Persisting low skin prick test prevalence among children receiving periodic anthelminthic treatment after recurrent soil-transmitted helminth infections: a one-year observation

Abstract

Background The immune system in human develops when they are exposed to severe helminth infections. Chronic soil-transmitted helminth (STH) infection can modulate and suppress allergic reactions particularly by changing the responses from the immune effector. This study observed how STH infections are correlated with allergic reactions as determined by skin prick test (SPT). Methodology Fourty-five primary school children with recurrent STH infections (determined by at least two positive results in 4-monthly Kato Katz examination over a year period) who received periodic treatment from Mandailing Natal, were classified as case, and 45 primary school students with no history of STH infections from Medan were classified as control in this study. Positive SPT occurred among 27% and 89% of children in the case and control groups (OR 22, 95% CI 7.032-68.827), respectively. No history of helminthiasis, history of allergy, history of parent's allergies, and history of sibling's allergies were associated with increased risks of positive SPT. Conclusion Our findings supported the hygiene hypothesis, where decreased exposure to infectious disease pathogens and decreased diversity of microbial exposures in the environment increases the prevalence of allergies, and anthelminthic treatment show limited effect in reversing the protective effect of STH infections to allergies.