Multifactorial causation of disease

Multifactorial Causation of Disease

1. MULTIFACTORIAL CAUSATION OF DISEASE SPEAKER:- Dr.KUMAR HIMANSHU PGT-1 ST YEAR DEPT. OF COMMUNITY MEDICINE K.M.C.H,KATIHAR

2. For long time man was grouping in darkness about the causation of diseases, Several theory of diseases were advanced from time to time to Explain disease causation such as:- Supernatural theory Theory of humors by Greek and Indians Theory of contagion The miasmatic theory Theory of spontaneous generation etc INTRODUCTION

3. The breakthrough came in 1860,when French bacteriologist Louis Pasteur demonstrated the presence of bacteria in air. In 1873 he advanced theory of Spontaneous generation .. Later Robert Koch discovered anthrax caused by bacteria and GOLDEN ERA of Bacteriology begun with discovery of microbe after microbe.. Gonnococus in 1879 Typhoid bacillus,Pneumococci in 1880 Tubercle bacillus in 1882 Cholera in 1883 Diptheria in 1884 and so on… Louis Pasteur Germ Theory of Disease

4. All attention was focused on microbes and their role in disease causation, and disease model accordingly is :- DISEASE AGENT MAN DISEASE In 1878 Robert Koch summarized his experiments on the etiology of wound infection,By inoculating animals with material from various sources, he produced six types of infection, each caused by a specific microorganism. He then transferred these infections by inoculation through several kinds of animals, reproducing the original six types. Robert Koch

5. In that study, he observed differences in pathogenicity for different species of hosts and demonstrated that the animal body is an excellent apparatus for the cultivation of bacteria. These theories of Pasteur and Koch confirmed the germ theories of disease. Later, Robert Koch has given Koch Postulates

6. Koch’s postulates, are : A specific microorganism is always associated with a given disease. The microorganism can be isolated from the diseased animal and grown in pure culture in the laboratory. The cultured microbe will cause disease when transferred to a healthy animal. The same type of microorganism can be isolated from the newly infected animal.

7. The Germ theory has many limitation , It was unable to explain Why only some people suffer from the disease after exposure to microorganism and not all,as with exposure to tubercle bacilli. Why some people do not suffer from the disease even through they harbor the pathogen in the body. As in carrier state This lead to demand of a broader concept of disease causation that synthesized the basic factors of Agent , Host and Environment.

8. The limitation of germ theory led to the concept of “ Epidemiological or Ecological Triad ”. According to the theory of Epidemiological triad everyone exposed to disease agent did not contract the disease, This means it is not only the causative agent that is responsible for disease. But there are another Factors also related to Man and Environment which contributes to disease.

9. ENVIORNMENT AGENT HOST The Triangle of Epidemiology

10. AGENT

11. HOST

12. ENVIRONMENT

13. According to this model of Epidemiological triad disease occurs when the equilibrium between agent , host and environment is disturbed. This model explains that some persons do not suffer from the disease even through they harbor the pathogens because an equilibrium is established between the causative agent and the host.

14. Epidemiological triad theory is not applicable for non infectious and chronic diseases like Coronary artery diseaes,Mental illness etc,because these disease has many causes and multiple factors. This led us to think for the Multiple Factors behind a disease causation.

15. The theory of Multifactorial Causation of Disease was first proposed by Galen in 130-150 AD In 1819-1901 ,this theory was again put forward by Peten Kofer of Germany, but this was overshadowed by germ theory at that time. Galen said the factors are:- Predisposing Exciting and Environmental Multifactorial Causation of Disease

16. THESE PREDISPOSING FACTORS ARE:- SOCIAL ECONOMICAL CULTURAL PSYCHOLOGICAL FACTORS (Including poverty,illiteracy,Ignorance , poor living condtion Overcrowding etc)

17. TUBERCULOSIS IS NOT MERELY DUE TO TUBERCLE BACILLI… Factors such as - Poverty , Overcrowding and Malnutrition Contribute to occurrence of tuberculosis

18. Now it is recognized that a disease is not only caused by an organism but also predisposed by many factors contributing to its occurrence . For example:- “Modern Diseases” of civilization like –lung cancer,diabetes,coronary heart disease and mental illness etc has several contributing factors behind for there occurrence.

19. It is now known that diseases such as Coronary heart disease and cancer are due to multiple factors. For Example- Excess of fat (saturated) intake, Smoking ,lack of physical exercise and obesity are involved in the Pathogenesis of Coronary Heart Disease Most of these factors are linked to Lifestyle and human behavior.

20. Causative Factors Group or Popullations and their Charcteristics Enviornment,Behaviour, Culture, Physiological Factors, Ecological Elements Advanced Model Of Triangle of Epidemiology TIME

21. WEB OF CAUSATION This model of disease causation was suggested by Macmahon and Pugh in their book: Epidemiology :Principles and Methods This model is ideally suited in the study of chronic disease, where the disease agent is often not known ,but is the outcome of interaction of multiple factors …

22. The “web of causation” considered all the predisposing factors of any type and their complex inter relationship with each other The figure illustrates the complexities of a casual web of myocardial infarction which is by no means complete)

23. WEB OF CAUSATION OF MYOCARDIAL INFARCTION

24. The basic tenet of epidemiology is to study the clusters of cause and combinations of effects and how they relate to each other casual web provides a model which shows variety of possible interventions that could be taken to reduce the occurrence of disease. The Multifactorial theory helps us to understand the various associated causative factors,prioritize and plan measures to control the disease CONCLUSION

25. References:- 1.Book of Community Medicine with Recent advances by AH Suryakantha 2.Textbook Of Preventive and Social Medicine by – K.Park 3.Image Sources-Wikipedia and Google