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TB 101: TB Basics and Global Approaches
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TB 101: TB Basics and Global Approaches

Feb 25, 2016

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TB 101: TB Basics and Global Approaches . Objectives. Review basic TB facts. Define common TB terms. Describe key global TB prevention and care strategies. Types of TB. Pulmonary TB: TB of the lungs Can be spread to others through the air. 70 -80% of TB cases. - PowerPoint PPT Presentation
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  • TB 101:

    TB Basics and Global Approaches

  • Objectives

    Review basic TB facts.Define common TB terms.Describe key global TB prevention and care strategies.

  • Types of TBPulmonary TB: TB of the lungs Can be spread to others through the air.70-80% of TB cases.

    Extrapulmonary TB: TB in any other part of the body Lymph nodes, lining around the lungs, kidneys, bones, brain, etc. Does not spread to others.More common among people living with HIV.

  • TB Infection versus TB DiseaseTB bacteria are present in the body but dormant.No symptoms; person does not feel sick.Cannot spread TB to others.Has a normal sputum smear test and chest x-ray.May have a positive skin test (Monteux or TB skin test [TST]).

    Latent TB Infection

  • TB Infection versus TB DiseasePerson is sick with symptoms: Bad cough for 2+ weeks, maybe with blood. Chest pain.Weight loss, no appetite, fatigue.Fever and chills, night sweats.Can spread TB to others (if in the lungs).May have a positive sputum smear, culture, or skin test, or abnormal chest x-ray.

    Active TB Disease

  • Risk Factors for Active TB DiseaseRecent TB infection (in the past two years).Weakened immune system:HIV, poor nutrition, stress, diabetes, cancer.Aging, immature immune system.Poor health status:Smoking, substance abuse.Occupational disease (e.g., silicosis from mining). HIV is strongest risk factor.

  • TB VaccineBCG is a vaccine for TB (Bacille Calmette-Gurin).

    BCG cannot prevent TB in adults.

    It can prevent severe forms of TB, such as TB meningitis, among infants and small children.

  • TB and HIVOut of 34 million people living with HIV, about one-third are co-infected with TB.TB is the leading cause of death among HIV-infected people worldwide.TB speeds up the replication of HIV.HIV speeds up progression of TB.Adapted from a presentation by A. Fauci, United States National Institute of Allergy and Infectious Diseases.

  • WHO TB/HIV PolicyCollaboration between TB and HIV programs.Three Is:Intensified case-finding.Isoniazid preventive therapy to prevent TB.Infection control.HIV testing and prevention for TB patients.

  • The Global Plan to Stop TBGlobal-level objectives and activities.Implementation overview.Key targets and indicators.ACSM included in each section.

  • The Stop TB Strategy 1. Pursue high-quality DOTS expansion and enhancement.2. Address TB/HIV, MDR-TB, and the needs of poor and vulnerable populations.3. Contribute to health system strengthening based on primary health care 4. Engage all care providers.5. Empower people with TB and communities through partnership.6. Enable and promote research.

  • DOTS Secure political commitment with adequate and sustained financing. Ensure early case detection and diagnosis through quality-assured bacteriology. Provide standardized treatment with supervision and patient support. Ensure effective drug supply and management. Monitor and evaluate performance and impact.

  • TB Diagnosis TermsSmear microscopy rapid sputum test:Smear negative (sputum smear negative, SS-): no bacteria in two samples, but still other signs.Smear positive (sputum smear positive, SS+): bacteria found, potentially contagious, high priority.Culture much slower laboratory test to grow TB bacteria.TB skin test (TST, Monteux) looks for latent infection.Person with presumptive TB

    Author - All suggested revisions made to Handout 1.5 (glossary) have been made here as well.

  • First-line drugs treat most cases of TB. Include:Ethambutol EMB or EIsoniazid INH or HPyrazinamide PZA or ZRifampicin RMP or RStreptomycin STM or S Second-line drugs treat TB that is resistant to first-line drugs. Isoniazid preventive therapy (IPT) prevents TB in people living with HIV or progression of latent to active TB disease.TB Treatment

  • Cured: Initially smear positive and is now smear negative in last month of treatment and on at least one previous occasion.Completed treatment: Finished treatment but did not meet the criteria for cure or failure. Died: Died from any cause during treatment.Failed: Initially smear positive and remained smear positive at month 5 or later during treatment.Defaulted: Treatment was interrupted for two or more consecutive months.Not evaluated: Treatment outcome is not known.Person lost to follow-upTB Treatment Outcomes

  • EpidemiologyRoutine case-reporting required reporting of suspected or confirmed TB cases to a public health authority.Active case-finding actively looking for unreported cases.Case detection rate estimated % of all smear-positive cases that have been diagnosed and reported to the NTP out of all cases existing in the community.Treatment success rate % of new, registered smear-positive (infectious) cases that were cured or in which a full course of treatment was completed.

  • Questions?

    *With this session, we want to be sure everyone has a similar understanding of the most common TB prevention and care terms and strategies. We will be using these terms frequently throughout the week, so it is important that we all understand these concepts in the same way.

    Refer participants to Handout 1.5 Glossary of TB Terms to reference during the session. *TB can infect any part of the body, but most often it infects the lungs. When a person breathes in TB bacteria, the bacteria can settle in the lungs and begin to grow. From there, they can move through the blood to other parts of the body. This is called extrapulmonary TB. The treatment is the same, but it cannot be diagnosed with a cough.*There is a significant difference between TB infection and TB disease. These two categories are often called latent TB and active TB.

    In the early stage of latent TB infection, people are not sick and cannot spread TB, even though the TB bacteria are present in the body. For this reason, the person may have a positive Monteux skin test but a negative sputum smear test.

    Only about 10% of people will develop active TB in their lifetime. For people living with HIV, the risk is three times higher. They have about a 10% annual chance of developing active TB. People with latent TB infection can take medicine so that they will not develop active TB disease.*When people develop these symptoms, they have active TB disease.

    If TB is in their lungs (pulmonary TB), they can spread TB to other people through coughing or sneezing.

    The sicker you are, the more infectious you are. This is why it is important to find people quickly. People with active TB disease can be treated and cured if they seek medical help.

    *There are many factors that can influence if people will develop active TB disease.

    Your body can fight TB infection unless something impacts your health that weakens your immune system. This may include poor nutrition, other health conditions, age, smoking, substance use, and others. Occupational illnesses can also be factors, especially in the mining community.

    However, HIV is the strongest risk factor for developing active TB, which is why it is so important for us to find or prevent TB in people living with HIV.*There is a vaccine for TB, but it is only effective in infants and children. It is called Bacille Calmette-Gurin, or BCG, named after the French scientists who developed it.*We have already talked about HIV being the strongest risk factor for TB. We really need to do all we can to prevent or quickly find TB in people living with HIV. People living with HIV get sicker faster and are more likely to die of TB. TB is the most common fatal opportunistic infection among people with HIV worldwide. But TB can be mitigated.*WHO released an update of its collaborative TB/HIV policy in early 2012. It provides guidelines in three key areas:Overall collaboration between TB and HIV programs.Reducing the burden of TB in people living with HIV through the Three Is, which are intensified case-finding, isoniazid preventive therapy, and infection control.Guidelines for HIV testing and prevention among TB patients.*WHO also releases a TB strategic plan. It is essentially a roadmap to highlight key activities and targets at the global level that can be used to prioritize activities at a regional or country level.

    There are clear goals and objectives for implementation and research, with key indicators and targets compared to baseline 2009 data. ACSM activities and targets are incorporated within each section.

    The current Global Plan to Stop TB goes until 2015. New strategies and targets are currently being negotiated for after 2015.

    *The current Stop TB Strategy focuses on six areas to strengthen TB programs, services, collaboration, integration, and research, and to involve people and communities in fighting TB.

    Review components briefly.

    For reference, the sub-headings under each component include:1. Pursue high-quality DOTS expansion and enhancement:Secure political commitment, with adequate and sustained financing. Ensure early case detection and diagnosis through quality-assured bacteriology.Provide standardized treatment with supervision, and patient support. Ensure effective drug supply and management. Monitor and evaluate performance and impact.2. Address TB/HIV, MDR-TB, and the needs of poor and vulnerable populations:Scale up collaborative TB/HIV activities.Scale up prevention and management of multidrug-resistant tuberculosis (MDR-TB).Address the needs of TB contacts, and of poor and vulnerable populations.3. Contribute to health system strengthening based on primary health care:Help improve health policies, human resource development, financing, supplies, service delivery, and information.Strengthen infection control in health services, other congregate settings, and households.Upgrade laboratory networks, and implement the Practical Approach to Lung Health.Adapt successful approaches from other fields and sectors, and foster action on the social determinants of health.4. Engage all care providers:Involve all public, voluntary, corporate, and private providers through public-private mix approaches.Promote use of the International Standards for Tuberculosis Care. 5. Empower people with TB and communities through partnership:Pursue advocacy, communication, and social mobilization.Foster community participation in TB care, prevention, and health promotion.Promote use of the Patients Charter for Tuberculosis Care. 6. Enable and promote research:Conduct program-based operational research.Advocate for and participate in research to develop new diagnostics, drugs, and vaccines.

    *DOTS is the first component under the Stop TB Strategy and underpins the basic approaches to strengthen TB services. It has five components which are key elements for better TB services.

    ACSM activities can help in all of these areas. Notice that monitoring and evaluation are included as essential DOTS components.

    We will now cover case detection and treatment in more detail.

    *There are several methods we use to diagnose TB infection. Which method is best for your country or region depends on factors such as cost, TB prevalence, laboratory infrastructure, personnel training, etc.

    Smear microscopy a rapid screening test to see whether there are TB bacteria in a sputum specimen. A laboratory worker smears the sputum on a glass slide, applies a special stain (acid-fast stain), and then looks for any TB bacteria on the slide under a microscope. This test allows the health staff to receive a preliminary report within 24 hours.Smear-negative TB (sputum smear negative, SS-) a diagnosis of TB that means the person does not have infectious TB. The persons smear test was negative in at least two samples, and no TB bacilli were visible on the slide under the microscope, but yet other diagnostic tests (e.g., chest x-ray) indicate TB, the person has symptoms, and the provider has decided to treat for TB. Smear-negative TB is common among people with TB/HIV co-infection and in children.Smear-positive TB (sputum smear positive, SS+) a diagnosis of TB that means that TB bacilli were visible on the slide under the microscope, so the person is possibly contagious. Smear-positive TB patients are often prioritized for interventions to avoid further transmission and because they are often very sick.

    Culture a laboratory test that grows TB bacteria in a tube or on a plate to see whether there are TB bacteria in a sputum specimen or other body fluids. TB bacteria grow very slowly, so it can take up to 8 weeks to confirm a TB diagnosis using culture, depending on how the laboratory is growing the bacteria. TB skin test (TST) a test that is often used to detect latent TB infection. A liquid called tuberculin purified protein derivative (or PPD) is injected under the skin (intradermally) on the lower part of the arm in a standard dose. If the area around the injection site becomes red, it means the client probably has latent TB infection. This test is also known as a Monteux test.

    Person with presumptive TB a person who presents with signs or symptoms that suggest TB infection. This is replacing the old term TB suspect.

    *There are two broad categories of drugs used to treat TB. First-line drugs are the most important drugs used to treat most cases of TB throughout the world, while second-line drugs are used to treat TB that has become resistant to the first-line drugs. All first-line anti-TB drug names have a standard three-letter and a single-letter abbreviation:Ethambutol is EMB or EIsoniazid is INH or HPyrazinamide is PZA or ZRifampicin is RMP or RStreptomycin is STM or S Isoniazid preventive therapy (IPT) a strategy used to prevent active TB disease in people who have latent TB infection or people with HIV who are at high risk for becoming sick with TB but who do not have active TB disease. Isoniazid is also one of the four most common medicines used to treat active TB disease.*THIS SLIDE IS ANIMATED.

    There are six outcomes of treatment according to WHO. Who can tell me what they are? Encourage responses.

    CLICK to display categories.

    Cured: Patient was initially smear positive and is now smear negative in the last month of treatment and on at least one previous occasion.Completed treatment: Patient finished treatment but did not meet the criteria for cure or failure. This definition applies to pulmonary smear-positive and smear-negative patients and to patients with extrapulmonary disease.Died: Patient died from any cause during treatment.Failed: Patient was initially smear positive and remained smear positive at month 5 or later during treatment.Defaulted: Treatment was interrupted for two or more consecutive months.Not evaluated: Treatment outcome for the patient is not known.

    Person lost to follow-up is a patient who starts TB treatment that is later interrupted for at least two consecutive months. This replaces the old term defaulter.

    *Now lets review some common terms you might hear regarding TB surveillance.

    The two basic methods for identifying suspected or confirmed TB cases are routine case-reporting and active case-finding.

    Routine case-reporting is the required reporting of suspected or confirmed TB cases to a public health authority. In routine case-reporting, physicians and other persons (e.g., infection control practitioners, pharmacists, laboratory staff) submit reports of suspected or confirmed TB cases, as they are detected, to a public health authority that collects and analyzes the information.

    In active case-finding, the TB program identifies unreported cases of disease by actively searching for TB cases. We do not wait until the patient shows up with symptoms but rather we go and try to find them. Active case-finding can be designed and implemented in several ways, depending on local needs and practices. Mass screenings, targeted community screenings, and laboratory and pharmacy audits are some examples.

    These methods influence our case detection rate, or the estimated percentage of all smear-positive cases that have been diagnosed and reported to the NTP out of all cases existing in the community.

    The TB treatment success rate is the percentage of new, registered smear-positive (infectious) cases that were cured or in which a full course of treatment was completed. *Are there any other terms you have heard that you are not clear about? Do not be shy to ask because it is very important that we all have the same understanding of TB control as we move forward.

    Encourage questions.*