NOVA scienceNOW: Pandemic Flu
Print this Teacher's Guide (PDF, 6 pages)
For background information on viruses and the diseases they cause,
including influenza, see the classroom activity, "Modeling an Avian-Human Hybrid Flu
Virus". Review the difference between viruses and bacteria, and provide
examples of illnesses that each can cause.
The avian influenza virus (called H5N1) that is currently circulating has
caused outbreaks in poultry populations since mid-2003 in the following
countries: the Republic of Korea, Vietnam, Japan, Thailand, Cambodia, Lao
People's Democratic Republic, Indonesia, China, Malaysia, Russia, Kazakhstan,
Mongolia, Turkey, and Romania. Some of these countries, such as Japan,
Malaysia, and the Republic of Korea, believe they have controlled the disease.
Human H5N1 cases have occurred in Cambodia, Indonesia, Thailand, Vietnam, and
Hong Kong. Write these countries on the board. Provide atlases and blank world
maps (showing country divisions) to pairs of students and have them locate and
label these countries.
Human influenza A spreads when an uninfected person touches contaminated
surfaces or inhales viruses emitted by an infected person through coughs or
sneezes. To help students understand how quickly an influenza infection can
spread, have them perform the following activity. Make teams of four students.
Provide each team with a package of colored dots, stickers, or labels. Each
team should have a different color. In round 1, tell teams to stick a label on
the hands of two students (i.e., one hand of each student) from another team
and also give these students a sheet of their labels. Now, many students will
have a label on their hands and two sheets of labels, their own team's original
color plus the one they just received. In rounds 2 and 3, repeat the process.
Select a color to represent the influenza virus (e.g., red). Ask: How many
in the class were originally infected with the virus? How many had the
infection after three rounds? Typically, adults are infectious from the day
before symptoms appear to about five days after symptoms appear. Children can
be infectious for many days before showing symptoms and for as long as 10 days
after symptoms begin. The 1918 influenza pandemic took only two years to spread
worldwide, killing about 50 million people. Have students brainstorm places
where influenza A viruses could quickly spread, such as crowded buses.
About 675,000 Americans and about 50 million people worldwide died in the
1918 flu pandemic. Help students develop a sense of the enormity of the
pandemic by having them compare their state's population to the number of
people killed by the pandemic in the United States and across the globe.
Viruses are so small that scientists must use electron microscopes to see
them. Have students study the
number line to help them
understand the size differences among viruses, cells, and larger organisms.
Then ask them to fill in the table and write a size-comparison analogy for two
of the number line's organisms or items. For example, viruses are about 100
times smaller than animal cells. If a paper clip (about 3 cm) were to represent
a virus, then an animal cell would be the floor-to-ceiling height of an average
room (about 300 cm).
Download the classroom activity, "Modeling an Avian-Human Hybrid Flu
Virus" to teach students about the structure of influenza A
viruses, how they replicate in a cell, and how, when a person is infected
simultaneously with an avian and a human virus, their RNAs can mix. The
hands-on activity has background information, illustrative diagrams, detailed
teacher notes, discussion questions, answers, standards correlations, and
student sheets. Using the worksheet, students make avian and human influenza A
virus models, infect a lung cell, and make a hybrid virus that has some avian
and some human RNA segments. They will see that the hybrids have surface
proteins from both the avian and human influenza A viruses. Unfortunately, the
human immune system does not quickly recognize this combination of surface
proteins, making it particularly dangerous.
Key Facts About Avian Influenza, or (Bird Flu) and Avian Influenza A (H5N1)
Includes specific information about avian Influenza in Asia and Europe.
More Flu Viruses Around than Expected, Mutate in Unexpected Ways
Explains viral co-infection and reassortment, and discusses the 1918 flu.
Scientists Identify Step in Process of Flu Virus Infection
Details how a flu virus infects a cell.
Tiptoeing Around Pandora's Box
Describes the structure of avian and human influenza and how the two virus
genomes can reassort in a host cell.
WHO:H5N1 avian influenza: a chronology of key events
Dates the spread of avian influenza and explains each case.
Essential Cell Biology by Bruce Alberts, Dennis Bray, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts, and Peter Walter. Garland Publishing, Inc., 1998.
Covers cell biology topics, such as proteins, DNA, protein synthesis, genetics, and
many more. High school and college textbook.
Killer Diseases by Hazel Richardson and John Gribben. Dorling Kindersley, 2002.
Introduces and explains many deadly diseases and how they spread, and includes