Students learn about epidemics and pandemics, as well as vaccines and other precautions that can help prevent infections such as influenza.
Flu, influenza, bacteria, virus, infection, disease, vaccine, immune, epidemic, pandemic, Black Death, smallpox, AIDS
At certain points in history, many people have become infected with a particular illness. For example, the Black Death ravaged Europe from the year 1347 to the early 1350s, killing almost one-third of the continent’s population.
When a large number of people become seriously ill due to the same bacteria or virus, it is called an epidemic—or, if the disease spreads globally, a pandemic. Help students put modern influenza outbreaks into perspective by comparing them with other epidemics and pandemics. Then, discuss how vaccines and other precautions work to reduce the likelihood of illness.
Begin with some basic terms and explanation:
1. Bacteria and viruses
Bacteria are microscopic one-celled organisms. Thousands of types of bacteria live almost everywhere. Bacteria can reproduce themselves (multiply). Some bacteria are helpful, while others can make us sick.
Viruses, another major cause of illness, are smaller than bacteria and may have a spiny outside layer. Viruses can’t reproduce on their own, so they infect cells and take them over in order to multiply.
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2. Epidemic vs. pandemic
While disease has affected humans since the beginning of time, it wasn’t until people began gathering in larger populations that infections began to reach epidemic levels. An epidemic happens when an infection (caused by a bacteria or virus) affects a large number of people within a given population, such as a city or geographic area. If it affects even greater numbers and a wider area, these outbreaks become pandemics.
The video below discusses how pandemics spread:
Older students can read more detailed information on pandemics, including what causes pandemics, the stages by which pandemics develop and a list of pandemics throughout history.
Here are some notable ones:
1300s - The Black Death
Brought to Europe from the Far East via infected fleas that were riding on the backs of ship rats, the Black Death (also known as the Bubonic Plague) would go on to wipe out over 20 million people. That figure represents one-third of the population. Fear gripped the continent as people began falling victim to the disease in increasing numbers. People did not understand how the disease was spread or how to treat it. To make matters worse, the gruesome nature of the illness added to the hysteria—the infected displayed the disease’s trademark black boils, which oozed blood and pus.
Symptoms: Chills, fever, vomiting, aches and pains, along with hard, painful, burning lumps on the body that turn black, split open and ooze pus and blood.
Caused by: Yersinia pestis bacteria
Does it still exist? There are 1,000 to 3,000 cases worldwide each year, including 10 to 15 cases in the United States. Due to improved sanitation, the disease is not likely to spread the way it did in the 1300s. The Bubonic Plague is now treatable with antibiotics, and a vaccine is also available.
Ancient time through 1970s – Smallpox
An astounding 300 million deaths were attributed to smallpox outbreaks during the 20th century alone. That figure certainly would have been greater were it not for the revolutionary work of a physician named Edward Jenner. Jenner realized that people who had already contracted cow pox did not contract smallpox. In 1796, he injected cow pox into an eight-year-old boy to test his theory. When the boy was proven to have been successfully inoculated, Jenner had created the world’s first vaccine. After successful vaccination campaigns throughout the 19th and 20th centuries, in 1979 the World Health Organization certified that smallpox had been eliminated.
Also see EducationWorld’s Internet Scavenger Hunt on the smallpox vaccine.
Symptoms: Fever, fatigue, aches and pains, along with red lesions (sores) that become filled with pus, then crust and scab.
Caused by: The variola virus
Does it still exist? Due to the success of vaccination campaigns, the disease was wiped out.
1918-1919 – Spanish (Avian) Flu
It may be hard to believe, but the flu killed nearly 40 million people at one point in history. In that 12-month period, more people succumbed to the flu than lost their lives in World War I, leading many to consider it the most devastating pandemics in all of recorded history.
Symptoms: Fever, nausea, aches, diarrhea and sometimes severe pneumonia. Victims show dark spots on the cheeks and turn blue, suffocating as their lungs fill with a frothy, bloody substance.
Caused by: A virus in the H1N1 family
Does it still exist? Different forms of the virus still exist, but scientists are not worried that this particular version will make a comeback.
1980s to today - AIDS (NOTE: This topic recommended for grades 9 and up.)
By the end of 2004, 20 million people had died from HIV (Human Immunodeficiency Virus/Aquired Immunodeficiency Virus (AIDS). Nine out of 10 people living with HIV live in the developing world; 60 to 70 percent of those are in Sub-Saharan Africa. But the disease is spreading in every region, including India, China, Russia and the islands of the Caribbean. Since the epidemic began, an estimated 1,129,127 people in the U.S. have been diagnosed with AIDS, and an estimated 48,000 Americans become infected with HIV each year.
Symptoms: Possible flulike symptoms at the time of HIV infection, and after 5 to 15 years left untreated (at which point the person develops AIDS), multiple, life-threatening illnesses such as rare cancers, pneumonia, fungal conditions, tuberculosis and other infections.
Caused by: Human Immunodeficiency Virus, a retrovirus that attacks the cells of the immune system
Does it still exist? Due to increased awareness, prevention efforts and treatment options, the U.S. incidence of AIDS is lower than that in some other countries. HIV/AIDS does, however, remain a top public health concern, and the disease is of particular concern on a global scale.
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3. The immune system and vaccines
The human immune system uses white blood cells to defend the body from harmful “intruders”—viruses and bacteria, also known as antigens. The white blood cells make antibodies specific to each intruder. The antibodies destroy the intruders or help white blood cells destroy them. Get a basic rundown of the immune system here.
Vaccines, special medicines developed to fight specific bacteria or viruses, help the body produce antibodies to attack dangerous intruders. A vaccine contains a dead or weakened version of an antigen. Because the germ has been killed or weakened before it is used to make the vaccine, it doesn't make the person sick. Instead, the body reacts to the vaccine by making antibodies. Basic information about vaccines appears here.
Using this timeline, older students can explore the history of vaccine development and learn how vaccines were used to eliminate the disease smallpox.
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4. The flu (influenza)
The flu (influenza) virus has been around a long time and appears in some form every year, although the severity of the outbreak and the particular “strain” (type of virus) varies. In 1918-1919, a severe pandemic killed millions, while in more recent history, the flu has sickened many, but resulted in vastly fewer deaths.
Kids may be seeing a lot of scary coverage of the flu in the news. To help put things in perspective, this article compares the 2013 flu epidemic (more severe than the previous year’s) with the 1918 pandemic, while this article downplays some of the “hysteria” about the 2013 flu.
NOTE: Use this lesson plan in future years by accessing information on the current year’s flu from the Centers for Disease Control (CDC).
Fighting the flu
Two ways of fighting the flu include vaccines and health precautions.
In 1945, the first effective flu vaccine was available, although it didn’t work perfectly. Today’s flu vaccines work about 60-70% of the time, meaning that some people who get the vaccine will still get the flu. They may, however, have less severe symptoms than people who didn’t get the vaccine. Since flu viruses can change over time, scientists need to keep working to make new ones, and people need to get a new vaccine every year.
Other health precautions include limiting contact with sick people, hand washing, using hand sanitizer, covering coughs and sneezes and taking antiviral medications.
Use the EducationWorld lesson News for You: Kids Can Lower Their Flu Risk to build media skills and teach about prevention.
Check Student Understanding:
Evaluate students using the 17 “Check Student Understanding” questions that appear throughout this lesson.
Jason Tomaszewski, EducationWorld Associate Editor
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