Detection of latent tuberculosis infection among migrant farmworkers along the US-Mexico border

Abstract

BackgroundMigrant 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.MethodsParticipants 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.ResultsOf 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, ĸ = 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).DiscussionTest 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.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-016-1959-3) contains supplementary material, which is available to authorized users.

Tuberculosis in farm workers exposed to dairy and beef livestock in Colombia

“…The frequency in males was 79.6% (537/674), given that most people who carry out activities associated with livestock production are usually male. This is coherent with other studies where the frequency of males was also high [9,17,23–25]. Likewise, according to WHO, worldwide, men have a significantly higher risk of contracting TB compared to women [26].…”

“…Likewise, Oren and collaborators analyzed 109 agricultural migrant workers from the US-Mexico border. They found that the prevalence of latent TB was 34% with TST and 50% with IGRA [17]. One of the possible reasons for the low frequency of latent TB found in this study may be the selected population.…”

“…It was considered that a ‘poor’ agreement was κ ≤ 0.20, an ‘acceptable’ agreement was 0.20 <κ ≤ 0.40, a ‘moderate’ agreement was 0.40 <κ ≤ 0.60, a ‘good’ agreement was 0.60 <κ ≤ 0.80, and a ‘very good’ agreement was 0.80 < κ ≤ 1. [17].…”

Conventional and Complementary Therapy Use among Mexican Farmworkers in North Carolina: Applying the I-CAM-Q

“…1 These farmworkers experience high rates of occupational injury and illness. 2,3 Many also experience chronic diseases, including diabetes, tuberculosis, and hypertension, [4][5][6][7][8] as well as significant mental health problems, including stress, depression, and alcohol use disorders. [9][10][11][12] However, these farmworkers have limited access to conventional health services.…”

DNA Extraction with DNAzol and LAMP, Performed in a Heating Block as a Simple Procedure for Detection of Mycobacterium tuberculosis in Sputum Specimens

“…In 2015, Mexico reported 21 cases per 100,000 people [2], indicating that TB remains prevalent in the current population. Remarkably, the Northern States listed the highest incidence values, with Baja California at the forefront [12,13]. Here, we present a simple DNAzol–LAMP procedure for the detection of M. tuberculosis in sputum specimens.…”