BIO 550 Week 1 Discussion Questions
BIO 550 Week 1 Discussion Questions
DQ1 What were early conceptions of the cause of disease?
DQ2 Develop or illustrate a timeline of epidemiologic milestones in public health. What is one of the most significant milestones to you? Why?
The connotations of the term “a disease” were investigated by studying the ways in which both medical and non-medical people used the word. A list of common diagnostic terms was read slowly to groups of non-medical academic staff of a university, secondary-school students, medical academics, and family practitioners, who then indicated whether they thought each word referred to disease.
All groups rated illnesses due to infections as diseases, but the doctors, and particularly the general practitioners, were more generous in accepting as diseases the terms for non-infectious conditions. Apart from the nature of the cause, the most influential factor in determining whether or not an illness was considered to be a disease was the importance of the doctor in diagnosis and treatment.
These findings provide further evidence that there is ambiguity about the meaning of the term disease. To the layman a disease seems to be a living agency that causes illness. Doctors have obviously accepted more heterogeneous defining characteristics but remain reluctant to adopt unequivocally nominalist ways of thought. The position is not unlike that in the physical sciences, in which there is a good precedent for distinguishing between the formal scientific and the everyday uses of terms such as “force” and “power”
Although many diseases are infectious, research in the twentieth century has revealed other kinds of cause of disease: genetic, nutritional, immunological, metabolic, and cytological. The Hippocratics saw some traits such as being phlegmatic as hereditary, but the first demonstration of the genetic basis of a disease was Archibald Garrod’s work on alkaptonuria in 1901 (Devor, 1993). Many other kinds of genetic disorders have been identified, and in recent years genetic engineering has offered the possibility of new kinds of treatment for such disorders. Hippocrates placed great emphasis on diet as a factor on disease, and the value of citrus fruits in preventing scurvy was established in 1747, but identification of vitamin C as a nutritional requisite of health occurred only in 1932. Diseases caused by nutritional deficiencies can easily be treated by providing the missing vitamins or other nutrient.
Knowledge of the immune system advanced rapidly in the 1950s, making possible the understanding of diseases that arise from attacks by the immune system on the body’s own organs, as occurs in diseases such as lupus erythematosus. Metabolic disorders such as diabetes have become increasingly understood as knowledge increases of the physiology of organs such as the pancreas, but causality in such cases is complex, involving an interaction of hereditary and environmental factors. Similarly, although knowledge is developing rapidly concerning the nature of the cells and genes involved in the growth of cancers, the causal interactions are enormously complex and hard to identify.
The authoritative Cecil Textbook of Medicine is divided into parts that implicitly classify diseases in two complementary respects: organ systems and pathogenesis. Table 5 lists the relevant parts of the textbook. Most of these are organized around physiological systems, such as the cardiovascular and respiratory systems. But there are also parts that group diseases in terms of pathogenetic mechanisms that can affect various organ systems: oncology, metabolic diseases, nutritional diseases, infectious diseases, and so on. Some diseases are naturally discussed in more than one part, as when myocarditis occurs both under cardiovascular diseases and infectious diseases. Modern medical classification thus blends two overlapping taxonomies of disease.