CHAP 10 DISEASE

DISEASE

is defined as the absence or lack of health of an individual or an organism which can be either physical or mental

1. Pre-modern era (Before 1850s)
2. Modern

2 THEORIES OF DISEASE CAUSATION

1. Demonic theory
2. Punitive theory
3. The miasmatic theory
4. Humorism

PRE-MODERN ERA

DEMONIC THEORY (WITCHCRAFT)

Disease was believed to be caused by demons, evil spirits, and other similar forces that simply aim to cause disease or misfortune to humans. This belief has led to treatments that involve sorcery, sacrifices and other supernatural practices that is believed to drive away the evil.

PUNITIVE THEORY

- Also known as the divine punishment theory, this theory proposed that disease was caused by punishment of a monotheistic deity that aims to punish humans for angering or offending it and hence, the treatment to diseases was believed to be to make the diseased individual try and appease the deity.

THE MIASMATIC THEORY "BAD AIR" (MAL ARIA)

- and proposes that disease comes from breathing in air from places that were thought to be rich in disease such as swamps, marshes, or any other places where the smell of rotting vegetables, animals, or any form of organic matter may dominate. A notable disease that sparked this theory was cholera, which was observed more frequently in areas near the aforementioned biomes, this, however, though a valid correlation, was not causation.

HUMORISM (INBALANCE)

-This theory proposes that health is determined by the four humors of the body – blood, phlegm, yellow bile, and black bile. This theory was developed by Hippocrates and expanded upon by his student, Galen. Humorism proposes that imbalances in the four humors of the human body causes disease and so the treatment for disease should be tailored to the specific imbalance that occurred be it through environmental means, exercise, diet, or the more common treatment: bloodletting.

blood, phlegm, yellow bile, and black bile

four humors of the body

1. Germ theory of disease
2. Biochemical theory
3. Epidemiological triad
4. Multifactorial causation
5. Web of causation
6. Wheel of disease causation
7. Rothman's component causes and causal pies

MODERN

GERM THEORY OF DISEASE

- This theory replaced the Miasma theory and was proposed in the late 1800s from the works of Louis Pasteur, Agostino Bassi, Ignaz Semmelweis, and most notably Robert Koch. The germ theory of disease proposes that disease is caused by microorganisms that invade the human body. Koch’s postulates elaborate further:

ISOLATE - CULTURE- INFECT- RE-ISOLATE

Louis Pasteur

Robert Koch

Agostino Bassi

Ignaz Semmelweis

PROPOSED THE GERM THEORY

BIOMEDICAL THEORY

- This theory states that disease comes from malfunctions of an otherwise perfectly functioning set of organs that contribute to the overall health of the human body. This theory, however, disregards psychological and social factors and attributes.

EPIDEMILOGICAL TRIAD

This theory considers three factors in disease causation. The host, the environment, and the agent, and that the imbalances in the interaction of these three are what causes disease.

host

environment

agent

EPIDEMILOGICAL TRIAD
- This theory considers three factors in disease causation. The?

MULTIFACTORIAL CAUSATION

- Proposed by Max Von Pettenkofer, this theory highlights the shortcomings of the germ theory of disease in that it proposes that disease is caused by multiple factors instead of just the organism.

Max Von Pettenkofer

MULTIFACTORIAL CAUSATION
- Proposed by

WEB OF CAUSATION

- An integration of social factors and biomedical etiologic factors proposed by MacMahon, Pugh, and Ipsen in 1960, this theory proposes that disease causation is not linear but rather a web of complex precursors that interact with each other leading to disease. This web of causation gives equal importance to each component in the interaction to recognize the correct determinants and thereby aid in planning interventions.

MacMahon, Pugh, and Ipsen

WEB OF CAUSATION
- An integration of social factors and biomedical etiologic factors proposed by

WHEEL OF DISEASE CAUTION

- Proposed by Mausner and Kramer in 1985, this theory emphasizes the complex interactions of physical, biological, and social environments. This theory also integrates genetics as the core surrounded by the different physical, social, and biological factors.

Mausner and Kramer

WHEEL OF DISEASE CAUTION
- Proposed by

ROTHMAN'S COMPONENT CAUSES AND CAUSAL PIES

- Proposes that disease is caused by a collection of causal factors. These causal factors are then subdivided into necessary and sufficient causes. Necessary cause should be present in all cases of the disease while sufficient causes may or may not be present in cases of the same disease. This therefore states that removal of the necessary cause or some of the component causes (the group of sufficient causes) can prevent or cure the disease.