Disease and illness occurance.pdf

MHBE 2013 BASIC EPIDEMIOLOGY ;
Disease and illness occurrence
(2 Hour)
Institut Latihan Kementerian Kesihatan Malaysia (ILKKM)
Prog : Diploma in Medical And Health Science (DPMH)
Year 1 Sem I

Learning outcome (LO) ;
i. Discuss biomedical model and biopsychosocial
model that influence management of disease.
ii. Describe natural history of disease process in
human.
9/10/2020 ILKKM ; DPMH ; MHBE 2013 Basic Epidemiology 2

Content outline :
1. Difference between illness
and disease.
2. Model of disease and illness.
3. Natural history of disease.
4. Disease occurrence.

Definiton ILLNESS and DISEASE;
1. ILLNESS as a state where the person
has feelings of pain or discomfort that
does not have an identifiable reason.
2. DISEASE refers to a condition where
the body or the parts of the body of a
person does not work properly. There is
usually a pathological reason behind
the condition.

• Illness is a condition in which
the body or mind is harmed because
an organ or part is unable to work as it usually.
• Disease is a condition of a person in
which its body or structure is harmed because
an organ or part is unable to work as it usually
(source ; dictionary.cambridge)
Con’t …Definiton ILLNESS and
DISEASE;

More differentiation ;
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More differentiation ;

Model of human healthy to unhealthy to illness
to disease ;
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Models of diseases and illness ;
• The biomedical model of disease has dominated
medical thinking since the time of Louis Pasteur
(1822-1895) and the microbiological revolution.
“ This model focuses on pathological processes, and
on understanding, diagnosing, and treating the
physical and biological aspects of disease”
• The GOAL OF TREATMENT is to restore the
patient’s physiological integrity and function.

These are 6 model:
1. Religious
2. Biomedical
3. Psychosomatic
4. Humanistic
5. Existential
6. Transpersonal
Models of diseases and illness ;
Source ; Tamm, M. E. (1993). Models of health and disease.
British Journal of Medical Psychology, 66(3), 213–228.

The model of Biomedical ;
• In 1977, psychiatrist George L. Engel
questioned the dominance of the
biomedical model, proposing the BIO
PSYCHOSOCIAL model to holistically
assess a patient's biological, social,
psychological, and behavioural
background to determine his or her
illness and path of treatment.
• Nowadays - Biopsychosocial-spiritual.

Def; The progression of a disease process in an
individual over time, in the absence of treatment /
intervention.
There are four stages in the natural history of a
disease:
1. Stage of susceptibility .
2. Stage of pre-symptomatic (sub-clinical)
disease.
3. Stage of clinical disease .
4. Stage of recovery or disability or death.
Natural History Of Disease ;

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Cont’….natural history of a disease
1 2 3 4

Source : Judith Allender et al.(2014). Community & Public Health Nursing: Promoting The Public's Health 8th edi.
Lippincott Williams & Wilkins.
Cont….Natural History Of Disease ;
Death or
Disability

1. Stage of susceptibility ; The process begins with the
appropriate exposure to or accumulation of factors
sufficient for the disease process to begin. eg ; smoking
initiate to a cancer.
2. Stage of pre-symptomatic (sub-clinical) disease ;
Pathological changes then occur without the individual
being aware (ASYMTOMATIC) of them, extending from
the time of exposure to onset of disease symptoms. In
infectious disease it is called the INCUBATION PERIOD,
for chronic disease it is called LATENCY PERIOD. eg ;
carcinogen agent become make changing DNA.
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3. Stage of clinical disease ; The onset of
symptoms marks the transition from subclinical
to clinical disease. Most diagnoses are made
during the stage of clinical disease. Illness
RANGES from mild to severe or fatal is called
the spectrum of disease.
4. Stage of recovery or disability or death ;
The disease process ends.
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Terminology For an infectious agent ;
1. INFECTIVITY refers to the proportion of
exposed persons who become infected.
2. PATHOGENICITY refers to the proportion of
infected individuals who develop clinically
apparent disease.
3. VIRULENCE refers to the proportion of
clinically apparent cases that are severe
or fatal.
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Carriers in SUB CLINICAL DISEASE;
Persons with in apparent or
undiagnosed infections may
nonetheless be able to transmit
infection to others.
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Exposure Clinical Effect Incubation/Latency Period
Saxitoxin and similar toxins
from shellfish
Paralytic shellfish poisoning (tingling,
numbness around lips and fingertips,
giddiness, incoherent speech, respiratory
paralysis, sometimes death)
few minutes–30 minutes
Organophosphorus ingestion Nausea, vomiting, cramps, headache,
nervousness, blurred vision, chest pain,
confusion, twitching, convulsions
few minutes–few hours
Salmonella Diarrhea, often with fever and cramps usually 6–48 hours
SARS-associated corona virus Severe Acute Respiratory Syndrome (SARS) 3–10 days, usually 4–6 days
Varicella-zoster virus Chickenpox 10–21 days, usually 14–16
days
Treponema pallidum Syphilis 10–90 days, usually 3 weeks
Hepatitis A virus Hepatitis 14–50 days, average 4 weeks
Hepatitis B virus Hepatitis 50–180 days, usually 2–3
months
Human immunodeficiency
virus
AIDS <1 to 15+ years
Atomic bomb radiation (Japan) Leukemia 2–12 years
Radiation (Japan, Chernobyl) Thyroid cancer 3–20+ years
Radium (watch dial painters) Bone cancer 8–40 years
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Discuss the Challenges ;
These carriers, unaware that they are
infected and infectious to others, are
sometimes more likely to unwittingly
spread infection than are people with
obvious illness.
Discuss ; Given few opinion how we can
trace the carriers and how to make
prevention.
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History of disease ;
1. Koch's postulates: In 1890 the German physician and
bacteriologist Robert Koch set out his celebrated criteria for
judging whether a given bacteria is the cause of a given disease.
2. A pump memorializing John Snow for his study of contaminated
water as a likely source of cholera during the 1854 Broad Street
Cholera outbreak
3. In 1961, researchers in Japan correlated elevated urinary
Mercury levels with the features of the previously mysterious
Minamata disease. Before the etiology of Minamata disease
was discovered, it plagued the residents around Minamata Bay
in Japan with tremors, sensory loss, ataxia, and visual field
constriction
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Movement of Pathogen Out of Host ;
Transmitted disease
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The disease ;
Causes;
1. Genetic , eg ; expose radiation.
2. Biological, eg ; expose pathogen.
3. Chemical, eg ; expose of Hcl Acid.
4. Physical , eg ; lack physical active.
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Type of Disease occurrence:
1. Infectious disease, eg; Cholera
2. Chronic disease, eg ; Diabetes Mellitus
3. Genetic disease and In born errors, eg ;
Down Syndrome.

Cont’..Disease occurrence:
1. Infectious disease,
Are disorders caused by organisms — such as bacteria, viruses,
fungi or parasites.
Many organisms live in and on our bodies.
They're normally harmless or even helpful. But under certain
conditions, some organisms may cause disease.
Some infectious diseases can be passed from person to
person. eg; Cholera.

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2. Chronic disease,
Chronic diseases are defined broadly as conditions that last 1 year
or more and require ongoing medical attention or limit
activities of daily living or both. eg ; Diabetes Mellitus
Source ; National Centre for Chronic Disease Prevention and Health Promotion (NCCDPHP)

3. Genetic disease;
A genetic disorder is a genetic problem caused by one or more
abnormalities formed in the genome. Most genetic
disorders are quite rare and affect one person in every
several thousands or millions.
Genetic disorders may be hereditary or non-
hereditary, meaning that they are passed down from the
parents' genes.

Student reading/ priority references :
Book / Journal / Article
No References
1. Gordis Leon (2013) Epidemiology, 5th edition,Elsevier
Suander,USA.
2. William C. Cockerham (2016) Medical sociology 13th edition,
Routledge,USA
3. Schneider.M.J(2014),Introduction to public health (4th
Edition),Jones & Bartlett Learning,USA
Internet/ e book/ online
No References
1. http://www.moh.gov.my/
2. https://www.who.int/
3. https://books.google.com.my/books?id=AXZz6JIV9ikC&pri
ntsec=frontcover#v=onepage&q&f=false
4. https://www.cdc.gov/csels/dsepd/ss1978/lesson1/section9.
html

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Recommendation for student Independent Learning (IL) ;
Activities Source
1. Search and download https://www.cdc.gov/csels/dsepd/ss1978/index.ht
ml
2. Reading related topic As above
3. Make short note related
topic
As above
4. Discus and answer
Exercise 1.10
https://www.cdc.gov/csels/dsepd/ss1978/lesson1
/section11.html
5. Terminology and
Definitions
Page slide 32 – 33 either one
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Independent learning (IL) ;Terminology and Definitions
1. Infection
2. Contamination
3. Infestation
4. Contagious disease
5. Incidence and prevalence
of infectious diseases
6. Epidemic
7. Endemic
8. Hyperendemic
9. holoendemic
10. Pandemic
1. Exotic
2. Sporadic
3. Attack rate
4. Primary/secondary cases
5. Zoonosis, epizootic and
enzootic
6. Nosocomial infection
7. Opportunistic infection
8. Eradication
9. Elimination

1. Virulence
2. Reproductive rate of
infection
3. Host
4. Vector (source)
5. Reservoir
1. Incubation period
2. Infectivity period
3. Serial interval
4. Latent period
5. Transmission Probability
ratio
Independent learning (IL) ;Terminology and Definitions

Disease and illness occurance.pdf

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