Post on 06-Sep-2015
Kapita Selekta Epidemiologi
Dr. Efyluk Garianto, M.Kes
Epidemiology Comes from Greek words
epi, meaning on or upon demos,meaning people logos, meaning the study of
Study of distribution and determinants of health-related conditions or events in populations
Ilmu yang mempelajari distribusi dan faktor-faktor penentu dari suatu kondisi atau kejadianyg berkaitan dengan kesehatan pd suatu populasi
Distribusi penyakit/masalah kesehatan
Menurut orang (umur, jenis kelamin, ras, status sosial, dll
Menurut tempat (Desa, kota, pesisir, pegunungan, sekolah, asrama, LP, tempatlahir, RS, dll)
Menurut waktu (hari, bulan, tahun, musim, dll)
Common Terms
Descriptive Epidemiology
organize and summarize data according to time, place, and person Time disease rates change over time the
seasonal increase in influenza with the onset of cold weather
time data is usually shown on a graph
Place - describe a health event by place to gain insight into the geographical extent of the problem. Residence Birthplace place of employment school district hospital unit, etc
Person
inherent characteristics of people Age Race Sex
Causation
cause of disease is a factor (characteristic, behavior, event, etc.) that influences the occurrence of disease An increase in the factors leads to an
increase in disease. Reduction of the factors leads to a reduction
in disease
Epidemiologic triangle
traditional model of infectious disease causation.
AgentAgent
HostHost EnvironmentEnvironment
Agent
Infectious microorganism - must be present for disease to occur Virus Bacterium Parasite other microbe
AgentAgent
HostHost EnvironmentEnvironment
Host factors
Intrinsic factors that influence an individuals exposure, susceptibility, or response to a causative agent. Age Race Sex socioeconomic status behaviors
AgentAgent
HostHost EnvironmentEnvironment
Environmental factors
Extrinsic factors which affect the agent and the opportunity for exposure
physical factors biologic factors socioeconomic factors
AgentAgent
HostHost EnvironmentEnvironment
Epidemiology and Disease
Chain of Infection
ReservoirReservoir
Mode of Mode of TransmissionTransmission
Susceptible Susceptible HostHost
Mode of Mode of TransmissionTransmission
Chain of Infection
reservoir of an agent is the habitat in which an infectious agent normally lives, grows, and multiplies.
Portal of Entry is the path by which an agent enters a susceptible host
Portal of exit is the path by which an agent leaves the source host
Pat
hoge
n R
eser
voirs
Humans are the most important reservoir of human infectious disease.
Por
tals
of E
xit
Por
tals
of E
ntry
Por
tals
of E
ntry Many
organisms that cause one disease if they enter one body site are harmless if they enter another, e.g., various enteric urinary-tract pathogens.
Chain of Infection Modes of transmission
Direct immediate transfer of the agent from a reservoir to a susceptible host by direct contact or droplet spread
Direct contact Droplet spread
Indirect an agent is carried from a reservoir to a susceptible host by suspended air particles or by animate (vector) or inanimate (vehicle) intermediaries
Airborne Vehicleborne Vectorborne Mechanical
Biologic
Mod
es o
f Tra
nsm
issi
on
Chain of Infection
Portal of entry means by which an agent enters a susceptible host
Host individual infected with the agent
Epidemic Disease Occurrence Level of Disease - amount of a particular
disease that is usually present in a community
SporadicSporadic
EndemicEndemic
EpidemicEpidemic
PandemicPandemicIncreasing amount of diseaseIncreasing amount of disease
Sporadic - irregular pattern of occurrence, with occasional cases occurring at irregular intervals
Endemic - persistent level of occurrence with a low to moderate disease level
Epidemic or Outbreak- occurrence of a disease within an area is clearly in excess of the expected level for a given time period
Pandemic - an epidemic spreads over several countries or continents, affecting a large number of people
Pat
hoge
n Tr
ansm
issi
on
ZoonosesZoonoses are Human Diseases with Animal Reservoirs.
ZoonosesToxoplasmosis
Contact Transmission
Rhinovirus?
Dire
ct-C
onta
ct T
rans
mis
sion
Dire
ct F
ecal
-Ora
l Tra
nsm
issi
on
Giardiasis in daycare centers.
Indirect-Contact Transmission
Beddings are an example of a Fomite, an inanimate object that can transmit pathogens between people.
Methicillin-resistant Staphylococcus aurius(MRSA)?
Indirect-Contact Transmission
Door knobs are another good example of a fomite.
Influenza virus?
Droplet Transmission
Measles?
Airborne Transmission
Mycobacterium tuberculosis?
Airborne Transmission
Contact with air from small room containing 12 people.
Contact with air from clean, empty room.
Wat
erbo
rne
Tran
smis
sion
Cryptosporidium parvum?
Wat
erbo
rne
Tran
smis
sion
Giardiasis from water.
Food
born
e Tr
ansm
issi
on
Hepatitis A
Food
born
e Tr
ansm
issi
on
Balantidium coli
Types of Epidemiological Studies
Type
s of
Epi
dem
iolo
gcal
Stu
dies q Descriptive studies are simply those that describe the
events and rates of disease. They tend to be the first sets of studies done. Quoted or paraphrased from http://dante.med.utoronto.ca/doch/Year1/EPIModule/Part6a.htm
q Observational/Analytical studies then look towards finding out the causes of the observed rates. They are called "observational" since the epidemiologist does not intervene in the assignment of exposure.
q Experimental studies are formal research experiments. The classic example is the randomized control trial where one group is randomly assigned a treatment and a control group gets the placebo or "usual" treatment.
q Experimental studies are expensive and test a very specific question. Usually a great deal of descriptive and observational studies are done first.