Infectious Disease Surveillance 2014 Active Tuberculosis (TB)

Data Collection

On admission, inmates are asked about their Tuberculosis (TB) history, including previous diagnosis of active tuberculosis and past treatment. Data from those assessments and TB case reports are recorded in the enhanced web-enabled Infectious Disease Surveillance System (WebIDSS). Data to year-end 2014 were analyzed. CSC works with local tuberculosis control regarding isolation, treatment and contact investigation protocols. CSC follows the Canadian TB Standards 7th Edition (2013)^{Footnote 1}.

Analysis and Results

TB Medical History

The annual number of inmates who reported a history of a previous diagnosis of active tuberculosis ranged between 27 (685/100,000) and 46 (1,181/100,000). Of these, between 42% and 74% reported being treated (shown as rate per 100,000) (see Figure 1).

Figure 1: Self-Reported Active TB Diagnosis and Treatment Among New Admissions, 1998-2014

Source: CSC WebIDSS 2017

Active TB Cases at CSC

There were 45 active TB cases diagnosed among inmates between 1998 and 2014, ranging between 0 and 6 per year. The corresponding rate ranged from 0 to 41.7 per 100,000 / year. A 3-year smoothed average rate is also shown which ranged from 6 to 27.5 per 100,000 / year (see Figure 2).

Figure 2: Annual Active TB Cases and Rates among Inmates, 1998-2014

Enhanced analysis was done on the 32^{Footnote 2} active TB cases diagnosed between 2002 and 2014:

• 1 (3%) was female;
• 11 (35%) were of Indigenous Ancestry and 10 (32%) were foreign-born;
• 3 (10%) were extra-pulmonary.

Of the 32 active TB cases 10 were prevalent on admission. There were 22 active pulmonary cases diagnosed post-admission of which 12 (54%) were smear positive. None were HIV-positive. Of 1,534 inmate contacts assessed for 17 of the cases, a total of 16 TST converters were identified for an overall 1% seroconversion rate (see Table 1).

Summary

Active TB disease is routinely diagnosed among inmates at admission and throughout incarceration. Detection of TST conversions is evidence of TB transmission in CSC.