This document provides information on tuberculosis (TB) including: 1. TB epidemiology statistics for Pakistan which has a high burden of TB with an estimated 250,000 new cases and 64,000 deaths per year. 2. Definitions of key TB terms such as prevalence, incidence, drug resistant cases, and treatment outcomes. 3. Descriptions of diagnostic tests for TB including the tuberculin skin test and its limitations, as well as the QuantiFERON blood test. 4. Overviews of the WHO recommended DOTS strategy for TB control, which involves direct observation of treatment, and the five elements of effective TB programs.

1. INFECTIOUS DISEASES
Tuberculosis
Dr. Farooq Ahamd
Assistant Professor
Community Medicine
Rawalpindi Medical College
Rawalpindi

2. WHO Slogan for 2009
24 March commemorates the day in 1882 when Dr Robert Koch astounded
the scientific community by announcing that he had discovered the cause
of tuberculosis, the TB bacillus

3. Mycobacterium Tuberculosis

4. Epidemiology World

5. Epidemiology Pakistan
• Estimated incidence of TB is around 250,000 per year in
Pakistan & existing patient population of around 1.8 million.
• TB kills 64,000 people in Pakistan each year, accounting for
26% of the nation's avoidable deaths
• Most patients are ages 15 to 45; 52% are males; and 48% are
females, according to government figures
• Pakistan ranks 6th among the 22 high burden countries of TB in
the world
• It has declared TB as national emergency in 2001

6. The Stop TB Strategy at a glance, 2009
VISION A world free of TB
GOAL To dramatically reduce the global burden of TB by 2015 in line with the
Millennium Development Goals and the Stop TB Partnership targets
OBJECTIVES
1. Achieve universal access to quality diagnosis and patient-centred treatment
2. Reduce the human suffering and socioeconomic burden associated with TB
3. Protect vulnerable populations from TB, TB/HIV and drug-resistant TB
4. Support development of new tools and enable their timely and effective use
TARGETS
1. MDG 6, Target 8: Halt and begin to reverse the incidence of TB by 2015
2. Targets linked to the MDGs and endorsed by Stop TB Partnership:
a. 2005: detect at least 70% of infectious TB cases and cure at least 85% of them
b. 2015: reduce prevalence of and deaths due to TB by 50%
c. 2050: eliminate TB as a public health problem

7. Important Definitions
• Prevalence of Infection
• Annual infection rate (incidence of infection)
• Case Rate ( Prevalence of disease)
• Incidence of new case
• Prevalence of suspect cases
• Prevalence of drug resistant case
• Mortality rate

8. Important Definitions
1. Sputum Smear 7. Failure Case
2. Smear Positive TB 8. Return after default
3. Smear Negative TB 9. Transfer in
4. Adherence/Compliance 10.Transfer out
5. New Case 11.Cured
6. Relapse 12. Treatment Completed

9. Agent, Host & Environment

10. Tuberculin test
The tuberculin skin test (TST) is not a test for
immunity to TB, but rather a measure of the
degree of tuberculin hypersensitivity as
measured by a cell-mediated immune
response. The Mantoux test, the Heaf test and
the tuberculin tine test—all variants of the
tuberculin skin test—can deliver tuberculin
PPD into the skin.

11. Tuberculin test
False Negative Tuberculin Skin Test
• Out-of-date tuberculin is used.
• Tuberculin leaks at the injection site.
• Testing is undertaken too early in cases of primary
exposure, before hypersensitivity has developed. (A
hypersensitivity reaction generally takes six to eight
weeks to develop.)
• The injection is too deep.
• The test reading is undertaken too early (before 48 hours)
or too late (after one week).
• The person has an inter current viral infection (such as
measles) or has had a recent live viral immunisation.
• The person is undergoing corticosteroid therapy
(especially if long term) or immunosuppressive therapy.

12. Tuberculin test
False Negative Tuberculin Skin Test
• The person is suffering from malnutrition, perhaps from a
period in a refugee or prison camp, or from significant
cachexia.
• The person is elderly.
• The person has a medical condition that may result in
partial immunosuppression, such as diabetes,
sarcoidosis, advanced alcoholism, renal failure, massive
trauma or burns.
• The person is an injecting drug user.
• The person has any malignancies, especially lymphoma.
• The person has HIV/ AIDS.
• The person is seriously ill, including when they have
advanced or miliary TB.

13. Tuberculin test
False Positive Tuberculin Skin Test
A false positive TST can occur as a result of:
• Recent BCG vaccination
• A ruptured small venule at the time of
injection
• Faulty test interpretation, such as the
measurement of erythema rather than of
induration.

14. QuantiFERON-TB Assay
a new blood test that is able to measure
quantitatively the production of the cytokine
Interferon-γ by lymphocytes sensitised to
mycobacterial proteins using an ELISA
technique.

15. TB Control
Case finding

16. ATT

17. Patients who interrupt Treatment

18. DOTS
• Directly observed administration of drugs
• Short course (six month) treatment
• A reliable, affordable supply of drugs
• Case detection (laboratory confirmation,
particularly smear-positive pulmonary TB)
• Reliable surveillance, including recording and
treatment include:
• Government commitment to TB control.

19. DOTS
DOTS has 5 elements:
1. Political commitment with increased and sustained financing
2. Case detection through quality-assured bacteriology
3. Standardized treatment with supervision and patient support
4. An effective drug supply and management system
5. Monitoring and evaluation system, and impact measurement
WHO Fact sheet 2008

20. DOTS
• 184 countries have adopted DOTS, although
services in
• many countries need to be expanded and
strengthened
• Funding for TB control implementation has increased,
• but for 2008 there is still a shortfall of US$ 1billion for
the 90 countries with 91% of global TB cases
• Nearly 32 million TB patients have been treated under
DOTS since 1995
WHO Fact sheet 2008

21. Chemoprophylaxis

22. BCG

23. NTP