TB Contact Investigation Interviewing Skills Course

After this session, participants will be able to:

Priority TB Control Activities

1. Identify and treat persons who have active TB disease
2. Find and evaluate persons who have been in contact with TB cases and provide appropriate latent TB infection (LTBI) or TB disease treatment as needed
3. Use targeted testing strategies to identify and treat persons with LTBI at risk for developing TB disease
4. Identify settings at high risk for transmission of M. tuberculosis and apply effective infection-control measures

Contact Investigations: A Priority TB Control Activity

• Conducting contact investigations (CIs) is one of the highest priorities for TB programs in the United States

       -Second in importance only to
      detection and treatment of TB disease

[IMAGE:  A man and a woman having a discussion while sitting in chairs facing each other.]

What is a Contact Investigation?

A systematic process to:

• Identify persons (contacts) exposed to cases of infectious TB disease
• Assess contacts for infection with M. tuberculosis and TB disease
• Provide appropriate treatment for contacts with LTBI or TB disease

[IMAGE: Ten black spokes radiating from a pink circle.]

Who are TB Contacts?

Contacts are persons who have shared airspace with a person with infectious TB disease. This might include

• Household members
• Friends
• Co-workers
• Others (e.g., cellmates, shelter residents)

[IMAGE: A circle with a TB case in the middle showing people the case might encounter at work, home, and/or leisure activities around the circle.]

Why is it Important to Conduct TB Contact Investigations? (1)

CIs help to:

• Interrupt spread of TB
• Prevent outbreaks of TB
• Ensure appropriate treatment for LTBI or TB disease

Why is it Important to Conduct TB Contact Investigations? (2)

•  On average, 10 contacts are identified for each case
  • 20% to 30% of household contacts have LTBI
  • 1% of contacts have TB disease

Who is Responsible for TB Contact Investigations?

• State and local health departments have legal responsibility to
  • Investigate TB cases reported in their jurisdiction
  • Evaluate effectiveness of TB investigations
• Although the health department maintains legal responsibility, some CI steps may be delegated
  • For example, with worksite exposures,  occupational health offices are often involved

Group Discussion

• Share a few examples from your CI experience when you successfully identified active TB cases.
• What are some barriers to conducting CIs in your area?

What Core Concepts and Skills are Required to Conduct TB Contact Investigations?

• Knowledge of TB transmission
• Knowledge of TB pathogenesis

Difference between LTBI  and TB disease
Risk factors for progressing to TB disease
Effective interviewing skills

• Data management and analysis skills

Contact Investigation Core Concepts

TB Transmission

Remember: TB is Transmitted
Person to Person!

Every TB case Began as a TB contact

[IMAGE: Stick people showing how TB can be transmitted.]

TB Transmission

• When a person with infectious TB disease coughs, sneezes, speaks, or sings, tiny particles containing M. tuberculosis (droplet nuclei) may be expelled into the air.
• If another person inhales droplet nuclei, transmission may occur; however, not everyone who is exposed to TB becomes infected with TB.

What Factors Influence TB Transmission? 

The probability that TB will be transmitted depends on the following factors:

1. Infectiousness of person with TB disease
2. Duration and frequency of exposure
3. Environment in which exposure occurred

1. Infectiousness of Person with TB Disease

Characteristics associated with infectiousness:

[IMAGE: A woman coughing into her cupped hands.]

[IMAGE: An x-ray of lungs with an arrow pointed at the diseased area of the lungs.]

1. Duration and Frequency of Exposure

Contacts at higher risk for TB
infection are those who:

* “A lot of time” is difficult to define, but may be determined locally based on experience

[IMAGE: A smiling man and woman sitting close and drinking a beverage.]

1. Environment in Which Exposure Occurred

Environmental characteristics that increase chances of TB transmission: 
Small or crowded rooms
Areas that are poorly ventilated
Rooms without air-filtering systems

[IMAGE: A House.]

STOP the Chain of Transmission

The BEST way to stop transmission is to
Identify and isolate infectious persons
Start infectious persons on effective treatment for TB disease

[IMAGE: Male and female stick people handing hands.]

Contact Investigation Core Concepts
TB Pathogenesis

What Happens Once Someone is Exposed To TB?

Not every person who is exposed to TB becomes infected
Persons who become infected will generally have a positive
Tuberculin skin test (TST)
Or
Blood test (interferon gamma release assay [IGRA])
Persons who become infected can have either:
LTBI
Active TB disease

Latent TB Infection (LTBI)

LTBI - immune system keepstubercle bacilli under control
LTBI characteristics
Usually positive TST or IGRA
Not infectious
No symptoms
Normal chest x-ray
Sputum smears and cultures are negative
Not a “case” of TB

[IMAGE: A granuloma surrounding tubercle bacilli.]

Active TB Disease

TB disease - immune system cannot stop tubercle bacilli from multiplying leading to active TB disease
Usually affects lungs, but can affect other areas of the body
Characteristics usually include:
Positive TST or IGRA
Infectious (before treatment)
Symptoms
Abnormal chest x-ray
Positive sputum smear and culture
Considered a “case” of TB

[IMAGE: A granuloma opened up and releasing tubercle bacilli.]