Theories of disease causation Presented by: Monika sharma M.Sc. Nursing 1st year
INTRODUCTIONDisease is a dynamic process and it is just opposite tothe health. Health denotes perfect harmony and normalfunctioning of all the body system or state of completewellness whereas disease denotes disharmony anddeviation from normal functioning of various bodyfunctioning system.
DEFINITION OF DISEASE: According to webster , “disease is a condition in which body health is impaired, a departure from state of health, an alteration of human body function and interrupting the performance of vital function".
CONT… According to oxford English dictionary ,”disease is a condition of body or some part of body or organ of body in which its function are disrupted”. OR According to ecological point of view, “ disease is a maladjustment of the human organism to the environment”
CONT… Before the discovery of micro-organism (bacteria by loies pasture in 1822-1895)several theories explaning the cause of disease were put forward time to time
germ theory epidemiological triad multifactorial causation theory web of causation devers epidemiological model
THE GERM THEORY: According to this theory, there is one single specific cause of every disease. This refers to one to one relationship between the causative agent and disease.
CAUSATIVE AGENT MAN DISEASECAUSE EFFECT(FOR EX..DIPTHERIA DUE TO CORNEBACYERIUMDIPTHERIA)
THEORY OF EPIDEMIOLOGICAL TRIAD : According to this theory, every one 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 contribute to disease.
MULTIFACTORIAL CAUSATIONTHEORY: Epidemiological theory is not applicable for non infectious and chronic diseases like coronary artery diseases etc. because it has many causes or multiple factors. This theory helps to understand the various associated causative factors, prioitise and plan preventive and plan measures to control the disease.
WEB OF CAUSATION Given by macmohan and pugh. according to him disease never depends upon single isolated cause rather it develops from a chain of causation in which each link itself is a result of complex interaction of preceding events these chain of causation which may be the fraction of the whole complex is known as web of causation.
DEVERS EPIDEMIOLOGICAL MODEL This model is composed of four major categories of factors human biologylifestyle,environment andhealth system.
CONT…. all these factors influence health status positively or negatively. Human biological --- epidemiological triad and include genetic inheritance, complex physiological systems, factors related to maturation and ageing Life style factors include daily living activities, customs, traditions, health habits etc
CONT… . Environmental factors include physical, biological, social and spiritual components Health care system factors include availability, accessibility, adequacy and use of health care services at all levels.
SPECTRUM OF DISEASE: “Spectrum of disease” is the graphical representation of variation in the manifestations of disease.
CONT… At one end of disease spectrum are subclinical infections which are not ordinarily identified and at the other end are fatal illness.. In the middle of the spectrum lie illness ranging in severity from mild to severe.
ICEBERG OF DISEASE: To this the disease can be closely related with an iceberg. The floating tip of the iceberg represents what the physician sees in the community i.e. clinical cases.
CONT… The vast submerge portion of the iceberg represents the hidden mass of disease i.e. latent, unapparent, presymptomatic and undiagnosed cases and carrier in the community. he waterline represents the demarcation between apparent and unapparent diseases
ROLE OF NURSE IN PREVENTION OF DISEASE: participate in early diagnosis and treatment. notification of certain specific diseases. identify source of infection and method of spread. health education of people in general. control of communicable diseases .
SUMMARIZATION: Introduction Definition of disease Various theories of disease causation - germ theory -epidemiological triad - multifactorial causation theory -web of causation
CONT… - deversepidimiological model Role of nurse in disease prevention Spectrum of disease Iceberg of disease
BIBLIOGRAPHY Gulani k.k.community health nursing.2009(new delhi):kumar publishing house.21-23 Park k .preventive and socialmedicine. 2007(New Delhi):banarsidas bhanot.24-28