UMD ENSP 101 - Chapter 8 – Environmental Health and Toxicology

Unformatted text preview:

ENSP101Chapter 8 – Environmental Health and Toxicology8.1 Environmental Health- Health – a state of physical and emotional well-being; the absence of disease or ailment- Disease – a deleterious change in the body’s condition in response to destabilizing factors, such as nutrition, chemicals, or biological agents- Diet and nutrition, infectious agents, toxic substances, genetics, trauma, and stress all play roles in morbidity (illness) and mortality (death)- Environmental health – the science of external factors that cause disease, including elements of the natural, social, cultural, and technological worlds in which we live- Public health successes:o Smallpox was completely wiped out 1977o Polio has been eliminated everywhere in the world except for a few remote villages in northern Nigeriao Epidemics of typhoid fever, cholera, and yellow that regularly killed thousands of people in North America a century ago are now rarely encounteredo AIDS, which once was an immediate death sentence, has become a highly treatable diseaseo The average HIV-positive person in the US now lives 24 yrs after diagnosis if treatedfaithfully with modern medicineso During the 20th century, world average life expectancies more than doubled from 30 to 64.3 years- A vital component of rising life expectancies is declining child mortality- Disability adjusted life years (DALYs) – a measure of premature deaths and losses due to illnesses and diabilities in a populationso DALYs combine premature deaths and loss of a healthy life resulting from illness or disabilityo This is an attempt to evaluate the total cost of disease, not simply how many people die- The world is now undergoing a dramatic epidemiological transitiono Chronic conditions, such as cardiovascular disease and cancer, no long afflict only wealthy peopleo Although the traditional killers in developing countries – infections, maternal and perinatal (birth) complications, and nutritional deficiencies – still take a terrible toll,diseases such as depression and heart attacks hat once were thought to occur only in rich countries are rapidly becoming the leading causes of disability and premature death everywhere- By 2020, its expected that 15 million people will have cancer and 9 million will die from it- A silent epidemic of diabetes is now sweeping through our populationo Obesity, diets high in sugar and fat, lack of exercise, and poverty (which encourages fast-food intake and makes health food unavailable) all play important roles in this diseaseo Blindness, circulatory problems, and kidney failure are common results of severe, uncontrolled diabeteso 70% of all lower limb amputations are diabetes-related- Taking disability as well as death into account in our assessment of disease burden reveals the increasing role of mental health as a worldwide problem- Although the ills of modern life have become the leading killers almost everywhere in the world, communicable diseases still are responsible for about 1/3 of all disease related mortality- Better nutrition, clean water, improved sanitation, and inexpensive inoculations could eliminate most of those deaths- A wide variety of pathogens (disease-causing organisms) afflict humans, including viruses, bacteria, protozoan’s (single celled animals), parasitic worms, and flukes- Influenza is caused by a family of viruses that mutate rapidly and move from wild and domestic animals to humans, making control of this disease very difficult- Every year there are 76 million cases of food-borne illnesses in the US, resulting in 300,000 hospitalizations and 5,000 deathso Both bacteria and intestinal protozoa cause these illnesseso They are spread from feces through food and water- Malaria is one of the most prevalent remaining infectious diseaseso Every year about 500 million new cases of this disease occur, and about 2 million people die form ito The territory allows mosquito vectors to move into new territory- Emergent diseases –a new disease or one that has been absent for at least 20 yearso E.g. swine flu in US, cholera in South America, TB in Russiao Rapid international travel makes it possible for these new diseases to spread aroundthe world at jet speed- The largest recent death toll from an emergent disease is HIV/AIDS- Domestic animals and wildlife also experience sudden and widespread epidemics, which are sometimes called ecological diseaseso Ebola hemorrhagic fever kills up to 90% of its victimso Chronic wasting disease (CWD)o Transmissible spongiform encephalopathies (TES) that include mad cow disease in cattle, scrapie in sheep- Climate change also facilitates expansion of parasites and diseases into new territories- Tropical diseases such as malaria, cholera, yellow fever, and dengue fever, have been moving into areas from which they were formerly absent as mosquitoes, rodents, and other vectors expand into new habitato This affects other species besides humans- One thing that emergent diseases in humans and ecological diseases in natural communitieshave in common is environmental change that stresses biological systems and upsets normal ecological relationships- We are coming to recognize that the delicate ecological balances that we value so highly – and disrupt so frequently – are important to our own health- Conservation medicine is an emerging discipline that attempts to understand how our environmental changes threaten our own health as well as that of the natural communities on which we depend for ecological services- Resistance to drugs, antibiotics, and pesticides is increasing- The heaviest burden of illness is borne by the poorest people who can afford neither a healthy environment nor adequate health careo Estimates that 90% of all disease burden occurs in developing countries where less than 1/10 of all health care dollars are spento Worldwide, only 2% of the people with AIDS have access to modern medicineso Every year, some 600,000 infants acquire HIV – almost all of them through mother-to-child transmission during birth or breast-feedingo Improved health care in poorer countries may also help prevent the spread of emergent diseases in a globally interconnected world8.2 Toxicology- Toxicology – the study of toxins (poisons) and their effects, particularly on living systems- Toxins damage or kill living organisms because they react with cellular components to disrupt metabolic functionso Because of this reactivity, toxins often are harmful even in extremely


View Full Document
Download Chapter 8 – Environmental Health and Toxicology
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view Chapter 8 – Environmental Health and Toxicology and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Chapter 8 – Environmental Health and Toxicology 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?