Journal of Community Health

, Volume 40, Issue 3, pp 576–580 | Cite as

A Workplace Tuberculosis Case Investigation in the Presence of Immigrant Contacts from High Prevalence Countries

  • Shrinivas KambaliEmail author
  • Nopakoon Nantsupawat
  • Melanie Lee
  • Kenneth Nugent


The highest prevalence of tuberculosis (TB) occurs in foreign born immigrants in the United States. Contact investigations at work sites with mostly immigrant workers present multiple practical problems. Recently 402 contacts were investigated at a meat packing plant in rural Texas by the Texas Department of State Health Services (DSHS). Our objective was to study the approach and effectiveness of this intensive investigation. We reviewed information, including symptoms, BCG status, TB history, X-rays, and treatment, on the sentinel case and 47 contacts managed by the Texas DSHS TB Division in Lubbock, TX. We used a gamma interferon release assay (T-SPOT.TB) to identify contacts with TB infection. The sentinel case was foreign born and had cavitary TB with acid-fast positive smears. Forty-two work site contacts were foreign born, and five were US born. The foreign born contacts were from Sudan, Somalia, Mexico, Burma, and Haiti; 18 contacts had a history of BCG vaccination. T-SPOT.TB tests were positive in 20 contacts, borderline in four, and negative in 23. Contacts with borderline results had negative repeat tests. Twenty-three contacts with negative T-SPOT.TB tests were scheduled for repeat tests in 4 weeks, but only four returned for this testing. Chest X-rays were abnormal in two contacts who were started on treatment. Sputum was collected in three individuals; one was culture positive for pan-sensitive Mycobacterium tuberculosis. Twelve contacts were treated for latent TB. Our investigation established an infection rate of 42.5 % in this work site contact cohort, which is similar to the 39 % prevalence reported by the Center for Disease Control. The use of T-SPOT.TB assays simplified testing in immigrants with high rates of BCG vaccination. Our investigation was complicated by language barriers, varying and uncertain levels of exposure, and a high rate of drop outs in the negative T-SPOT.TB contacts. This concerted effort provides a model for investigating work site contacts, especially with numerous immigrants, and illustrates the problems associated with these investigations.


Tuberculosis Contact Foreign born Interferon gamma release assay Work site 


  1. 1.
    World Health Organization. (2011). World Health statistic 2011: WHO library cataloguing-in-publication data. 2011:79.Google Scholar
  2. 2.
    CDC. (2012). Reported tuberculosis in the United States, 2011. Atlanta, GA: U.S. Department of Health and Human Services, CDC.Google Scholar
  3. 3.
    Fenton, K., Castro, K. G. (2005). Guidelines for the investigation of contacts of persons with infectious tuberculosis. Recommendations from the National Tuberculosis Controllers Association and CDC. MMWR 2005, Vol. 54 (No. RR-15, 1-37).Google Scholar
  4. 4.
    Davidow, A. L., Katz, D., Reves, R., Bethel, J., & Ngong, L. (2009). The challenge of multisite epidemiologic studies in diverse populations: Design and implementation of a 22-site study of tuberculosis in foreign-born people. Public Health Reports, 124, 391–399.PubMedCentralPubMedGoogle Scholar
  5. 5.
    Fine, P. E., Carneiro, I. A., Milstien, J. B., Clements, C. J. (1999). Issues relating to the use of BCG in immunization programs: a discussion document (pp. 1–45). Geneva: Department of Vaccines and Biologicals, World Health Organization.Google Scholar
  6. 6.
    Zwerling, A., Behr, M. A., Verma, A., Brewer, T. F., Menzies, D., et al. (2011). The BCG world atlas: A database of global BCG vaccination policies and practices. PLoS Med, 8(3), e1001012. doi: 10.1371/journal.pmed.1001012.CrossRefPubMedCentralPubMedGoogle Scholar
  7. 7.
    Centers for Disease Control and Prevention. (2010). Updated guidelines for using interferon gamma release assays to detect Mycobacterium tuberculosis infection, United States. MMWR 2010, 59(No. RR-5):1–25.Google Scholar
  8. 8.
    Chee, C. B., Gan, S. H., KhinMar, K. W., et al. (2008). Comparison of sensitivities of two commercial gamma interferon release assays for pulmonary tuberculosis. Journal of Clinical Microbiology, 46, 1935–1940.CrossRefPubMedCentralPubMedGoogle Scholar
  9. 9.
    Goletti, D., Stefania, C., Butera, O., et al. (2008). Accuracy of immunodiagnostic tests for active tuberculosis using single and combined results: A multicenter TBNET-study. PLoS One, 3, e3417.CrossRefPubMedCentralPubMedGoogle Scholar
  10. 10.
    Detjen, A. K., Keil, T., Roll, S., et al. (2007). Interferon-gamma release assays improve the diagnosis of tuberculosis and nontuberculous mycobacterial disease in children in a country with a low incidence of tuberculosis. Clinical Infectious Diseases, 45, 322–328.CrossRefPubMedGoogle Scholar
  11. 11.
    Lee, J. Y., Choi, H. J., Park, I. N., et al. (2006). Comparison of two commercial interferon-gamma assays for diagnosing Mycobacterium tuberculosis infection. European Respiratory Journal, 28, 24–30.CrossRefPubMedGoogle Scholar
  12. 12.
    Arend, S. M., Thijsen, S. F., Leyten, E. M., et al. (2007). Comparison of two interferon gamma assays and tuberculin skin test for tracing tuberculosis contacts. American Journal of Respiratory and Critical Care Medicine, 175, 618–627.CrossRefPubMedGoogle Scholar
  13. 13.
    Tsiouris, S. J., Austin, J., Toro, P., et al. (2006). Results of a tuberculosis-specific IFN-gamma assay in children at high risk for tuberculosis infection. Int J Tuberc Lung Dis, 10, 939–941.PubMedGoogle Scholar
  14. 14.
    Diel, R., Loddenkemper, R., Meywald-Walter, K., Gottschalk, R., & Nienhaus, A. (2009). QuantiFERON-TB-gold in tube assay and T-Spot TB test in contact investigations for tuberculosis. Chest, 135(4), 1010–1018. doi: 10.1378/chest.08-2048.CrossRefPubMedGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2014

Authors and Affiliations

  • Shrinivas Kambali
    • 1
    Email author
  • Nopakoon Nantsupawat
    • 1
  • Melanie Lee
    • 2
  • Kenneth Nugent
    • 1
  1. 1.Department of Internal MedicineTexas Tech University Health Sciences CenterLubbockUSA
  2. 2.Department of State Health Services Region 1 Tuberculosis ServiceLubbockUSA

Personalised recommendations