ENV221 MULTIDISCIPLINARY STUDIES
ON THE ENVIRONMENT FINAL EXAM
QUESTIONS WITH CORRECT
ANSWERS
Very sensitive individuals will be first to react, majority will be in the middle, some
because of genetics will be immune to a certain disease
Antibiotic Resistance - Answer-Drugs & pharmaceuticals that kill bacteria
Mutation and selection create drug-resistant strains
Bacterial colony (mutation) --> resistant bacterium --> resistant colony
Mutation can confer advantage to a particular colony/bacterium
By not completing full course of antibiotics, selecting for resistant part of the bacteria
population to form and grow
Natural selection and ability to evolve rapidly
Indiscriminate and over-enthusiastic pesticide
Increasing use of antibiotic in large scale feedlots
Half of human antibiotic prescriptions unnecessary?
Potential for super virulent pathogens
Tuberculosis - Answer-Infectious disease caused by mycobacteria
Attacks the lungs, chronic cough
Thought that TB was essentially eradicated by middle of last century
Then immune deficiencies of people with AIDS allowed latent Mycobacterium
tuberculosis infections to progress to the active state of the disease during which it
could be transmitted to others (opportunistic or secondary infection)
Relationship between TB and AIDS - Answer-Infectious anti-tuberculosis therapy
then leads to the emergence of drug-resistant and multidrug-resistant strains for the
bacteria
Drug must be taken every day for 6-8 months, while symptoms typically disappear
after a few weeks
TB in general is associated with crowding and inadequate hygiene. The continuing
expansion of global populations living in poverty is going to make TB difficult to
control
,Actually in the city of Toronto, especially in the wintertime
Concerning area: homeless shelter, high in areas in the north
Currently infects 9 million people/year and kills ~1.7 million
The WHO estimates that there will be 1 billion TB cases worldwide by 2020 with 28
million deaths if TB control efforts are not increased
How Malaria Spreads - Answer-The malaria parasite depends on both humans and
mosquitos to carry out its deadly cycle of life
Infected mosquito bites a human
Parasite rapidly goes into liver within 30 minutes
Gets out into the bloodstream and is carried through RBCs
Malaria - Answer-Caused by a parasitic protozoa that is transmitted between
humans by mosquitos
Malaria-associated mortalities have risen quickly with the emergence of drug
resistance in the parasite
Projected risk of malaria transmission in the year 2020 based on a global
temperature increase of 1 degree C and no human efforts to control the spread of
malaria
DDT - Answer-Wide-spread use of DDT and apparently effective malaria control by
way of mosquito control lead to the abandonment of other malarial control and the
disease was neglected for several decades
When DDT was banned (mosquitos had developed resistance to it in any event),
malaria re-emerged
Re-emergence was followed relatively quickly by Plasmodium resistance to the only
two antimalarial drugs available at the time (chloroquine and mefloquine)
Cases of Malaria - Answer-There are more cases of malaria today than 30 years ago
(we have caused this)
Malaria now kills over 1 million people/year, and an estimated 300-500 million are
infected with the protozoan parasites that cause malaria
Prevention is best approach to slowing spread
Screens on homes and mosquito nets for beds, biological control, altering marsh
areas, zinc & vitamin A supplements to boost resistance in children, insecticides
Despite a ban on DDT, special dispensation to allow 25 countries to continue using
DDT for malaria control until other alternatives are available
SARS (The Cough Heard Round the World) - Answer-Severe acute respiratory
syndrome
SARS coronavirus
, First recognized as global threat in March 2003 (thought origin was animal virus!)
Believed to be an animal virus that crossed the species barrier to humans
Natural reservoir suspected to be Himalayan masked civet, Chinese ferret badger
and the raccoon dog
SARS- Vulnerability Revealed - Answer--Spread from person to person
-Required no vector
-Incubated silently for over a week
-Mimicked symptoms of other diseases
-Killed about 10% of those infected
-Spread easily along international air travel routes ~2 billion passengers/year
-Spread in city hospitals
-Damaged economies, societies, politics, and the international image of countries
-Globalization- first time we saw how infectious diseases cross and transfer
internationally
-Trying to see how SARS went from one Asian country to that many countries in the
world
-Illustrated probable SARS transmission on flight CA112 in March 2003
West Nile Virus - Answer-Mosquito-borne illness with mild flu-like symptoms, but
some can develop permanent neurological issues
High of < 5,500 cases in US in 2012
Zika Virus - Answer-First discovered in monkey in Zika forest of Uganda
-Outbreaks in the tropical Africa, southeast Asia, pacific islands
-Related to deregue, yellow fever, etc.
-No current treatment
-Virus spread though infected mosquitos bite
-Most symptoms pretty mild
-Pregnancy
-Can cause microcephaly and other severe brain defects
How is Zika spread? - Answer-• Zika can be spread through
o Mosquito bites
o From a pregnant woman to her fetus
o Sex with an infected person
o Laboratory exposure
o Zika may be spread through blood transfusion
o No reports of infants getting Zika through breastfeeding
o Microcephaly syndrome
♣ Birth defect
♣ Head shrinks
♣ No vaccine or treatment currently
Epidemic vs. Pandemic
(WHO Definition) - Answer-- Epidemic: occurs when there are more cases of that
disease than normal
- Pandemic: worldwide epidemic of a disease
o Emergence of a disease new to a population
o Agents infect humans, causing serious illness; and agents spread easily and
sustainably among humans
Annual Influenza - Answer-- Estimated to affect 5-15% of the global population
ON THE ENVIRONMENT FINAL EXAM
QUESTIONS WITH CORRECT
ANSWERS
Very sensitive individuals will be first to react, majority will be in the middle, some
because of genetics will be immune to a certain disease
Antibiotic Resistance - Answer-Drugs & pharmaceuticals that kill bacteria
Mutation and selection create drug-resistant strains
Bacterial colony (mutation) --> resistant bacterium --> resistant colony
Mutation can confer advantage to a particular colony/bacterium
By not completing full course of antibiotics, selecting for resistant part of the bacteria
population to form and grow
Natural selection and ability to evolve rapidly
Indiscriminate and over-enthusiastic pesticide
Increasing use of antibiotic in large scale feedlots
Half of human antibiotic prescriptions unnecessary?
Potential for super virulent pathogens
Tuberculosis - Answer-Infectious disease caused by mycobacteria
Attacks the lungs, chronic cough
Thought that TB was essentially eradicated by middle of last century
Then immune deficiencies of people with AIDS allowed latent Mycobacterium
tuberculosis infections to progress to the active state of the disease during which it
could be transmitted to others (opportunistic or secondary infection)
Relationship between TB and AIDS - Answer-Infectious anti-tuberculosis therapy
then leads to the emergence of drug-resistant and multidrug-resistant strains for the
bacteria
Drug must be taken every day for 6-8 months, while symptoms typically disappear
after a few weeks
TB in general is associated with crowding and inadequate hygiene. The continuing
expansion of global populations living in poverty is going to make TB difficult to
control
,Actually in the city of Toronto, especially in the wintertime
Concerning area: homeless shelter, high in areas in the north
Currently infects 9 million people/year and kills ~1.7 million
The WHO estimates that there will be 1 billion TB cases worldwide by 2020 with 28
million deaths if TB control efforts are not increased
How Malaria Spreads - Answer-The malaria parasite depends on both humans and
mosquitos to carry out its deadly cycle of life
Infected mosquito bites a human
Parasite rapidly goes into liver within 30 minutes
Gets out into the bloodstream and is carried through RBCs
Malaria - Answer-Caused by a parasitic protozoa that is transmitted between
humans by mosquitos
Malaria-associated mortalities have risen quickly with the emergence of drug
resistance in the parasite
Projected risk of malaria transmission in the year 2020 based on a global
temperature increase of 1 degree C and no human efforts to control the spread of
malaria
DDT - Answer-Wide-spread use of DDT and apparently effective malaria control by
way of mosquito control lead to the abandonment of other malarial control and the
disease was neglected for several decades
When DDT was banned (mosquitos had developed resistance to it in any event),
malaria re-emerged
Re-emergence was followed relatively quickly by Plasmodium resistance to the only
two antimalarial drugs available at the time (chloroquine and mefloquine)
Cases of Malaria - Answer-There are more cases of malaria today than 30 years ago
(we have caused this)
Malaria now kills over 1 million people/year, and an estimated 300-500 million are
infected with the protozoan parasites that cause malaria
Prevention is best approach to slowing spread
Screens on homes and mosquito nets for beds, biological control, altering marsh
areas, zinc & vitamin A supplements to boost resistance in children, insecticides
Despite a ban on DDT, special dispensation to allow 25 countries to continue using
DDT for malaria control until other alternatives are available
SARS (The Cough Heard Round the World) - Answer-Severe acute respiratory
syndrome
SARS coronavirus
, First recognized as global threat in March 2003 (thought origin was animal virus!)
Believed to be an animal virus that crossed the species barrier to humans
Natural reservoir suspected to be Himalayan masked civet, Chinese ferret badger
and the raccoon dog
SARS- Vulnerability Revealed - Answer--Spread from person to person
-Required no vector
-Incubated silently for over a week
-Mimicked symptoms of other diseases
-Killed about 10% of those infected
-Spread easily along international air travel routes ~2 billion passengers/year
-Spread in city hospitals
-Damaged economies, societies, politics, and the international image of countries
-Globalization- first time we saw how infectious diseases cross and transfer
internationally
-Trying to see how SARS went from one Asian country to that many countries in the
world
-Illustrated probable SARS transmission on flight CA112 in March 2003
West Nile Virus - Answer-Mosquito-borne illness with mild flu-like symptoms, but
some can develop permanent neurological issues
High of < 5,500 cases in US in 2012
Zika Virus - Answer-First discovered in monkey in Zika forest of Uganda
-Outbreaks in the tropical Africa, southeast Asia, pacific islands
-Related to deregue, yellow fever, etc.
-No current treatment
-Virus spread though infected mosquitos bite
-Most symptoms pretty mild
-Pregnancy
-Can cause microcephaly and other severe brain defects
How is Zika spread? - Answer-• Zika can be spread through
o Mosquito bites
o From a pregnant woman to her fetus
o Sex with an infected person
o Laboratory exposure
o Zika may be spread through blood transfusion
o No reports of infants getting Zika through breastfeeding
o Microcephaly syndrome
♣ Birth defect
♣ Head shrinks
♣ No vaccine or treatment currently
Epidemic vs. Pandemic
(WHO Definition) - Answer-- Epidemic: occurs when there are more cases of that
disease than normal
- Pandemic: worldwide epidemic of a disease
o Emergence of a disease new to a population
o Agents infect humans, causing serious illness; and agents spread easily and
sustainably among humans
Annual Influenza - Answer-- Estimated to affect 5-15% of the global population
