National TB Prevalence SurveyNational TB Prevalence Survey

in in Lao PDRLao PDR

Regional Surveillance workshop HCM City, 1Regional Surveillance workshop HCM City, 1--4 June 20104 June 2010

Lao PDR National Tuberculosis Control Programme

NationalNational TB Centre, VientianeTB Centre, Vientiane

TB burden in Lao PDRTB burden in Lao PDR

LAO PDR NTC 2010 1

1990 2007*

Population 4.08 M 5.85 M

Prevalence TB all forms 428 (17,449) 289 (16,906)

Incidence TB all forms 179 (7,278) 151 (8,851)

Incidence new S+ PTB 80 (3275) 67 (3954)

Mortality due to TB 38 (1,538) 24 (1,410)

WHO 2009 Report, Global Tuberculosis Control

National average of ARIT: 1.2 - 1.3% in 1995 (Arnadottir and Coll.)

TB case detection, 1995-2009

* revised WHO estimates in 2010

LAO PDR NTC 2010 4

Prevalence Survey objectivesPrevalence Survey objectives

� Primary objective is to determine the prevalence of bacteriologically confirmed pulmonary TB (smear and/or culture positive)

� Two secondary objectives are to determine:

– the prevalence of smear positive PTB

– the prevalence of radiologically active PTB

LAO PDR NTC 2010 5

Screening algorithm*Screening algorithm*

*Assessing tuberculosis prevalence through population based survey, WHO 2007

LAO PDR NTC 2010 6

• PTB suspect

– TB Symptoms: cough ≥ 14 days AND/OR blood in cough

– Abnormal chest X-ray consistent with TB at first reading (on site)

• PTB case

– Bacteriology positive (smear AND/OR culture)

– CXR suggestive at second reading (central)

DefinitionsDefinitions

LAO PDR NTC 2010 7

Sampling (detailed in protocol)Sampling (detailed in protocol)

� estimated prev. 251 S+ PTB/100,000 pop. ≥15y old, precision: 25%, participation: 80%, design effect: 1.3 (in protocol)

� sample size ≈40,000 persons 15y old or more

� 50 clusters of 800 subjects (no strata)

� random selection of 50 districts (in population ≥ 15 years old, National Census)

� random selection of 1st village of each cluster in list of all villages of district

� randomisation rules in protocol for selection of more villages and household groups

LAO PDR NTC 2010 8

TBPS Organisation (1)TBPS Organisation (1)

� Survey Committee (SC) chaired by Minister and Vice Minister of Health

� Executive Committee (EC) chaired by NTC: Chairman (NTP director), Vice Director, 1 coordinator, 9 team leaders, 6 chiefs of sub committees

� The Technical Committee (TC) supports the EC and includes 6 sub committees: Census & interview (5), X-ray (5), Lab (5), Statistics (3), Admin & Logistic (4), Finance (2)

LAO PDR NTC 2010 9

TBPS Organisation (2): Central teamTBPS Organisation (2): Central team

� Central CXR unit (2 radiologists): training/supervision of 3 field readers and second reading and final diagnosis

� NRL: training and supervision of 2 regional labs, primary culture and ID for all positive culture

� Two regional laboratories: primary culture only

� Optional: DST (solid media in NRL), Molecular testing (Merieux Foundation)

� Data Management unit NTC, TA for data processing and analysis

� Administration & logistic and finance: NTC

LAO PDR NTC 2010 10

TBPS organisation (3): Field TeamTBPS organisation (3): Field Team

� 2 teams in field and 1 team in standby in rotation.

� Each team has one team leader and 12 permanent staffs (3 census and interview, 4 CXR, 2 laboratory, 3 drivers)

� 8-10 local staffs including PTC, DTM, HC staff, VHVs, village volunteers

LAO PDR NTC 2010 11

� Establish culture capacity with proficiency review in 3 labs (started Sep-09)

� Field test operations (November 2009)

� Field assessment: selection and mapping of villages and household groups, description of conditions, roads, time for transport of sputum specimens

� 2d visit in cluster 2 weeks before survey: to complete household register forms and prepare arrival of survey team

� Ethic: Signed informed consent from each survey participant is needed

PreparationPreparation

LAO PDR NTC 2010 12

TrainingTraining

� Census & interview unit: sampling rules, conducting interview and filling questionnaires

� CXR unit on first reading on site and reporting

� Laboratory unit:

� collection, conservation, packaging, sending of specimens and reporting

� Training on inoculation and primary culture of lab technicians from the 2 regional labs (Savannakhet and Luangnamtha)

LAO PDR NTC 2010 13

Field operationsField operations

� 50 clusters in 8 months (one cluster per week) by 2 teams (+ 1 in standby)

� 1 team has 13 staffs: 1 team leader, 3 census and interview, 4 CXR, 2 laboratory, 3 drivers

� local staff: province and district TB staff, HC nurse, village volunteers, chief of villages, police, mass organisation

� 1 cluster requires:

� up to 800 interviews and CXR,

� 120 TB suspects identified (~15%),

� 240 sputum specimens collected send to labs (preferred) or on site inoculation if delay to process specimen >72 h

LAO PDR NTC 2010 14

Central level operationsCentral level operations

� Primary culture (in NRL and 2 regional culture labs):

� 6000 TB suspects x 2 = 12,000 specimen and smear slides

� X 2 = 24,000 culture tubes (in 3 labs)

� Identification of positive cultures in NRL

� CXR unit: second reading of all films

� Data management unit in NTC: one international expert in epidemiology for data collection and analysis

LAO PDR NTC 2010 15

PS field testPS field test

� Test survey in one Naxaithong district in

Vientiane Municipality (22-28 Nov 09)

� Preparation visit 2 weeks before

� D0 = plan census day and give appointments to

chiefs of villages

� D1= Census in 3 villages, 244 households, 826

eligible subjects

� D2 to D6: 732 Interviews (88.6%), 722 CXR, 121

TB suspects provided 2 sputum specimens

LAO PDR NTC 2010 16

Next stepsNext steps

� Second laboratory review by KIT in NRL and 2 primary culture laboratories (16-22 May 2010)

� 23 /50 clusters assessed by end May-10

� Ongoing testing data collection and data analysis software

� Organise second CXR reading (central level)

� Possible to start survey in June-July 2010 in clusters located in South and centre regions (accessible by road during rainy season)

LAO PDR NTC 2010 17

Items US$

1

Lab equipment (including NRL

upgrade) 462 000

2 CXR equipment 111 128

3 Vehicles 89 000

Sub total 662 128

4 Screening of clusters 465 941

Total 1 128 069

Budget Needed for Prevalence SurveyBudget Needed for Prevalence Survey

LAO PDR NTC 2010 18

• Dr Bounlay Phommasack for making possible field test in Vientiane

• Naxaithong district authorities, chiefs of village and population

• NTC team leaders and NTP team from Vientiane municipality and Naxaithong district for field test

• Dr Oroth: Radiology central hospital Mahosot and radiologists and technicians

• Dr Satha (CENAT, Cambodia) for radiology expertise and field testing of operations

• F. Nzabintwali and lab technicians of NRL and regional lab team

• Survey design reviewers: SJ. Kim, P. Glaziou, I. Onozaki, C. Sismanidis, D. Sagebiel

• Laboratory support and reviews: SJ Kim and CK Kim (KIT)

• Data management software design: I Law

AcknowledgementsAcknowledgements

LAO PDR NTC 2010 19

• Assessing tuberculosis prevalence through population based survey, ISBN 978 92 9061 314 5 © World Health Organization 2007

• The Public Health Service National Tuberculosis Reference Laboratory and the National Laboratory Network, Minimum Requirements, Role and Operation in a Low-Income Country, ISBN2-9504238-7-6 © International Union Against Tuberculosis and Lung Diseases 1998

ReferencesReferences