Toxocara infection in children with type 1 diabetes mellitus in Iran: a case-control seroprevalence study

Parasitic diseases and subsequent immunity against helminth infections involves profound changes in both the innate and adaptive immune compartments, which can have a protective effect in inflammation and autoimmunity diseases such as type 1 diabetes mellitus. The aim of the study is to evaluate the prevalence of anti-Toxocara antibodies and associated risk factors among diabetic children in a case-control study.

A total of 105 blood samples from diabetic children, and 101 non-diabetic controls attending the Comprehensive Imam Ali Children's Hospital, Alborz University of Medical Sciences in Karaj, Iran, were collected and tested by ELISA for anti-Toxocara antibodies. A questionnaire administered by direct interviews was used to collect socio-demographic information and data on associated risk factors.

The total seroprevalence of anti-Toxocara antibodies was significantly higher in healthy control individuals (5.9%) than in diabetic children (1.9%) (COR: 0.341, 95% CI: 0.079-1.480; AOR: 0.168, 95% CI: 0.029-0.967). Furthermore, seropositivity for toxocariasis was higher in the uncontrolled diabetic group than in controlled diabetic children, this was statistically significant (P = 0.046). Female participants (62.5%) were more susceptible to Toxocara infection. Also, living in rural areas (62.5%), illiteracy (75.0%), and contact with non-domesticated animals and/or soil (75.5%) were found to be the highest risk factors for toxocariasis in the studied children.

The finding of the study supports the hypothesis of an association between parasitic helminths infections and diabetes mellitus, and that T1DM can be considered as a stimulus in regulating and modulating the immune system in toxocariasis. More accurate results could be obtained from a larger than necessary sample better representative of the population.