students aware of the existence of viruses and the different routes of infection. Use the following resources:
1)Slide show of different viruses(make sure to provide pictures where structural differences amongst viruses are present; this will facilitate class discussion)
2)You-tube video of what a virus is and how humans become infected
Instructional sequence

Start by asking what they think a virus is, what do they do, and how can they spread.
Show the students a video describing what a virus is and how we become infected.

Proceed to showing slides of viruses and go over interesting facts about them. It is advisable to pick viruses which are commonly known in the community, such as those to which we become vaccinated against and/or those that make the news.Use the viruses listed below as a starting point.
When giving general facts talk about: how we get infected? What is the natural host of the virus? Can it infect animals?

15 min / Explore
Purpose: Have students simulate viral spread and track which person was the index case.
Instructional sequence

Fill up the cups half way with water. Place sodium carbonate into one of the cups without the students knowing which cup. The latter is a white solid that when dissolved in water is colorless. The purpose of it being colorless is so that all the cups look the same.
Number the cups on the outside.
Assign cups randomly. Make sure to note to whom you gave the cup containing sodium carbonate (index case). This way is easy to keep tract for the person that served as the original viral vector.
Allow students to exchange water for 2min, approximately mix solutions three times (tell the students to write down the # with whom they mixed solutions). Instruct them to exchange half of the content they have in their cups. If this ends up being a problem use Pasteur pipettes to facilitate the transfer of solutions.
Add pH indicator to all the cups
Make a list on the board of cups that turned pink (infected) and cups that didn’t.
Then have the class collectively figure out who was the index case by having the students make a list of people they exchanged water with. Make this a class discussion.
After students have identified which person was the index case talk about who in society plays this role (epidemiologists) and ask question of what could they have done to prevent the infection? This then facilitates going over some of the preventive measures there are to protect oneself from future infections

*Prior to starting the class period, make sure that all the cups have been prepared. This way you won’t take time away from the activity and lose the student’s attention.
Safety: Although sodium carbonate is not dangerous, you might consider having the students wear gloves when performing the activity.
10 min / Explanation
Purpose-Discuss what role dose an epidemiologist play in viral outbreaks and go over some of the preventive measures one can do protect oneself from a future infection.
Instructional sequence

Using the above list of viruses (the list of viruses?) go over some of the non-profit organizations that monitor viral outbreaks. Talk to them about how members from society work together to elucidate the index case and back track to the origin of the infection, similar to what they did.
Present slides and videos from a recent viral outbreak. Focus on preventive measures that become installed when a situation like this arise. I recommend you use the Influenza virus (flu) because this way it’s easy to explain that yearly vaccines are generated to protect the people from having the seasonal flu and it transitions well with the next activity.During the discussion also mention that we have successfully eradicated smallpox and close to eradicating poliovirus just by the implementation of vaccination.

*preventive measures: quarantines; avoid touching your face; constant hand washing with soap or disinfectant; masks to protect against airborne viruses; disinfect surfaces; etc.
Sample questions: “Who here has heard the word ‘quarantine’ before? What can you tell us about what a ‘quarantine’ is?” If no one knows or the answer is incomplete then briefly describe what a quarantine is then ask “How do you suppose a quarantine can stop or slow down the spread of a virus?”
20 min / Expand
Purpose-Have students come up with their own virus, transmission, disease, and preventive measures.
Instructional Sequences

Assign students to trios and allow them to be creative. They have to come up with a virus, a source, how humans become infected, what disease it causes, and how can infection be prevented.
Project on the board a slide with different viruses and their structures.
While students are working on their model go around and ask the following questions :
What’s their virus name
What kind of host would it infect
What mechanism of entry would the virus use to get in (e.g. dengue infects humans through mosquito bite)
What disease would it cause
What would be the incubation period
Are there antiviral treatments
Are there any vaccines available to prevent disease

*It is advisable to bring a pre-made model of what a virus might look like using the same materials the students will use. This way student has a concrete experience of the task at hand.
10 min / Evaluate
Purpose-Verify that students understand that viruses are non-living particles capable of causing disease and that following preventive measures can safeguard oneself.

Pick a virus created by the students.
Give 2 students cups with sodium carbonate (infected students); others water with lime juice(vaccinated students); others simply water(un protected).
Allow them to exchange solution (see above).
After the 2minutes, add the pH indicator to the cups.
Count how many turned pink vs those that did not; make note of a difference in light pink and dark pink. Announce that those with really dark pink represent the % of people that died from the disease induced by the virus; while those with light pink became infected but their immune system protected them from the infection; those that don’t turn pink were vaccinated therefore also protected.
Compare those numbers to the previous activity
Have the students discuss:

Why the difference in infected people now vs previously?
What led to that?
What are vaccines?
What will happen to the people that became infected?
What would happen to the people that didn’t?
What other preventive measures could lower the number of infected cases and death?
**Prior to starting the class period, make sure that all the cups have been prepared. This way you won’t take time away from the activity and loose the student’s attention. Make sure that the lime juice is really concentrated. This will prevent the solution from turning pink simulated a protected individual because of vaccination.
Safety: Although sodium carbonate is not dangerous, you might consider having the students wear gloves when performing the activity.

Background Information (for the teacher)

A virus is considered a nonliving particle.These are able to cause an ample of diseases once they enter an appropriate living organism or host.A host can become infected by being in close contact with another organism carrying the virus.The common routes of infection are the respiratory tract, alimentary tract, urogenital tract, and blood.

Once virus gains entry into host it looks for susceptible and permissive cells in which they can start their process of replication. First the virus attaches to the cell surface releasing the genomic content into the cells cytoplasm. Once inside the cell, the virus utilizes its own replication machinery or highjack’s the cells machinery. Replication is the sole goal of a virus. The latter guarantees more virus particles, which in turns means spreading of the virus to neighboring cells and finally to a new host.

Once a virus has replicated to a substantial number then the infected organism can show signs of disease. Not all organisms that become infected suffer from a disease. The reason being, that all organisms have defense mechanisms that become activated when it senses foreign particles within their environment.

Aside from the host intrinsic mechanisms of defense, vaccines have been developed which prevent an organism from becoming sick (experience disease). Vaccines are used as a preventive measure, and ensure that once an organism becomes infected the natural defense mechanism is prepped to neutralize the virus. Neutralization inhibits the virus from replicating and spreading to non-infected organisms.

This lesson plan is intended to introduce students the concept of virus. The following activities depicted above guide students through the different facets of viral spread and prevention. Unknowingly students will dramatize how viruses inconspicuously are transmitted from one person to another through day to day life activities such as hand shaking, sneezing/coughing and touching objects, improper sanitary hygiene practices, sharing fluids (e.g sharing drinks).

A great way of having students simulate viral spread is by using solutions with different chemical properties, alkaline (sodium carbonate) and neutral (water) solutions. When sodium carbonate is mixed in water it increases the pH of the solution making it basic. Addition of a pH indicator turns the colorless solution pink. The student with the carbonate solution will represent the index case (first known viral case). The rest will have cups filled with water. They will be asked to randomly mix their solutions for a couple of minutes. After which pH indicator will be added and students that became infected will have their solutions turn pink, while the ones that didn’t will remain colorless.

As part of the instructional materials, a video which dramatizes common flu spread will be played. The video shows how viruses are carried in mucous particles when people sneeze and how these then are contagious to other individuals. It summarizes the life cycle of a virus.

Once the basic principle of what a virus is understood the students will be allowed to create their own virus particle. This activity allows for assessing what the student grasped from the prior discussion.

The intended lesson plan makes students aware of the existence of viruses; that humans become infected and provides a suitable environment for the virus to reproduced and spread throughout a population; and that there are preventive methods that can be implemented to stop a viral spread.

Engage

This section of the lesson plan comes with a power point. The main function of the power point is to have visual references of a virus and show that in the world they exist with different morphological characteristics. As part of the introduction and discussion, use the following table as reference. The table includes some of the viruses that are commonly known. Talk about how the virus spread and what types of diseases can they cause.

Virus name / Transmission / Route of infection
Yellow fever virus / Mosquito bite / skin
Measles virus / Airborne (coughing and sneezing ) or direct contact of fluids / Nose, mouth, eyes
Dengue virus / Mosquito bite / skin
Ebola virus / Eating raw meat infected with virus; entering in contact with bodily fluids / Nose, eyes, mouth, skin
Influenza virus (flu) / Airborne (sneezing and coughing)or touching surfaces contaminated with virus / Mouse, nose , eyes
Chikungunya / Mosquito bite / skin
Varicella Zoster Virus (Chickenpox) / Airborne or direct contact with secretions from the rash / Skin, mouth, nose

Possible sequence of introduction:

Show a slide of earth and ask what does the earth provide for humans to survive? Then show another slide of an astronaut and ask could a human being survive without his special suit in space? Use this analogy to explain what a virus is and how it needs a suitable environment to survive and reproduce.After this small introduction then go ahead and present slides a couple of viruses and ask them what do they see?? What makes the virus unique (you want them to note morphological differences)?For the following activity visit Viral Zone and get pictures of the virus.

Also, present a slide where the life cycle of the virus can be admired. This way you can talk about how viruses infect specific organisms in order to reproduce and not become eradicated.

At this point play the video This video summarizes the life cycle of a virus.

Explore

Before starting the lesson plan prepare the Styrofoam cups:

Mark all the cups with a number (this will aid students keep track of the people they exchanged with)
Add water halfway
To one of the cups add sodium bicarbonate (this will be your index case; the person who was infected and is responsible for the virus spread)
Ask the students to go around the room and only exchange with three different people and write down the number with whom they made the exchange. Tell the students to only exchange half of their content, otherwise the activity won’t work.
Add pH indicator to all the cups
Have one student go to the board and make two lists: infected and non-infected.
The individuals infected will have their cups turn pink.
Those who are infected will need to track down which was the person who started the spread of the virus amongst the population.

Explanation

In this section make questions such as:

Why did some people become infected?

Why others didn’t?

How come the index case didn’t know he was incubating a virus? (the person didn’t show any signs of infection) This is a great question to expand on. Talk about the incubation period of a virus (use the above table as reference) and what is the virus doing during that period. Also, go ahead and give examples of some viruses and the disease it causes.

Ask if they have ever heard of an epidemiologist. If not, ask what they think an epidemiologist responsibility is? (make the analogy of how doctors take care of the sick). Once you have discussed the role of an epidemiologist ask the following:

What could have been done to prevent the spread of the virus?

What preventive measures can be implemented?

(wash hands; don’t touch eyes or mouth; disinfect surfaces; wear masks; quarantine; vaccinate)

Have they heard of vaccination?

Who has been vaccinated and against what? On the note ask, have they suffered from the disease? (give the personal example of having had chickenpox because there was no vaccine in the past)(discuss in general terms what does a vaccine confer)

Expand

Bring a model of your own virus using the same materials the students will use. Name your virus, how the organism becomes infected, what disease those it cause, what is the incubation period.
Divide the students and trio and let them be creative
Go around the room asking the questions depicted above.

Evaluate

Mark all the cups with a number (this will aid students keep track of the people they exchanged with)
Add water halfway
To two of the cups add sodium bicarbonate (this will be your index case; the person who was infected and is responsible for the virus spread)
To half of the total number of cups add lemon juice (this will be the vaccinees)
Ask the students to go around the room and only exchange with three different people and write down the number with whom they made the exchange. Tell the students to only exchange half of their content, otherwise the activity won’t work.
Add pH indicator to all the cups
Have one student go to the board and make two lists: infected and non-infected.
The individuals infected will have their cups turn pink.
Those who are infected will need to track down which was the person who started the spread of the virus amongst the population.

Why the difference in infected people now vs previously?

What led to that?

What are vaccines?

What will happen to the people that became infected?

What would happen to the people that didn’t?

What other preventive measures could lower the number of infected cases and death?