Executive Director of the Science and Environmental Health Network
This excerpt is reprinted with permission of the author. The full post can be found on the SEHN blog.
1. There are taxonomies of human health and disease. Taxonomies are conceptual frameworks that organize our thinking by grouping things that share characteristics. One taxonomy of disease is based on the system of the body that is diseased: the endocrine system, the cardiovascular system, the nervous system. Within those systems there can be various disorders such as birth defects, cancer, or poisoning. Another taxonomy is the kind of disease: infectious disease, injuries, or chronic disease, as examples. Within the category of those diseases there can be further subdivisions. Within the domain of infectious diseases there are those known as zoonotic diseases. These are diseases that cross between species and are often carried by a vector such as mosquitoes or ticks.
2. Epidemiology specializes in two kinds of disease, infectious and chronic. Frequently epidemiologists studying infectious disease investigate causes because there is usually a direct cause and a single effect with infectious diseases. Chronic disease specialists often study effects because many chronic diseases have multi-factorial causes making it harder to study causes.
3. Since the rise of industrialization the disease pattern has changed from primarily infectious disease to primarily chronic disease. Small pox and polio have been replaced by cardiovascular disease, diabetes and asthma.
3. When it focuses on effects, rather than causes of chronic disease, the medical professions emphasize treatment of disease, rather than prevention of disease.
4. The causes of chronic diseases are often complex, ecological (both biological and geological) and result from cumulative impacts of multiple stressors.