Last Update: 4/5/2004 Division of Tuberculosis Control Virginia Department of Health Richmond,...

Last Update: 4/5/2004

Division of Tuberculosis Control

Virginia Department of Health

Richmond, Virginia

Tuberculosis Infection & Disease: Fundamentals for the General Public

Picture of tuberculosis bacteria under the microscope


Table of Contents

1. Introduction2. Role of the Public Health Department

and the Virginia Tuberculosis Control Laws

3. Tuberculosis Transmission and Pathogenesis

4. Epidemiology of Tuberculosis in Virginia5. Screening for Tuberculosis Infection6. Evaluating for LTBI and TB Disease7. Treatment of LTBI and TB Disease8. Infection Control Guidelines


1. Introduction


Tuberculosis (TB): A Disease ofPublic Health Significance

Potentially fatal disease transmitted by droplet nuclei after close contact with a person who has infectious, TB diseaseLong, multidrug treatment regimens increase potential risk of nonadherenceSerious impact on community if TB treatment is improper and/or inadequateDisproportionate impact on persons with inadequate access to health care


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 cases21 deaths from TB in 2003 TB is a curable disease


2. Role of the Health Department


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


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


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


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


3. Transmission and Pathogenesis of TB


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


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


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


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


TB Infection or Latent TB Infection (LTBI)

Occurs when TB bacteria are in the body, but are inactiveDoes not have any clinical symptoms of active TB disease Is not infectious to othersProduces a “positive” reaction to the TB Skin TestPresents a normal chest X-ray


Active TB Disease

Occurs when the inactive TB bacteria in the body (LTBI) become active

May be infectious

Has clinical symptoms (see next slide)


Symptoms of Active TB Disease

Prolonged cough(may produce sputum)*Chest pain*Hemoptysis*FeverChills

*Symptoms commonly seen in cases of pulmonary (lung) TB

Night sweatsFatigueLoss of appetiteWeight loss orfailure to gain weight


TB Infection (LTBI) vs. Active TB Disease

TB Infection Pulmonary (Lung) TB Disease

Tubercle bacilli in body Tubercle bacilli in body

Tuberculin skin test reaction usually positive

Tuberculin skin test reaction usually positive

Chest X-ray usually normal Chest X-ray usually abnormal

Sputum smear & culture negative

Sputum smear & culture positive

Asymptomatic Often infectious before treatment

Not a case of TB (Reportable only in children < 4 years of age)

A case of TB (Reportable)

Treated with 1 drug Treated with multiple drugs


Persons at Higher Risk forBecoming Infected with TB

Close contacts of persons known or suspected to have active, infectious TB diseaseForeign-born persons from areas in the world where TB is commonResidents and employees of high-risk congregate settingsHealth care workers (HCWs) who serve high-risk clients

(Continued on next slide)


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


Once Infected with TB, Factors That Would Increase the Risk for Developing TB Disease

These high-risk persons should be tested for TB infection, and if positive, treated.

HIV infectionSubstance abuseRecent TB infectionLow body weight (10% or more below the ideal)

Diabetes mellitusSilicosisProlonged corticosteroid therapyOther immunosuppressive therapyEnd-stage renal diseaseCancer of the head or neck


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!


4. Epidemiology of TB in Virginia


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


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


TB Cases Reported in Virginia, 1992-2003

See Notes pages for an explanation of this graph. [In the menu bar, click “View,” then “Notes Pages.”]

332 in 2003


Percent of TB Cases by Age and Sex inVirginia, 2003

See Notes Pages for an explanation of the graph.

0

10

20

30

40

50

60

70

Num

ber of

Cas

es

0-14 15-24 25-44 45-64 65+

Age Group in Years

Male

Female


Percent of TB Cases in Virginia, by Region2002 and 2003

Black30%

White19%

Asian/Pacific Islander

32%

Hispanic19%

Hispanic22%

Asian/Pacific Islander

32% White20%

Black28%

20032002


5. Screening for TB Infection (LTBI)


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]


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


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


6. Evaluating for LTBI and TB Disease


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 TestRefer persons for Chest x-rayCollect sputum and/or other specimen

to determine presence of TB


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


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


7. Treatment of LTBI and TB Disease


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


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


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


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


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


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


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 medicationsAssess the adverse reactions to

medicines


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


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]


8. Infection Control and TB


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


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


When are Persons with TB Disease Considered Non-Infectious?

Patients with TB disease are considered non-infectious if they meet all of the following criteria: They are on adequate therapy for at

least 2 weeks They have had a significant positive

clinical response to therapy They have had 3 consecutive negative

specimen smear results


How to Protect Yourself FromTB Infection

When in close contact with a person with infectious TB disease: Wear a mask Open windows in rooms Get screened for TB at your local

health department Learn more about TB infection and

disease from your local health department


How to Protect Others From TB If You Have Infectious TB Disease

Eliminate contact with others if you are infectiousIf close contact with others is inevitable, make sure that you always:

Wear a mask Open windows in rooms Cover your mouth and nose with hands

when sneezing, speaking, coughing, singing, etc.

Encourage persons who spend a great deal of time with you to be screened for TB infection


For More Information…

Virginia Department of Health Division of TB Control1500 East Main St, Room 119, Richmond, VA 23218804-786-6251 (Telephone); 804-371-0248 (Fax)http://www.vdh.state.va.us/epi/tb

Local Health Departmentshttp://www.vdh.state.va.us/LHD/LocalHealthDistricts.asp

Centers for Disease Control and PreventionDivision of TB Eliminationhttp://www.cdc.gov/nchstp/tb/default.htm

Last Update: 4/5/2004 Division of Tuberculosis Control Virginia Department of Health Richmond,...

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