1. KONSEP DASAR EPIDEMIOLOGI 2/2014
DISIAPKAN OLEH
PROF. DR.DRH.PRATIWI, TS. MS
DRH.ROSITAWATI, I. MP
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2. Epidemiologic Triad
Disease is the result of forces within a dynamic system consisting of:
agent of infection
host
environment
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4. Infectious disease
Terminology untuk menggambarkan penyakit infeksi berkaitan dengan keadaan dan prevalensi penyakit pada populasi meliputi
Infectivity
Pathogenicity
Virulence
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5. Factors Influencing Disease Transmission
Agent
Environment
Weather
Housing
Geography
Occupational setting
Air quality
Food
Infectivity
Pathogenicity
Virulence
Immunogenicity
Antigenic stability
Survival
Age
Sex
Genotype
Behaviour
Nutritional status
Health status
Host
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6. Infectivity
the percentage (or proportion) of individuals exposed to a particular agent who become infected
No of infected following exposure
Total of population at exposure
Infectivity =
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7. Pathogenicity
the percentage of infected individuals who develop clinical disease due to the particular agent
Pathogenicity =
No of clinically affected following exposure
Total of infected at exposure
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8. Virulence
the percentage of individuals with clinical disease who become serious ill or die
Virulence =
No of severe (fatal) cases following exposure
Total of clinically infected cases at exposure
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9. Agents Biological Chemical Physical
Viruses Bacteria Parasites or prions
Chemical
Toxins
Man-made (Dioxins and melamine)
Inorganic/organic: zearalenone
Physical
Foreign bodies
Trauma
Radiation
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10. Natural host: Atypical host: Agent Factors Host Dose
Environmental hardiness
Virulence (microbial)
Infectivity (microbial)
Toxicity (poisons)
Natural host:
agent has adapted itself and co-exists in balance in the host
Atypical host:
agent is not normally encountered
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11. Herd immunity Susceptibility Host Host Innate (genetic capability)
Demography
Age, Sex, Species, Breed
Production type / level, Density
Biology
Genetics, behavior
Management
Intensive (housing) / extensive (free roaming)
Nutrition
Hygiene
Husbandry
Vaccination / medication
Herd immunity
Innate (genetic capability)
Acquired through vaccination or deliberate exposure
Proportion of total population that is resistant to a disease agent
Susceptibility
Lack of resistance to the disease agent
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12. Host Factors Behavior (e.g. mutual grooming, dominance, pica)
Innate resistance (e.g. gastric barrier, mucocilliary transport mechanism)
Previous exposure
Passive immune status (neonates)
Vaccination status and response
Age
Gender
Behavior (e.g. mutual grooming, dominance, pica)
Production status (e.g., lactating vs. non- lactating)
Reproductive status (e.g., pregnant vs. non- pregnant, sterile vs. intact)
Genetics
Host Factors
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13. Epidemiologic Triad-Related Concepts
Infectivity (ability to infect)
(number infected / number susceptible) x 100
Pathogenicity (ability to cause disease)
(number with clinical disease / number infected) x 100
Virulence (ability to cause death)
(number of deaths / number with disease) x 100
All are dependent on host factors
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14. Predisposition to Infections
(Host Factors)
Gender
Genetics
Climate and Weather
Nutrition, Stress, Sleep
Smoking
Stomach Acidity
Hygiene
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15. Ecological Factors in Infections
Altered environment
{Air conditioning}
Changes in food production & handling
{intensive husbandry with antibiotic protection; deep-freeze; fast food industry}
Climate changes
{Global warming}
Deforestation
Ownership of (exotic) pets
Air travel & Exotic journeys / Global movements
Increased use of immunosuppressives/ antibiotics
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16. Dua (2) Jenis studi epidemiologi
Deskriptif
Analitik
Menelaah distribusi suatu penyakit pada suatu populasi & mengamati gambaran mendasar sebarannya menurut waktu – tempat – individu terserang
Desain studi:
Sigi kesehatan ‘masyarakat’ (≈ studi cross sectional, studi deskriptif
Menguji hipotesis tentang hubungan antara kejadian penyakit dengan kemungkinan penyebabnya, melalui pelaksanaan studi epidemiologi yang menghubungkan exposure dengan penyakit yang diduga
Desain studi:
Cohort, case-control
Dua (2) Jenis studi epidemiologi
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17. 2/22/2014 PTS-RST-PKH- 2- 2014 Agen Nutrients Poisons Allergens
Radiation
Physical trauma
Faktor Lingkungan
Kepadatan
Atmosfir
Modus komunikasi (vector, vehicle, reservoir)
Faktor Inang
Genetic endowment
Immunologic state
Age
Personal behaviour
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18. KONSEP EPID DALAM POPULASI
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19. TRIAD dasar epidemiologi deskriptif
Tiga karakteristik esensial kejadian suatu penyakit yang berusaha dielusidasi dalam epidemiologi deskriptif
Waktu
Tempat
Individu
TRIAD dasar epidemiologi deskriptif
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20. 2/22/2014 PTS-RST-PKH- 2- 2014 Waktu Berubah atau stabil? topografi
Variasi musiman
Clustered (epidemic) or evenly (endemic) distributed
Point source or propagated
Tempat
Secara geografis terbatas atau tersebar (pandemi)
Berhubungan dengan suplai air/pakan?
Multiple cluster or one?
Individu
Spesies
Bangsa/Ras
Umur
Kelamin
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21. TRIAD dasar epidemiologi analitik
Tiga phenomena yang dikaji dalam epidemiologi analitik
Inang
Lingkungan
Agen
Catatan: ingat terminologi necessary – sufficient - contributory
TRIAD dasar epidemiologi analitik
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22. 2/22/2014 PTS-RST-PKH- 2- 2014 Agen Nutrients Poisons Allergens
Radiation
Physical trauma
Faktor Lingkungan
Kepadatan
Atmosfir
Modus komunikasi (vector, vehicle, reservoir)
Faktor Inang
Genetic endowment
Immunologic state
Age
Personal behaviour
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24. Penularan Penyakit Vertikal horizontal langsung tidak langsung
media penularan vektor
mekanik daur hidup
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25. Infectious Disease Definitions Note Infectious diseases
Caused by an infectious agent
Communicable diseases
Transmission – directly or indirectly – from an infected person
Transmissible diseases
Transmission – through unnatural routes – from an infected person
Note
Infections are often subclinical – infections vs infectious diseases!
Antonyms not well-defined
Non-communicable diseases – virus involved in pathogenesis of diabetes?
Chronic diseases – HIV?
Tetanus
Measles
vCJD
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26. Transmission Cases Index – the first case identified
Primary – the case that brings the infection into a population
Secondary – infected by a primary case
Tertiary – infected by a secondary case P S T
Susceptible
Immune
Sub-clinical
Clinical
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27. Chain of transmission Mode of Transmission Direct Direct contact
Secretions, Blood, Faeces/urine
Droplet spread
Indirect
Food/water
Aerosol
Animal vectors
Fomites
Medical devices and treatments
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28. Chain of transmission Reservoir Human Person with symptomatic illness
Carriers:
Asymptomatic
Incubating
Convalescent
Chronic
Animal: zoonosis
Environmental: soil, plant, water
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29. Chain of transmission Portal of exit Human/animal Respiratory tract
Genito-Urinary tract
Faeces
Saliva
Skin (exanthema, cuts, needles, blood-sucking arthropods)
Conjunctival secretions
Placenta
Environmental
Cooling towers
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30. Chain of transmission Portal of entry Mouth (faecal-oral transmission)
Respiratory tract
Mouth (faecal-oral transmission)
Skin
Mucous membranes
Blood
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31. Chain of transmission Mode of Transmission Indirect Food/water Aerosol
Animal vectors
Fomites
Medical devices and treatments
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32. Chain of transmission Mode of Transmission Direct contact
Secretions, Blood, Faeces/urine
Droplet spread
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33. Chain of Transmission Reservoir Susceptible Host Agent
Person to person transmission
Reservoir
Susceptible Host
Portal of exit
Portal of entry
Agent
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Mode of transmission

34. Chain of transmission Portal of exit Human/animal Respiratory tract
Genito-Urinary tract
Faeces
Saliva
Skin (exanthema, cuts, needles, blood-sucking arthropods)
Conjunctival secretions
Placenta
Environmental
Cooling towers
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35. Routes of transmission
Direct
Skin-skin
Herpes type 1
Mucous-mucous
STI
Across placenta
toxoplasmosis
Through breast milk
HIV
Sneeze-cough
Influenza
Indirect
Food-borne
Salmonella
Water-borne
Hepatitis A
Vector-borne
Malaria
Air-borne
Chickenpox
Ting-borne
Scarlatina
Exposure
A relevant contact – depends on the agent
Skin, sexual intercourse, water contact, etc
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36. Sampai jumpa minggu ke 3
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