Disease Detectives: An Expedition Into the World of Yuck!
Betsey White
Disease Detectives: An Expedition Into the World of Yuck!
Lesson #1: Discovering the Yuck!
Lesson #2 Microbes, Microbes, Everywhere!
Lesson #3 Disease on the Run!Zombie, Zombie Everywhere!!
Lesson #4 It’s All About Prevention!
“Do you know what's lurking on your pencil? What about on that desk you lay your head on in class? In this unit students will discover the world of the microscopic as they journey into the land of germs. We will research diseases, conduct experiments, track the spread of disease in this entirely gross experience.”
ESSENTIAL QUESTION: IS POWER RELATED TO SIZE?
Betsey White
SPED 6402 Spring 2013
East Carolina University
CONTENT RESEARCH PAPER
Disease Detectives
Elizabeth G. White
Leigha Detiberus
East Carolina University
For much of known history, the cause of illness has been a mystery. Lacking the understanding of diseases and their causes, people reverted to the superstitious—illness was blamed on bad air and other elements, witchcraft, or even God’s punishment. The basic understanding of germs as disease-causers has only been around for about 150 years (Ollhoff, 2010, p. 4). In the last 150 years many gains have been made in the discovery of germs and germ theory. Scientists have learned that microorganisms such as bacteria, viruses, protists, and fungi are the cause of disease. Advances have been made in treating and tracking diseases as well: antibiotics and vaccines have become favored over bloodletting and promoting basic hygiene, such as simple hand-washing, has been found do decrease death rates and instances in the spread of disease (Ollhoff, 2010, p. 15).
With the new knowledge of germs, a new area of science emerged: microbiology. Microbiology is the study of microorganisms—tiny (microscopic) living things. Scientists learned that microbes, another name for microorganisms, are the actual causes of disease. Most microbes belong to one of four categories: bacteria, viruses, fungi and protists—though in this unit we will only focus on the firs three (“Microbes,” 2012). Thanks to the advancements in the field of microbiology we have learned about the structures, shapes, and reproduction methods of these microorganisms.
Bacteria are single-celled, prokaryotic, organisms. Prokaryotes are organisms that lack a nucleus; this means the genetic material (DNA) floats around freely inside the cell’s cytoplasm. Prokaryotes are the most basic of cells. They lack many of the organelles that eukaryotic cells have. Prokaryotic cells have three basic parts: a cell membrane, genetic material, and ribosomes. The function of the cell membrane is to protect the bacterial cell and provide it with structure, the genetic material directs the cell’s daily activities, and the ribosomes allow the cell to produce protein that gives the cells their specific structure and function (“Prokaryotes: Single-Celled Organisms,” 2013). Bacteria come in three different shapes. You are able to tell the shape of a bacterium based on its name. Bacteria with “cocci” in their name are round shaped bacteria; these bacteria look like spherical balls. “Spirilla” (or –i, -u,) denote spiral shaped bacteria, like spirals. “Bacilli” are bacteria that have a rod, or straight shape.
Bacteria are able to cause disease by releasing poisons that kill or damage our body cells. The dying of our cells is what causes us to feel ill. Bacteria are able to reproduce very quickly in the right conditions through a process called binary fission (binary means two, fission means to split into). Bacterial growth is called exponential growth—one bacteria becomes two, two becomes four, four becomes eight and so on. As more bacteria are produced, more toxins are released into the body, making a person feel more ill. Some examples of diseases caused by bacteria are food poisoning, cholera, typhoid, bubonic plague (“Defending Against Infection,” 2013). In 1928 Alexander Fleming, a Scottish biologist, discovered the antibiotic penicillin. Through his continued experiments Fleming learned that penicillin was not simply a topical antiseptic, but a medicine that could actually work inside the body that could stop the spread of bacterial infections by killing bacteria (Ollhoff, 2010, pp. 27-29).
While bacteria are small, viruses are even smaller. Viruses are so small in fact, that they are able to infect bacterial cells. Viruses, like bacteria come in many shapes—balls, bullets, rods, and even tiny little robots! Many scientists argue about whether viruses should be considered living things. Most scientists classify a living organism as something that requires energy (from a food source), responds to its environment, and is able to reproduce. Technically speaking, viruses do none of that. Viruses are simply genetic material, either DNA or RNA, wrapped inside a protein coat. Viruses have no other parts. They lack mitochondria so do not convert food to the energy a cell uses to survive. They also do not reproduce on their own. Viruses cannot reproduce without infecting a host cell. In order for a virus to replicate it invades a cell, inserts its own genetic material inside the host’s DNA and tricks the cell into making more virus parts and pieces that the cell then uses to build more viruses. Once the virus turns on the virus-making machine inside the cell the cell is unable to turn it off. The cell continues to make more and more copies of the virus until the cell explodes. The virus copies burst free from the host cell and are able to infect more cells, perpetuating the cycle (Biskup, 2009, pp. 11-12).
While bacteria cause illness by releasing toxins into the surrounding cells, viruses cause illness by killing cells when they trick them into becoming virus-making factories. Over and over the cells die until your body begins to feel sick. Most viruses are cell-specific. This means they only attack certain specific types of cells, for example the virus that causes the common cold reproduces in the cells of the nose and throat. This is because the viruses have an outer protein coat that “unlocks” the cell, tricking the cell into letting the virus inside, giving it the ability to force the cell into replicating virus parts (Biskup, 2009, 13-15). Examples of diseases caused by viruses are: chickenpox, smallpox, and AIDS. Since viruses are not considered to be living things we have no medicine, like antibiotics, that can kill them (you can’t kill something that’s not alive). Our main method of defense against viral infections is vaccination. Vaccinations give your immune system a peak at what viruses look like, this lets them identify them and quickly go to work trying to collect them and destroy them.
Fungi are a third type of microbe. There are many different types of fungi: those that look like black slime in your bathroom walls, the kind that grow off the side of trees, even the mushrooms you eat are all types of fungus. Mold on bread and the yeast that makes bread rise are also types of fungi. The penicillin we use to treat bacterial infections comes from a fungus (Ollhoff, 2010, p. 10). Fungi are eukaryotic, meaning they have a nucleus that contains the genetic material of the cell. Most fungi are multicellular, meaning that many cells make up one fungus organism, however some fungi are unicellular (yeast for example). Fungi that cause disease in humans are known as pathogenic fungi. They are able to cause disease by either releasing toxins, or using the tissue as a food source. The treatment of fungal infections is a bit trickier than the treatment of bacteria. Because bacteria are not the same type of cell as human cells (bacteria are prokaryotic and human cells are eukaryotic) we are able to create medicines (antibiotics) that target the bacterial cell. Fungal cells, however, are also eukaryotic cells, so in trying to cure fungal infections, often time body cells are often damaged (“Fungi as Human Pathogens”). Fungal infections are rarely deadly (most, in fact are just annoying infections like Athlete’s Foot), but some, like convulsive egotism can be quite serious.
Epidemiology is the study of disease. Specifically what causes disease and the patterns one might find in the spread of disease. It is through the tracking of disease that scientists are able to predict what forms of disease might be prevalent during a specific year (as in the case of creating influenza vaccines) or determining “patient zero” (the initial patient in an outbreak of a disease) in order to determine what population of people might be affected by an illness. There are several organizations that are responsible for tracking disease both in our country and the world. Two of these organizations are the Centers for Disease Control (CDC) and the World Health Organization (WHO). The CDC and WHO are both organizations that track epidemics (the spread of disease in one specific area) and pandemics (the worldwide spread of disease). An epidemic, or outbreak, occurs when a large number of people in one area are stricken with the same disease. This group of people is known as a cluster. Epidemiologists, scientists who study these outbreaks, assume that these cases are all related to each other and try to find the connecting thread. When epidemiologists first learn about an outbreak they begin to collect as much data as possible: the who, the what, the when, and the where of each situation. This information allows them to see connections. Epidemiologists then use mathematical models to create projections of the spread of a disease. Once the scientists know what microbe is causing the disease, how and how quickly the disease is spreading, they’re ready to inform the public about what to do if they suspect that they have been infected. Each day epidemiologists engage in a race against time to collect data, identify disease, predict infection patterns, and save lives.
Although microbes are incredibly small, they have truly had a huge impact on human history. While some microbes are harmless others are truly powerful. Scientists are constantly battling the small, yet powerful force of the germ.
References
BBC—GCSE Bite size (2013). Defending against infection.Retrieved from
Bio 183 Introductory Biology 2 (2013). Prokaryotes: Single-Celled Organisms. Retrieved from
Biskup, A. (2009). Understanding Viruses with Max Axiom. Mankato: Capstone Press.
Grady, D. (2006) Deadly invaders: virus outbreaks around the world, from Marburg Fever to Avian Flu. Boston, Ma: Kingfisher Publications.
Matossian, M.K. 1989. Poisons of the Past: Molds, Epidemics and History. New Haven: Yale University Press
Miedema, K. (2011). Diseases/History. Retrieved from
National Institute of Allergy and Infectious Disease. (2012). Microbes. Retrieved from
Ollhoff, J. (2010). A History of Germs: What Are Germs? Edina: ABDO Publishing Company
Science Museum of Minnesota. Infectious Diseases Through Time. Retrieved from
Townsend, J (2006). Pox, Pus & Plague: A History of Disease and Infection. Chicago: Raintree Publishing.
Wong, G. Ergot of Rye-I: Introduction and History. Retrieved from
Wong, G. Fungi As Human Pathogens. Retrieved from
CONNECTION TO THE THEME
Power is the ability to effect change. Power is not dependent on size or stature, but on the effect that the power has. For instance one, small cancer cell has the power to change lives. In the same step one small bacteria cell has the ability to shape a culture and change history.
Power can be a positive or negative force. It can be a constructive force and institute positive change, like the formation of penicillin from mold or it can be a destructive force that can tear a society apart, for example the suspected convulsive ergotism that caused the Salem Witch Trials.
In this unit, students will ponder the question “Is power related to size?” In an interactive unit on disease. Students will also learn how they can take power back in their lives and protect themselves against disease in very simple ways.
TECHNOLOGY INTEGRATION
Disease Detectives: Battling the Yuck starts day one with interactive technology and interesting resources. First, students will be introduced to Glow-germ and black lights. Glow-germ is a product that is put on your hands to show how well or in some cases, not so well how the students have washed their hands. This is a great way to show just how prevalent germs and bacteria can be. The rationale behind using Glow-germ is that it jumps the students right into the “yuck” of germs. Next, students will use a digital circle map using Thinking Maps to brainstorm where the most germs would be lurking in a school. After this, the students will be going on a walking field trip to swab and collect cultures in fast acting petri dishes of the places they felt would have the most germs and bacteria. Daily, students will be using iPads to take pictures and use Weebly to blog and track their observations. The first blog will focus on where they chose to swab and why. Making a picture journal and blog is an interactive way students can write about the cultures they have created. These observations and pictures can also be used in the culminating activity for day four. In addition, as the cultures grow, students will use Microscopes to track the growth of certain cultures.
Video clips, YouTube, and pictures will be used daily to hook the student’s attention for the daily lesson. For example, a video cartoon may be used about microbes on day two will introduce the differences between bacteria, virus, and fungus. In addition, on day two, students will use various research sites such as Instagrok, Discovery Education, Infotopia, and NC Wise Owl to begin research and collect information on a disease that may relate to the symptoms of the Zombie Outbreak for the culminating project for day four.
On day one, a clip from the hit television show Grey’s Anatomy will be used to introduce patient zero. The students will participate in a Patient Zero activity/lab. This is a lab that looks at the process of how microscopic a microbe can really be by re-creating the example of the glove and water seen in the Grey’s Anatomy clip. Students will play roles and investigate the Zombie outbreak at AIG camp by following the rules of behavior of different societal stereotypes to track how the disease has been passed. They will create and track this investigation using a visual representation (disease board). Students will use technology to write a reaction journal to this activity and their feelings on what it could be like to be patient zero. Students will also have access to iPads and will be able to “Solve the Outbreak” using the CDCs educational app (enrichment) or fun game will help them track down diseases and use their newly learned detecting skills!
The culminating project is going to be a Public Service Announcement (PSA) on how the Zombie disease spread and what people can do to protect themselves. Using the research done on previous days, students write a rough draft, then using the iPads upload these to the Weebly. Students will also be introduced to iBuild an app or to create an informational appto Battle the Yuck against the Zombies (or to give more rigor a disease of their choice.)
Overall, Disease Detectives: Battling the Yuck will be rigorous four days, full of fun yet appropriate technology so that students will have a true understanding of disease and epidemiology.
Essential Question: Is power related to size?
Lesson 1: Discovering the Yuck!
- Microbes cause outbreaks.An outbreak is a term used in epidemiology to describe an occurrence of disease greater than would otherwise be expected at a particular time and place. It may affect a small and localized group or impact upon thousands of people across an entire continent.
- Examples of most common causes of communicable disease: bacteria, virus, and fungus.
1. Viruses cause HIV, influenza, the common cold, HPV, small pox, chicken pox.
They infect by inserting their DNA and forcing a cell to replicate the virus parts.
2. Bacteria: cause Lyme disease, tuberculosis, and tetanus. Infect by producing
poisons that kills surrounding cells.
3. Parasites: malaria (protist), dysentery (protist), athletes foot (fungus)
4. Contagions: disease-causing agents that cause spreadable diseases
5. Mutagens: Cause mutations in the DNA that cause disease
(these are not spreadable).
- Diseases prefer to live in warm, wet, unclean conditions.
- Bacteria reproduce by dividing in half (one becomes two, two becomes four, etc.)
- Microbes are spread through physical contact, touching contaminated objects, unsanitary practices. The term "contamination" is sometimes used to describe accidental transfers of organisms from one natural environment to another.
- Make effective observations using the scientific method
A scientific experiment involves many steps, including: