Tuberculosis

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 (LTBI) are also reportable. Please use the Positive Report: TB Skin Test form.

 

Epidemiology

Community Outbreak - Thunder Bay - March 2018

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

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).

    A tuberculosis skin test (TST) is used to diagnosis 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 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

    TST

    The use of TST or interferon gamma release assay (IGRA) for the diagnosis of active TB in adults is not recommended. Preference and exceptions are outlined in the Canadian Tuberculosis Standards.

    The TST can be used to diagnosis LTBI:

    A TST can be completed with publicly funded solution (tubersol) 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 not insured when requested solely as a condition of employment or if required by an employer on an annual or other periodic basis.

    This information was retrieved from the January 30, 2017 Ministry of Health and Long Term Care of Ontario OHIP bulletin .

    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.

    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:

     

    Patient Information

    Patient Fact Sheet

     

    References

    1. Ministry of Health and Long Term Care, Infectious Diseases Protocol, 2018. Appendix A (2015) and Appendix B (2015)
    2. Public Health Agency of Canada. Canadian Tuberculosis Standards 7th Edition, 2014.

     

    Additional Resources

    1. Ontario Lung Association. Tuberculosis: Information for Health Care Providers 5th Edition, 2015
    2. Thunder Bay District Health Unit. Tuberculosis Skin Test (TST) - A Guide for Health Care Providers (administration, reading results and interpretation)

     

    Last Updated: 08/04/2019