Area for Tuberculosis Control

Assessment of Community Infection Ratio in the r "Model DOTS Project" area for Tuberculosis Control

P. Paul Kumaran

Dissertation submitted in partial fulfilment of the requirements for the award of the degree of Master of Public Health

Achutha Menon Centre for Health Science Studies Sree Chitra Tirunal Institute for Medical Sciences and Technology Thiruvananthapuram, Kerala, India. June 2002 DECLARATION

I hereby certify that the work embodied in this dissertation entitled "Assessment of

Community Infection Ratio in the 'Model DOTS Project' area for Tuberculosis

Control" is the result of original research and has not been submitted for any

degree in any other University / Institution.

is\v4"2- Dr.P.Paul Kumaran

Place: Thiruvananthapuram, Kerala

Date: I (kA a-10

ii CERTIFICATE

Certified that the dissertation titled "Assessment of Community Infection Ratio in the 'Model DOTS Project' area for Tuberculosis Control" is a bonafide record of original research work undertaken by Dr P Paul Kumaran in partial fulfillment of

the requirement for the award of the Master of Public Health degree under our

guidance and supervision.

Co-Guide Guide Dr Aleyamma Thomas Dr K R Thankappan Deputy Director (Sr Gr) Associate Professor & acting HOD Tuberculosis Research Centre (ICMR) AMCHSS, SCTIMST • Chennai, Tamil Nadu, India Thiruvananthapuram, Kerala, India

iii ACKNOWLEDGEMENTS

At the outset, I would like to express my heartfelt thanks to Prof Arthur L Reingold, Professor of Epidemiology, School of Public Health, University of California, Berkeley, CA, for enlightening me about the concept of 'community infection ratio for tuberculosis control', and I dedicate this piece of work to him. My sincere thanks are also due to him for his healthy and constructive criticism in improving the methodology of my study. I take this opportunity to thank Dr P R Narayanan, Director, Tuberculosis Research Centre for his whole hearted and constant support, which enabled to undertake and complete the study in due time without any hindrances. I thank Prof Richard A Cash from Harvard School of Public Health, Boston, USA, Dr Thomas R Frieden, Dr Reuben Swamickan and Dr Alka Aggarwal Singh, Programme Medical Officers for Tuberculosis Control, WHO-SEARO and WHO-India, and Dr V Mohanan Nair, Dr R Sukanya, Mrs Shiney C Alex and Mrs Betty Susan Ninan from AMCHSS for their valuable guidance during the planning process of my study. My sincere thanks are due to Mr R Subramani and Mr P G Gopi, TRC, who helped me in planning the execution of the data collection process. My special thanks are due to Mr S Janakiraman and Mr K S Venkatesan, TRC, who were with me through out the data collection period and helped me in all possible ways for its successful completion. I would like to thank Dr P Sankara Sarnia, AMCHSS, for his talented advice regarding statistical analysis. I will be failing in my duty if I do not acknowledge Dr K R Thankappan, AMCHSS, and Dr Aleyamma Thomas, TRC, my guide and co-guide, who traveled along with me through the whole stretch of this research piece of work. Last, but not the least, I like to thank the Almighty for blessing and guiding me throughout my life and for making this research possible.

I' Paul Kumaran

It1111 01111RIIIIE CONTENTS

I. Introduction 2 - 4

2. Review of literature 5 - 12 a. Epidemiology of tuberculosis 6 b. Tuberculosis infection 7 c. Control of tuberculosis 8 d. Identification of tuberculosis infection 9 e. Revised National Tuberculosis Control Programme 10 f. Assessment of Community Infection Ratio 1 I

3. Aim and Objectives of the study 13 - 14

4. Methodology 15 - 23 a. Study population 16 b. Study area and sampling frame 17 c. Contact-Control household definition 17 d. Sample size 17 e. Methods 20 f. Data entry and analysis 22 g. Definitions of parameters used during analysis 22 h. Calculation of Community Infection Ratio 23

5. Results 24 - 39 a. Interpretation of tuberculin skin test 28 b. Community Infection Ratio 37

6. Discussion 40 - 43

7. Conclusion 44 - 45

8. References 46 - 49

9. Appendix 50 - 56 a. Annexure 1: Form for Contact households 51 b. Annexure 2: Form for Control households 52 c. Annexure 3: Work instructions for filling the forms 53 d. Map I : Geographical position of Tiruvallur district 54 e. Map 2: Tuberculosis Units in Tiruvallur district 55 f. Map 3: Tiruvallur — Model DOTS Project area 56 LIST OF TABLES AND FIGURES

1. Table 1: Disease survey and tuberculin survey villages (with NSS+ve cases and children less than 15 years): Baseline — Model DOTS Project area — TRC. 18 - 19

2. Table 2: Frequency distribution of household characteristics of the study population ... 26

3. Table 3: Frequency distribution of the baseline characteristics of children 27

4. Table 4: Frequency distribution of the baseline characteristics of contact cases 29

5. Table 5: Mean distribution of the baseline characteristics of the study population 30

6. Table 6: Distribution of tuberculin skin test results by household characteristics • • - 32

7. Table 7: Distribution of tuberculin skin test results by characteristics of children 34

8. Table 8: Distribution of tuberculin skin test results by characteristics of contact cases 35

9. Table 9: Mean distribution of tuberculin skin test results of the study population ... 36

10. Table 10: Risk factors associated with tuberculin skin test positivity (Univariate analysis)

• ,• 38

11. Figure 1: Frequency distribution of tuberculin test reading among the study population 31

vi dedicaled t6 Arthur aang-old fir Introducing- the concept of Foinniunitg, o7nfiction 6Qatio

1 assessment of 6ommunO9njeretion) aa-tio in the i'Modela0("C'33 Z'reject' areafir (nbercularir ontre,/

o7ntroduction...

2 Assessment of community infection ratio in the Model DGIS Project area lor tuberculosis control

INTRODUCTION

It is more than two millennia since humankind saw tuberculosis and more than a century since Sir Robert Koch discovered Mycobacterium tuberculosis as the causative organism, the magnitude of the global tuberculosis problem is still expanding. It continues to be a stigmatized disease and a major public health problem. It is estimated that, globally, one in three persons alive today is infected with the tubercle bacilli 1 , that there are more than 8 million new cases of active tuberculosis and about 3 million deaths per year 2, making tuberculosis the leading etiological agent among lethal infectious diseases for adults in the world. Tuberculosis is responsible for 5% of all deaths worldwide and 9.6% of adult deaths between 15 and 59 years of age 3. The global burden of disease study, initiated in 1992 at the request of the World Bank for use in its 1993

World Development Report 4, has estimated an increase in the disability adjusted life years for tuberculosis worldwide from 38.4 million in 1990 to 42.5 million in 2020 5. The reemergence of tuberculosis in countries where it was under control, the advent of human immunodeficiency virus--HIV that is likely to increase the burden of tuberculosis, and the emergence of drug resistant tuberculosis forced the World Health Organization to declare tuberculosis as a global emergency in 1993.

In India, tuberculosis is the single leading infectious killer disease and it has more cases of tuberculosis than any other country in the world. Though India's population is

3 Assessment nl community mreetion ratio in the Motitl S l'fuject area !or luberculusts control R•

only about 16% of the world's total *, it contributes to 30% of the world's tuberculosis

6 cases . Every year, 2 million people develop the disease and nearly 5 lakhs die from it -

more than 1000 every day '. The disease prevalence is about 8 per thousand (4 per 1000

bacteriologically positive tuberculosis cases and another 4 per thousand bacteriologically

negative but radiologically positive cases) 8. About 50% to 60% of the nation's

population is infected with tuberculosis 9 and the annual risk of tuberculosis infection

ranges between 1% and 2% 8. Furthermore, tuberculosis is a major barrier to economic

development, costing India approximately Rs.12,000 crore (USS 3 billion) a year 7. It has

devastating social costs as well; data suggests that each year, more than 300,000 children

are forced to leave school because their parents have tuberculosis, and more than 100,000

women with tuberculosis are rejected by their families 7.

The world's population is 6,137 million [mid 2001] (Ref ht 2://www.census.gol) and that of India is 1,027 million [2001] (Ref. Provisional population totals: India. Census of India 2001, Series 1, India, Paper 1 of 2001),

4 Assessment (y-Fommunio) c7n1ction Catio rrl the

11 /(odel L- rcyccen areafir tuberculoses Fontrol

Certor o ll'oraturc...

5 AStiCtiS111(71111. t 1 eur Inuuniy LaCc(1011 ran in MOtlel 00.1S Pt.ujec urea fot 11.11/creLLIOSIS Condit)] 4

REVIEW OF LITERATURE

EPIDEMIOLOGY OF TUBERCULOSIS

To facilitate understanding of the relevance of epidemiology in implementing a

successful control programme, the study of a model following the pathogenesis of

tuberculosis in humans, from exposure to cure or death, is useful.

Mycobacterium tuberculosis is most commonly transmitted from a patient with

infectious pulmonary tuberculosis to another person through droplet nuclei. Exposure to

a potentially infectious case is a prerequisite for becoming infected. The risk factors for

becoming exposed include the number of incident tuberculosis infectious cases in the

community, the number of case-contact interactions per unit time, the degree and

duration of infectiousness of the case and the shared environment of the contact case 10.

Once an individual is exposed, the airborne transmission of the infectious droplet

nuclei, ventilation and host immune response are some of the factors that determine the

risk of becoming infected 1°. Thus, the risk of acquiring tuberculosis infection is

determined mainly by exogenous factors.

The time elapsed since becoming infected, the host immune response, age of the

individual, genetic, environmental, and social factors, including smoking, are some of the

major risk factors that determine the probability that an infected individual will develop

tuberculosis disease 10. Therefore, the risk of developing disease after being infected

depends largely on endogenous factors.

Untreated tuberculosis is often fetal and about one third of them die within 1 year;

half of them die within five years I . Five-year mortality among sputum smear positive

6 .19.111111111 Assessment eel community infe.oion ratio in the Model DO.1 .S Project arca fol. tnheri calnsis control

case is 65%. Of the survivors at 5 years, about 60% undergo spontaneous remission, while the remaining still excrete tubercle bacilli II. The site of the disease, delay in diagnosis and treatment, and age of the person play an important role as risk factors that determine the probability that a diseased individual will die from tuberculosis 1° '

TUBERCULOSIS INFECTION

The probability of becoming infected with Mycobacterium tuberculosis depends on the number of infectious droplet nuclei present per volume of air (infectious particle density) and the duration of exposure of a susceptible individual to that particle density.

Talking, coughing, sneezing or singing produces droplets 12 and the droplets produced by a patient with bacteriologically positive tuberculosis may contain tubercle bacilli.

Successful transmission of the bacilli to an individual requires the airborne droplet nuclei to he small enough to reach the alveolus in the periphery of the lung; such kind of particles may remain suspended in air for several hours. Majority of the particles above 5 millimeter in diameter are trapped in the nostrils, while those smaller than 0.1 millimeter tend to remain suspended in air and are able to reach the alveoli 13 . Also, the number of bacilli found in the sputum specimen correlates well with its infectiousness 1 '1 . The probability of being infected following contact with an infectious source decreases with decreasing proximity of the contact person to the index case 15. Crowding in poorly ventilated rooms is one of the most important factors in the transmission of tubercle bacilli, since it increases the intensity of contact with a case.

The most effective intervention for reducing infectiousness is treatment of cases, which reduces their infectiousness within a matter of few weeks 16' 17 ; and adequate Assessment °Icor/imolai)/ iilib(3i0r1 ratio in the Model DOTS Project area lbr tuberculosis control

ventilation is the most important measure to reduce the infectiousness of the environment.

CONTROL OF TUBERCULOSIS

Tuberculosis control programmes worldwide have relied heavily on case detection and treatment of the diseased plus preventive therapy for young (less than 5 years of age) contacts with positive results in the purified protein derivative (PPD) skin 18 test . Detection and treatment of tuberculosis cases are the intervention strategies to prevent the progress of disease to death and preventive therapy is the intervention strategy to prevent the progress of infection to disease. This two-pronged approach followed by the tuberculosis control programmes, when implemented effectively, will result in cutting the chain of tuberculosis transmission leading to prevention of the progress from exposure to infection.

About 6% to 8% of recent infections evolve into clinical tuberculosis 19 and treating infection can prevent evolution to clinical tuberculosis. Preventive therapy

(secondary chemoprophylaxis) is applied either to freshly infected so-called tuberculin converters or to those who have been infected with virulent tubercle bacilli in the more distant past 19. Preventive therapy, the main alternative to treatment of the diseased, is recommended for people at high risk of developing tuberculosis, but not for the entire population because the incidence rates are lower than 0.2% per year in most parts of the world 18. Younger individuals benefit most from preventive treatment because the drug is most effective when the infection is recent and because older individuals often have already outlived a substantial part of their risk.

8 Assessment of community infection ratio in the Model DOTS Project arca 16r tuberculosis control

Based on evidence and scientific information, the Revised National Tuberculosis

Control Programme—RNTCP in India advocates preventive treatment with Isoniazid, five milligram per kilogram body weight, daily for six months, for all children less than six years of age who have a family member with bacillary pulmonary tuberculosis 20

IDENTIFICATION OF TUBERCULOSIS INFECTION

The tuberculin skin test is the standard method for detecting people infected with tuberculosis. It was first described in 1891 21. Even though a positive response is not diagnostic of tuberculosis, it significantly increases the suspicion of tuberculosis 22.

Despite a number of potential pitfalls in administration, reading and interpretation, it remains the most sensitive test for detection of tuberculosis infection 23. The tuberculin, purified protein derivative (PPD), developed by Florence Siebert in 1939, is a crude mixture prepared from filtrates of heat-sterilized cultures of Mycobacterium tuberculosis and it still remains the standard reference material for all tuberculin 24.

The tuberculin skin test is a simple, cheap and easy to read test. It is performed by injecting one unit of PPD-RT23 with Tween 80 * intradermally to produce a lump in the skin of 5 to 6 mm diameter. The test reaction is read 48 to 72 hours later 25. An indurated

In 1954, it was proposed that one very large batch of PPD should be prepared for intra- cutaneous tuberculin testing of human beings in a quantity sufficient to meet the world demands for 10 years. One of the aims in preparing such a large batch was to avoid some of the problems in standardizing tuberculin produced by different manufacturers. Such a batch, designated RT23, was prepared in Copenhagen between 1955 and 1957, and this has been issued since 1958. (Ref Lee B Reichinan. Tuberculin skin testing: the state of the art. Chest 1979; 76 (6) (Supply: 764-70) Unfortunately, RT23 is markedly affected by the adsorption of the active principle to the glass or plastic surfaces. To combat this, Tween 80, a polysorbate, is added to stabilize PPD. This polysorbate decreases the loss of potency of PPD. (Ref Tuberculin (Chapter 1). In: Mwavell Caplin (eds). The tuberculin test in clinical practice: an illustrated guide. Bailliere Tindall, London, 1980: 4)

9 Assessment of community infection ratio in the Model DOTS Project area for tuberculosis control

reaction at 48 to 96 hours is helpful in identifying persons who have been infected with

Mycobacterium tuberculosis 26

Bacillus Calmette Guerin (BCG) vaccination induces PPD hypersensitivity. Prior vaccination with BCG is a possible source of 'false-positive' tuberculin skin test 27 because sensitivity following natural infection cannot be separated from sensitivity following BCG vaccination 27. But post-vaccination sensitivity is observed to peak at 2'12 months after which it begins to wane with time 2 Also, the dermal reaction following

BCG is usually not as large as that which follows natural infection and varies between different strains of vaccine 29.

REVISED NATIONAL TUBERCULOSIS CONTROL PROGRAMME (RNTCP)

RNTCP is being implemented in India in a phased manner, starting in 1993 3t); it has adopted the World Health Organization's strategy of DOTS (directly observed treatment, short course) for tuberculosis control. Large-scale implementation began in the late 1998 31 and from 1993 through mid 1999, more than 1,46,000 tuberculosis patients were started on treatment 32. Treatment success rates are more than double and the death rates are less than a seventh, compared to the previous National Tuberculosis Programme

(NTP) 32. Now, India has the second largest, next to China in size, and the fastest growing tuberculosis control programme in the world following universal DOTS strategy, covering more than 45() million of India's one billion population, up from less than 2% in mid 1998, and is still expanding 31 . The current challenge is to maintain the quality of implementation during the continued expansion phase, when the entire country will be

10 Assessment of community infection ratio in the. Model DOTS Project area for tuberculosis control

covered as soon as technically and operationally feasible 30, which is expected to cover

80% of the country by 2004 and the entire country by 2005 7' 31 .

ASSESSMENT OF COMMUNITY INFECTION RATIO (CIR)

As RNTCP is being implemented, one of the crucial programme management

strategies is to periodically assess its impact in bringing down the burden of disease in the

population. This is done based on evaluation of programme indicators like tuberculosis case detection rate, sputum smear conversion rate and tuberculosis cure rate. The ultimate goal of the programme is to create an epidemiological impact on the transmission dynamics of the disease in the community. Trend analysis of the prevalence and incidence of both tuberculosis disease and infection over time is the gold standard impact assessment tool currently available. But conducting periodic disease surveys for tuberculosis in such a vast country like India with more than one billion population is near to impossible with the available scarce resources. The next alternative is the conduction of infection surveys with the help of tuberculin. The main drawback with the technique is that tuberculin is an invasive procedure requiring syringes and needles for its administration intradermally. Also, it is a cumbersome procedure for conducting population surveys and needs expertise in the form of standardized tuberculin testers and readers. As on date, there is no simple, and easy to use rapid epidemiological assessment tool for tuberculosis control.

Effective implementation of tuberculosis control strategies is expected to result in cutting down the chain of transmission, thus stopping the bacillary positive population from exposing and infecting new people. Though the importance of the household as the

11 AS4e:ot7liv111 t11 commuillly uilrrIiuu toll° til 1114, rtitmiel DOI% holt t I melt lot litIktictlitirtm c ∎ totlittl

main source of infection has been assumed, it is not well-documented B. Assessment of

CIR, which is the odds ratio of tuberculin positive 'controls' to that of 'contacts' 33, is expected to throw light on the situation as to the source of infection to the younger population of the community. When assessed periodically over time, the relative shift in the source of infection from the household to the community can be studied, which implies a good programme implementation.

12 Aonsmall (-Pon/mull/127 (51-Oceirm (9a--Irr, in 1116)

"aC,IVel a-t-ca- fir rnbcrailosis (Fontroi

Aim 00ectigros,.

13 Assessment of community infection mho in the Model DUES Project area for tuberculosis control

AIM OF THE STUDY

The aim of the study is to compare the tuberculin reactivity in children between one and fifteen years of age who share the same household with a person who has a newly diagnosed active form of (bacteriologically positive) pulmonary tuberculosis and among those without such a contact.

OBJECTIVES

1. To assess the tuberculosis infection status in children with and without a close

family contact suffering from a newly diagnosed bacteriologically positive

pulmonary tuberculosis.

2. To calculate the odds ratio of tuberculin positive children without a close family

contact with a newly diagnosed bacteriologically positive pulmonary tuberculosis

patient to that of tuberculin positive children with such a contact (Community

Infection Rat io—C

oip, oip,

Ito1p 0 ajmnuriuolo ajmnuriuolo 0 * . 01/i Lfu Lfu 01/i /149111559.5-5F /149111559.5-5F

0& ppoyp„ ppoyp„ 0& ) IK)0 sisoino,agnQ - j j -1‘Y P0,09 JOal.I P0,09

dFolopoqpyp dFolopoqpyp ci ci Assessment of community infection ratio in the Model DOTS Project area for tuberculosis control

METHODOLOGY

Preamble

The 'Model DOTS Project- MDP', based on the Revised National Tuberculosis

Control Programme—RNTCP, was initiated in May 1999 in a population of about 5.8

lakhs in Tiruvallur District, Tamil Nadu, India. Its main objective is to establish a model

center for rural 'directly observed treatment, short course—DOTS' implementation,

training and research in tuberculosis control. The population covered by the MDP is the

same as that covered by the `Chengleput BCG Trial'. Assessment of the potential

epidemiological impact of the DOTS strategy in cutting down the chain of transmission,

thus affecting the transmission dynamics of tuberculosis, is the integral part of the

project. Tuberculosis disease surveys, and tuberculin surveys to assess the annual risk of

tuberculosis infection (ARTI), are being conducted periodically to assess the changing

trend of the disease and infection rates over time in that community following

implementation of control strategies.

1. Study population

Children between one and fifteen years of age who are clinically normal, residing

in the Model DOTS Project area form the study population. They arc either living with or

without a close family contact who is a newly diagnosed bacteriologically positive

pulmonary tuberculosis patient. Assessment of community infection ratio in the Model DO I'S Project area for tobetetilosis control

2. Study Area and Sampling frame

A population of 5.8 lakhs belonging to a tuberculosis unit (TU) in Tiruvallur district, Tamil Nadu, adopted by the Tuberculosis Research Centre for the MDP, forms the sampling frame. The population is spread over an area of 659.53 sq kms and the study area covers the whole of the TU, comprising of five blocks namely Ellapuram, Ikkadu,

Kadambathur, Poondi and Thiruvalangadu [Table 1]. Each block has three primary health centres (PHC); apart Ikkadu and Poondi blocks has a general hospital each. Thus, the study area was the population catered by these 15 PHCs and 2 general hospitals.

3. Contact-Control household definition

Contact: A 'contact household' is defined as one with a newly diagnosed bacteriologically positive pulmonary tuberculosis patient and has one or more children between one and fifteen years of age.

Control: A 'control household', selected from the same village as that of the contact household, is defined as one that is free of tuberculosis (any form of tuberculosis, both at present and in the past) and has one or more children between one and fifteen years of age.

Contact-Control Ratio: One contact household and four corresponding control households from the same village forms a cluster.

4. Sample size

For a probability of being infected while residing at the control household as 20%, a case-control ratio of 1 : 4, a statistical power of 80% with a 95% confidence interval,

d d ie d tu s

HHs HHs

e e cas

4 5

2 1

2 3

1 1

N 2 f f SS+ve SS+ve o No.

dren dren il h c

h h it w HHs HHs case case

1 2

2 15

3 1

1 4

e e f NSS+v f o No. No.

cases cases NSS+ve NSS+ve

h h it w H f f Hs Hs o No. No. 2 2

4 2

2 12 23 3

2 4

(

s s ll) ll) a case

h h it w HHs HHs f f o

No. No. 75 28 57

107 49 22

43 27

s) s) re ta Hec ( a a Are

241.6

318.16 875.07

232.13

294.07

187.18

710.47

749.35

714.12

139.73 1262.1

360.91

955.55 454.68

438.29

) ) "/D ( ion ion t la u op p

ta l l to to to

C f f hildren hildren o No No 30.2

30.1

26.8 30.3 27.9 27.8

32.9

30.1 33.2

27.9

28.3 30.9

30.8 32.4 23.9

Sex

Ratio

918.5

854.5

877.0 876.4 954.4

891.7 919.4

968.7 968.8

898.1

955.3 969.6 1053.5 852.5

1078.2

351 516 Total 471

653 810

638 1742 754 1326 630

298

713 831

402

1118

834 611 164

241 230

335

388

527

331 310

371 141

406

351 185

Female

Population less than 15 years

Male 908

715 187

275 241

318

422 591

307

320

157 383

362 425

217

Page 1 of 2

Sex

Ratio

980.1 978.5

1009.2 1020.2

1064.7

1032.0 1056.0

1053.7 1068.9

1015.2

1035.2 1068.7

1007.4

1052.2

1052.4

(Enumeration • 1999)

Total

5770

4410 964 1310 1703

1691

2353,

2459 1922 3709

2255

2660

2200 2696 1683

658 860

872

2856 993

2181

498

Total Population

1195 1263 863 1903

Female

1136

1353

Baseline Survey - Model DOTS Project area - TRC

1128 1353

Male

652

819 843

929 2914

2229

466

1158

820 1196

1806

1119

1307

1343

1072

lds lds se ho Hou

f f o ber ber m Nu

336 368 468

580

698

566 1328 593 751 1065

293 713

552

453

1146

Study Village

Name of the CIR

Periyapalayam

Vengal

irulanjeri

Kallambedu Koovam

Kottaiyur

Tirupandiyur

Thodukadu

Pirayankuppam

Mudugur Vidaiyur

Mambakkam

de de Co e e llag Vi

4 2

8 10 Sethupakkam 9

• • 8

10 Polivakkam 11

12 Voyalur

ea ea k ar k loc l B l ta To

Km Km 54 Sq Sq 54 260.

E cr

O vi

0) cr>

Table 1: Disease Survey and Tuberculin Survey Villages (with NSS+ve cases & Children less than 15 years

k 7 7 k Bloc MDP MDP

LT,

1 2 3

4 5

7 8 ONS 9

d d die tu s

HHs HHs case case

1 1

1 2

4 1

NSS+ve NSS+ve f f o No. No. 55

hildren hildren c

h h it w HHs HHs ase ase c

2 1

1 1

6 2

NSS+ve NSS+ve f f o No. No. 77

cases cases e e S+v NS

h h it 1 w f HHs HHs f o 3 No. No. 7

2 3

3 9

118

ll) ll) (a cases cases

h h it w f HHs HHs f o No. No. 24 29

57 40

71 31

1274

) ) res ta Hec ( a a Are

379.4

1312.6 454.08 473.97 431.66 374.84

579.12 413.11

547.62 494.78 1520.7

289.89 16335

648.14

481.55

%) %) ( ion ion t la u op p

l l ta to to to

f Children Children f o No No 27.2 29.1 28.1 29.6 29.4

38.8

31.5 27.1

23.2

29.1

26.7 29.4 29.2

27.9

29.4

Sex

Ratio

947.2 992.2 840.0 993.7

823.5

967.7

964.3 951.2 935.0

909.8

946.9

1019.6

1038.2

1071.9

1222.2

368

553 512 824 632

640

Total 288

244 372 770 300

387

487

1200

18830

168

269

255 315

416

326 149

120

168

165

378 187 585

232

9158

Female

Population less than 15 years

284 200

Male 408 257 317

314

139

124 135 204

392

200 255

615

9672

Page 2 of 2

Sex

Ratio

989.8 992.8

986.4

989.7

1006.1

1027.9

1007.5

1061.3

1044.7

1013.4

1170.5 1007.6

1046.1 1002.0

1021.2

(Enumera ion - 1999)

Total 914

902

1310

2034

1759

2784 2148

1649

1605

1031

2887

1327 1747

4088

63970

657

875

849

467

454

797 556

666

869

1031

1387 1078

Total Population 1476

2046

Female

Baseline Survey - Model DOTS Project area - TRC

32320

884 653

Male

800

447

448

808

475 661

878

1003

1397 1070

1411

2042

31650

lds lds ho House

f f o ber ber Num

594 339

455

517 702

399 216

465

253

315

879

331

991 474

16840

Study Village

Name of the CIR

Kaverirajapuram Tholudavvur Kanchipadi

Manur Chinnamapet

Harichandrapura Orathur

Athipattu

Poonimangadu

Kuppamkandigai

Kakkalur

Melakondaiyur

de de Co e e Villag

2 4

6 7

10 Nedumbaram

13 Arumbakkam

16 14

rea rea k a k l Bloc l ta To Cr

Table 1: Disease Survey and Tuberculin Survey Villages (with NSS+ve cases & Children less than 15 years)

,;; Y k k P Bloc P MD

du du a lang a Thiruv

o n

17 19 16 18

Total '

22 24 23

25 27

kg) Assessment of community infection ratio in the Model DUI 'S Project area Ior tuberculosis control

the sample size calculated using the software package EPI-INFO* ver 6.04b is fifty (50) clusters, to be selected randomly from the community in the MDP area.

5. Methods

The MDP area comprises of 218 villages with habitats. The disease and tuberculin surveys are conducted on a representative sample, with the unit of randomization being a village. A total of 67 villages (9 villages in Ellapuram block, 15 villages in Kadambathur block, 14 villages in Poondi block, 16 villages in Thiruvalangadu block and 13 villages in

'firuvallur block) are randomly selected (to satisfy sample size calculation) for tuberculosis disease survey; and mutually exclusive one third of the villages are randomly selected for every round of tuberculin survey. The baseline survey was conducted between December 1998 and June 2001 (21 /2 year period). All the residents ofthe selected villages who were more than 15 years of age are subjected to symptom screening, exposure to mass miniature radiography, and sputum examination; those below 15 years were subjected to tuberculin skin testing. This gives the disease status in the population above 15 years of age and infection status in the population below 15 years of age.

Both the baseline disease and infection surveys were conducted in 39 villages, out of which 29 villages had households with new bacteriologically positive pulmonary tuberculosis patients and children less than 15 years of age (with tuberculin status).

Among a population of 63970 in these 29 villages living in 16840 households, 1274

Ref Fleiss, "Statistical Methods for Rates and Proportions". 2nd ed., Wiley, 1981, pp. 38-45.

20 Assessment or community infection ratio in the Model DOTS Project area liar tuberculosis control

households had cases of any form of tuberculosis (both old and new cases); 77

households had a new bacteriologically positive patients and children less than 15 years

of age. One village (Vengal) had about 20% (15/77) of all the households with new

bacteriologically positive pulmonary tuberculosis patients. In order to give equal

representation to all the villages, 50% of the households (7/15) were randomly selected and included among contact households to be evaluated.

Selection of contact & control households

Out of the total 69 contact households, 6 households had migrated and could not be traced; 5 households had bacteriologically positive pulmonary tuberculosis patients who have had previous history of tuberculosis treatment; and 3 households had two patients with bacteriologically positive pulmonary tuberculosis. After exclusions, 55 households were included as contact households to be evaluated [Table 1].

The control households were chosen randomly from the same village as that of the selected contact households; they did not have or had any member of the household suffering or suffered from any form of tuberculosis and they were geographically situated two streets apart or more than 100 feet away from households with any form of tuberculosis.

The contact households were visited individually to confirm their disease status namely, previous history of tuberculosis in the household, and baseline characteristics of the house, households and individual children within the household. The control households were visited to confirm their geographical position, their non-disease status, and baseline characteristics of the house, households and individual children within the

21 Assessment of community infection ratio in the Model DOTS Project area for tuberculosis control

household. If the household had more than one child, then one child was randomly selected from within the household for the study purpose.

The tuberculin status of the selected children was taken from the tuberculin survey data. Trained and standardized 'testers' of the Tuberculosis Research Centre

Epidemiology Unit administered the tuberculin skin test; and also, trained and standardized 'readers' performed the tuberculin skin test reading. The test was performed using 1TU of PPD-RT23 Tween 80, given intradermally on the volar surface of the left forearm. The reading was done 48 to 96 hours after the testing.

6. Data entry and analysis

The data collected, based on a pre-prepared questionnaire [Annexure 1 to 3], was entered in Microsoft Excel workbook (MS Office 2000) and the analysis was done using

SPSS ver 8.0 for Windows and EPI INFO ver 6.04b with Y2k compatibility.

Chi-square tests, Chi-square tests for linear trend, and Student 1' tests were used as measures of statistical significance. Odds ratio were used as measures of association.

7. Definitions of parameters used during analysis

Household characteristics like 'family size', 'number of adults', 'number of children', 'total expenditure on food', 'per-capita expenditure on food', and 'number of rooms', characteristics of children like 'age group', 'weight', 'height', and body mass index (BMI) [weight (in kilograms) divided by height square (height in metres)], and characteristics of contact patients like 'age group' were grouped based on tertile values of the total population.

22 ASStiSSMICIll Of COMMLItlity 1.11reCtil/11 ruin in the Model DOTS Project :ova for otherettloSIS cnntrnl

The weight for age and height for age of the children was calculated based on data for affluent Indian children taken from reference number 34. 'Normal' was defined as th those values between the 10th and 90 percentiles. All values below this cut off was taken as 'below normal' and all values above this cut off as 'above normal'. The weight for

age, height for age, and BMI were used as proxy variables to assess the nutritional status

of the children.

The sputum smear grading for acid-fast bacilli was done as per the reference

number 35.

Relationship of the contact 'case' to the child was graded as 'first order' if the

contact was a father, mother or brother of the child, and as 'second order' if the contact

was an uncle, aunt, grandparents or great grandparents.

8. Calculation of Community Infection Ratio

The community infection ratio [CIR] is an index to describe the ratio between the

risk of transmission of tuberculosis in the community to the risk of transmission to

household contacts. The higher the CIR, the higher is the risk that tuberculosis infection

is transmitted outside the immediate household.

The CIR and 95% confidence interval was calculated as an index of the relative

importance of within-household and community spread of tuberculosis infection. It is

defined as the odds ratio of PPD-positive 'controls' to PPD-positive 'contacts' and is

calculated as

CIR = Prevalence of infection in controls 1(1 - Prevalence of infection in controls) x 100 Prevalence of infection in contacts 1(1 - Prevalence of infection in contacts).

23 Assessment of Fong/mm.1p 71/1eatim- Ca-tth m the ibcirodcl3aD(C35 'Zirject"area * Vuberculosis Fmtrol

6asitits Assessment or community infection ratin in the Model DOTS Project are:116r tuberculosis 0.111 ml

RESULTS

A total of 274 children, 55 from contact households and 219 from the control households, were studied. Their baseline characteristics are presented in Tables 2 to 5.

Household characteristics

The median family size was 5 and the median number of adults and children in a family was 3 and 2, respectively. The contact households had a bigger family size with more number of adults. The odds ratio was 2.71 for a family size more than 6 as against 1 for those less than 4; the odds ratio was 3.54 for households with more than 4 adults as against 1 for those with less than 2. Ventilation of the household was better among the control households than the contact households. Except for crowding and ventilation of the households, other household characteristics, namely, number of rooms in the house and per-capita expenditure for food was similar among the contact and control households [Tables 2 & 5].

Characteristics of children

There was no statistically significant difference between the children in the contact and control households with regard to age, sex, weight, height, BCG scar status, history of BCG vaccination and BMI [Tables 3 & 5]. Children in the contact households were comparable with those in the control households, except for the presence of a close family contact with a newly diagnosed bacteriologically positive pulmonary tuberculosis patient.

•

Table 2: Frequency distribution of household characteristics of study population

Total Chi-Square S No Characteristic Contacts A Controls population A value

Total Population 274 (100) 55 (100) 219 (100)

II Characteristics of households

"I Family size (Range: 2 to 14)

Less than 4 93 (34) 17 (30.9) 76 (34.7)

4 to 6 136 (49.6) 21 (38.2) 115 (52.5) 4.449*

More than 6 45 (16.4) 17 (30.9) 28 (12.8) (p = 0.035)

2 Total number of adults (Range: 1 to 8)

Less than 2 114 (41.6) 12 (21.8) 102 (46.6)

2 to 4 126 (46) 33 (60) 93 (42.5) 9.847*

More than 4 34 (12.4) 10 (18.2) 24 (10.9) (p = 0.002)

3 Total number of children (Range: 1 to 6)

1 69 (25.2) 17 (30.9) 52 (23.7)

2 113 (41.2) 21 (38.2) 92 (42) 0.832*

More than 2 92 (33.6) 17 (30.9) 75 (34.3) (p = 0.362)

4 HH Expenditure for food (Range: Rs 200/- to Rs 10000/- pm)

Less than Rs 901/- per month 95 (34.7) 19 (34.5) 76 (34.7)

Rs 901/- to 1500/- per month 115 (42) 23 (41.8) 92 (42) 0.002*

More than Rs 1500/- per month 64 (23.3) 13 (23.7) 51 (23.3) (p = 0 965)

5 Percapita expenditure for food (Range: Rs 50/- to Rs 1250/- pm)

Less than Rs 1681- per month 95 (34.7) 22 (40) 73 (33.3)

Rs 168/- to 250/- per month 90 (32.8) 15 (27.3) 75 (34.3) 0.264*

More than Rs 250/- per month 89 (32.5) 18 (32.7) 71 (32.4) (p = 0.607)

6 Number of rooms (Range: 1 to 11)

1 89 (32.5) 18 (32.7) 71 (32.4)

2 to 3 137 (50) 28 (50.9) 109 (49.8) 0.028*

More than 3 48 (17.5) 9'(16.4) 39 (17.8) (p = 0.867)

7 Ventilation

Present 81 (29.6) 10 (*18.2) 71 (32.4) 4.28

Absent 193 (70.4) 45 (81.8) 148 (67.6) (p = 0.04)

Chi-square value for linear trend A Figures within brackets represent percentages

Table 3: Frequency distribution of baseline characteristics of children

Total Chi-Square S No Characteristic Contacts " Controls ^ population A value 1 Total Population 274 (100) 55 (100) 219 (100)

11 Characteristics of children

1 Age group (Range: 2 to 16 years)

Less than 6 years 51 (18.6) 9 (16.4) 42 (19.2)

6 to 10 years 130 (47.4) 20 (36.4) 110 (50.2) 3.315 *

More than 10 years 93 (34) 26 (47.2) 67 (30.6) (p = 0.07) 2 Bex

Female 138 (50.4) 22 (40) 116 (53) 2.96

Male 136 (49.6) 33 (60) 103 (47) (p = 0.09) BCG scar status Present 154 (56.2) 32 (58.2) 122 (55.7) 0.11

Absent 120 (43.8) 23 (41.8) 97 (44.3) (p = 0.74) 4 History of BCG vaccination Present 197 (71.9) 40 (72.7) 157 (71.7) 0.02

Absent 77 (28.1) 15 (27.3) 62 (28.3) (p = 0.88) 5 Weight (Range: 9 to 63 kgs)

Less than 18 kgs 93 (34) 20 (36.4) 73 (33.3)

18 to 26 kgs 91 (33.2) 9 (16.4) 82 (37.5) 1.479 *

More than 26 kgs 90 (32.8) 26 (47.2) 64 (29.2) (p = 0.224) 6 Weight for age

Below NORMAL 80 (29.2) 20 (36.4) 60 (27.4)

NORMAL 190 (69.3) 34 (61.8) 156 (71.2)

Above NORMAL 4 (1.5) 1 (1.8) 3 (1.4)

7 Height (Range: 71 to 175 cms)

Less than 114 cms 93 (34) 20 (36.4) 73 (33.3)

114 to 133 cms 90 (32 8) 11 (20) 79 (36.1) 0.654 *

More than 133 cms 91 (33.2) 24 (43.6) 67 (30.6) (p = 0,419) 8 Height for age

Below NORMAL 75 (27,4) 16 (29.1) 59 (27)

NORMAL 192 (70 1) 38 (69.1) 154 (70.3)

Above NORMAL 7 (2.5) 1(1.8) 6 (2.7)

9 Body Mass Index (Range: 10.93 to 23.71)

Less than 14 87 (31.7) 17 (30.9) 70 (32)

14 to 15.5 103 (37.6) 18 (32.7) 85 (38.8) 0.471

More than 15.5 84 (30.7) 20 (36.4) 64 (29.2) (p = 0.492)

' Chi-square value for linear trend Figures within brackets represent percentages 27 Assessment of community infection ratio in the Model DOTS Project area Ibr tuberculosis control

Characteristics of the contact tuberculosis patients

More than 70% (40/55) of the patients were between 30 and 60 years of age.

Majority of the patients (47/55) were males. There were less number of patients with

grade-3 sputum smear positives for acid-fast bacilli (6/55) when compared with patients

with grade-1 smear positives (33/55) [Tables 4 & 5].

INTERPRETATION OF TUBERCULIN SKIN TEST

The cut off point for interpretation of the tuberculin skin test as either positive or

negative was estimated using the anti-mode method. In this method, the frequency

distribution of the tuberculin reading of all the 274 children was plotted [Figure 1]. The

anti-mode of the distribution was between 11 and 12 mins. So, the cut off point for the

skin test positivity was taken as above 11 mms.

Out of the 274 children, 46 (16.79%) were tuberculin positive. Stratified analysis of the population showed that 41.8% (23/55) of the children were tuberculin skin test positive among those with a close family contact with a new bacteriologically positive pulmonary tuberculosis patient and 10.5% (23/219) of the children were tuberculin skin test positive among those without a close family contact.

Characteristics of the households

A statistically significant difference was observed between the tuberculin positive and negative group with regard to their family size, number of children in the household and ventilation of their residence [Table 6 & 9]. The number of rooms and expenditure on food, both total and per capita, did not influence the tuberculin status of the children. The

Table 4: Frequency distribution of baseline characteristics of contact cases

S No Characteristic Contacts "

I Characteristics of the new bacillary positive pulmonary tuberculosis cases

1 Age group (Range: 22 to 82 years)

Less than 30 years 8 (14.5)

30 to 40 years 11 (20)

40 to 50 years 14 (25.5)

50 to 60 years 15 (27.3)

More than 60 years 7 (12.7)

2 Sex

Female 8 (14.5)

Male 47 (85.5)

3 Sputum smear grades* for acid fast bacilli

Grade - 1 33 (60)

Grade - 2 16 (29.1)

Grade - 3 6 (10.9)

4 Relationship** with the child studied

First order relation 37 (67.3)

Second order relation 18 (32.7)

Grade-1 = 10-99 acid-fast bacilli per 100 oil immersion fields

Grade-2 = 1-10 acid-fast bacilli per oil immersion field

Grade-3 = More than 10 acid-fast bacilli per oil immersion field

** First order relation = Father, mother or brother

Second order relation = Uncle, aunt, grand parents or great grand parents

A Figures within brackets represent percentages

29 Table 5: Mean distribution of baseline .1-laracteristics of study population

Student 't' test S No Characteristic Total population " Contacts A Controls A value

I Total Population 274 55 219

II Characteristics of households

Average number of family 5.27 (5.08 to 5.46) 5.67 (5.23 to 5.12) 5.17 (4.96 to 5.38) 4.33 (p = 0.038) members

2 Average number of adults 3.07 (2.92 to 3.23) 3.6 (3.23 to 3.97) 2.94 (2.78 to 3.11) 11.884 (p = 0.001)

3 Average number of children 2.2 (2.08 to 2.32) 2.07 (1.82 to 2.33) 2.23 (2.09 to 2.36) 1.071 (p = 0.302)

Average household expenditure 4 1364.78 (1246.18 to 1483.39) 1340.91 (1130.12 to 1551.70) 1370.78 (1231.44 to 1510.12) 0.039 (p = 0.843) for food per month Average percapita expenditure for 5 265.1 (244.45 to 255.75) 248.27 (209.37 to 287.17) 269.33 (245.3 to 293.36 0.646 (p = 0.422) food per month

6 Average number of rooms 2.31 (2.13 to 2.48) 2.18 (1.84 to 2.53) 2.34 (2.14 to 2.54) 0.501 (p = 0.48)

III Characteristics of children

Mean age (years) 8.72 (8.24 to 9.19) 9.64 (8.46 to 10.82) 8.48 (7.97 to 8.99) 3.765 (p = 0.053)

2 Mean weight (kgs) 23.65 (22.43 to 24.88) 25.84 (22.75 to 28.92) 23.11 (21.78 to 24.43) 3.124 (p = 0.0780

3 Mean height (cms) 122.82 (120.11 to 125.52) 127.15 (120.8 to 133.49) 12 1.7 3 (118.74 to 124.72) 2.507 (p = 0.115)

IV Characteristics of new bacillary positive pulmonary tuberculosis cases

Mean age (years) 46.98 (43.11 to 50.85)

Figures in brackets represent 95% Confidence Interval

80 77 Figure 1: Frequency distribution of tuberculin skin test reading among the study population 70

hildren Antimode of this distribution falls at 11-12mms. f c 40 So, the tuberculin skin test positivity in this population is taken as above 11 mms. o ber

Num 30 24 21 20 17 14 13

10 8 7 7 6 6 5 4 4 5 3 \\: 2 2 0 :=s

0 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 24 Tuberculin skin test reading (in rrini)

Table 6: Distribution of tuberculin results by household characteristics

Total Tuberculin skin test result Chi-Square S No Characteristic population ^ Positive ^ Negative A value I Total Population 274 (100) 46 (100) 228 (100)

II Characteristics of households 'I Family size (Range: 2 to 14)

Less than 4 93 (34) 21 (45.7) 72 (31.6)

4 to 6 136 (49.6) 21 (45.7) 115 (50.4) 4.4 •

More than 6 45 (16.4) 4 (8.6) 41 (18) (p = 0.036) 2 Total number of adults (Range: 1 to 8)

Less than 2 114 (41.6) 17 (37) 97 (42.5)

2 to 4 126 (46) 25 (54.4) 101 (44.3) 0.011 *

More than 4 34 (12.4) 4 (8.6) 30 (13.2) (p = 0.918) 3 Total number of children (Range: 1 to 6)

1 69 (25.2) 20 (43.5) 49 (21.5)

2 113 (41.2) 17 (37) 96 (42.1) 9.903 *

More than 2 92 (33.6) 9 (19.5) 83 (36.4) (p = 0.0017) 4 HH Expenditure for food (Range: Rs 200/- to Rs 10000/- pm)

Less than Rs 9011- per month 95 (34.7) 16 (34.8) 79 (34.6)

Rs 901/- to 1500/- per month 115 (42) 21 (45.7) 94 (41.2) 0.148 *

More than Rs 1500/- per month 64 (23.3) 9 (19.6) 55 (24.1) (p = 0.7) 5 Percapita expenditure for food (Range: Rs 50/- to Rs 1250/- pm)

Less than Rs 1681- per month 95 (34.7) 15 (32.6) 80 (35.0)

Rs 168/- to 250/- per month 90 (32.8) 16 (34.8) 74 (32.5) 0.039 *

More than Rs 250/- per month 89 (32.5) 15 (32.6) 74 (32.5) (p = 0.84) 6 Number of rooms (Range: 1 to 11)

1 89 (32.5) 17 (37) 72 (31.6)

2 to 3 137 (50) 22 (47.8) 115 (50.4) 0.529

More than 3 48 (17.5) 7 (15.2) 41 (18) (p = 0.467) L 7 Ventilation

Present 81 (29.6) 8 (17.4) 73 (32) 3.932

Absent 193 (70.4) 38 (82.6) 155 (68) (p = 0 047) 8 Family contact with a new bacteriologically positive tuberculosis case

Present 55 (20.1) 23 (50) 32 (14) 30.86

Absent 219 (79.9) 23 (50) 196 (86) (p = 0.00000) • r-h{-square value for linear trend

A Figures in brackets represent percentages

32 Assessment of community infection ratio m the Model 1)015 Project area Mr tubereuloSIti C(1111'01

odds ratio was 0.33 for a family size more than 6 and 0.63 for a family size between 4 and 6 as against 1 for those less than 4; the odds ratio was 0.27 for households with less than 2 children and 0.43 for households with 2 children as against 1 for those with 1

child. The odds ratio was 0.72 for households with more than 3 rooms 0.81 for

households with 2 to 3 rooms as against 1 for households with one room.

Characteristics of children

Age of the child, and also their weight and height influenced tuberculin positivity.

As age increased, the probability of a child being tuberculin positive also increased. The

odds ratio was 5.06 for children more than 10 years of age, 1.42 for children between 6

and 10 years of age as against 1 for children less than 6 years of age.

A similar pattern was also observed for the weight and height of the child. The

odds ratio was 5.84 for children more than 26 kg weight, 1.52 for children between 18

and 26 kg weight as against 1 for children less than 18 kg weight. The odds ratio was

5.18 for children more than 133 cm tall, 1.89 for children between 114 and 133 cm tall as

against 1 for children less than 114 cm tall.

Sex of the child, BCG scar status, history of BCG vaccination, and BMI did not

influence tuberculin positivity [Tables 7 & 9].

Characteristics of the contact tuberculosis patients

The age and sex of the contact patient did not have an influence on the tuberculin

status of the child, whereas, the relationship of the contact with the child and the grade of

sputum positivity of the contact patient had a significant influence on the tuberculin

status of the child [Table 8 & 9].

Table 7: Distribution of tuberculin results by characteristics of children

Total Tuberculin skin test result S No Characteristic Chi-Square population A Positive A Negative " value

I Total Population 274 (100) 46 (100) 228 (100) II Characteristics of children

Age group (Range: 2 to 16 years)

Less than 6 years 51 (18.6) 4(8.7) 47 (20.6) 6 to 10 years 130 (47.4) 14 (30.4) 116 (50.9) 14.894 * More than 10 years 93 (34) 28 (60.9) 65 (28.5) (p = 0 00011) 2 Sex

Female 138 (50.4) 21 (45.7) 117 (51.3) 0.491

Male 136 (49.6) 25 (54.3) 111 (48.7) (p = 0.483) 3 BCG scar status

Present 154 (56.2) 26 (56.5) 128 (56.1) 0.002

Absent 120 (43.8) 20 (43.5) 100 (43.9) (p = 0.962) 4 History of BCG vaccination

Present 197 (71.9) 34 (73.9) 163 (71.5) 0.111

Absent 77 (28.1) 12 (26.1) 65 (28.5) (p = 0.739) 5 Weight (Range: 9 to 63 kgs)

Less than 18 kgs 93 (34) 7 (15.2) 86 (37.7)

18 to 26 kgs 91 (33.2) 10 (21.7) 81 (35.5) 19.74 "

More than 26 kgs 90 (32'.8) 29 (63) 61 (26.8) (p = 0.00001) 6 Weight for age

Below NORMAL 80 (29.2) 11 (23.9) 69 (30.3)

NORMAL 190 (69.3) 35 (76.1) 155 (68)

Above NORMAL 4 (1.5) 0 (0) 4 (1.7) 7 Height (Range: 71 to 175 ems)

Less than 114 cms 93 (34) 7 (15.2) 86 (37.7)

114 to 133 cms 90 (32.8) 12 (26.1) 78 (34.2) 16.031 *

More than 133 cms 91 (33.2) 27 (58.7) 64 (28.1) (p = 0.00006) 8 Height for age

Below NORMAL 75 (27.4) 10 (21.7) 65 (28.5)

NORMAL 192 (70.1) 36 (78.3) 156 (68.4)

Above NORMAL 7 (2.5) 0 (0) 7(3.1) 9 Body Mass Index (Range: 10.93 to 23.71) Less than 14 87 (31.7) 14 (30.4) 73 (32) 14 to 15.5 103 (37.6) 15 (32.6) 88 (38.6) 0.512 * More than 15.5 84 (30.7) 17 (37) 67 (29.4) (p = 0.474) *Chi-square value for linear trend A Figures in brackets represent percentages

34 Table 8: Distribution of tuberculin results by characteristics of contact cases

S No Characteristic Tuberculin skin test result Total population A Chi-Square Positive A Negative A value I Total Population 55 (100) 23 (100) 32 (100) ft Contacts of new bacteriologically positive tuberculosis cases

1 Age group

Less than 40 years 19 (34.6) 9 (39.1) 10 (31.3)

40 to 53 years 18 (32.7) 9 (39.1) 9 (28.1) 1.4 * More than 53 years 18 (32.7) 5 (21.8) 13 (40.6) (p = 0.237) 2 Sex

Female 8 (14.5) 3 (13) 5 (15.6)

Male 47 (85.5) 20 (87) 27 (84.4) 3 Sputum smear grades** for acid fast bacilli

Grade - 1 33 (60) 7 (30.4) 26 (81.25) 14.4 Grade - 2 16 (29.1) 12 (52.2) 4(12.5) (p = 0.0001) Grade - 3 6 (10.9) 4 (17.4) 2 (6.25) 4 Relationship*** with the child studied

First order relation 37 (67.3) 19 (82.6) 18 (56.25) 4.22 Second order relation 18 (32.7) 4 (17.4) 14 (43.75) (p = 0.039)

Grade-1 = 10-99 acid-fast bacilli per 100 oil immersion fields

Grade-2 = 1-10 acid-fast bacilli per oil immersion field

Grade-3 = More than 10 acid-fast bacilli per oil immersion field

*** First order relation = Father, mother or brother

Second order relation = Uncle, aunt, grand parents or great grand parents

' Chi-square value for linear trend ^ Figures in brackets represent percentages

35 value

3.43 (p = 0.065)

Student test

0.002 (p = 0.964) 8.824 (p = 0.003)

0.987 (p = 0.321)

0.063 (p = 0.802)

1.015 (p = 0.315)

21.755 (p = 0.000) 18.889 (p = 0.000)

20.789 (p = 0.000)

1.635 (p = 0.207)

228

(2.9 to 3.25)

(5.13 to 5.57)

(2.15 to 2.41)

(2.15 to 2.54)

(242,7 to 289.88)

(7.73 to 8.74)

(21.18 to 23.77)

(1254.28 to 1529.06)

(43.37 to 54_75)

(117.18 to 123.02)

Negative

3.07

5.35

2.28

2.35

8.23

22.48

49.06

266.29

120.1

1391.67

to 49.15)

75 to 2.47)

Tuberculin skin test result

(4.5 to 5.24)

(2.73 to 3.4)

(1.55 to 2.06)

(219.27 to 299.19)

(26.44 to 32.51) (130.4 to 142.16)

(1039.03 to 1424.01)

Positive

4.87

3.07 1.8

2.11 (1.

1 1 .1 1 (10.07 to 12.15)

29.48

44.09 (3103

136_28

259.23

1231.52

274

(5.08 to 5.46)

(2.92 to 3.23)

(2.13 to 2.48)

(8.24 to 9.19)

(2.08 to 2.32)

(22.43 to 24.88)

(1246,18 to 1483.39)

(120.11 to 125.52)

(244.45 to 285.76)

positive pulmonary tuberculosis cases

2.2

5,27

3.07

(43.11 to 50.85)

2.31

8.72

23.65

Total population

265.1

122.82

1364.78

46.98

Table 9: Mean distribution of tuberculin results of study population

members

food per month

Characteristic

for food per month Mean age (years)

Mean age (years)

Mean weight (kgs)

Mean height (cms)

Average number of family

Average number of adults

Average number of rooms

Average number of children

Average household expenditure

Average percapita expenditure for

Characteristics of children

Characteristics of new bacillary

I Total Population

1 II Characteristics of households

4 5

2 3

III

S No

A Figures in brackets represent 95% Confidence Interval

Assessment orcommunity uniection ratio in the Modei Project area ibr tuberculosis control

COMMUNITY INFECTION RATIO

The prevalence of tuberculin positivity among the 'control' population was 10.5%

(23/219) and that among the 'contact' population was 41.82% (23/55). The CIR for the whole population was calculated to be 16.33 [95%C1: 7.74 to 34.25] [Table 10].

Stratified analysis

1. For children with BCG scar: BCG scar was present in 56.2% (154/274) of the

children. The prevalence of tuberculin positivity among the 'control' population

with BCG scar was 9.84% (12/122) and that among the 'contact' population was

43.75% (14/32). The CIR was calculated to be 14.03 [95%CI: 5.05 to 38.46].

2. For children with history of BCG vaccination: History of BCG vaccination was

reported by 71.9% (197/274) of the mothers of these children. The prevalence of

tuberculin positivity among the 'control' population with history of BCG

vaccination was 10.82% (17/157) and that among the 'contact' population was

42.5% (17/40). The CIR was calculated to be 16.43 [95%CI: 6.79 to 39.53].

3. For children without BCG scar: BCG scar was absent in 43.8% (120/274) of the

children. The prevalence of tuberculin positivity among the 'control' population

was 11.34% (11/97) and that among the 'contact' population was 39.13% (9/23).

The CIR was calculated to be 19.9 [95%CI: 6.15 to 63.7].

4. For children less than 10 years of age: Children less than 10 years of age

contributed to 66.06% (181/274) of the total population. The prevalence of

tuberculin positivity among the 'control' population was 5.92% (9/152) and that Table 10: Risk factors associated with tuberculin positivity (Univariate analysis)

Tuberculin result S No 95% Confidence Characteristic ODDs Ratio * Positive Negative Interval

Total population 46 228 16.33 7.74 to 34.25 1 Age group

Less than 6 years 4 47 1.00

6 to 10 years 14 116 1.42

More than 10 years 28 65 5.06

Less than 10 years 13.99 4.4 to 44.05

More than 10 years 22.64 7.62 to 66.23 2 Sex

Females 21 117 1.00

Males 25 111 1.25 0.64 to 2.48

Females 16.67 5.2 to 52.91

Males 16.23 5.74 to 45.25

3 Weight

Less than 18 kgs 7 86 1.00

18 to 26 kgs 10 81 1.52

More than 26 kgs 29 61 5.84

4 Height

Less than 114 cms 7 86 1.00

114 to 133 cms 12 78 1.89

More than 133 cms 27 64 5.18

5 Family history of tuberculosis

No 23 196 1.00

Yes 23 32 6.125 2.92 to 12.92 6 BCG Vaccination

BCG Scar 26 128 14.03 5.05 to 38.46

I-I/O BCG Vaccination 34 163 16.43 6,79 to 39.53

No BCG Scar 20 100 19.9 6.15 to 63.7 Community Infection Ratio, i.e., odds ratio of tuberculin positive controls to that of contacts, multiplied by 100. Assessment of community infection ratio in the rviodel DOTS ProiccL area lor Litbactilosis clintrui

among the 'contact' population was 31.03% (9/29). The CIR was calculated to be

13.99 [95%CI: 4.4 to 44.05].

5. For children more than 10 years of age: Children more than 10 years of age

contributed to 33.94% (93/274) of the total population. The prevalence of

tuberculin positivity among the 'control' population was 20.9% (14/67) and that

among the 'contact' population was 53.85% (14/26). The CIR was calculated to

be 22.64 [95%0: 7.62 to 66.23].

6. For male children: 49.6% (136/274) of the children were males. The prevalence

of tuberculin positivity among the 'control' population was 10.68% (1 1/103) and

that among the 'contact' population was 42.42% (14/33). The CIR was calculated

to be 16.23 [95%C1: 5.74 to 45.25].

7. For female children: 50.4% (138/274) of the children were females. The

prevalence of tuberculin positivity among the 'control' population was 10.35%

(12/116) and that among the 'contact' population was 40.91% (9/22). The CIR

was calculated to be 16.67 [95%Cl: 5.2 to 52.91].

c gio moutcussy moutcussy gio gqi ur ur gqi , 91ito a)runiuulo 91ito um° 9/1i2 9/1i2

- - proyy iwiza iwiza ll yotv sgolizvoq/Q, Jelirrip Jelirrip sgolizvoq/Q, yotv

o o

uoismose

... OP OP Assessment olcommunity inlection ratio in the Model DOTS Project area tier tuberculosis control

DISCUSSION

The MDP area is a semi-rural area with a near homogenous population, most of

whom are agricultural labourers. Crowding in poorly ventilated rooms is one of the most

important factors in the transmission of tubercle bacilli, since it increases the intensity of

contact with the source case. More than 80% of the houses included in the study were

having 1 to 3 rooms, about 70% of the houses were ill ventilated and more than 65% of the households had a family size of more than 4.

The risk of acquiring tuberculosis infection is determined mainly by exogenous factors, while, the risk of developing disease after being infected depends largely on endogenous factors. The prevalence of tuberculosis infection (i.e., tuberculin positivity) was 41.8% among children with a close family contact with a new bacillary positive pulmonary tuberculosis patient and 10.5% among children without a close family contact.

The CIR for children less than 15 years of age, being 16.33, suggests that the household still remains the major source of tuberculosis infection. If left untreated, approximately

5% of the children with tuberculosis infection are likely to develop active disease within

2 years of infection and an additional 5% are likely to develop the disease during their lifetime 36. Chemoprophylaxis can substantially reduce this risk of developing disease.

Tuberculin reactivity develops soon after vaccination with BCG and it develops only in about 14% of those vaccinated at birth 37. BCG induced tuberculin reactivity tends to wane with time 11 . In this study, the CIR was found to be lower in children with

BCG scar (14.03) when compared with children without BCG scar (19.9), though there was no significant difference in the children's BCG scar status between the contact and Assesmliclit inlet:turn ial$4) in the Atu,lrl DOIN Pi ijerl alea fn, 1111wiltiIllllh 0,11111.11

control households. This may suggest that close family contact may be the major source of infection for BCG vaccinated children whcn compared with those unvaccinated. One probable explanation could be that BCG has offered protection against tuberculosis bacilli in these children, and so, exposure with larger dose of the bacilli for a prolonged period of time is needed to re-infect them, which is possible only with a close family contact.

Children with BCG scar have had a definite BCG reaction and children without a

BCG scar have not had a BCG reaction. An intermediary group of those children whose mothers have given a positive history of BCG vaccination have had a presumptive BCG reaction. The CIR in this group of children was 16.43, which is in between the CIR of the

BCG scar group (14.03) and that of the no scar group (19.9), thereby strengthening the above argument. Further age-stratified analysis could not he attempted for want of a larger sample size. This hypothesis need to be further explored in greater detail to study the role of BCG vaccination in inducing tuberculin sensitivity in an individual.

A child, residing within the MDP area, who is more than 10 years of age is 5 times more likely to he infected with tuberculosis than a child who is less than 5 years of age. As the child grows older, the source of infection tends to shift from the household to the community at large. This is evident by the increase in CIR from 13.99 for children

less than 10 years of age to 22.64 for children more than 10 years of age. Madico et al 33 have already drawn a similar conclusion based on progressive increase in CIR for children less than 1 year.

42 t)I Lognmultly r; Ili) in 1) IS l'rojcct outttid

Sex of the child did not have any influence on the mode of acquiring infection,

either from within the household or from the community. Male children had a CIR of

16.23 as against female children who had a CIR of 16.67. The influence of the sex of the

source case, i.e., the newly diagnosed bacteriologically positive pulmonary tuberculosis

patient, in affecting the transmission dynamics of tuberculosis could not be explored in this study because more than 85% of the source cases were males. This is an area that requires further inputs to identify sex/gender differentials in augmenting the risk of acquiring tuberculosis infection.

43 -----assumumum■•• 1

ifdffiliali Of (?01111111,1171-129 Onfiction Cok)a-tr.o in the

"C-)Wariel `&(yect " ffeafir (niberculos-6- 6ontral

6'one/us/on.,

44 Assessmcni or community infection ratio in the Model DOTS Project area tOr hiberculosis control

CONCLUSION

This study suggests that the household still is the major source of tuberculosis infection. So, effective implementation of RNTCP based preventive therapy strategies for - - - - preventing children less than 6 years age from acquiring the infection disease from their family member is recommencled._This needs screening of all children living with patients --- having bacillary pulmonary tuberculosis, to enable simultaneous treatment, both for the contact and the index case. It may be more difficult to ensure compliance when treating children with tuberculosis infection than when treating those with active disease. If chemoprophylaxis is administered to the child while the family member with active disease is also being treated, compliance and monitoring may be easier.

Effective implementation of tuberculosis control programme based on the DOTS strategy is expected to result in cutting down the chain of tuberculosis transmission. Early detection of infectious cases and effective treatment of the index cases (case holding strategy) will reduce the mycobacterial parasite load in the environment. This will reduce the risk of being exposed to the tuberculosis bacilli, which is the pre-requisite for becoming infected. Also, the number of case-contact interactions per unit time and the duration of infectiousness of the case will decrease.

Assessment of CIR for a geographical population, if performed periodically, is expected to enrich the knowledge about the transmission dynamics of tuberculosis in that population. CIR can be a potential rapid epidemiological assessment tool for monitoring the performance of the tuberculosis control programme in a specific area.

45 assessment of ommunitcri 070c/ion aartio in the

"G rdeldaerC33 `.)rojectll a-rea- fir Tuberculosis ()ntral-

6Q0 rencres..

..• 46 Assessment olcommunny infection ratio in the Model 1)01S Project area 1br tubereulosts control

REFERENCES

1. Christopher Dye, Suzanne Scheele, Paul Dolin, et al. Global burden of tuberculosis. Estimated incidence, prevalence and mortality by country. JAMA 1999; 282: 677-86. 2. Raviglione MC, Snider DE, Kochi A. Global epidemiology of tuberculosis. Morbidity and mortality of a worldwide epidemic. JAMA 1995; 273:220-26. 3. Tuberculosis diagnostic initiative. Weekly Epidemiological Record 2001; 76(35): 271-72. 4. Murrey CJL, Lopez AD, eds. The global burden of disease: a comprehensive assessment of mortality and disability from diseases, injuries and risk factors in 1990 and projected to 2020. Cambridge, MA: Harvard University Press, 1996. 5. Jonathan Cohen. The global burden of disease study: a useful projection of future global health? Journal of Public Health Medicine 2000; 22(4): 518-24. 6. Pathania V, Almedia J, Kochi A. Tuberculosis patients and private for-profit health care providers in India. wHorrB/97.223. 7. Joint tuberculosis programme review: India, February 2000. WHO project no: ICP TUB 030. SEA-TB-224. 8. Chakraborthy AK. Prevalence and incidence of tuberculosis infection and disease in India: a comprehensive review. WHO/TB/97.231. 9. Gothi GD. Epidemiology of tuberculosis in India. Ind J Tub 1982; 29(3): 134-48. 10. Hans L Rieder. Epidemiologic basis of tuberculosis control (1S1 edition), International Union Against Tuberculosis and Lung Disease, 1999. 11. Mario C Raviglione, Richard J O'Brien. Tuberculosis (Chapter 169). In: Braunwald, Fauci, Kasper, et al (eds). Harrison's principles of internal medicine (15th edition), Volume 1. International Edition, McGraw-Hill Companies, Inc., 2001: 1024-35. 12. Loudon RG, Roberts RM. Droplet expulsion from the respiratory tract. Am Rev Respir Dis 1966; 95: 435-42.

47 Asse■ismciit of colturniiiily infection Iloilo in thy Riodel IX IIN l'culcct itrytt fin luhcrculnr ik control

13. Sonkin LS. The role of particle size in experimental air-borne infection. Am J Hyg 1951; 53: 337-54. 14. Shaw JB, Wynn-Williams N. Infectivity of pulmonary tuberculosis in relation to sputum status. Am Rev Tuberc 1954; 69: 724-32. 15. Veen J. Micro-epidemics of tuberculosis: the stone-in-the-pond principle. Tuberc Lung Dis 1992; 73: 73-76. 16. Gunnels JJ, Bates JH, Swindoll H. Infectivity of sputum-positive tuberculosis patients on chemotherapy. Am Rev Respir Dis 1974; 110: 810-12. 17. Rouillion A, Perdrizet S, Parrot R. Transmission of tubercle bacilli: the effects of chemotherapy. Tubercle 1976; 57: 275-99.

18. Christopher Dye, Geoffrey P Garnett, Karen Sleeman et al. Prospects for worldwide tuberculosis control under the WHO DOTS strategy. Lancet 1998; 352: 1886-91. 19. CJL Murray, K Styblo and A Rouillon. Tuberculosis in developing countries: burden, intervention and cost. Bull Int Un Tuberc Lung Dis 1990; 65(1): 6-24. 20. Module on 'Administering treatment'. In: Managing the Revised National Tuberculosis Control Programme in your area. A training course, Modules 1-4. Central TB Division, Directorate General of Health Services, Ministry of Health

and Family Welfare, Nirman Bhavan, New Delhi 110 011, July 1999. 21. Myers JA. Man's greatest victory over tuberculosis. Springfield, Ill: Charles C Thomas, 1940. 22. Koch R. Weitere Mitteilungen uber ein Heilmittle gegen Tubercuose. Dtsch Med Wschr 1891; 17: 101-02. 23. Tuberculin surveys — why? Editorial Int J Tuberc Lung Dis 1998; 2(4): 263-64. 24. Nancy E Dunlap, David E Briles. Immunology of tuberculosis. Medical Clinics of North America 1993; 77 (6): 1235-51. 25. Crfton J, Horne N, Miller R. Mantoux test. In Clinical Tuberculosis. CBS Publications &Distributors, Daryaganj, New Delhi 1996; 188-90.

48 Assessment of community infection ratio in the Model DOTS Project area for tuberculosis conu-ol

26. Pediatric Tuberculosis. In: Michael D Iseman. A Clinical Guide to Tuberculosis, Chapter 9. Lippincott Williams & Wilkins, A Wolters-Kluwer Company, 2000. 27. The Tuberculin test. Chapter 2 in 'Selected Papers', Volume 24. Epidemiology of Tuberculosis by Dr K Styblo. Royal Netherlands Tuberculosis Association, The Netherlands, 1991. 28. Tuberculosis Prevention Trial, Madras. Trials of BCG vaccine in south India for tuberculosis prevention. Ind J Med Res 1980; 72 (Suppl): 1-74. 29. Thomas M Daniel. Tuberculosis (Chapter 130). In: Isselbacher, Braunwald,

Wilson, et al (eds). Harrison's principles of internal medicine (13th edition), Volume 1. International Edition, McGraw-Hill Companies, Inc., 1994: 710-18. 30. GR Khatri. The Revised National Tuberculosis Control Programme: A status report on first 1,00,000 patients. Ind J Tub 1999; 46: 157-66. 31. Progress towards tuberculosis control, India, 2001. Weekly epidemiological Record 2002; 77 (12): 89-93. 32. GR Khatri, TR Frieden. The status and prospects of tuberculosis control in India. Int J Tuberc Lung Dis 2000; 4 (3): 193-200.

33. Guillermo Madico, Robert H Gilman, William Checkley, et al. Community Infection Ratio as an indicator for tuberculosis control. Lancet 1995; 345: 416-19.

34. Growth and development. In: O.P.Ghai. Essential Pediatrics (31d Edition). New Delhi, Interprint, 1993: 6-7. 35. Module on 'Supporting laboratory services'. In: Managing the revised national tuberculosis control programme in your area: A training course. Modules 1-4. Central TB Division, Directorate General of Health Services, Ministry of Health and Family Welfare, Nirman Bhavan, New Delhi - 110 011, July 1999: 49.

36. Jeffery R Starke, Flor Munoz. Chapter 212. Tuberculosis. In: Section 6: Mycobacterial Infections. Eds. Behrman, Kliegman, Jenson. Nelson Textbook of Pediatrics (16th edition). India, Harcourt Asia Pte Ltd, 2000: 885-97. 37. Kathipari K, Seth V, Sinclair S, et al. Cell mediated immune response after BCG as a determinant of optimum age of vaccination. Ind J Med Res 1982; 76: 508-11.

49 /.3kssarsment ofcminutzi (_nfictian7 (9 )61-tio in the

(1 ./c/Cadel r915'ct". Vitherculasis antrol

Appaida

50 Assessment of Community Infection Ratio in the 'Model DOTS Project' area for Tuberculosis Control Form for Contact Households Form I Study Number: Date: CASE DOTS: _Yes / No_ Tuberculosis Number: / PHC:. Village: Name: Age: Sex: _M/F_ Date of Rx: No. of members in the household: Adults: Children: S.No: Name Relation to child Education Occu , ation 1. 2. 3. 4. 5. 6. Household Expenditure per month: (1) Rs (ii) Rs Previous h/o tuberculosis in the household: _ Yes / No _ If 'Yes', when: HOUSING: Number of rooms: Ventilation: _ Yes / No —

CONTACT Name: Age: Sex: _M/F_ BCG Scar: — Yes / No _ H/O BCG Vaccination: _Yes / No_ Weight:, Kgs. Height: cms. Illness, if any: _Yes / No_ If 'Yes', Details: Duration: (a) Cough: _Yes / No (b) Fever: _Yes / No (c) Difficulty in breathing: _Yes 1 No_ Clinical Examination: (i) Lymph Nodes, if any: _Yes / No_ If 'Yes', Site: Matting: _Yes / No_ (ii) Joint / Bone swelling, if any: _Yes / No_ (iii) Abdominal mass / Ascitis, if any: _Yes / No_ (iv) Angular Deformity of the spine, if any: _Yes / No_ (v) Abnormal lung sounds: _Yes / No_ Clinical Impression: Tuberculin: Date of testing: Date of reading: Induration: mm Remarks: General Remarks, if any:

Assessment of Community Infection Ratio in the 'Model DOTS Project' area for Tuberculosis Control Form for Control Households Form II Study Number: Date: CONTROL PHC: Village: No. of members in the household: Adults: Children: S.No: Name Relation to child Education Occu i ation 1. 2. 3. 4. 5. 6. Household Expenditure per month: (i) Rs (ii) Rs Previous h/o tuberculosis in the household: _ Yes / No _ If 'Yes', when: HOUSING: Number of rooms: Ventilation: Yes / No

CONTACT Name: Age: Sex: _M/F_ BCG Scar: Yes / No H/0 BCG Vaccination: _Yes / No_ Weight: Kgs. Height: ems. Illness, if any: _Yes / No_ If 'Yes', Details: Duration: (a) Cough: _Yes / No_ (b) Fever: _Yes / No_ (c) Difficulty in breathing: _Yes / No_ Clinical Examination: (i) Lymph Nodes, if any: _Yes I No_ If 'Yes', Site: Matting: _Yes I No_ (ii) Joint / Bone swelling, if any: _Yes / No_ (iii) Abdominal mass / Ascitis, if any: _Yes / No_ (iv) Angular Deformity of the spine, if any: _Yes / No_ (v) Abnormal lung sounds: _Yes / No Clinical Impression: Tuberculin: Date of testing: Date of reading: Induration: mm Remarks: General Remarks, if any:

52 Assessment of Community Infection Ratio in the 'Model DOTS Protect' area for Tuberculosis Control

Work Instructions for filling up Forms I and II

1. Study number: Form I — begins with I and ends with 50 Form II — I a ... Id; 2a ... 2d; ... for each form in Form 1

2. Tuberculosis Number: Registration number, as in the Tuberculosis Register

3. PHC: Name of the Primary Health Centre reporting the 'case'

4. Village: Name of the village from which the 'case' hails

5. Date of Rx: Date of start of anti-tuberculosis therapy for the 'case'

6. Education: Actual number of years of schooling

7. Occupation: Major work of the individual helping to earn one's living

8. Household Expenditure: Self reported expenditure of that household in the previous months, as by the interviewee

9. Number of rooms: Actual number of all the rooms in that household

10. Ventilation: Principal Investigator's assessment based on the number of doors and windows present in a room, along with the presence of cross ventilation

53 latilspj *muumuu TO unifursod Jr artiduinan OF

BAY

BENGAL

..t

POONAMALLEE

KANCHIPURAM DISTRICT

THIRUVALLUR DISTRICT

2000

POPULATION 28 72 700 BEERA KUPPAM

VELLORE DISTRICT

Tuberculosis Units in Tiruvallur District SHOLAVARAM BLOCK

• a

VE NG AL

419

VILLIVAKKAM BLOCK

GUMMIDIPOONDI BLOCK

PER IYA PA LAPA M4 . GOVERNMENT HOSPITAL

PULI YU R • DESIGNATED MICROSCOPY CENTRE

ea lb 4

114 TUBERCULOSIS UNIT

Itt

VA L LI U R

PER

LATCHIVAKKAM

kTlitUVA LLUR

ZINHOWiligrimmowww.

0a o

ULU NDAI

K ADA M BAT 14 UR

UT H U KOTT+

POO N DI

PERMBAKKAM

PATTA RA IP ERNI P U D UR

KATC II UR

TRIR UVALAN GAD U

KA NAMM ACH ATRA M

ANIM IR, PRADESH

-_-5,80,000

2000

POON IM ANG ADU

POPULATION L

Ellaburam Block Kadambathur Block

Poondi Block Thiruvalangadu Block Tiruvallur Block

Tiruvallur Model DOTS Project area

1. 2. 3. 4. 5.

THIRrnHANI BLOCK