Question

4. Describe the significance for epidemiology of the following historical developments: a. associating the environment with disease causality b. use of vital statistics c. use of natural experiments d. identification of specific agents of disease

Answer 1

4. Describe the significance for epidemiology of the following historical developments:

a. Associating the environment with disease casualty- this represented a movement away from super natural explanations of disease causation to a rational account of the origin of human kind’s illness. The significances for epidemiology in associating the environment with disease causality would be to help decrease the spread of diseases within the environment. From the readings in the book the Hippocrates and Thucydides in 400 B.C believed that disease may beassociated with the physical environments and a movement away from supernatural explanations of diseases causation to a rational account of the origin of humankind illnesses. The CDC uses vital statistic for state and local governments to gather data on a continuing basis to determine whether an epidemic is taking place. The surveillance of vital statistics helps keep an eye out on possible infection diseases, influenza and foodborne outbreaks. (Friis, 2014).

b. Use of vital statistics- recording descriptive characteristics of birth and death data, including seasonal variations, infant mortality, and excess male over female differences in mortality. Graunt is said to be the first to employ quantitative methods in describing population vital statistics by organizing mortality data in a mortality table and has been referred to as the Columbus of statistics. His procedures allowed the discovery of trends in births and deaths due to a specific cause.

c. Use of natural experiments- refers to naturally occurring circumstances in which subsets of the population have different levels of exposure to a supposed casual factor in a situation resembling an actual experiment, where human subjects would be randomly allocated to groups. The presence of persons is typically nonrandom. John Snow used natural experiments to track a cholera outbreak in Golden Square, London. The significance in epidemiology with the use of natural experiments is important due to they are naturally occurring circumstancesin which subsets of the populations all have different levels of exposure to a casual factor in a situation resembling an actual experiment. The human subjects would be placed in a random select group for their natural experiments which is from John Snow natural experiments. (Friis, 2014)

d. Identification of special agents of disease- in the late 1800’s, Robert Koch verified that a human disease was caused by a specific living organism. His postulates advanced the theory of specific disease agents. This breakthrough made possible greater refinement of the classification of disease by specific casual organisms. Koch's postulates are the following:

• The microorganism must be found in abundance in all organisms suffering from the disease, but should not be found in healthy organisms.
• The microorganism must be isolated from a diseased organism and grown in pure culture.
• The cultured microorganism should cause disease when introduced into a healthy organism.
• The microorganism must be reisolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent