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Global Geography 12
Chapter 4 (Atmospheric and Biological Disasters) Review Assignment
Please review your notes and give thoughtful answers that demonstrate a full
understanding of the topic!
Answer in full sentences or paragraphs.
1. Describe two similarities and two differences between Hurricane Katrina and the 1998
ice storm (case study, page 82)? (2 pts)
2. What two conditions are needed for a tropical storm to form? (2 pts)
3. What are the two main aspects of tropical storms that cause damage? (2 pts)
4. Explain how deaths may occur in the aftermath of a weather disaster. (1 pt)
5. What two conditions are needed for a tornado to form? (2 pts)
6. Give two reasons why hurricanes cause more deaths than tornadoes, even though
tornadoes have higher wind speeds. (2 points)
7. What causes most floods? (1 pt)
8. What kind of river is most likely to flood? (1 pt)
9. What are two causes of the most serious seasonal flooding? (2 points)
10. What is the “almost inevitable” effect of drought? (1 pt)
11. What makes drought one of the most significant natural disasters? (1 pt)
12. What are three long term effects of drought? (3 pts)
13. If the WHO decided to attempt to eradicate another one of the diseases we
discussed during this unit, which disease do you think should be the target, and why?
Give several reasons to support your answer in a well written paragraph. (5 pts)
Disease without borders
Spread by mosquitoes, malaria kills one child every 30 seconds
Malaria is an infectious disease that kills an average of more than one million people every year,
mostly infants, young children, and pregnant women. Most of those deaths are in Africa.
(CBC) Every 30 seconds, a child dies of malaria. But you
don't have to be a child or a pregnant woman to be infected.
Every year, more than 500 million people become severely
ill from the disease.
According to the World Health Organization, malaria is
endemic — or constantly occurring — in more than 100
countries around the world. Most cases occur in sub-Saharan
Africa, but parts of Asia, Latin America, the Middle East and
Europe are also affected.
People from malaria-free countries are especially vulnerable
to the disease when they travel to areas where malaria is present. They have little or no immunity
to the disease and are often misdiagnosed when they return home and begin showing symptoms.
Marking the first World Malaria Day held on Friday, April 25, 2008 United Nations SecretaryGeneral Ban Ki-moon announced an initiative to offer indoor spraying and bed nets to "all people
at risk, especially women and children in Africa."
Only about two per cent of African children currently sleep under insecticide-treated bed nets —
one of the most effective tools in the prevention of malaria. Ban is calling for coverage for an
additional 500 million people. The plan will also ensure public health facilities have access to
effective malaria treatment and diagnosis. The secretary-general hopes to put a stop to malaria
deaths by "ensuring universal coverage by the end of 2010."
Less than six months later, the World Health Organization released a report saying that progress
was being made in the battle against malaria. The World Malaria Report 2008 found that there
were 247 million cases of malaria across the globe in 2006. Previously, the estimate was 350
million to 500 million cases.
What causes malaria?
The disease is caused by several species of single-celled parasite of the genus Plasmodium, and it
is transmitted mostly commonly by mosquitoes.
Scientist James Mutunga who specialises in mosquito
research, holds up a tube containing mosquito larvae to be
taken to a laboratory and tested for malaria, Karatina,
Kenya, Nov. 7, 2006. (Kirsty Wigglesworth/Associated
Press)Infected female mosquitoes carry the spores of the
parasite. When a mosquito bites, it can transfer the spores to
a person through its saliva. The spores collect in the person's
liver and multiply there. Some species of the parasite can
remain dormant in the liver for several months.
From there, the spores divide and enter red blood cells,
where they multiply even more, sometimes bursting out of
the blood cells. The waves of fever every few days that are
characteristic of the disease are caused by the parasites
bursting out of blood cells simultaneously.
There are four types of malaria that infects people:
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Plasmodium falciparum.
P.vivax.
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P.malariae.
P.ovale.
P.falciparum and P.vivax are the most common. P.falciparum is by far the most deadly type of
malaria infection.
What are the most common symptoms of malaria?
Symptoms of malaria include:
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Headache and fever.
Muscle and joint pain.
Convulsions.
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Chills.
Nausea and vomiting.
Symptoms normally begin showing up 10 to 15 days after infection. If the person is not treated
promptly, the disease can rapidly worsen, turning into severe illness that can be fatal.
The symptoms of malaria can be mistaken for those of other diseases, so a diagnosis requires a
blood test.Health Canada warns that if you unexpectedly develop fever within three months of
returning from a malaria-endemic area, see a doctor immediately. Consider yourself a medical
emergency. Get your blood tested and repeat those tests within 12 to 24 hours if your symptoms
persist.
Am I at greater risk of developing malaria at specific times of the year?
It depends where you travel. Malaria is always a risk in certain tropical countries, especially in
sub-Saharan Africa.
But malaria transmission can occur seasonally as well, differing in intensity and regularity
depending on local factors such as rainfall patterns, proximity of mosquito breeding sites and
mosquito species. You should monitor the Public Health Agency of Canada's travel advisories
website for information on problem areas before you travel.
How is malaria treated?
The treatment of malaria depends on several things: the species of parasite, the severity of the
infection and the age of the person infected. In some parts of the world, parasites have become
resistant to some of the drugs used in treatment.
Almost all malaria can be completely cured if identified and treated early. But if left untreated, you
can go from being asymptomatic to severely ill very quickly. Death can occur within 36 to 48
hours. The types of drugs used will vary depending on where you've been, which parasite has
infected you and how sick you are.
How can malaria be prevented?
The World Health Organization estimates that $5.3 billion is needed to help control the spread of
malaria worldwide in 2009. That figure should rise to $6.2 billion in 2010.
Current anti-malaria efforts are focused on providing people in high-risk areas with protective nets,
as well as widespread spraying of insecticides, providing diagnostic services and effective drugs
for treatment.
One of the problems with insecticides is that mosquitoes develop tolerances. The more insecticides
are used, the less effective they can be.
Dr. Andrew Read, a professor of biology and entomology at Penn State University, has proposed
smarter use of pesticides to make them more effective. His research suggests that we can exploit
what we know about the life cycle of both the mosquito and malaria parasite to use pesticides
smarter. The trick is targeting only the older mosquitoes, which are the ones carrying infectious
parasites, but are also the most vulnerable.
Read says it's the older mosquitoes that are dangerous to human health. Sparing younger
mosquitoes means you're not giving them the chance to develop resistance to insecticides. When
they get older and become a threat to human health, they are more likely to be killed by
insecticide. Read says older mosquitoes can be targeted by diluting current pesticides.
"We think we can take the existing insecticides and dilute them down to the point where they don't
kill the young ones but still kill the old ones and that would give this benefit," Read told CBC
Radio's Quirks & Quarks. "You could also develop new chemicals that just kill the old mosquitoes.
And old mosquitoes are an easy target — they are like humans, they're more frail, more delicate
with age. They are much easier targets."
What can I do to protect myself?
The most effective strategy for preventing malaria infection is to avoid being bitten by infected
mosquitoes:
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

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Stay indoors from dusk to dawn, when mosquitoes are biting most.
Wear clothing that reduces the amount of your exposed skin.
If you are out between dusk and dawn, wear light-coloured long-sleeved shirts, long pants,
socks and shoes.
Impregnate all clothing with an insecticide such as 0.5% permethrin to make them
repellant.
Sleep under a mosquito net impregnated with permethrin.
Use DEET-based insect repellents.
When travelling in areas where malaria is endemic, children are at higher risk of infection than
adults. For children, sparingly apply DEET in a concentration of not more than 10 per cent to
exposed surfaces only. Wash it off after your child comes indoors.
While there is no vaccine for malaria, there are antimalaria medications available that can reduce
the risk of developing symptoms of the disease. These medications will not provide 100 per cent
protection against the disease.