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TB: The Coventry perspective Dr Thekli Gee University Hospitals Coventry & Warwickshire.

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Presentation on theme: "TB: The Coventry perspective Dr Thekli Gee University Hospitals Coventry & Warwickshire."— Presentation transcript:

1 TB: The Coventry perspective Dr Thekli Gee University Hospitals Coventry & Warwickshire

2 Outline TB in Coventry: Epidemiology Resources New diagnostic approaches

3 Epidemiology

4 Occurrence Nearly a third of the worlds population is infected with TB TB kills almost 3 million people per year.

5 Tuberculosis notifications England & Wales Source: Statutory Notifications of Infectious Diseases (NOIDs) chemotherapy BCG vaccination

6 Coventry TB rate by year Rate per 100,000 population rate Coventry PCT West Midlands England & Wales Linear (Coventry PCT) Coventry 2007

7 Tuberculosis case reports and rates by region/country, England, Wales and Northern Ireland, 2006 Coventry 2007

8 Coventry

9 Why Is TB Increasing?

10 Multiple contributing factors: Homelessness Intravenous drug use HIV infection Drug-resistant strains of TB Reduced TB control and treatment resources Immigration from high TB prevalence areas

11 Tuberculosis case reports by place of birth and ethnic group, England, Wales and Northern Ireland,

12 Changing populations Coventry City council –1215 asylum seekers on housing list Coventry refugee centre –8000 asylum seekers & refugees registered –1571 registered at Meridian Health Centre

13 Changing populations Afghanistan Iraq Iran Burundi Democratic Republic of Congo Ethiopia Eritrea Somalia Sudan Zimbabwe

14 Resources Increasing numbers of TB cases Increased demand on TB services

15 Impact on resources Hospital & community TB services –TB clinic –TB nurse time Infection control –Isolation facilities –TB incidents Occupational health –Pre-employment screening –HCW contacts Laboratory services

16 Impact on resources Hospital & community TB services –TB clinic –TB nurse time Infection control –Isolation facilities –TB incidents Occupational health –Pre-employment screening –HCW contacts Laboratory services

17 TB incidents at UHCW NHS Trust 23 incidents in since January 2007 –18 Patients Not isolated early enough / at all during admission Mostly medical wards 2 Cardiothoracic ward 1 haematology day unit –5 Health care workers 3 qualified nurses 1 nursing student Ward host

18 Impact on resources Hospital & community TB services –TB clinic –TB nurse time Infection control –TB incidents –Isolation facilities Occupational health –Pre-employment screening –Annual reminders –HCW contacts Laboratory services 2007

19 Impact on resources Hospital & community TB services –TB clinic –TB nurse time Infection control –TB incidents –Isolation facilities Occupational health –Pre-employment screening –Annual reminders –HCW contacts Laboratory services 2006

20 TB national strategy

21 Controlling TB: 1.Diagnosing primary cases 2.Treating active disease 3.Preventing transmission 4.Identifying secondary cases 5.Controlling latent infection

22 Current diagnostic test for latent TB Diagnosis of latent TB relies on the tuberculin skin test. 101 years old –Developed 1907 by Charles Mantoux The oldest diagnostic test still in use. The skin test enters its 6 th decade of use. (Canada 1957)

23 Tuberculin skin tests Mantoux test Heaf test hours later No longer available

24 Tuberculin skin tests Poor specificity: –antigenic cross-reactivity BCG environmental mycobacteria Poor sensitivity: –75-90% in active disease lower in disseminated TB and HIV infection Need for return visit –50% DNA rate Operator variability –inoculation & reading Painful inflammation & scarring Boosting effect if used repeatedly

25 New approaches

26 TB Interferon- release assays (TIGRA) Principle of TIGRA –Detect IFN- produced by effector T-cells that recognise M. tuberculosis proteins ESAT-6 & CFP-10 Absent in BCG Absent in most non-tuberculous Mycobacteria –Exceptions: M. marinum, M. kansasii

27 Two Tests available T-Spot.TB® Detects individual effector T- cells that produce IFN- in response to M.tuberculosis antigens Enzyme linked immunospot technique (ELISPOT). QuantiFERON Gold® Measures IFN- in the supernatant of the antigen stimulated cells Enzyme linked immunosorbant assay technique (ELISA)

28 T-Spot.TB®Quantiferon Gold® Sensitivity Immunocompetent83-97%70-89% Immunocompromised + malnourished + children <1% indeterminate results20-24% indeterminate results

29 T-Spot.TB®Quantiferon Gold® Sensitivity Immunocompetent83-97%70-89% Immunocompromised + malnourished + children <1% indeterminate results20-24% indeterminate results Specificity99.99%98%

30 T-Spot.TB®Quantiferon Gold® Sensitivity Immunocompetent83-97%70-89% Immunocompromised + malnourished + children <1% indeterminate results20-24% indeterminate results Specificity99.99%98% Cost (including labour etc) £55-60 per test £30 per test

31 T-Spot.TB®Quantiferon Gold® Sensitivity Immunocompetent83-97%70-89% Immunocompromised + malnourished + children <1% indeterminate results20-24% indeterminate results Specificity99.99%98% Cost (including labour etc) £55-60 per test £30 per test Problems Must process within 8 hours of venepuncture Expertise in cell separation Must process within 8 hours of venepuncture -in tube assay? Not reliable enough in the Immunocompromised & children

32 Method - T-Spot.TB® Specimens must be processed within 8 hours of venepuncture

33

34 -ve +ve ELISPOT

35 ELISPOT Reader

36 Role of TIGRAs Detection of latent TB: –TB contacts –Healthcare workers New employment screens Following TB exposure incidents –Before starting immunosuppression anti-TNF-α drugs e.g infliximab Pre-transplantation Detection of active extra-pulmonary TB –If difficult to diagnose by conventional methods –Closely competing diagnoses e.g. Sarcoid vs TB

37 Contact tracing: When to use a TIGRA –NICE: Following positive Mantoux test –Most cost effective –May miss some cases –CDC In place of Mantoux test –Shifts burden of work from TB nurses to lab

38 Business case Laboratory service –5 day to 6 day service –Warwickshire wide (Network) TIGRA –Tspot.TB –Microbiology / Immunology

39 Summary TB increasing in Coventry Increased demand on resources New approaches considered –e.g. TIGRAs


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