Occult endemic tuberculosis in a chronic care facility.

Area of Science:

• Infectious Diseases
• Public Health
• Epidemiology

Background:

• Tuberculosis (TB) remains a significant public health concern, particularly in healthcare settings.
• Chronic care facilities present unique challenges for controlling infectious disease transmission.
• Undiagnosed or delayed diagnosis of TB can lead to prolonged periods of infectiousness.

Purpose of the Study:

• To investigate evidence of occult tuberculosis transmission within a chronic care Veterans Administration Medical Center.
• To evaluate the effectiveness of tuberculosis skin testing programs for both patients and employees in identifying and controlling disease spread.
• To highlight the importance of investigating skin test conversions in a healthcare environment.

Main Methods:

• Implementation of a tuberculosis skin testing program for patients and employees.
• Retrospective investigation tracing skin test conversions to an index case diagnosed posthumously.
• Analysis of tuberculin positivity rates and skin test conversion prevalence among patient and employee populations.

Main Results:

• Occult transmission of tuberculosis was identified, linked to a patient diagnosed three years prior at autopsy.
• Eight patients and two employees showed positive skin test conversions, indicating active transmission.
• High prevalence of tuberculin positivity (33% patients, 28% employees) and booster phenomenon (10.8% patients) were observed.
• Twelve percent of initially negative employees converted during their employment, underscoring ongoing transmission risk.

Conclusions:

• Tuberculosis skin testing is invaluable for detecting occult transmission in chronic care settings.
• Vigorous investigation of all skin test conversions, especially in healthcare workers, is essential for timely disease control.
• Proactive surveillance and prompt response are critical to prevent endemic tuberculosis spread in vulnerable populations.