This document discusses traditional theories of disease occurrence, including supernatural, contagious, and germ theories. It provides definitions of disease and outlines factors that were traditionally believed to cause illness such as punishment from gods, witchcraft, or moral failings. The document also summarizes the germ theory and its role in establishing microbes as the cause of many diseases. Additionally, it introduces the multiple causation theory which recognizes an interplay between agents, hosts, and environments in disease development.

1. SMART MIND GROUP
COMPILED AT LUPANE STATE
UNIVERSITY, ZIMBABWE BY:

2. TRADITIONAL THEORIES OF DISEASE
OCCURANCE
• WHAT IS A DISEASE?
• ACCORDING TO OXFORD DICTIONARY, ‘THE TERM DISEASE REFERS TO THE
CONDITION OF BODY OR SOME PARTS OF BODY OR ORGAN OF BODY IN WHICH
ITS FUNCTION ARE DISRUPTED.’
• ACCORDING TO ECOLOGICAL POINT OF VIEW, ‘ DISEASE IS A MALADJUSTMENT
OF THE HUMAN ORGANISM TO THE ENVIRONMENT.’
• ACCORDING TO WEBSTER, ‘ IT IS A CONDITION IN WHICH BODY FUNCTION IS
IMPAIRED, DEPARTURE FROM A STATE OF HEALTH AND AN ALTERATION OF THE
HUMAN BODY INTERACTING THE PERFORMANCE OF THE VITAL FUNCTIONS.’
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3. CONT’
• BEFORE THE RISE OF MODERN MEDICINES DISEASE WAS ATTRIBUTED TO A
VARIETY OF SPIRITUAL OR MECHANICAL FORCES INCLUDING:
A PUNISHMENT FROM GOD FOR A SINFUL BEHAVIOR
WEAK MORAL CHARACTER
WITCHCRAFT
• THEREFORE THE ABOVE MENTIONED CAUSES ARE CATEGORIZED UNDER THE
SUPERNATURAL THEORY.
• ACCORDINGLY, PEOPLE USED TO PLEASE GODS BY PRAYERS AND OFFERINGS OR
USED TO RESORT TO WITCHCRAFT TO TAME THE DEVILS.
SMART MIND GROUP

4. •
• SUPERNATURAL IS THE OLDEST EXPLANATION OF DISEASES OCCURRENCE THAT DATES TO
PREHISTORY TIMES.
• THERE ARE DIFFERENT BELIEFS IN THE CAUSES OF ILLNESS, THESE BELIEFS VARY AS SOME ARE
INFLUENCED BY REGION OR CULTURE.
• SUPERNATURAL BEINGS ARE SAID TO BE THE MAIN CAUSE OF DISEASES IN THIS THEORY.
• THIS THEORY POSTULATES THAT DISEASES ARE ATTRIBUTED TO ANCESTRAL SPIRITS AND
WITCHCRAFT.
• THE SICK WERE THOUGHT TO BE POSSESSED BY DEMONS.
• THE THEORY IS WEAK IN THE SENSE THAT IT LACKS SCIENTIFIC EXPLANATION IN DISEASE
OCCURRENCE.
• SICKNESS WAS SEEN AS A FORM OF PUNISHMENT FORM THE GODS.
• THE THEORY IS ALSO SUBJECT TO CRITICISM BECAUSE OF THE FACT THAT ILLNESS WAS
BELIEVED TO BE A SIGN OF BAD LUCK OR BAD KARMA.
• THE ANCIENT GREEKS REJECTED THE THEORY BY REFUSING THE NOTION THAT DISEASES WAS
A PUNISHMENT FOR SIN OR THE CONSEQUENCE OF WITCHCRAFT AND SAW DISEASES AS BEING
RELATED TO THE NATURAL ENVIRONMENT OR THE WAY HUMAN POPULATION LIVED AND
WORKED OPENING A ROOM FOR THEORIES LIKE THE GERM THEORY.
SMART MIND GROUP

5. SMART MIND GROUP

6. • MICROBES (GERMS) WERE FOUND TO BE THE CAUSE FOR MANY KNOWN
DISEASES. PASTEUR, HENLE AND KOCH WERE THE STRONG PROPONENTS OF
MICROBIAL (GERM) THEORY AFTER THEY DISCOVERED THE MICRO-ORGANISMS
IN THE PATIENTS’ SECRETIONS OR EXCRETIONS.
• HENLE AND KOCH HAVE POSTULATED THAT EACH DISEASE IS CAUSED BY A
GERM; WITHOUT THAT GERM THAT DISEASE WILL NOT BE CAUSED; BY
INTRODUCING THAT GERM THAT DISEASE CAN BE CAUSED IN ANIMALS
EXPERIMENTALLY AND THAT GERM CAN AGAIN BE ISOLATED FROM THAT SICK
ANIMAL EXPERIMENTED WITH.
• DESPITE THE SPICES BROUGHT BY THIS THEORY, THERE ARE WEAKNESS SUCH AS:
IT FAILED TO ADDRESS SOME ISSUES FOR INSTANCE, IT DOESN’T EXPLAIN THE
EXCEPTIONS AND THE ANOMALIES AND THAT THE DISEASE CAN BE CAUSED BY
MORE THAN ONE FACTOR THUS IT WAS FURTHER IMPROVED BY BELIEFS
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7. CONT’
• WHICH STATED THAT GERMS, HOST AND ENVIRONMENT THEY WORK HAND IN
GLOVE IN CAUSING A DISEASE THUS TERMED THE MULTIPLE CAUSATION THEORY.
• THIS STATES THAT THE OCCURRENCE OF A DISEASE IS A RESULT OF AN INTERPLAY
OF A NUMBER OF FACTORS. THUS THE DEVELOPMENT OF A DISEASE IS DEPENDENT
ON THE COMPLEX INTERACTION BETWEEN THE AGENT, HOST AND ENVIRONMENT.
THIS KIND OF RELATIONSHIP IS KNOWN AS THE EPIDEMIOLOGICAL TRIANGLE.
• ANY CHANGE IN ANY ONE OF THE ELEMENTS WILL INFLUENCE THE OCCURRENCE OF
A DISEASE EITHER BY INCREASING OR DECREASING THE HOST PRONENESS FOR
EXAMPLE, LUNG CANCER IS CAUSED BY CONSTILATION OF CAUSES LIKE SMOKING,
UNFILTERED CIGARETTES AND THE 10 YEARS DURATION OF HOST VULNERABILITY.
SMART MIND GROUP

8. Bacteria
Viruses
Fungi
Age
Sex
Health
Behavior Immunity
Genetic makeup
Air
Water
Sanitation
Noise
SMART MIND GROUP

9. CONTAGIOUS THEORY
• IT STATES THAT A DISEASE IS CAUSED BY CONTACT THUS THE DISEASE COULD
BE SPREAD FROM ONE INDIVIDUAL TO ANOTHER THROUGH COMING INTO
CONTACT WITH AN INFECTED INDIVIDUAL.
• CONTAGIOUS DISEASES SUCH AS EBOLA AND CHICKEN POX ARE GOOD
EXAMPLES.
• HOWEVER THIS THEORY FAILED TO ACKNOWLEDGE THE FACT THAT NOT ALL
DISEASES ARE CONTAGIOUS THOUGH IT GAVE A CLEAR AWARENESS THAT
DISEASES CAN BE SPREAD CONTAGIOUSLY.
SMART MIND GROUP

10. MORDEN THEORY
• IT REFERS TO THE SHIFTING LEVEL OF ANALYSIS LEVEL OF INDIVIDUAL TO
POPULATION.
• EPIDEMIOLOGY HAS CEASED TO LIVE AT MULTIDISCIPLINARY APPROACH TO
UNDERSTAND THE CAUSATION OF THE DISEASE IN POPULATION BUT RATHER IT
HAS CONCENTRATED IN INDIVIDUALS.
SMART MIND GROUP

11. EPIDEMIC AND DISEASE MANAGEMENT
• EPIDEMICS IT IS A SUDDEN AND UNEXPECTED INCREASE OF A DISEASE OF
HEALTH RELATED EVENTS IN AN UNIDENTIFIED AREA.
• SEVERITY OF INCREASE AND SPREAD DEPENDS ON THE GEOGRAPHIC LOCATION,
ENVIRONMENTAL CONDITIONS, DISTRIBUTION OF HOST AND SOCIO-CULTURAL
BEHAVIOR OF PEOPLE.
• MANAGEMENT OF EPIDEMICS INVOLVES THE STEP BY STEP ACTIVITIES STARTING
FROM FORECASTING TO PREVENTION FOR FUTURE OCCURRENCE.
TYPES OF EPIDEMICS
1. COMON SOURCE EPIDEMIC
• POINT OR SINGLE EXPOSURE
• MULTIPLE EXPOSURE FROM VIABLE SOURCESMART MIND GROUP

12. CONT’
2. PROPAGATED EPIDEMIC
3. SEASONAL EPIDEMIC
4. CYCLIC EPIDEMIC
5. EPIDEMIC OF NON-COMUNICABNLE DISEASE
EPIDEMIC MANAGEMENT STEPS
EPIDEMIC
MANAGEMENT
INVESTIGATING
CONTROLLING
PRENVENTION
FORECASTING
SMART MIND GROUP

13. FORECASTING EPIDEMIC
• FORECASTING IS AN EARLY WARNING SYSTEM TO HET PREPARED TO MEET THE
CHALLENGE OF IMPENDING EPIDEMICS.
• IT IS MORE APPROPRIATE IN CYCLIC AND SEASONAL EPIDEMICS WHERE THE PATTERN
HAS BEEN STUDIED FROM THE PAST DATA.
• BY FORECASTNG ONE MAY NOT TOTALLY PREVENT THE EPIDEMICS BUT DEFINITELY
CONTROL ITS SEVERITY AND SPREAD TO OTHER AREAS.
• THERE ARE VARIOUS METHODS NEEDED FOR FORECASTING TO BE COMPLETED:
I. STUDY OF INCIDENCE AND PREVALENCE RATE
II. DISEASE SPECIFIC MORBIDITY AND DISEASE SPECIFIC MORTALITY
III. TABULATE DATA FOR FUTURE USE COMPARISON
IV. COLLECTED DATA PLOTTED ON GRAPH FOR IMMEDIATE DETECTION AND VISUAL
APPRECIATION THROUGH TREND ANALYSIS OF THE DISEASE
V. PLOT DATA ON MAP OF LOCAL AREA WHICH HELPS IN IMMIEDIATE ASSESMENT,
WHETHER THE CASES ARE GROUPED OR CLUSTERED.
VI. DEVELOPING A SURVEILLANCE SYSTEM FOR CONTINOUS DATA REPORTING AND
OBSERVETION.
SMART MIND GROUP

14. CASE INVESTIGATION
• IN AN UNFORTUNATE OCCURANCE OF AN EXPECTED EPIDEMIC, THE CASE
INVESTIGATION MUST BE STARTED TO CONFIRM THE OUTBREAK.
STEPS TAKEN IN INVESTIGATING
 VERIFICATION OF DIAGNOSIS
CONFIRMATION OF EXISTENCE OF EPIDEMICS(BY CLINICAL TEST OR LAB TEST)
DEFINING THE POPULATION AT RISK
RAPID SEARCH FOR ALL CASES IN THE AREA(ASKING QUESTION LIKE WHEN, HOW
MANY AND WHO ARE AFFECTED)
ANALYSIS OF DATA
FORMULATE AND TESTING OF HYPOTHESIS
EVALUATE ECOLOGICAL FACTORS
EXPAND THE SEARCH IN OTHER AREAS.
WRITE A GOOD REPORT
SMART MIND GROUP

15. CASE INVESTIGATION CYCLE
CASE
INVESTIG
ATION
DEFINE
POPULATI
ON AT
RISK
START
SCREENIN
G OF
AREA
PREPARE
FOR
EPIDEMIC
CONFIRM
EXISTENC
E
SMART MIND GROUP

16. PREPAREDNESS OF EPIDEMICS
• ONCE THE EPIDEMIC IS SUSPECTED AND CAUSE IDENTIFIED, ACTION SHOULD BE TAKEN, TO
CONTROL IT BY:
 DRUGS OR IMMUNIZATION
 INVESTIGATIONS
 SETTING UP A SURVEILLANCE CENTERS
 PUBLIC EDUCATING THROUGH MEDIA
 TRAINING OF MEDICAL AND PARAMEDICAL STAFF
CONTROL OF EPIDEMICS
• TO CONTROL AN EPIDEMIC ONE MUST HAVE THE INFORMATION ON:
 CAUSATION ORGANISM OR SOURCE
 DISEASE TRANSMISSION
 MODE OF TRANSMISSION(DIRECT CONTACT OR INDIRECT CAN BE VIA SKIN CONTACT, BLOOD,
URINARY TRACT OR RESPIRATORY TRACT).
 REMOVAL OF SOURCE OF INFECTION ( TREATMENT OF INFECTED SOURCES)
 PREVENTION OF TRANSMISSION ( HAND WASHING, IMPROVE SANITATION AND HEALTH
EDUCATION)
 VECTOR CONTROL MEASURES (PREVENT BREEDING OF VECTORS FOR EXAMPLE MOSQUITOES BY
SMART MIND GROUP

17. PREVENTING MEASURES
• THERE'S A SAYING, ‘ THE MORE YOU SWEAT DURING PEACE, LESS YOU BLEED
DURING WARS’. APPROPRIATE MEASURES AT RIGHT TIME, RIGHT PLACE IN RIGHT
QUANTITY CAN PREVENT THE SEVERITY OF ANY EPIDEMIC.
PERSONAL MEASURES
o NUTRITIONAL DIET
o REGULAR YOGA OR EXERCISE
o GIVING AWAY ADDICTION
ENVIRONMENTAL MEASURES
o CLEAN WATER SUPPLY
o PREVENT OPEN AIR DEFECATION
o PROPER DISPOSURE OF GARBAGE
o ADEQUATE SEWAGE SYSTEM
o WELL VENTILATED HOUSES AND REGULAR HEALTH EDUCATION TO PUBLIC
THROUGH MASS MEDIA, GROUP MEETINGS AND SEMINARS AND WORKSHOPS.
SMART MIND GROUP

18. SMART MIND GROUP