This document discusses patterns of disease occurrence, including endemic, epidemic, and pandemic diseases. It defines each term and provides examples. Endemic diseases have a constant presence in a population within an area. Epidemics occur when a disease exceeds normal levels in a community or region. Pandemics are global epidemics that spread over multiple countries. The document outlines the World Health Organization's phases of a pandemic and describes pandemics such as the 2009 H1N1 influenza outbreak. It recommends references for further reading on epidemiology concepts.

1. Institut Latihan Kementerian Kesihatan Malaysia (ILKKM)
Prog : Diploma in Medical And Health Science (DPMH)
Year 1 Sem I
MHBE 2013
BASIC EPIDEMIOLOGY ;
Pattern of disease occurrence
(1 Hour)

2. Learning outcome (LO) ;
i. Compare occurrence of the endemic, epidemic,
and pandemic.
ii. Describe WHO phase of pandemic stages.
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3. Content outline;
i. Overview level of infectious disease.
ii. Endemic.
iii. Epidemic.
iv. Pandemic and phases pandemic by
WHO.
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4. Overview level of disease ;
• The amount of a particular disease that is usually present in
a community is referred to as the baseline or endemic level
of the disease.
• This level is not necessarily the desired level, which may in
fact be zero, but rather is the observed level.
• In the absence of intervention and assuming that the level is
not high enough to deplete the pool of susceptible persons,
the disease may continue to occur at this level indefinitely.
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Epidemiology
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5. Definition of terminology ;
i. Endemic
ii. Epidemic
iii. Pandemic
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6. 1- Endemic ;
 Endemic refers to the constant presence
and/or usual prevalence of a disease or
infectious agent in a population within a
geographic area. Ie; Malaria fever.
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7. Cont’…..1- Endemic ;
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Cont’…..1- Endemic ;

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Cont’…..1- Endemic ;

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Cont’…..1- Endemic ;

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2- Epidemic ;
 Epidemic is defined as the occurrence in a community or
region of a group of illnesses of similar nature, clearly in
excess of normal expectancy , and derived from a common
or from a propagated source. Ie; Severe Aacute Respiratory
Syndrome(SARS) Pandemic.
 Pandemic refers to a worldwide epidemic.
 Also refers to an increase, often sudden, in the number of cases
of a disease above what is normally expected in that population in
that area.
 The previous description of epidemics presumes only infectious agents,
but non-infectious diseases such as diabetes and obesity exist in epidemic
proportion in the U.S

13. Cont’ …. 2- Epidemic ;
• Epidemics occur when an agent and susceptible hosts are present
in adequate numbers, and the agent can be effectively conveyed
from a source to the susceptible hosts.
• Outbreak carries the same definition of epidemic, but is often
used for a more limited geographic area. ie; cholera outbreak
at penang.
• Cluster refers to an aggregation of cases grouped in place and
time that are suspected to be greater than the number expected,
even though the expected number may not be known. Ie; Cholera
outbreak in London (large population).
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14. More specifically, an epidemic may result from:
1. A recent increase in amount or virulence of the agent,
2. The recent introduction of the agent into a setting where it has
not been before,
3. An enhanced mode of transmission so that more susceptible
persons are exposed,
4. A change in the susceptibility of the host response to the agent,
and/or
5. Factors that increase host exposure or involve introduction
through new portals of entry
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Cont’ …. 2- Epidemic ;

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3- Pandemic ;
Pandemic refers to an
epidemic that has spread
over several countries or
continents, usually affecting
a large number of people.

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Cont’….3- Pandemic ;
The 2009 flu outbreak in Malaysia is
part of a larger flu pandemic involving a
new type of influenza A virus subtype
H1N1 (A (H1N1)) virus.

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Cont’….3- Pandemic ;
Source ; Global Alert and
Response (GAR) Pandemic and
Epidemic Diseases Pandemic
(H1N1) 2009

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Cont’…. Pandemic stage;
Source ; Illustration of WHO Pandemic Influenza Phases (2009)

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Cont’….3- Pandemic ;

20. The best reading include ;
1. Global Outbreak Alert and Response Network
(GOARN)
2. The International Health Regulations (2005) or
"IHR (2005)"
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21. 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
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Internet/ e book/ online
No References
1. http://www.moh.gov.my/
2. https://www.who.int/
https://www.ncbi.nlm.nih.gov/books/NBK143061/
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/section1
1.html
5. https://accessmedicine.mhmedical.com/content.aspx?boo
kid=337&sectionid=39810361

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23. Recommendation for student Independent Learning (IL) ;
Activities Source
1. Search and
download
• https://www.cdc.gov/csels/dsepd/ss1978/lesson1/section8.html
2. Reading, making
short note on
related topic
As above and,
• https://www.cdc.gov/csels/dsepd/ss1978/lesson1/section11.html
• https://www.who.int/csr/disease/swineflu/phase/en/
• https://www.who.int/csr/alertresponse/en/
3. Discus and
answer
Exercise 1.10
• https://www.cdc.gov/csels/dsepd/ss1978/lesson1/section11.html
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