Effective TB Interviewing for Contact Investigation: Facilitator Led Training Guide 2006
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10. Course Activities
Activity 4: Infectious Period Exercise
- To understand the considerations for determining
- To formulate an infectious period
|30 minutes total
- 5 minutes for instructions and distributing exercises
- 10 minutes of group work
- 15-minute large group discussion of answers
- Copies of the “Infectious Period Exercise” on page
43 (one for each participant)
|The answers to this exercise
will vary based on your health department’s guidelines for
the calculation of an infectious period. Therefore,
no answers are provided to these questions. Copy
the exercise on page 43 and hand a copy to each participant.
- Ask the participants how to calculate the infectious
period for their area. This should include a.
beginning date, b. end date, c. criteria for onset of
- Ask the participants to work for about 10 minutes
individually to calculate the infectious period for
- After 10 minutes, ask for volunteers to share with
the class the infectious period for each example. Whether
correct or incorrect, ask the participant the way in
which this period was calculated for each example.
Correct any incorrect answers.
- The participant should draw a diagram to visually
explain how the infectious period was calculated.
The diagram should look like Figure 7 with included
dates as the answers.
|Figure 7. Diagram
of infectious period
5. Answer any questions that may arise. Be prepared
to answer questions on topics such as
- Having multiple infectious periods for the same
- Criteria for ending the infectious period;
- Varying an infectious period in the context of each
contact such as if the patient did not have contact
with a close contact at some point before being hospitalized
for infectious TB, i.e., the infectious period can end
when contact is broken; and
- Formulating the infectious period without the presence
of cough or any TB symptoms.
The infectious period brings focus to the TB interview
process. Here is a quick review of the formulation
of the infectious period. This is the time frame during
which potential exposure to others may have occurred while
the patient was infectious or able to transmit TB.
Often, the beginning of the infectious period is the date
of the onset of symptoms, especially coughing.
Local or state standards should be used to determine the
beginning of the infectious period. Some health department
guidelines denote a specified period prior to the patient’s
recollection of the onset of symptoms, particularly cough.
For the purpose of the contact investigation, the end
of the infectious period is determined by all of
the following criteria:
- Symptoms, such as frequency and intensity of cough,
- Patient has been receiving adequate treatment for
at least 2 weeks
- Patient has shown some evidence of a bacteriological
response, such as the reduction of the grade of the
AFB sputum smear or conversion to negative sputum smears.
- Exposure to contacts has ended
The infectious period should be stated in the form of
start date to end date. The infectious period provides
a timeframe for the patient when identifying information
Activity 4: Infectious Period Exercise
Calculate the infectious period for the
following cases. It should include start and end dates.
Base your answers on your health department’s standards for
calculating an infectious period. Be prepared to discuss
with the class how you came up with your answer. You can
use a diagram like the one below to calculate the infectious
- Joe was hospitalized on June 6 and started TB
treatment that day. He claimed he had been coughing since
April 20. He had three consecutive negative smear results
as of July 10 and had improved symptoms. What is the
- Philip was hospitalized on December 4 with symptoms
of fever, night sweats, and cough. He was diagnosed with TB
on December 10 and started on TB treatment that day. Philip
states that he started coughing around November 6. His
symptoms resolved on January 27. Three consecutive sputum
smears were not negative until February 10. What is the
- Mary complained that she had been coughing since
March 10. She started TB treatment on May 24. Mary left
the hospital against medical advice on June 7 but was
readmitted on July 8. She had three consecutive negative
smears as of August 1, during the second hospitalization.
What is the infectious period?
- David was diagnosed with TB on February 10, based on
skin test and chest X-ray results. He was asymptomatic and
treated on an outpatient basis. His sputum smears were
negative prior to treatment but sputum culture was
identified as M. tuberculosis. His treatment ended
on August 5. What is the infectious period?
- Carla was diagnosed with TB disease and had night
sweats, fever, and weight loss when admitted to the hospital
on May 19. She claims her symptoms began around April 3.
She denies ever having had a cough. Carla was admitted into
the hospital and three consecutive induced sputum smears
were negative on June 21. What is the infectious period?