2. Introduction
• Tuberculosis is a specific infection caused by
M.Tuberculosis.
• Primarily affects lungs and causes Pulmonary
tuberculosis.
• It is one of the oldest diseases known.
• In March 1882, Dr. Robert Koch discovered
Mycobacterium Bacillus, in Germany.
4. The Mycobacterium tuberculosis belongs to the genus
Mycobacterium.
It is:
•aerobic,
•non motile,
•rod-shaped bacteria.
It has two distinguishing characteristics :
•acid alcohol-fastness (AAFB), so strongly resistant,
•slow growth.
5. • Extra-pulmonary TB (e.g.
miliary, skeletal, meningeal, gastro-intestinal)
also occur,
– particularly in children,
– immigrants from countries where TB is more
common,
– In people with impaired immunity.
6. • The risk of disease is highly dependent on:
• the immune status of the host,
• co infection with HIV,
• HIV markedly increases the incidence of both
forms of disease, that is primary and secondary
forms of TB.
7. • Due to a combination of :
• economic decline,
• the breakdown of health systems,
• insufficient application of TB control measures,
• the spread of HIV/AIDS and
• the emergence of multidrug-resistant TB.
TB is on the rise in many developing and
transitional economies.
8. • Between 2000 and 2020 ,it is estimated that
nearly:
• One billion people will be newly infected with TB,
• 200 million people will become sick,
• And TB will claim at least 35 million lives.
9. • Currently, the principal control strategy for
those with TB is contact-tracing and DOT
(Directly Observed Therapy, to ensure patients
complete treatment).
• Between 1992 and 1997 following the
introduction of DOT and other controls on
treatment adherence, new cases of TB in New
York decreased by 55% and MDRTB by 87%.
• DOT both maximizes cure-rates and minimizes
the risk of encouraging drug-resistant strains
of TB bacilli.
13. Problem statement
• Tb remains a public heath problem, even after
100 years of discovery of the
microorganism, highly effective drugs and
vaccine available.
• Spectacular results in developed countries.
• TB death rate in US: 199 (1900) 0.5 (1980)
per lakh population.
• Changes started long before BCG and
chemotherapy.
14. Problem statement - Global
• Change attributed to:
– Improvements in standard of living
– Improvements in quality of life
– Application of available technical knowledge
– Availability of health resources.
15. Global Burden of Disease
(2008 Estimates)
• Incident cases : 9.4 million
• Prevalent cases : 11.1 million
• Tb among PLHA : 1.4 million
• Deaths : 1.8 million
• MDR-TB cases : 0.5 million
• MDR-TB deaths : 0.15 million
• XDR-TB cases : 50,000
• XDR-TB deaths : 30,000
16. Achievements (1995 - 2008)
• 86% cure rate
• Cured 36 million cases
• Averted 6 million deaths due to DOTS (as
compared to non-DOTS regimen)
• CFR decreased from 7.6% 4%
17. • Tuberculosis is the world's second commonest
cause of death from infectious disease, after
HIV/AIDS.
• TB is the world's leading killer among infectious
diseases, with one person dying of it every 15 sec
across the globe.
• Most cases (56 million) are in people aged 15 -
49 years.
• Tuberculosis is the world's greatest infectious
killer of women of reproductive age and the
leading cause of death among people with
HIV/AIDS.
19. Problem statement - INDIA
• India has the dubious distinction of being the
highest TB burden country in the world
• Accounts for 20% of global and 66% of SEAR
burden.
• 2 out of 5 Indians are infected.
• 50,000 people develop the disease everyday.
20.
21. Every year in India,
• 1 diseased Indian infects 10-15 persons.
• 1.8 millions develop TB.
• 0.8 million new smear positive highly
infectious cases.
• 3.2 lakh deaths.
• Annual risk of infection is 1.5%
22. TB Estimates of India (2008)
• Global rank : 1
• Incidence : 170
(All cases per lakh population)
• Incidence : 75
(new smear +ve cases/lakh pop/year)
• Prevalence : 185
(all cases per lakh population)
• Mortality : 24
(per lakh population per year)
23. TB Estimates of India (2008) contd
• New TB cases HIV +ve : 5%
• New cases MDR : 2%
• Previously treated MDR : 12-17%
• Case detection rate : 67%
• Treatment success rate : 87%
26. Prevalence of infection
• Percentage of Individuals who show a positive
reaction to standard tuberculin test.
• Age specific prevalence is a far more superior
indicator than mere total +ve reactors.
• It represents a cumulative experience of a
population to recent and remote infection.
• Limitations
– Complicated interpretation
– Cross sensitivity
27. Incidence of Infection
• Also known as Annual Rate of Infection and
tuberculin conversion index.
• It is the percentage of population newly
infected by M.tuberculosis among non-
infected of the previous survey during the
course of 1 year.
• Presents the annual risk of being infected with
M.tb in a course of 1 year or the attacking
force of TB in the community.
28. Contd..
• An ARI of 1% is said to correspond to 50 new
cases per year per lakh population.
• One of the best indicators of the TB burden
and its trend.
• Higher the rate, greater the problem.
• It was 1.5% in 2008.
29. Prevalence of the DISEASE
• Also called as case rate.
• It is the percentage of individuals whose
sputum is positive for TB bacilli on microscopic
examination.
• Best available practical index to estimate the
case load in the community.
• Age-specific prevalence is more relavent
index.
30. Incidence of new cases
• It is the percentage of new bacteriologically TB
cases per 1000 population occurring during 1
year.
• Is used to know the trend of the problem and
for impact of control measures.
• Extremely difficult to measure.
• Can be done in countries where notification is
reliable and where proportion of new cases is
high
31. Mortality rate
• Number of deaths occurring in an year per
1000 population.
• In the past it was used as an index for TB
problem in the community.
• After introduction of chemotherapy and
BCG, this has lost its importance as an index.
32. Case Detection Rate:
• Number of notified new and relapse cases in
an year divided by estimated incidence of
such cases.
Prevalence of drug resistance cases:
• Prevalence of patients with ATT drug resistant
tuberculosis bacilli.
• Directly related to Chemotherapy
40. References and further reading
• Park’s textbook of Preventive and Social
Medicine, K.Park, 21/e, 2011 , Bhanot publications
• WHO (2010), Weekly Epidemiological Record, No.12, 19-03-2010
• WHO (2010), Weekly Epidemiological Record, No.9, 26-02-2010
• WHO (2010), Tuberculosis Control in SEAR, Regional Report, 2010
• TB INDIA 2011 Revised National TB Control Programme: Annual
Status Report
• Global tuberculosis control: WHO report 2011.
• Tuberculosis, Surendra K Sharma, 2/e, 2009, Jaypee Publications
• Textbook of Community Medicine, Brig. Rajvir Singh et
al, 2/e, 2009, AFMC Pune.
• National Health Programs of India, Jugal
Kishore, 10/e, 2012, Century Publications
• www.who.int/tb
