Tuberculosis Surveillance in Canadian Federal Penitentiaries 1999-2001

Reported Results of the Correctional Service Canada Tuberculosis Tracking System

FOREWORD

I am pleased to provide this report on the tuberculosis surveillance system for the prevention and control of tuberculosis among inmates and staff in federal penitentiaries in Canada 1999-2001.

Tuberculosis (TB) among incarcerated populations around the world is recognized as a public health concern. After years of successful control, the public health threat of emergent multi-drug resistant TB among inmates in the former Soviet Union demonstrates the importance of maintaining vigilance in the fight against the spread of TB.

Inmates are often at increased risk of TB due to the social and behavioural risk characteristics that define this population before they even enter the prison gates. By the very nature of incarceration, the risk of contracting TB may be heightened among inmates at close proximity with shared ventilation.

The Correctional Service of Canada (CSC) has partnered with the Public Health Agency of Canada (PHAC) in the surveillance of TB among inmates and staff in Canadian federal penitentiaries. Inmates are offered screening for TB on admission and are followed throughout their incarceration for any sign or symptom that might indicate infection with TB or progression to active disease. Our nursing staff represents the front line workers in this most important battle against the spread of one of the world's leading killers.

The challenge posed by TB to CSC and to public health in Canada should not be taken lightly; indeed, constant vigilance to the task is required, as the tools available to public health for the control and detection of latent TB infection (LTBI) and active TB disease are cumbersome and logistically difficult to administer. Together, with our provincial, territorial, and federal colleagues, CSC is working to control the spread of tuberculosis among those incarcerated and those who work in our institutions.

Sincerely,

Dr Françoise Bouchard, MD, MPH, FRCP(C)
Director General, Health Services
Correctional Service of Canada

In the mid 1990's, an alarm was raised in several Ontario institutions about a number of simultaneous active tuberculosis cases and the possibility of an outbreak of tuberculosis (TB). While fortunately this did not turn out to be the case, thus began an active collaboration between Correctional Service Canada and the Public Health Agency of Canada (then Health Canada). Since then, Tuberculosis Prevention and Control Program has continued to be involved in the tuberculosis prevention and control program at CSC.

A system for tracking tuberculosis among inmates and staff was designed, built and implemented. The CSC Tuberculosis Tracking System, or TBTS, is a database that electronically stores the results of the tuberculosis assessments among inmates and staff and facilitates the analysis of these data and the production of reports such as this one. However, it is but one part of the whole prevention and control program at CSC, which depends on the attention, understanding, and dedication of the nurses and health services staff, from the institutions, regions, and national teams within CSC.

This report contains a number of detailed tables and analyses on the results of the tuberculosis assessments in CSC from 1999-2001. While of more of an historical importance, they allow public health officials to measure tuberculosis infections among inmates and staff; they allow a comparison of results to other national and international data in order to better understand TB among those living or working in Canadian federal penitentiaries; and they allow an assessment of the prevention and control program itself which suggests changes and adjustments in order to improve TB prevention and control activities in CSC.

TBPC and PHAC remain committed to our involvement with our federal, provincial and territorial departmental partners in promoting and maintaining the health of all Canadians. Indeed, the relationship between CSC and PHAC has grown to include technical and scientific services and advice on a number of infectious diseases and issues. We look forward to the continued partnership on this important public health issue.

Sincerely,

 

Dr Edward Ellis, MD, MPH, FRCP(C)
Manager, Tuberculosis Prevention and Control Program
Community Acquired Infections Division
Centre for Infectious Disease Prevention and Control
Public Health Agency of Canada

SUMMARY

Participation of inmates in tuberculosis (TB) screening was high at 77.3%, 76.0%, and 73.8% for 1999, 2000 and 2001 respectively. However, the participation rate for staff was low at 28.4%, 23.1%, and 22.1%. Results relating to staff must be interpreted with caution as the low rate of participation means the results may not be representative of the general population of staff members working within federal correctional institutions. Efforts should be made to identify any barriers to staff participation in TB screening assessments.

On the Initial Assessment, 17.9%, 19.2%, and 19.9% of inmates in 1999 to 2001 respectively had a significant tuberculin skin test (TST) result. Among staff, the proportion significant on Initial Assessment was 7.5%, 10.1%, and 8.3%. Generally, this represents admission to a federal institution for inmates and employment for staff, although this may not always be the case. Of concern, 38.2%, 27.4%, and 26.3% of staff in 1999-2001 did not have a complete or valid baseline two-step TST. The functional reasons behind this finding should be investigated and attempts made to remove barriers to completion of testing.

One of the objectives of the TB prevention and control program at Correctional Service of Canada is the identification of those who convert their TB infection status - that is, they have a significant TST while they are incarcerated. Among inmates having an Ongoing Non-significant Assessment, 1.7%, 1.4%, and 2.7% for 1999-2001 had a significant TST result. It is unclear whether the observed rise in the significant rate in 2001 can be ascribed to increased vigilance for TB, or whether it represents a true increase in the transmission of TB among inmates who are incarcerated. Among those who tested significant, not all had a documented Previous Non-significant TST and could be considered converters; the annual conversion rate among inmates for 1999-2001 was estimated to be of 1.04%, 0.86%, and 1.9%.

Among staff, the proportion testing significant on an Ongoing Non-significant Assessment was 0.7%, 0.5%, and 0.4% for 1999-2001 respectively. However, given the low participation rate among staff, it is unclear whether the observed downward trend among staff in the significance rate on the Ongoing Non-significant Assessment is reflective of a true decrease in TB transmission. The annual conversion rate among staff was estimated to be 0.30%, 0.23%, and 0.28% for 1999-2001 respectively.

Overall, the proportion of inmates TST significant and therefore considered to have latent TB infection (LTBI) was 21.9%, 20.5%, and 21.1% for 1999-2001 respectively; the highest prevalence was reported in Quebec, Ontario, and Prairie regions. Higher rates of LTBI were reported among foreign-born and Aboriginal inmates. The overall proportion of staff TST significant and therefore considered to have LTBI was 11.2%, 11.5%, and 7.5% for 1999-2001 respectively. The highest LTBI rates among staff were reported in Prairie and Pacific regions, and among staff of foreign-born or Aboriginal origin.

The CSC TB Tracking System (TBTS) was designed to capture data on LTBI. Epidemiological data on cases of active TB disease are essential to understand the scope of TB transmission within Canadian federal correctional facilities. The TB surveillance system has been updated to systematically capture this information as of the beginning of 2005.

These findings highlight the importance of screening and tracking of TB in penitentiaries and emphasize the public health role that CSC plays in the prevention and control of this disease in Canada.

PART 1: INTRODUCTION

BACKGROUND

The Correctional Service of Canada Tuberculosis Tracking System (CSC TBTS) was developed in 1997 in conjunction with the Public Health Agency of Canada (PHAC - then Health Canada) to capture information on reported tuberculosis (TB) screening results. CSC nurses in all federal correctional facilities across Canada report their results on inmate TB screening to the National Infectious Disease Program (NIDP), Health Services Branch, CSC National Headquarters (NHQ); Workplace and Public Safety Program (WHPSP) nurses report their results on staff TB screening separately to Tuberculosis Prevention and Control (TBPC) at the PHAC. TBPC subsequently analyze the collected data and together with the other members of the CSC Infectious Diseases Surveillance Committee (CSC IDSC, Appendix 1) produce surveillance reports. A former surveillance report on tuberculosis in CSC was published in 2000 (CSC, 2000). This second report Tuberculosis Surveillance in Canadian Federal Penitentiaries, 1999-2001, contains TB screening information collected on inmates and staff for 1999-2001.

This report consists of eight parts. Part 1 gives an introduction to the Correctional Service of Canada and the tuberculosis surveillance system. Part 2 gives the background, definitions, and methods. Parts 3-5 gives the results, for each of the three years 1999, 2000, and 2001. For each year, the results are listed separately for inmates and staff. The results are presented by assessment type - initial two-step tuberculin skin test (TST) at baseline and follow-up assessments for those with a non-significant TST - and are displayed by age, place of origin, and gender. Finally, the distribution by age, place of origin, and gender are displayed for all those with a significant TST - including those with a follow-up assessment for a Previous Significant TST.

Part 6 provides a brief discussion of the findings of this report. Parts 7 and 8 discuss the limitations of these results and list some aspirations for the TB surveillance program at CSC.

TUBERCULOSIS (TB)

There are three health-related outcomes for TB: latent TB infection (LTBI), active TB disease, and in persons with active disease, the potential to spread TB infection to others (TB infectiousness).

TB is caused by the bacterium Mycobacterium tuberculosis. Most adults who become infected with TB never develop active TB disease. A person with LTBI does not feel sick or have any symptoms and cannot spread TB to others. Factors that weaken the immune system increase the risk of progression to active TB disease in persons with LTBI. These factors include human immunodeficiency virus (HIV) infection, diabetes mellitus, substance abuse, being more than 10% underweight, end-stage kidney disease, silicosis, receipt of an organ transplant, cancer in the head or neck, lymphoma or leukemia, anti-cancer drug therapy, radiotherapy, and steroid use. The weakened immune system is less able to stop the TB bacteria from growing and spreading within the body, and symptoms begin to appear (Long, 2000).

People with active TB disease feel sick. Although the symptoms a person develops will depend on where in their body TB disease develops, active TB disease of the lungs or vocal cords classically causes a prolonged cough ( > three weeks). After a few weeks of appropriate antibiotic treatment, most people will no longer be infectious and will feel much better. However, completing the full course of treatment (at least six months) is needed to kill all the TB bacteria and to prevent the recurrence of active TB disease or the development of drug-resistant TB disease.

A person with active TB disease of the lungs or vocal cords can spread TB by coughing or sneezing. M. tuberculosis goes into the air and people nearby can inhale the bacterium and become infected. TB is not as contagious as chickenpox or measles; people with active TB disease are most likely to infect people whom they spend time with every day.

The Correctional Service of Canada (CSC)

CSC is responsible for the administration of correctional sentences of two years or more and for the preparation of inmates for their successful return and reintegration into the community. CSC operates 53 correctional institutions, which include minimum, medium, maximum and multi-level security facilities in five regions. Five of the facilities are dedicated to women inmates and are located in Atlantic, Quebec, Ontario and Prairie regions. In Pacific region, women inmates are housed in a provincial facility through an Exchange of Service Agreement with the province of British Columbia. In addition, a small number of women inmates are held in dedicated sections of male institutions in several CSC regions (see Appendix 2).