Tuberculosis Infection & Disease: Fundamentals for the General Public

1. Tuberculosis Infection & Disease: Fundamentals for the General Public Division of Tuberculosis Control Virginia Department of Health Richmond, Virginia Picture of tuberculosis bacteria under the microscope

2. Table of Contents • Introduction • Role of the Public Health Department and the Virginia Tuberculosis Control Laws • Tuberculosis Transmission and Pathogenesis • Epidemiology of Tuberculosis in Virginia • Screening for Tuberculosis Infection • Evaluating for LTBI and TB Disease • Treatment of LTBI and TB Disease • Infection Control Guidelines

3. 1. Introduction

4. Tuberculosis (TB): A Disease ofPublic Health Significance • Potentially fatal disease transmitted by droplet nuclei after close contact with a person who has infectious, TB disease • Long, multidrug treatment regimens increase potential risk of nonadherence • Serious impact on community if TB treatment is improper and/or inadequate • Disproportionate impact on persons with inadequate access to health care

5. Current TB Challenges in Virginia • Increasing proportion of TB patients born outside the US • 48 different countries of origin in 2003 • At least 20 primary languages, other than English, spoken in 2003 • High incidence of drug-resistant TB cases • 21 deaths from TB in 2003 • TB is a curable disease

6. Role of the Health Department

7. The Public Health Department • Is a recognized expert in TB control for the local community • Is a resource for the latest on testing and treatment standards • Has access to medical experts at CDC for consultation on complicated TB cases

8. Health Department’s Role in Community TB Control • Provides follow-up care to persons diagnosed with TB • Has ultimate responsibility for TB control in Virginia • Has authority to legally enforce the VA Health Code • Requires compliance to TB treatment • See Guidebook for the 2001 TB Control Laws • www.vdh.state.va.us/epi/tb/guidebook.htm • Assists in interjurisdictional referrals for patients who move residences

9. VA Division of TB Control (DTC)Role of the Central Office in Richmond • Mission of the DTC • Provide leadership in overcoming barriers to protect the people of Virginia from tuberculosis • Objectives of the DTC • Detect all cases of TB disease • Treat all cases of active TB disease • Complete treatment of all cases of active TB disease and their infected contacts

10. Virginia TB Control Laws: Key Points • Require reporting of TB disease • Require treatment and adherence to TB treatment • Allow isolation of infectious TB disease patients who refuse TB treatment and/or put the public at risk for TB infection

11. 3. Transmission and Pathogenesis of TB

12. How TB is Transmitted • TB is caused by a bacteria, Mycobacterium tuberculosis (tubercle bacillus) • TB transmission occurs when a person with active, infectious TB disease coughs, sneezes, laughs, sings, etc. • TB spreads through the air by inhaled droplet nuclei • TB needs prolonged contact for transmission

13. Factors That Determine TB Transmission • Infectiousness of the person with TB disease • The more infectious a person, the more likely the TB will be transmitted to others who are in close contact with this individual • Environment in which exposure to TB occurs • Room size and ventilation -- Transmission of TB is likely to occur in rooms that are small and with poor ventilation • Length of time spent with the infectious TB patient • The longer the time spent with an infectious TB patient, the more likely TB transmission will occur • Virulence (strength) of the TB bacteria • The stronger the TB bacteria, the more likely the transmission of TB infection will occur

14. Pathogenesis of TB • TB occurs most commonly in lungs (85% of the time), but can occur in other parts of the body • A person with TB infection and a normal immune system has a 10% chance of developing active TB disease in his/her lifetime • This risk is greatest within the first 2 years after acquiring TB infection

15. Common Sites in the Body Where TB Disease May Occur • Pulmonary (Lungs) -- (85% of the time) • Extrapulmonary (outside the lungs) • Pleura (lining of the lungs) • Central nervous system • Lymphatic system • Genitourinary systems • Bones and joints • Multiple sites in the body

16. TB Infection or Latent TB Infection (LTBI) • Occurs when TB bacteria are in the body, but are inactive • Does not have any clinical symptoms of active TB disease • Is not infectious to others • Produces a “positive” reaction to the TB Skin Test • Presents a normal chest X-ray

17. Active TB Disease • Occurs when the inactive TB bacteria in the body (LTBI) become active • May be infectious • Has clinical symptoms (see next slide)

18. Symptoms of Active TB Disease Night sweats Fatigue Loss of appetite Weight loss orfailure to gain weight • Prolonged cough(may produce sputum)* • Chest pain* • Hemoptysis* • Fever • Chills *Symptoms commonly seen in cases of pulmonary (lung) TB

19. TB Infection (LTBI) vs. Active TB Disease

20. Persons at Higher Risk forBecoming Infected with TB • Close contacts of persons known or suspected to have active, infectious TB disease • Foreign-born persons from areas in the world where TB is common • Residents and employees of high-risk congregate settings • Health care workers (HCWs) who serve high-risk clients (Continued on next slide)

21. Persons at Higher Risk for Becoming Infected with TB (continued) • Medically underserved, low-income populations • High-risk racial or ethnic minority populations • Children exposed to adults in high-risk categories • Persons who inject illicit drugs

22. HIV infection Substance abuse Recent TB infection Low body weight (10% or more below the ideal) Once Infected with TB, Factors That Would Increase the Risk for Developing TB Disease Diabetes mellitus Silicosis Prolonged corticosteroid therapy Other immunosuppressive therapy End-stage renal disease Cancer of the head or neck These high-risk persons should be tested for TB infection, and if positive, treated.

23. TB and HIV Coinfection: A Concern • For persons infected with TB, HIV positive status is the strongest risk factor for developing active TB disease • In persons who are HIV positive and have TB infection, the chances of developing TB disease increases from 10% in a lifetime to 7% to 10% each year!

24. 4. Epidemiology of TB in Virginia

25. What is Epidemiology? • Epidemiology is the study of the distribution and determinants of disease in human populations • Epidemiological data tell us: • who in the population is most at risk for developing TB disease • what risk factors these individuals possess • where TB disease is most prevalent • how to best protect the public from the spread of TB disease

26. Epidemiology & Surveillance • Epidemiology guides the efforts of the Virginia Division of TB Control and health departments • Epidemiology helps determine which persons to screen for TB • Surveillance is an epidemiological method where there is an on-going systematic collection of disease data to obtain a thorough understanding and analysis of disease patterns

27. TB Cases Reported in Virginia, 1992-2003 332 in 2003 See Notes pages for an explanation of this graph. [In the menu bar, click “View,” then “Notes Pages.”]

28. Percent of TB Cases by Age and Sex inVirginia, 2003 See Notes Pages for an explanation of the graph.

29. Percent of TB Cases in Virginia, by Region2002 and 2003 2002 2003

30. 5. Screening for TB Infection (LTBI)

31. Goal of Screening for LTBI • Find persons with LTBI who would benefit from treatment to prevent the development of TB disease • Find persons with TB disease who would benefit from treatment[Persons at no risk for TB infection should not be tested for TB]

32. Mantoux Tuberculin Skin Test (TST) • A test for TB infection only • Preferred test for TB infection • Clinician performs procedure • An injection • Interpretation of TST result (positive, negative) based on: • Size of the induration (swelling) and • Person’s risk factors for TB

33. Persons Who Have Had the BCG Vaccine • Persons born outside the US, and in a country where TB is common may have received the Bacille Calmette-Guerin (BCG) vaccine one or more times • These persons can still receive the TB skin test • Persons who had the BCG vaccine and have a positive TB skin test should be treated for TB infection

34. 6. Evaluating for LTBI and TB Disease

35. Steps in Evaluating forLTBI and TB Disease • Health care worker will perform the following when evaluating persons for LTBI or TB disease: • Assess risk for TB infection, and if necessary… • Administer TB Skin Test • Refer persons for Chest x-ray • Collect sputum and/or other specimen to determine presence of TB

36. What is the Purpose of a Chest X-Ray? • Chest x-rays… • Are needed if the TB skin test is positive, or if a patient has symptoms of TB disease • Help determine if LTBI has progressed to TB disease in persons who have a positive TB skin test • Check for lung abnormalities in persons with symptoms of TB disease

37. What is the Bacteriology Process? • Patients provide specimen (sputum or other) • Laboratories: • Prepare a smear of the specimen to assess the presence of the tubercle bacilli • Guides in making a presumptive diagnosis of TB • Culture (grow) the specimen for presence of TB bacteria • Positive culture confirms diagnosis of TB disease • If culture is positive, further tests are done to determine the susceptibility/resistance to TB drugs • Helps clinicians choose correct drugs for patient

38. 7. Treatment of LTBI and TB Disease

39. Basic Principles of TB Treatment • Goals of treatment for TB disease are: • Provide the safest, most effective therapy in the shortest possible time • Give multiple drugs to which the TB bacteria are susceptible • Ensure patient adherence to therapy

40. Treatment of LTBI • Treating LTBI prevents the development of TB disease, especially for persons at high risk for developing TB disease if infected with TB • Usual medication regimen for treating TB infection • Isoniazid (INH) for 9 months is optimal • 6 months of INH is acceptable • Rifampin for 4 months is alternative in certain circumstances

41. Medications for TB Disease • Usual medication regimen • Minimum of 6 months of therapy, sometimes longer • Initial 4 drug therapy standard, and they are: • Isoniazid (INH) • Rifampin • Pyrazinamide (PZA) • Ethambutol • Medications may need to be changed if the TB is drug resistant to any medication listed above

42. Treatment of Extrapulmonary TB Disease • In most cases, extrapulmonary TB is treated with same regimens as those used for pulmonary (lung) TB • A minimum of 12 months of treatment is recommended for bone and joint TB, miliary TB, or TB meningitis in children

43. Treatment of Multidrug-Resistant (MDR) TB Disease • MDR presents difficult treatment problems • Treatment must be tailored to each patient and the strain of the patient’s TB bacteria • Use of directly observed therapy (DOT) is mandatory in treating persons with MDR-TB

44. Causes of Drug Resistance • Physician prescribes an inappropriate drug regimen • Patients do not take their TB medications exactly as instructed • Infection with a TB bacteria that is already drug-resistant

45. Monitoring of Treatment • Patients will be monitored for adverse reactions to the TB therapy • Clinicians will conduct baseline tests to assess a patient’s health at the start of therapy • Patients will be seen at least monthly to: • Assess the response to medications • Assess the adverse reactions to medicines

46. Directly Observed Therapy (DOT) • A health care worker watches a TB patient swallow each dose of the prescribed drugs • DOT is recommended for all persons who have TB disease • The health care worker will conduct DOT at a time and place convenient for each patient who has TB disease

47. Benefits of DOT • DOT allows for the rapid identification of problems patients may experience with the TB medicines • Health care workers can intervene earlier to resolve any reactions to medication • [Health care workers are routinely checking on patients’ progress]

48. 8. Infection Control and TB

49. Infectiousness of TB Patients • Persons with active TB disease of the lungs and throat are considered infectious if they: • Are coughing • Are undergoing cough-inducing or aerosol-generating procedures • Have sputum smears positive for acid-fast bacilli and are not receiving therapy • Have just started TB therapy • Have poor clinical response to therapy

50. Infectiousness of TB Patients (continued) • The infectiousness is directly related to the: • number of tubercle bacilli the TB patient releases into the air • clinical characteristics of the patient’s TB disease • patient’s response to therapy • Infectiousness declines rapidly after adequate treatment is started