BMC Infectious Diseases
Volume 16, Issue 1, 2016

Detection of latent tuberculosis infection among migrant farmworkers along the US-Mexico border (Article) (Open Access)

Oren E.* , Fiero M.H. , Barrett E. , Anderson B. , Nuñez M. , Gonzalez-Salazar F.
  • a Mel and Enid Zuckerman College of Public Health, University of Arizona, Department of Epidemiology and Biostatistics, 1295 N. Martin Ave., P.O. Box 245211, Tucson, AZ 85724, United States
  • b Mel and Enid Zuckerman College of Public Health, University of Arizona, Department of Epidemiology and Biostatistics, 1295 N. Martin Ave., P.O. Box 245211, Tucson, AZ 85724, United States
  • c Mel and Enid Zuckerman College of Public Health, University of Arizona, Department of Epidemiology and Biostatistics, 1295 N. Martin Ave., P.O. Box 245211, Tucson, AZ 85724, United States
  • d Mel and Enid Zuckerman College of Public Health, University of Arizona, Department of Epidemiology and Biostatistics, 1295 N. Martin Ave., P.O. Box 245211, Tucson, AZ 85724, United States
  • e Yuma County Health Services District, 2200 W 28th St, Yuma, AZ 85364, United States
  • f Mexican Social Security Institute, Juárez, México City, Mexico, University of Monterrey, Avenida Ignacio Morones Prieto 4500 Pte., Jesus M. Garza, San Pedro Garza García, NL, 66238, Mexico

Abstract

Background: Migrant farmworkers are among the highest-risk populations for latent TB infection (LTBI) in the United States with numerous barriers to healthcare access and increased vulnerability to infectious diseases. LTBI is usually diagnosed on the border using the tuberculin skin test (TST). QuantiFERON-TB Gold In-Tube (QFT-GIT) also measures immune response against specific Mycobacterium tuberculosis antigens. The objective of this study is to assess the comparability of TST and QFT-GIT to detect LTBI among migrant farmworkers on the border, as well as to examine the effects of various demographic and clinical factors on test positivity. Methods: Participants were recruited using mobile clinics on the San Luis US-Mexico border and tested with QFT-GIT and TST. Demographic profiles and clinical histories were collected. Kappa coefficients assessed agreement between TST and QFT-GIT using various assay cutoffs. Logistic regression examined factors associated with positive TST or QFT-GIT results. Results: Of 109 participants, 59 of 108 (55 %) were either TST (24/71, 34 %) or QFT-GIT (52/106, 50 %) positive. Concordance between TST and QFT-GIT was fair (71 % agreement, k = 0.38, 95 % CI: 0.15, 0.61). Factors associated with LTBI positivity included smoking (OR = 1.26, 95 % CI-1.01-1.58) and diabetes/high blood sugar (OR = 0.70, 95 % CI = 0.51-0.98). Discussion: Test concordance between the two tests was fair, with numerous discordant results observed. Greater proportion of positives detected using QFT-GIT may help avoid LTBI under-diagnosis. Assessment of LTBI status on the border provides evidence whether QFT-GIT should replace the TST in routine practice, as well as identifies risk factors for LTBI among migrant populations. © 2016 The Author(s).

Author Keywords

interferon-gamma release assay Latent tuberculosis infection Migrants Tuberculin skin test

Index Keywords

hyperglycemia Mycobacterium tuberculosis test kit demography agricultural worker human factor analysis middle aged statistics and numerical data diabetes mellitus interferon gamma release assay Interferon-gamma Release Tests controlled study Aged Logistic Models BCG vaccine Farmers Mexico ethnology procedures United States Young Adult Humans migrant smoking Adolescent diagnostic value male latent tuberculosis female risk factor Risk Factors software diagnostic test accuracy study sensitivity and specificity Article major clinical study tuberculin test adult migration statistical model Transients and Migrants anamnesis gold standard reference value
Link
https://www.scopus.com/inward/record.uri?eid=2-s2.0-84994316623&doi=10.1186%2fs12879-016-1959-3&partnerID=40&md5=92e5cb9fc92cde8ec7fe74257ae099c3
DOI: 10.1186/s12879-016-1959-3
ISSN: 14712334
Cited by: 4
Original Language: English