Association between parasitic infections and tuberculin skin test results in refugees.
BACKGROUND
Parasitic infections are known to modulate the immune response necessary for controlling Mycobacterium tuberculosis infection. We sought to investigate species-specific effects of parasite infection on M. tuberculosis infection.


METHODS
As part of the Refugee Health Assessment Program, stool examinations and tuberculin skin testing were performed on refugees seen at Boston Medical Center between 1995 and 2012. Tuberculin skin test (TST) and stool examination data were collected for 6669 refugees; 3349 (50.2%) were TST positive (≥10 mm).


RESULTS
Among TST-positive subjects, 176 (5.3%) had helminth infections and 1149 (34.3%) protozoa. After adjusting for sex, age, and country of origin, helminth and protozoan infections were not associated with TST-positivity. When species-specific effects were examined, subjects infected with Trichuris trichiura and Giardia lamblia had reduced odds of TST-positivity (adjusted OR [aOR] 0.65 [95%CI 0.44-0.96; p = 0.03] and aOR 0.79 [95%CI 0.65-0.95, p = 0.01], respectively).


CONCLUSIONS
Our findings suggest that T. trichiura and G. lamblia may provide protection against M. tuberculosis infection. This study adds to a growing body of literature suggesting that immune response modulation and susceptibility to M. tuberculosis infection is parasite species-dependent.
Department of Epidemiology, Boston University School of Public Health, Boston, MA, United States; Department of Biostatistics, Boston University School of Public Health, Boston, MA, United States. Electronic address: nwatts@g.harvard.edu.
Nathaniel S
NS
Watts
Department of Epidemiology, Boston University School of Public Health, Boston, MA, United States. Electronic address: mucho@bu.edu.
Mucho M
MM
Mizinduko
Department of Pediatrics, Boston University School of Medicine, Boston, MA, United States. Electronic address: Elizabeth.Barnett@bmc.org.
Elizabeth D
ED
Barnett
Department of Biostatistics, Boston University School of Public Health, Boston, MA, United States. Electronic address: lfwhite@bu.edu.
Laura F
LF
White
Department of Epidemiology, Boston University School of Public Health, Boston, MA, United States; Department of Medicine, Section of Infectious Diseases, Boston University School of Medicine, Boston, MA, United States. Electronic address: nhoch@bu.edu.
Natasha S
NS
Hochberg
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D005243:Feces / Q000469:parasitology; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D010272:Parasitic Diseases / Q000150:complications / Q000453:epidemiology*; D012036:Refugees / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D014374:Tuberculin Test; D014376:Tuberculosis / Q000150:complications / Q000453:epidemiology*; D055815:Young Adult
Immigrant; Latent tuberculosis; Parasites; Tuberculin test; Tuberculosis