Tuberculosis Outbreak in a Long-term Care Facility

Abstract

Tuberculosis (TB) was a major cause of morbidity and mortality in Canada early in the 20th century. Elderly populations in Canada remain at high risk for TB disease. Elderly patients may present atypically, with the result that many active cases can remain undiagnosed. We present an outbreak of TB that occurred in a Residential and Long-Term Care (LTC) facility in Ontario. Case finding was carried out through the conventional concentric circle approach. Three rounds of tuberculin skin testing were conducted at 8-12 week intervals. Laboratory analysis was conducted at the Public Health Ontario Laboratories. An indoor air quality assessment was conducted to determine whether inadequate engineering controls were a transmission risk factor. A case of active pulmonary TB was confirmed in May 2010 in a staff member at the facility. By January 2011, 3 additional active cases and 24 latent tuberculosis infections among residents and staff had been identified. Genotyping methods confirmed that the 4 active cases were infected by an identical strain. Nine of 15 locations tested in the facility had air exchange rates below published guidelines. Prompt reporting of the initial case allowed for a quick initiation of the epidemiologic investigation. Given the epidemiology of TB in elderly populations, outbreaks should remain a concern for LTC facilities and physicians, even in jurisdictions of low TB incidence. Baseline and annual TB screening for residents and staff, early diagnosis of active TB, and adequate ventilation are important to reduce the incidence of disease.