Mycobacterium Tuberculosis

Decline� During 2000 - 16,377 cases of TB

(5.8/100,000 of U.S. population) were reported to CDC

� 7% dec from 1999

� 39% dec from 1990

� In 1992 there was a resurgence of TB in U.S. (due to AB resistance, immigration, travel, HIV+)

Population at highest risk – foreign born

Rate per Population

Source: CDC

Mycobacterium Tuberculosis (TB)� Slow growing bacteria that primarily

affects the respiratory tract of humans.

� Other areas that can be affected:

TB Spreading

� What happens after the bacteria have entered the body?

Begins to grow in alveoli (small air sacs) of lungs and then spreads throughout lung and body via blood

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Lung Anatomy

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Source: CDC

1

Incubation� What is usual TB incubation period?

2-10 weeks for TB infectionUp to 2 years for TB disease (highest risk)

� TB infected (Latent TB): (carrier)Positive Skin Test, but not contagious (& no

symptoms)

� TB disease/active: + Skin test and showing symptoms (bad cough,

fever, chills, blood in sputum) and is highly contagious

Testing

PPD (Purified Protein Derivative) – tuberculin injected intradermally & read 48 hours later

PPD Testing

Source: CDC

Transmission

� Inhalation of infectious particles:Infectious particles are carried in air after an

active TB individual speaks, coughs, sneezes, or certain medical procedures are performed

� These particles are called droplet nuclei

� 1-5 microns/ 1/5000 of an inch in size

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Infected Person

Transmitting Droplets Inhalation of Droplets

Cough-Sneeze-Talking

Respirator� A PPE device that removes air contaminants

such as dust, mists, and aerosols from ambient air

� TB Respirator filters out material down to 0.3 microns at 95% efficiency (N95).NIOSH approved

TB Respirator Mask N 95 NIOSH Approved

Must be fit tested (sized correctly)

TB (AFB) Isolation� Acid Fast Bacilli (AFB) isolation room:

Warning signsMust be maintained under negative pressure. Exhaust air from isolation room away from air

intakes for building, usually on roof.

Filters

� High Efficiency Particulate Air filter (HEPA):Used to filter air for recirculation in an AFB

isolation room at 0.3 microns at 99.97% efficiency

Settings at TB Risk� High Risk Settings:

Health care settingsCorrectional institutionsHomeless sheltersLong-term care facilities for the elderlyDrug treatment centers