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 Chapter 17-1
 Environmental Hazards
 Goals for today:
 Contrast biological, physical, chemical, and cultural hazards (with examples of each)
 Contrast transmissible and non-transmissible diseases (with examples)
 Describe how to reduce the number of malaria cases
 Review of HIV/AIDS…
 What does HIV stand for?
 What is the difference between HIV and AIDS?
 How does HIV affect a person?
 There is no vaccine for HIV – if you get AIDS, you will eventually die from it.
 Drugs help some infected people live longer, but only a tiny fraction can afford them.
 HIV/AIDS Epidemic
 The virus itself is not deadly, but it cripples the immune system, leaving the body susceptible to infections such
as Kaposi’s sarcoma (above). (HIV + type of Herpes)
 Risk is a measure of the likelihood that you will suffer harm from a hazard.
 Hazard: may cause economic loss, environmental loss, injury, disease or death
 4 types of hazards:
 Biological hazards
 Chemical hazards
 Physical hazards
 Cultural hazards
 Biological hazards: from more than 1,400 pathogens. Pathogen is anything that makes you have an immune
 Examples?
 Bacteria, viruses, protozoa, pollen, insects, parasites, fungi
 Chemical hazards: in air, water, soil, and food.
 Examples?
 Mutagens, radiation, teratogens, carcinogens
 Physical hazards:
 such as fire, earthquake, volcanic eruption…
 Cultural hazards: such as
 smoking, poor diet, unsafe sex, drugs, unsafe working conditions, and poverty.
 nontransmissible disease: cannot spread from one person to another
 Can you think of any examples?
 transmissible or infectious
 Transmissible diseases
 Caused by living organisms
 These infectious agents are spread by air, water, food, bodily fluid, insects and other vectors
 80% of illness in less developed countries is from waterborne infectious diseases. Why?
 Hepatitis- inflamed liver cells, virus
 Typhoid fever- bacteria, fecal oral
 Cholera- diarrhea, vibrio cholerae, gram - bacteria
 Transmissible Disease
 WHO estimates that each year the world’s seven deadliest infections kill 13.6 million people – most of them the
poor in less developed countries.
 Pneumonia and Flu
 Pneumonia: fluid in lungs, respiratory infection, can be caused by bacteria
 Flu: caused by a virus. (influenza)
 The influenza virus is the biggest killer virus worldwide.
 Pigs, chickens, ducks, and geese are the major reservoirs of flu. As they move from one species to
another, they can mutate and exchange genetic material with other viruses.
 Spanish Flu (1918 pandemic)
 Spanish flu: 1918, killed 20-50 million people within a few months
 Killed mostly young adults.
Pandemic: global spread of a disease, covering a wide range of geographic regions
Epidemic: a widespread outbreak of an infectious disease, many people are infected at the same time.
Resistance to Antibiotics
Genetic resistance: how do bacteria become resistant to antibiotics?
 Tuberculosis (TB)
The highly infectious tuberculosis (TB) kills 1.7 million people per year and could kill 25 million people 2020.
Caused by bacteria, infects lungs
Recent increases in TB are due to:
 Lack of TB screening and control programs especially in developing countries due to expenses.
 Genetic resistance to the most effective antibiotics.
 Inc. pop. size
More Viral Diseases
SARS: severe acute respiratory syndrome
Chicken pox
Small pox- virtually eradicated
West Nile virus
Viral Diseases
Five major priorities to slow the spread of the disease are:
 Quickly reduce the number of new infections to prevent further spread. How?
 Concentrate on groups in a society that are likely to spread the disease.
 Provide free HIV testing and pressure people to get tested.
 Implement educational programs.
 Provide free or low-cost drugs to slow disease progress.
 Malaria – Death by Mosquito
Malaria kills about 2 million people per year and has probably killed more than all of the wars ever fought.
caused by a plasmodium parasite (protozoan)
Economists estimate that spending $2-3 billion on malaria treatment may save more than 1 million lives per
How do some countries try to reduce number of malaria cases?
Drain swamplands
spray DDT
Mosquito nets
Use drugs to kill parasites in blood
Where did the SARS outbreak first occur?
Hepatitis B is caused by _____ and affects _____ cells.
Check for Understanding:
1. Give an example of each of the 4 types of hazards.
2. Give an example of a transmissible and non-transmissible disease.
3. How can malaria be reduced?