National TB Prevalence Survey in Lao PDR

Transcription

1 Lao PDR National Tuberculosis Control Programme National TB Prevalence Survey in Lao PDR Regional Surveillance workshop HCM City, June 2010 National TB Centre, Vientiane

2 TB burden in Lao PDR * 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: % in 1995 (Arnadottir and Coll.) LAO PDR NTC

3 TB case detection, * revised WHO estimates in 2010

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5 Prevalence 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

6 Screening algorithm* *Assessing tuberculosis prevalence through population based survey, WHO 2007 LAO PDR NTC

7 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 Definitions Bacteriology positive (smear AND/OR culture) CXR suggestive at second reading (central) LAO PDR NTC

8 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

9 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

10 TBPS 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

11 TBPS 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

12 Preparation 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 LAO PDR NTC

13 Training 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

14 Field 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

15 Central level operations Primary culture (in NRL and 2 regional culture labs): 6000 TBsuspects 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

16 PS 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

17 Next 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

18 Budget Needed for Prevalence Survey Items US$ Lab equipment (including NRL 1upgrade) CXR equipment Vehicles Sub total Screening of clusters Total LAO PDR NTC

19 Acknowledgements 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 LAO PDR NTC

20 References Assessing tuberculosis prevalence through population based survey, ISBN 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, ISBN International Union Against Tuberculosis and Lung Diseases 1998 LAO PDR NTC