1. Bellringer/20.2 Notes

2. The Environment’s Role in Disease
Some of the damage to human health is due to organisms that carry disease.
Infectious diseases are caused by pathogens:
virus, microorganism, or other substance that causes disease
Some of these diseases are spread from person to person through the air
Others are spread by water that contains the pathogen

3. A vector is an intermediate host that transfers a pathogen or a parasite to another organism. Example: Mosquitoes that carry malaria or West Nile.
Cholera and Malaria
Nearly three-fourths of infectious disease are transmitted through water
The deadliest waterborne diseases, such as those that cause cholera and dysentery, come from drinking water polluted by human feces
These diseases cause the body to lose water and become dehydrated, and they cause most of the infant mortality around the world

4. Malaria once the world’s leading cause of death
Malaria caused by parasitic protists; transmitted by a bite from female mosquito
No effective vaccine for exists
Historically, controlled by draining marshes and rice paddies and pesticides
Now, mosquitoes are controlled by spreading growth regulators that prevent mosquito larvae from maturing into adults or that sterilize the female mosquitoes

5. Cross-Species Transfer
Cross-species transfer – A disease that moves from one species to another
These pathogens have lived for centuries in some species of wild animals and have often done little damage
Pathogens invade humans; the pathogens cause serious diseases
Example West Nile virus and HIV

6. Pop Quiz!
Which of the following is a naturally occurring pollutant?
pesticides
radon
sewage
vectors

7. What is the study of the spread of disease called?
antibiology
epidemiology
pathogenology
toxicology

8. What is the difference between pollution from natural sources and pollution from human activities?
Naturally occurring pollutants are less toxic.
Pollution from human activities has not been researched.
Pollution from human activities can be predicted and controlled.
Naturally occurring pollutants are only hazardous in small dosages.

9. How has the construction of irrigation canals and dams enabled the spread of infectious disease?
The construction allows viruses to evolve.
Canals and dams provide sites for waste disposal.
Canals and dams provide increased habitats for vectors.
The construction eliminates the natural predators of pathogens.

10. In which of these regions is non-environmental pollution the largest percentage of the total?
China
India
Latin America
Sub-Saharan Africa

11. In which of these regions are non-environmental causes of poor health the smallest percentage of the total?
China
India
Latin America
Sub-Saharan Africa

12. What is the main factor in the poor health of undeveloped countries?
too few doctors
infectious disease
industrial pollution
more imports than exports

13. Pop Quiz - Answers
Which of the following is a naturally occurring pollutant?
pesticides
radon
sewage
vectors

14. What is the study of the spread of disease called?
antibiology
epidemiology
pathogenology
toxicology

15. What is the difference between pollution from natural sources and pollution from human activities?
Naturally occurring pollutants are less toxic.
Pollution from human activities has not been researched.
Pollution from human activities can be predicted and controlled.
Naturally occurring pollutants are only hazardous in small dosages.

16. How has the construction of irrigation canals and dams enabled the spread of infectious disease?
The construction allows viruses to evolve.
Canals and dams provide sites for waste disposal.
Canals and dams provide increased habitats for vectors.
The construction eliminates the natural predators of pathogens.

17. In which of these regions is non-environmental pollution the largest percentage of the total?
China
India
Latin America
Sub-Saharan Africa

18. In which of these regions are non-environmental causes of poor health the smallest percentage of the total?
China
India
Latin America
Sub-Saharan Africa

19. What is the main factor in the poor health of undeveloped countries?
too few doctors
infectious disease
industrial pollution
more imports than exports