Weather
and Living Things
|
|
|
|
|
Lesson 1
Rainfall, Rodents, and the Hantaviruses.
Introduction | Invitation | Exploration | Explanation | Taking Action | Conclusion
Introduction
Recently, scientists have begun to investigate the
connection between climate change and the incidence of
certain diseases such as cryptosporidium, malaria, and
hantavirus pulmonary syndrome (HPS). As the earth's
climate changes, we can expect that the incidence and
severity of certain diseases to change too. In this
lesson, we will explore the link between heavy rainfall and
outbreaks of hantavirus pulmonary syndrome.
Objectives
Upon
completion of this lesson, you should be able to discuss the
nature of a hantavirus, the symptoms of HPS, and the link
between rainfall, rodent density, and the spread of this
disease.
Materials
The Chain Game Worksheet and Game Pieces
Hantaviruses are part of a larger family of viruses which can transmit disease from animals to
humans. Like other viruses, they are parasitic, non living particles that consist of an inner core of genetic material and an outer protective coat made from protein. These particular viruses are surrounded by a lipid fatty envelope that makes them somewhat fragile. This is a good thing since it means that the viruses are relatively easy to kill. But before we investigate them further, we need to know what kind of organisms carry theses viruses and how they are transmitted to humans. To learn more about this, check out the following web site and then answer the questions given below. But before you do, check out the critters below and see if you can guess which one of these animals is a common carrier of virus.
|
|
Questions:
1. What kinds of organisms carry hantaviruses?
2. List four ways in which these hantaviruses can be transmitted to humans?
3. Is is possible to get a hantavirus from your pet cat or dog?
4. Describe the primary symptoms of
HPS.
Now it is time to
explore the link between lots of rain and catching these
hantaviruses. We can thank El Niño, a
disruption of the ocean-atmosphere system in the tropical
Pacific, for causing important weather changes around the
globe. To see how El Niño may be connected to
the spread of the hantaviruses, check out the following
link:
Questions:
1. How has El
Niño affected the weather of the the southern
United States and parts of Central and South
America?
2. Explain how
scientists think increased rainfall in the South West U.S.
has helped to increase the rodent
population.
3. Describe
the connection between rodent density and human exposure to
the hantaviruses.
Top
Exploration
The following activity from the Institute for Global Environmental Strategies will help you understand how an increase in rainfall may play a part in the hantavirus outbreak.
Please print out a copy of the this activity including the game pieces.
The Chain Game
Part 1
Hantavirus lives in
the white-footed
deer mouse. The
virus is not helpful
to the mice, but it
does not seem to
make them sick or
die.
Use
Set A pieces and the
food chain game board to arrange a
food chain for the deer mouse.
Record the food to the right. Discuss
your arrangement with other groups
and see if they agree.
Part 2
The "Four Corners"
area of the United
States - where
Colorado, Utah, Arizona,
and New Mexico meet -
had undergone
six years of severe
drought, when in the
Spring of 1993, a
period of heavy rains
began.
Using
Sets A and B and the
game board, show the
food chain as it
might have been just
before the heavy rains
started.
Consider adding
pieces from Set C (they
maybe placed on the
board outside of the
squares).
Record the food
chain that you developed
to the right and
discuss your arrangement
with other
groups.
Part 3
With Sets A and B,
the game board, and the
pieces as in Part 2,
show the food chain as it
might have been shortly
after the heavy rain
started.
Consider adding the
pieces from Set C to the
food chain
board.
Record the food
chain the you developed to the
right and discuss your
arrangements with other
groups.
Note: It may be helpful
to remember
that owls have only one
family of young per
year and that mice
often have several.
Part 4
With Sets A and B
and the game board, show
the food chain as it
might have been about a
year after the heavy
rains began.
Consider adding the
pieces from Set C to the
food chain
board.
Record the food
chain that you developed to
the right and discuss
your arrangement with
other
groups.
It has been
suggested that the top predators
were still not abundant
after a year of heavy
rains. Discuss the
factors that you thing could
explain this and record
your answer to the right.
Materials for the Game:
Game Pieces: Please use the box below as a template to cut out each of the game pieces.
Set
A
Set
B
Set B (continued)
A B B
A B B
A B B
A B B
Set C:
C C
C
Explanation
After you have completed Step 4 in the Chain Game, discuss the following concepts with the class:
1) The effects of temperature and moisture on the food chain.
2) How diseases are passed through the food chain.
3) How climate change can affect the spread of diseases
through the food chain.
Taking Action
Now that you have seen the connection between an increase in rainfall and the spread of the hantaviruses, it is time to take action by completing one or more of the following activities:
1) Make a poster showing ways to prevent hantavirus
exposure ( see the "prevention section" of
the
Hantavirus Facts site).
2) Make a commercial to inform people of HPS and ways to prevent it's infection.
3) Research another disease that is affected by climate. Summarize the factors that affect this disease.
4) Research an area in the United States or
Russia that has recently experienced an increase in
rainfall.
See if you can determine how food chains were affected and
whether or not there was a
corresponding increase in diseases including the
hantaviruses.
Conclusion
Hopefully, you are now beginning to see and understand the
relationship between climate change and disease. The change
of climate in this lesson was due to El Nino, a natural
weather phenomenon. Some scientists suggest that human
actions may have powerful impacts on weather and
climate. You will investigate some of these ideas in a
later lesson.