Parasite infection and tuberculosis disease among children: a case-control study.

We conducted a case-control study to examine associations between parasite infection, including protozoa infection, and tuberculosis (TB) in children in Lima, Peru. We enrolled 189 matched-pairs. In multivariable conditional logistic regression analyses, Blastocystis hominis infection (rate ratio = 0.30, 95% confidence interval = 0.14-0.64, P = 0.002) was strongly associated with a lower risk of TB. We observed a statistically significant inverse linear dose-response relationship between Blastocystis hominis infection and TB. These findings should be confirmed in future prospective studies.