Environmental Hazards and Human Health Chapter 14
Core Case Study: HIV/AIDS (1) • Acquired immune deficiency syndrome (AIDS) • Human immunodeficiency virus (HIV) • Mode of transmittance • Exponential increase of infection worldwide
Core Case Study: HIV/AIDS (2) • No vaccine for HIV • No cure for AIDS
Kaposi’s Sarcoma Fig. 14-1, p. 323
Impact of AIDS on the Age Structure of Botswana, Africa Fig. 14-2, p. 323
14-1 What Major Health Hazards Do We Face? • Concept 14-1 People face health hazards from biological, chemical, physical, and cultural factors and from the choices they make in their lifestyles.
Risk and Hazards • Risk • Probability • Possibility • Risk assessment • Risk management
Risk Assessment and Risk Management Fig. 14-3, p. 324
Major Types of Hazards • Biological • Chemical • Physical • Cultural • Lifestyle
14-2 What Types of Biological Hazards Do We Face? • Concept 14-2 In terms of death rates, the most serious infectious diseases are flu, AIDS, diarrhea, and malaria, with most of these deaths occurring in developing countries.
Biological Hazards (1) • Nontransmissible diseases • Transmissible (infectious) disease • Pathogens • Epidemic • Pandemic
Biological Hazards (2) • Good news • Bad news
Pets Livestock Wild animals Insects Food Water Air Fetus and babies Other humans Humans Fig. 14-4, p. 326
Pets Livestock Wild animals Insects Food Water Air Fetus and babies Other humans Humans Stepped Art Fig. 14-4, p. 326
Disease (type of agent) Deaths per year Pneumonia and flu (bacteria and viruses) 3.2 million HIV/AIDS (virus) 3.0 million Diarrheal diseases (bacteria and viruses) 2.1 million Malaria (protozoa) 2.0 million Tuberculosis (bacteria) 1.6 million Hepatitis B (virus) 1 million Measles (virus) 800,000 Fig. 14-5, p. 326
Science Focus: Growing Resistanceto Antibiotics • High bacterial reproductive rate • Genetic resistance • Global travel • Use of pesticides • Overuse of antibiotics
Global Threats from Disease • Tuberculosis • Viral diseases • Malaria
Distribution of Malaria Fig. 14-6, p. 329
Female mosquito bites infected human, ingesting blood that contains Plasmodium gametocytes Merozoites enter bloodstream and develop into gametocytes causing malaria and making infected person a new reservoir Plasmodium develop in mosquito Sporozoites penetrate liver and develop into merozoites Female mosquito injects Plasmodium sporozoites into human host. Fig. 14-7, p. 329
Female mosquito bites infected human, ingesting blood that contains Plasmodium gametocytes Merozoites enter blood-stream and develop into gametocytes causing malaria and making infected person a new reservoir Plasmodium develops in mosquito Sporozoites penetrate liver and develop into merozoites Female mosquito injects Plasmodium sporozoites into human host Stepped Art Fig. 14-7, p. 329
Ecological Medicine • Zoonotic diseases • Ecological (conservation) medicine • Human actions encourage spread of disease • Clear-cutting and fragmentation • Harvesting animals • Global trade and travel • Trade in wild species
Science Focus: A Nightmare Flu Scenario • Common flu • Potent varieties of flu virus • Spanish flu of 1918 • Future pandemics • Animals as reservoirs for flu virus • H5N1 avian flu virus (bird flu)
Preventing or Reducing the Incidence of Infectious Diseases Fig. 14-8, p. 331
14-3 What Types of Chemical Hazards Do We Face? • Concept 14-3 There is growing concern about chemicals that can cause cancer and disrupt the human immune, nervous, and endocrine systems.
Chemical Hazards (1) • Toxic chemicals • Hazardous chemicals • Mutagens • Teratogens • Carcinogens
Chemical Hazards (2) • Metastasis • Immune system • Neurotoxins • Hormonally active agents (HAA) • DDT, PCBs, atrazine, aluminum, mercury, bisphenol-A
14-4 How Can We Evaluate Chemical Hazards? • Concept 14-4A Any synthetic or natural chemical can be harmful if ingested in a large enough quantity. • Concept 14-4B Many health scientists call for much greater emphasis on pollution prevention to reduce our exposure to potentially harmful chemicals.
Determining Chemical Safety (1) • Toxicology • Toxicity • Dose • Relevance of genetic makeup • Multiple chemical sensitivity (MCS)
Determining Chemical Safety (2) • Water and fat soluble toxins • Persistence • Bioaccumulation • Biomagnification • Chemical interactions
Type and Severity of Health Damage • Response – dose dependent • Acute • Chronic • Mechanisms which reduce harmful effects • Age-related effects • Effects of trace levels of toxic chemicals
Water pollutant levels Air pollutant levels Soil/dust levels Food pesticide levels Nutritional health Overall health Lifestyle Predicted level of toxicant in people Personal habits Genetic predisposition Metabolism Accumulation Excretion Lung, intestine, and skin absorption rates Fig. 14-9, p. 335
Teddy bear Some stuffed animals made oversees contain flame retardants and/or pesticides Shampoo Perfluorochemicals to add shine Clothing Can contain perfluorochemicals Baby bottle Can contain bisphenol-A Nail polish Perfluorochemicals and phthalates Mattress Flame retardants in stuffing Perfume Phthalates Hairspray Phthalates Carpet Padding and carpet fibers contain flame retardants, perfluorochemicals, and pesticides Food Some food contains bisphenol-A TV Wiring and plastic casing contain flame retardants Milk Fat contains dioxins and flame retardants Sofa Foam padding contains flame retardants and perfluorochemicals Frying pan Nonstick coating contains perfluorochemicals Fruit Imported fruit may contain pesticides banned in the U.S. Toys Vinyl toys contain phthalates Water bottle Can contain bisphenol-A Tennis shoes Can contain phthalates Tile floor Nonstick coating contains perfluorochemicals, phthalates, and pesticides Computer Flame retardant coatings of plastic casing and wiring Fig. 14-10, p. 336
Protection against Harmful Chemicals • Pollution protection • Precautionary principle • Persistent organic pollutants (POPs) • The dirty dozen • Can we have a risk-free society?
14-5 How Do We Perceive Risks and How Can We Avoid the Worst of Them? • Concept 14-5 We can reduce the major risks we face by becoming informed, thinking critically about risks, and making careful choices.
Evaluating Risks (1) • Risk analysis (risk assessment) • Comparative risk analysis • Risk management • Risk communication
Evaluating Risks (2) • Poverty – the greatest risk • Risks from lifestyles
Cause of death Annual deaths Poverty/ malnutrition/ disease cycle 11 million (150) Tobacco 5.4 million (74) Pneumonia and flu 3.2 million (44) Air pollution 3 million (41) HIV/AIDS 3 million (41) Malaria 2 million (27) Diarrhea 1.9 million (26) Tuberculosis 1.6 million (22) Automobile accidents 1.2 million (16) Work-related injury and disease 1.1 million (15) 1 million (14) Hepatitis B Measles 800,000 (11) Fig. 14-11, p. 338
Comparison of Risks in the United States Fig. 14-12, p. 339
Comparative Risk Analysis Fig. 14-13, p. 340
Annual Deaths in the United States from Tobacco Use and Other Causes in 2004
Cause of Death Deaths Tobacco use 442,000 101,500 (43,450 auto) Accidents Alcohol use 85,000 Infectious diseases 75,000 (16,000 from AIDS) Pollutants/toxins 55,000 30,600 Suicides Homicides 20,622 17,000 Illegal drug use Fig. 14-14, p. 340
Estimating Risks from Technologies • System reliability (%) = Technological reliability + Human reliability • Difficulties in estimating reliability • Perceived risk vs. actual risk
Improving Risk Evaluation • Carefully evaluate news reports • Compare risks • Concentrate on most serious risks
Animation: HIV Replication PLAY ANIMATION