VPD
Surveillance
Surveillance is the …
Ongoing systematic collection,
collation, and analysis of health data
and the dissemination of that
information to those who need to know
so appropriate action can be taken
Surveillance is the continued vigil over the
occurrence and distribution of disease and
conditions which increase the risk
of disease transmission
Surveillance is information for action
A surveillance system should:
•Describe each person having an infection or disease
•Determine source of infection and mode of
transmission
•Identify exposed, susceptible person to whom the
infection may have been transmitted
•Specify frequency of occurrence of infection
in different population groups
•Prepare and distribute surveillance reports
A major objective of disease
surveillance is…
To determine the extent of infections
and the risk of disease transmission
…so control measures can be applied
effectively and disease can be
prevented
Five functions of a surveillance system
•Case detection and notification
•Investigation and confirmation
•Data collection and consolidation
•Data analysis
•Information dissemination
All done to guide public health action
Additional supporting functions
of disease surveillance:
• Setting standards (e.g case definition)
• Training and supervision
• Setting up laboratory support
• Establishing communication network
• Optimizing resource management
• Improve coordination/integration
Surveillance tasks differ
depending upon the level
District level
Provincial level
Central or National level
Surveillance at the district level
• Diagnosis and case management
• Reporting of cases
• Simple tabulation and graphing of data
Surveillance at the Provincial level
• Case
management for more difficult cases
• Analyze data from peripheral level for
epidemiological links and trends
• Monitor data to check if control targets
have been met
• Investigate suspected outbreaks.
• Feed back to the district
• Report to central level
Surveillance at the National level
• overall support and coordination of national
surveillance activities.
• provision of laboratory diagnosis data
•analyze data from intermediate level for:
• epidemiological links
• trends
• achievement of control targets.
• support intermediate level for outbreak control
•feed back to intermediate level, and report to WHO
regional office
Information gathered from Disease
Surveillance can be used to…
• Estimate the magnitude of health problem
• Determine geographic distribution
• Portray natural history of a disease
• Detect epidemics
• Monitor changes in infectious agents
• Evaluate control measures
• Facilitate and improve planning
• Generate hypothesis and stimulate research
Sources of data for surveillance
• Notifiable disease reports
• Laboratory results
• Vital records
• Sentinel surveillance
• Birth/death registries
• Surveys
•Vaccine utilization records
• Vaccine adverse event reporting system
Types of surveillance
Passive surveillance: data are routinely collected and forwarded
to more central levels
Active surveillance: data are sought out by visiting or contacting
a reporting site
Comprehensive surveillance: data are collected from numerous
sites throughout a country in order to
achieve representation of whole population
Sentinel surveillance: selected sites report data, can be used to
monitor trends and collect detailed information, but may not
represent the entire country
Community-based, facility-based and laboratory-based
surveillance: involve detection and notification by communities,
health facilities and laboratories
Prioritize which diseases need
surveillance, diseases:
• does the disease result in a high disease impact? (morbidity,
mortality, disability)
• does the disease have a significant epidemic potential
(cholera, measles)
• is the disease a specific target of a national / international
control program
• will the collected information lead to significant public
health action?
What needs to be addressed for each disease
under surveillance?
•The case definition should be
•Clear
• Appropriate
• Consistent throughout the surveillance system
• The reporting mechanism should be
• Clear
• Efficient
• Appropriate reporting periodicity
• Available to all relevant persons
•The analysis of data should be
• Appropriate
• Allow for proper presentation
• Used for decision-making
• The people doing the surveillance should
• Have a good understanding of the value of surveillance
system
• Understand their surveillance task
• Have sufficient resources
• The personnel involved should receive appropriate
• Training
• Supervision
• The feed-back from central levels should be
• Appropriate in format
• Sufficient and frequent enough
• Motivating
Objectives of Measles Surveillance in
Pakistan
• Estimate disease burden
• Detect and characterize cases
• Detect and Investigate outbreaks
• Identify populations at risk
• Monitor program activities
• Evaluate and guide policy
Basic Epidemiology
• Measles virus is RNA virus of the genus
Morbillivirus, a member of the Paramyxoviridae
family
• Exclusively human pathogen, no animal
reservoir, no vector
• Transmitted by respiratory droplets, via aerosol
and direct contact
• Average incubation period (from exposure to
rash onset) is 14 days (range 7 – 18 days)
• Patients are contagious from 2 – 3 days before
until 1 – 2 days after rash onset
Main Characteristics
• Two components
– Routine Weekly Reporting
– Outbreak Detection and Investigation
Routine Weekly Reporting
• Case-based
– Investigation of every suspected measles cases using standard
Case Investigation Form (CIF) with blood specimen collection for
confirmation of diagnosis
– Weekly reporting of all suspected measles cases
• Facility-based
– All government facilities and
– Private facilities included in weekly AFP zero reporting
• Laboratory Component
– IgM verification of all suspected cases
Identification of Measles Suspected
Cases
• Patients presenting at health facility
satisfying case definition
• Patient with history of measles (satisfying
case definition) and presenting common
complications of measles within past one
month at health facility
Measles Case Definition Algorithm
Yes
No
Did the person have maculo-papular rash?
No
Did the person have fever?
Yes
Not
Measles
Not
Measles
Did the person have any of the followings?
Yes
Cough
No
Yes
Running
nose
Measles
No
Yes
Red eye
Measles
Yes
Measles
No
Not
Measles
Action Points – Health Facility
Suspected Measles Case
• Record patient’s details in Measles Case Investigation
Form (CIF)
• Arrange collection of blood specimen (3-5 ml) for IgM test
• Label specimen and record type and date of specimen
collection in the measles CIF
• Sent specimen to EDO (Health) office in reverse cold chain
along with a copy of CIF
• At the end of week (Saturday), compile all suspected cases
in weekly report (Form B) and send to EDO (Health) office.
• IF NO CASES FOUND DURING THE WEEK, ZERO
REPORT MUST BE SENT
Action Points - District Level
• Gather weekly reports (Form B) from all reporting health facilities
• Assign EPID Number to all suspected cases
• Prepare weekly district compilation report
– Take data from weekly reports from health facilities and
– Case Investigation Form
• Separate serum from the whole blood specimen sent from health
facilities (if not done already)
• Transship specimen collected from health facilities to National
Measles Laboratory at NIH Islamabad with EPID number on it’s
sticker
Contd:
Action Points - District Level
• Check for outbreaks (see below in Outbreak
Investigation)
• Analyze data (see below in Reporting)
– Epidemiology
– System indicators
 Send compilation report to provincial EPI office
by Tuesday
EPID Number - Suspected Case
• District Surveillance Coordinators (DSC) will
allocate an unique EPID number to each
suspected case with the following format:
• Country code/Province Code/District ID/
Year/Msl/Case Serial # # # #
• EPID Number on:
– CIF
– Compilation report
– Sticker on specimen
Trigger for Outbreak Investigation
• More than 5 suspected measles cases from one first level
health care facility (RHC and below) in one week
OR
• More than 5 suspected measles cases in a higher level
facility coming from one geographical area
OR
• Report of more than 5 suspected measles cases in one
area by trained LHW
Initial Outbreak Confirmation
• DSC with support of SO-WHO to confirm
outbreak by visiting affected area (initial phase)
– Through community assessment with the goal to find
cases in the past 30 days
– Arrange collection of at least 5 blood samples if
already not done
• If confirmed
– Form investigation team
Definition of Measles Outbreak
• More than 5 suspected measles cases
including at least one laboratory confirmed
measles case in the identified area during
the recall period of 30 days prior to
investigation.
Thank you