Contact Tracing - Making the Connections

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Contact Tracing
Making the connections Kathleen Flynn BScN
RN 7th TB Conference 2010
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Outline

• Focus on our role in initiating and directing
  contact investigations
• Review case study through combined effort between
  the Provincial Program and the Community.

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Contact Tracing

• In epidemiology, contact tracing is the
  identification and screening of persons who may
  have come into contact with infectious
  tuberculosis. ...

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Terminology around contact tracing

• Index case
• First case identified of active Tuberculosis
• Source case
• The individual who was the original source of
  infection for secondary cases and or contacts.
  This person may or may not be the index case.
• Contact
• An individual identified having been in contact
  with an active case of TB

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Objectives of contact tracing

• Find any secondary cases and if yes start
  treatment.
• Identify all contacts who have been newly
  infected with Mycobacterium tuberculosis and
  offer treatment of Latent Tuberculosis Infection
  (LTBI)
• If the index case is a child and has primary TB
  or has non-respiratory TB, the source case who
  infected the child must be identified.

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Determining Infectiousness of an active case

• Type of TB diagnosis
• Lab results
• Smear , Smear -, Culture , Culture -
• Chest X-ray
• Presence of cavitation is an independent risk
  factor of infectiousness
• Signs and Symptoms
• Cough? /or other symptoms

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How it all starts

• All positive mycobacteriology is immediately
  reported by phone to the Public Health department
  by Provincial Laboratory (all mycobacteriology is
  performed by the provincial lab).
• TB Control manages cases and contacts outside of
  the Edmonton and Calgary area as well as most
  correctional facilities and First Nation Reserves

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Continued

• With respect to the source case need to
  determine
• prior file with TB Control
• signs and symptoms
• length of current illness
• history of contact, travel
• country of birth
• clients living situation

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Next steps

• If decision has been made to admit patient need
  to look at
• Transportation
• If time permits, Public Health Nurse performs
  initial interview with patient to get as much
  contact information as possible to start on
  contact tracing

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Setting Parameters

• Determined on a case by case basis
• No black or white
• Investigation parameters may change during the
  course of an investigation based on new
  information received
• Start with household contacts and or close
  non-household contacts first priority are those
  under 5 years of age and immunocompromised.

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Children under 5 years of age

• In Alberta we give first priority to those
  infants or children under 5 years as they are at
  an increased risk of progressing from latent
  infection to active and sometimes severe disease
  if not treated.

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Primary Prophylaxis Guideline

• All children under 5 years who are deemed as
  close contacts are offered primary prophylaxis
• Prior to initiation need
• symptom inquiry, chest x-ray (PA Lateral),
  current weight, blood work, initial TST
  completed, all ASAP
• 8 week post contact TST negative/CXR normal/ and
  asymptomatic- meds stopped

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Case Study Part 1

• 35 year old female
• Canadian born - First Nation
• Living on reserve, in a community 45min. outside
  major urban centre
• BCG history unknown

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Case study continued

• Patient started feeling ill in middle of January.
• Sought medical attention at nearest hospital
  emergency February 6
• Symptoms included cough x 2-3 weeks, fever,
  weight loss
• CXR done, that day

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Case Study

• February 24, returned to same emergency
  department with persistent symptoms that now
  included hemoptysis
• Chest x-ray repeated
• Sputums collected smear positive 3 for AFB
  fully susceptible isolate

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continued

• Lives in a house with 16 people
• Three children under the age of 5 years, no one
  sick in the home
• Worked in the community Daycare from October to
  January 28 of that year
• February 1, became a student in a school in
  another community

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Concentric Circle
Household contacts (Close) Daycare children and
staff (Close non-household)
Low risk casual
Classmates at school- Non-household casual
med.risk Emergency rm contacts-
Med risk casual
Community contacts
High risk close
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Results of Investigation
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Timeline
February 24 4
February 6 3
February 1 2
March 1
January 1
January 28 1
February 26 5
Legend 1 Stopped working at Daycare 2
Became student attended school 3 Sought
medical services for first time 4 Returned to
same ER with persistent symptoms and
hemoptysis 5 Admitted to Hospital on negative
isolation
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Conclusion

• This case study
• Speaks to the importance of early diagnosis
• Demonstrates how quickly a source case can go
  from non-infectious to infectious, resulting in
  converters and secondary cases
• Shows importance of LTBI Treatment in contacts to
  decrease the possibility of future development of
  active disease.