Tuberculosis | Thunder Bay District Health Unit

Reporting Obligations

Individuals with suspect or confirmed cases must be reported to the Thunder Bay District Health Unit by the next working day:

Fax: (807) 625-4822
Phone: 625-8318 or toll-free at 1-888-294—6630, ext. 8318

Positive tuberculosis skin tests and positive IGRA serology (LTBI) are also reportable. Please use the LTBI Reporting Form for positive TB Skin Test or positive IGRA serology.

Epidemiology

Community Outbreak

A community outbreak of tuberculosis was declared on March 9, 2018.Updates were sent to health care providers and are available below:

World TB Day: Tuberculosis Update 2024
World TB Day: Tuberculosis Update 2023
World TB Day: Tuberculosis Update 2022
Update #1 - HCP - TB Cluster - March 5, 2018 (PDF)
Update #2 - HCP - TB Outbreak - March 8, 2018 (PDF)
Update #3 - HCP - TB Outbreak - May 16, 2018 (PDF)
Update #4 - HCP - TB Outbreak - Sept 12, 2018 (PDF)
World TB Day: Tuberculosis Update 2019 (PDF)
Update #5 - HCP - TB Outbreak - June 20, 2019 (PDF)
Update #6 - HCP - TB Outbreak - April 6, 2021 (PDF)

For more information on TB and the outbreak, visit the Tuberculosis Outbreak page.

Aetiologic Agent:

The infectious agent is the Mycobacterium tuberculosis complex, which consists of Mycobacterium tuberculosis and includes M.canetti, M.africanum, M.caprae, M.microti, M.pinnipedii, and M.bovis. Mycobacteria are aerobic, non-spore forming and non-motile bacteria.

Clinical Presentation:

Of the people who are infected 5% will develop active TB disease within 18 to 24 months. The remaining 95% will develop latent TB infection (LTBI). Among those with newly developed LTBI, approximately 90% will never develop active disease. The remaining 10% will develop active disease at some point in their lifetime, half of these within the first two years of infection.

Active TB disease symptoms include:

a persistent cough; lasts longer than 2 weeks with phlegm, blood
chest pain
weakness or tiredness
unplanned weight loss
a lack of appetite
chills and fever night sweats

The risk of developing active TB is higher when other risk factors or comorbidities are involved, such as HIV co-infection. Those with HIV co-infection have an increased risk of 10% per year of developing active TB disease. Symptoms may include; a persistent cough (of more than 3 weeks), sputum production (sometimes with hemoptysis), chest pain; and shortness of breath, fever and night sweats, loss of appetite and weight loss and fatigue.

Modes of transmission:

Variable. 5% of infected individuals develop primary or progressive primary active disease within 18 to 24 months after infection, and 5% develop post-primary disease over the remainder of their lifetime. While the subsequent risk of active pulmonary or extrapulmonary TB is greatest within the first 2 years after infection, without treatment, LTBI will persist for a lifetime.

Incubation Period:

5% of infected people develop active disease within 24 months and 5% will develop over the remainder of their lifetime. LTBI will persist for a lifetime.

Period of Communicability:

Communicable as long as viable tubercle bacilli are discharged in the sputum. The degree of communicability depends on the number of bacilli discharged, virulence of the bacilli, and adequacy of ventilation, and opportunities for aerosolization through coughing, sneezing or procedures such as intubations, bronchoscopes. For smear positive or symptomatic infections the period of communicability may be 3 months before symptom onset, asymptomatic smear negative with no evidence of cavities may be infectious 4 weeks prior to date of diagnosis. Effective antibiotic treatment eliminates communicability within 2-4 weeks.

Risk Factors/Susceptibility

The first 18 to 24 months after infection constitutes the most hazardous period for the development of clinical disease. Once infected, the risk of developing active TB disease is influenced by the time since infection, age, and medical conditions or therapies that affect the immune system of the infected person. The risk is highest in the persons recently infected (i.e., the first 1 to 2 years), very young children (under 5 years of age), and in persons who are immunosuppressed, particularly those who have HIV/AIDS, diabetes, and certain types of cancer.

Diagnosis & Laboratory Testing

LTBI

Use a TST or IGRA to screen for latent TB infection (LTBI).

Individuals with LTBI do not present with active TB disease and are not infectious.

For more information, view the World TB Day video with a focus on LTBI.

TST

Please see this factsheet: Tuberculosis Skin Test (TST) - A Guide for Health Care Providers Factsheet

A TST can be completed with publicly funded solution (tuberculin) as indicated below:

Contacts of an active case of TB
When it is deemed medically necessary by a physician
When it is required for admission or continuation in a day care or pre-school program or a school, community college, university or other educational institution or program.

To order tuberculin, use the Vaccine Order Form (IMT-508B).

A TST is is not covered by OHIP when requested solely as a condition of employment or if required by an employer on an annual or other periodic basis.

Preference and exceptions are outlined in the Canadian Tuberculosis Standards.

IGRA

The Interferon Gamma Release Assay (IGRA) blood test screens for exposure by indirectly measuring the body’s immune response to antigens derived from the TB bacteria. The IGRA test can differentiate a Bacille Calmette-Guerin (BCG) response from a TB exposure-response.

Positive IGRAs MUST to be reported to TBDHU using the LTBI reporting form.

Situations where IGRAs are used:

Persons from groups that historically have poor return rates for TST reading (only single visit required)
Persons who have received BCG vaccination after1 year of age and/or have had BCG vaccination more than once (often from endemic countries, may not know age BCG was received)
Clarifying LTBI diagnosis in low-risk person with positive TST to assist in treatment decision by provider and person

IGRA Testing:

Life Labs on 1040 Oliver Road from Monday-Thursday.
Cost is approximately $100; NOT COVERED by OHIP

Active TB

Testing for active tuberculosis (TB) is indicated for someone with signs and symptoms of TB or is considered to be at high risk of TB disease. Every effort should be made to obtain a microbiological diagnosis, which requires demonstration of acidfast bacilli on smear microscopy and/or culture of Mycobacterium tuberculosis.

Chest radiography is an integral part of the TB diagnosis algorithm but cannot provide a conclusive diagnosis on its own.

At least three sputum specimens should be collected and tested with microscopy as well as culture.

The use of TST or IGRA for the diagnosis of active TB in adults is not recommended.

Detailed testing guidance is available in the Canadian Tuberculosis Standards 8th Edition (2022) and through Public Health Ontario.

Testing Information & Requisition

Treatment & Case Management

Treatment is under the direction of the attending Health Care Provider. It is recommended that all active or suspect cases of TB be referred to a medical specialist knowledgeable and experienced in the clinical management of TB. Refer to: