Enterobius vermicularis and Risk Factors in Healthy Norwegian Children

Background: The prevalence of Enterobius vermicularis in neighboring countries of Norway show large variation. The goal of this study was to investigate the prevalence among Norwegian children and possible risk factors. Methods: The children were participants in "Environmental Triggers of Type 1 Diabetes: the MIDIA study." The study involved 2 groups with different genetic risks of type 1 diabetes: A high-risk group carries the Human Leukocyte Antigen genotype conferring the highest risk for type 1 diabetes and a nonhigh-risk group consisting of children without this genotype. Scotch tape samples were collected on 3 consecutive days and examined by light microscopy. Results: A total of 18% (72/395) of children were positive for E. vermicularis. The highest prevalence (34%) was in children 6-11 years of age. Only 2 children were prior known positives. Increased number of siblings was linked to more infections, and there were fewer infections in the children with the high-risk genotype. Conclusion: E. vermicularis is a common parasite in Norwegian children. The likelihood of E. vermicularis infection depends on family size and prevalence increases with age. The reduced number of infections in the children carrying the high-risk genotype for type 1 diabetes is intriguing and should be investigated further.