COMMUNICABLE DISEASE SURVEILLANCE Dr.Somsak Wattanasri, M.D. Board - - PowerPoint PPT Presentation
COMMUNICABLE DISEASE SURVEILLANCE Dr.Somsak Wattanasri, M.D. Board of Pediatrics, FETP does@health.moph.go.th Bureau of Epidemiology Department of Disease Control Ministry of Public Health Epidemiology and and Public Health Public Health
Dr.Somsak Wattanasri, M.D. Board of Pediatrics, FETP does@health.moph.go.th
Bureau of Epidemiology Department of Disease Control Ministry of Public Health
“Laws of nature mattered for health
rate of disease simply by studying
The The study study of
the distribution distribution and and determinants determinants of
the health health status status or
events in in the the population population and and its its application application to to control public control public health health problems problems
Source: Source: Last Last 2001. A Dictionary of Epidemiology: 4
th Edition. Oxford University Press: New
York. York.
Community Health Problem Community Health Problem
– – Descriptive Epidemiology (generate hypotheses) Descriptive Epidemiology (generate hypotheses)
Person
– – Age, sex, occupation Age, sex, occupation
Place
– – Spot map Spot map
Time
– – Epidemic curve Epidemic curve
Interview cases -
hypothesis generation
– – Analytic Epidemiology (test hypotheses) Analytic Epidemiology (test hypotheses)
2-
x-
2 Tables
– – Associations between outcome (e.g., illness) and exposure (e.g., Associations between outcome (e.g., illness) and exposure (e.g., food eaten) food eaten)
More sophisticated analyses
I t uses a data m odel, standardizes,
fair.
I t em phasizes quality in data and
w ork.
I t links analysis, prevention, and
control.
I t’s been tested. I t w orks. I ts benefit to costs is large and
undeniable
I t is additive: recom m ends, teaches,
and builds to a logical experim ent and believable results.
Notification within 24 hours
1 SARS and Avian Flu 2.Cholera
๑๑ Diptheria ๑๒ Rabies
1 Measles
Organization of Surveillance System Organization of Surveillance System
Ministry of Public Health Dep of Disease Control International Organization Bureau of Epidemiology Provincial Epidemiological Unit Private hospitals and clinics Hospitals and clinic under universal coverage scheme District Surveillance information center
Hospitals Under MOH And universal coverage schemes
ขอมูลรายงานโรค ขาวสาร/ขาวกรอง Regional Disease Control Center
506/507 Report E.1 E.0
D.R. E.2 E.3 E.4
TIME PERSON PLACE TABLE CHART GRAPH ANALYSIS & INTERPRETATION NORMAL KNOWLEDGE ABNORMAL RECOMMENDATION RECOMMENDATION & & ACTION ACTION INVESTIGATION Review other outbreaks and other source of information EPIDEMIOLOGICAL STUDY
Thailand have surveillance of acute viral hepatitis for 5 extinct viruses : hepatitis for 5 extinct viruses :
1971 began with Total Acute Hepatitis ( infectious, serum) infectious, serum)
1980 established Hepatitis A, Hepatitis B and Non A , Non B and Non A , Non B
1997 fully divided into 5 extinct viral hepatitis, A , B, C, D and E hepatitis, A , B, C, D and E
Hepatitis B vaccine was routinely introduced nationwide in 1992 nationwide in 1992
Clinical Criteria Clinical Criteria
Have jaundice without receiving Have jaundice without receiving hepatotoxic hepatotoxic agents and at least one of the following agents and at least one of the following
Dark urine
Fever
Abdominal discomfort
Right upper quadrant pain
Anorexia
Fatigue/Weakness
Laboratory Criteria Laboratory Criteria General Lab General Lab
SGPT (ALT) > 100 U/L in all age group
Specific Lab Specific Lab
Positive anti HAV IgM IgM 2.
Hepatitis B: Positive anti
Positive anti HBc HBc IgM IgM and/or and/or positive positive anti anti HBs HBs IgM IgM and/or positive and/or positive HBs HBs Ag Ag 3.
Hepatitis C: Positive anti HCV (total
Positive anti HCV (total antibody) antibody) and/or detect and/or detect HCV RNA HCV RNA 4.
Hepatitis D: Positive
Positive HBs HBs ag ag with with anti HDV anti HDV IgG IgG 5.
Hepatitis E: Positive anti HEV
Positive anti HEV IgM IgM
Suspected case Suspected case
Refer to patient who met clinical Refer to patient who met clinical criteria criteria Probable case Probable case Refer to patient who met clinical Refer to patient who met clinical criteria and criteria and SGPT (ALT) > 100 U/L
SGPT (ALT) > 100 U/L
Confirmed case Confirmed case
Refer to Refer to patient who met clinical patient who met clinical criteria and has confirmed specific criteria and has confirmed specific laboratory testing laboratory testing
Virus Virus No of No of Case Case Median Median age age Sex Sex Hospitalize Hospitalize d d
Hepatitis A Hepatitis A 2,421 2,421 2,742 2,742 407 407 22 years 22 years (14,33) (14,33) M:F M:F 1.5:1 1.5:1 10.6% 10.6% Hepatitis B Hepatitis B 33 years 33 years (22,44) (22,44) M:F M:F 1.5:1 1.5:1 12.3% 12.3% Hepatitis C Hepatitis C 42 years 42 years (30,53) (30,53) M:F M:F 1.5:1 1.5:1 12.0% 12.0%
1 2 3 4 5 6 7 8 8 2 8 4 8 6 8 8 9 9 2 9 4 9 6 9 8 2 2 2 2 4
Rate/100,000
Year
HB Vaccine, 1992
Source: Report 506, BoE
Person Place Time
5 10 15 20 25 1 2 3 4 5 6 7 8 9 10
200 400 600 800 1000 1200 0-4 '5-14 '15- 44 '45- 64 '64+ Age Group
Evaluate information Pathogen? Source? Transmission?
32
Compare R
ates
Know the E
xpected
Use R
andom Controls
Provide F
eedback
Take A
ction
Count cases, of course, but compare rates
rates
– – Rate requires numerator and denominator Rate requires numerator and denominator
Numerator: cases
Denominator: Population or persons at risk at risk
One case may or may not be significant
Numerator Numerator Number of cases Number of cases RATE = RATE =
=
Denominator Number at risk Number at risk
When you have a rate, it must be compared to the rate you expect compared to the rate you expect
This is why we do routine surveillance
– – To know what is the expected To know what is the expected
Definition of an epidemic:
– – More than the expected, more than usual More than the expected, more than usual
To what can you compare when no surveillance has been done? surveillance has been done?
– – Create comparison groups of Create comparison groups of controls
controls
Using the best data and evidence, have the courage to take action have the courage to take action
– – John Snow example John Snow example – – AIDS in America AIDS in America
Blood banking industry (Red Cross, AABB) refused to acknowledge transfusion risk refused to acknowledge transfusion risk
– – Don Francis and Jim Curran of CDC forced the Don Francis and Jim Curran of CDC forced the issue in public meetings issue in public meetings
– – SARS in Asia SARS in Asia
Unprecedented WHO criticism of a member state for suppressing SARS cases state for suppressing SARS cases
When lacking surveillance, proper controls create one create one’ ’s comparison group s comparison group
– – Similar to cases except without the outcome Similar to cases except without the outcome (disease) (disease)
Retrospective studies (case control)
Prospective studies (cohort, intervention trial)
Random selection: every member of target group has equal chance of selection group has equal chance of selection
– – Avoid conscious or subconscious bias Avoid conscious or subconscious bias
Attractive or more cooperative subjects
– – Avoid investigator convenience Avoid investigator convenience
Closer location have greater chance
Surveillance depends on reporting from local levels levels
Boring work; give it meaning
Provide incentive to report from the lowest levels of the system levels of the system
Distribute data and analyses to all reporters, so they see how data used so they see how data used
Give credit by name to encourage reporting
Family 1 Family 2 Family 3….…………... Family N
I.C. Failure
2. Collation:
synthesis
How to improve Surveillance
Surveillance and Rapid Response Team (SRRT) Surveillance and Rapid Response Team (SRRT)
ตําบล จังหวัด อําเภอ สวนกลาง D-SRRT-District P-SRRT R-SRRT C-SRRT เขต
หมูบาน
Information
Confine easy H2H transmission
6 multi-countries
Influenza Pandemic
“SRRT ” 1030 Surveillance and Rapid Response Team
Health services
SRRTs
AI provincial Team (Human and Animal) MoPH assigned “Mr. Bird Flu”
(800,000 village health volunteers & community leaders)
Lay report
Governor
Network Network
household member for 10 days
Hospital
(SRRT)
Laboratory
Veterinarian
Pathologists
Early pandemic Alert phase 4
Ro = 1.5 - 2
Operational criteria for action: “5 or more cases within 10 days”
for all contacts
in affected area
Types of exercise:
16 Apr 05
National preparedness National preparedness
National preparedness Thailand’s preparedness
Influenza A (H1) outbreak at Samutsakorn
Evaluation of surveillance system Evaluation of surveillance system
practice
Mandate Mandate Structure Structure Input Input Output Output Impact Impact
Network of Epidemiological Report in Thailand Ministry of Public Health Department of Disease Control Bureau of Epidemiology Provincial Health Office District Center of Epidemiological Information Office of Disease Control and Prevention 1-12 Subdistrict Center of Epidemiological Information CUP Reporting Unit in Health Insurance Project CUS, CUT Reporting Unit outside the Health Insurance System WHO
Section Section of
Surveillance and and Investigation Investigation
1.
Detect abnormal health events and
2.
Verify outbreak and follow the outbreak situation through the responsible
3.
Investigate the complicated outbreak which needs epidemiological expertise.
4.
Analyze health situation and conduct recommendation to prevent and control.
5.
Perform executive summary of health situation for administors and responsible units by weekly.
FWBD
VPD
Vector-
borne Diseases
Zoonosis
CNS Infectious Diseases
Respiratory Infectious Diseases
Contact,
EIDs and other infectious and other infectious diseases diseases
Others non-
infectious diseases
5 10 15 20
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 Rate per 100,000 Pop.
Reported Cases of Leptospirosis per Reported Cases of Leptospirosis per 100,000 100,000 Population Population, , Thailand Thailand, , 1990 1990-
1999.
43
5
2
35 14 149
22
960
102
1540
228
1105
271
714
212
397
113
157 54
300 600 900 1200 1500 1800
Number of Cases 0-4 5-9 10-14 15-24 25-34 35-44 45-54 55-64 65+ M ale Female
Reported Cases of Reported Cases of Leptospirosis Leptospirosis by Age by Age-
Group and Sex, , Thailand Thailand, , 1999 1999
5
2
35 14 149
22
960
102
1540
228
1105
271
714
212
397
113
157 54
300 600 900 1200 1500 1800
Number of Cases 0-4 5-9 10-14 15-24 25-34 35-44 45-54 55-64 65+ M ale Female
12 19 25 26 1 1 1 7 8 1 16 1 1 6 1 1 5 10 15 20 25 30 35 40
19/11/43 21/11/43 23/11/43 25/11/43 27/11/43 29/11/43 16041 16043 16045 16047 16049 16051 16053 15/12/43
Date of onset Number of patient
Confirmed case Suspected case Flood Investigation