An outbreak investigation was conducted after 48 people attended a village feast on September 29th, where 24 people subsequently developed gastrointestinal symptoms requiring treatment. The illnesses were reported on September 29th (7 cases), September 30th (13 cases), and October 1st (4 cases). An investigation team traced 47 of the 48 exposed villagers. The team would first design an investigation plan and conduct the investigation according to steps like establishing the presence of an epidemic, conducting case finding and contact tracing, compiling information, and communicating findings.

1. OUTBREAK
INVESTIGATION

2. On 29th September 2004,48 people enjoyed a feast in a
village in Udupi district.
The feast was a lunch served at 13:00 hrs.
At varying times subsequently,24 of the 48 people
developed G.I.symtoms which required treatment.
7 of the cases were reported on 29th
13 on the 30th and 4 on the 1st of October.
47 out of 48 villagers who attended the feast were traced.
If you were the part of out break investigation team
( cont’d)

3. What will you do at this point?
List the steps in order of priority
►A plan for conducting an outbreak investigation
will be designed
► Itwill be conducted according to the following
steps.

4. Clinical cases + surv+
Comm.representatives Information regarding possible epidemic
Records & seasonal
Establish presence of epidemic incidence
EPIDEMIC ?
Investigation Control
component Confirm diagnosis Isolate & treat cases component
Conduct case finding Attack source & transmission
Trace contact prevention
Conduct environmental Continue
Compile information
Assessment surveillance
Process & analyse data
Communicate findings
Health plans for prevention of recurrence

5. b.Construct a proforma / questionnaire with
which you can collect data .

8. C. Comment on the response rate of the survey.
Why is it important?
► Response rate = It is the percentage of total
number of people traced divided by the total no
of people exposed.
► Response rate = 47/48 x 100 = 97.91%
► Goodresponse rate ensures better description
of the magnitude and geographic extent of the
outbreak

9. d. Construct an epidemic curve using the relevant data
provided.
comment on the shape of the curve and the type of
epidemic
50
45
40
35
No.of.people 30
epidemic
25
curve
20
15
10
5
0
29th 30th 1st

10. ► Thecurve rises and falls steep with peak
during the second day.
► Theepidemic curve shows it’s a point
source epidemic
► Because all the cases occur within one
incubation period of the disease