Introduction
Allergic asthma is the most common chronic disease in different communities ((1). On average, hundreds of millions people have been suffered from allergic asthma at least once (1). The increasing prevalence of this disorder worldwide has imposed considerable pressure on the healthcare system, especially in developing countries (2). Exposure rate and type of inhaled allergen play an essential role in developing allergic asthma symptoms (1). Although genetics, food, pollen, house dust mites, and chemicals all have a role in the onset of allergic symptoms, there is growing evidence that human immune responses to parasitic worm glycan antigens may influence the development of allergy symptoms. This statement is defensible since in response to helminth infections high levels of total and specific IgE antibodies are produced which cause mast cells to degranulate, releasing vasoactive substances, including histamine, and also Th2 pathway responses are activated that are characterized by the cytokines production including IL-4, IL-5, and IL-13 (3).
In the same direction, strong evidence from experimental and clinical studies has documented that human toxocariasis (HT), a parasitic zoonotic disease caused by Toxocara spp., afflicts humans as an incompatible host in the parasite’s life, might be linked with childhood asthma (4). In addition, some studies showed a correlation between Toxocara spp. infection and development of allergy in human individuals and animal studies (5).
The high prevalence of human toxocariasis in tropical countries has sounded the alarm calling to prevent and control this infection, especially among children (6). Children are significantly more prone to Toxocara infection due to poor personal hygiene and habits such as geophagy, finger sucking, and nail biting (7). Therefore, studying toxocariasis in childhood asthmatics gained much attention in places where toxocariasis and childhood allergic asthma is a big challenge for the healthcare system. Due to the lack of comprehensive study on toxocariasis as a potential risk factor in children, as well as its possible association with the etiology of allergic asthma in southwest Iran, this study aimed to compare the seropositivity rate of anti-Toxocara IgG in children with allergic asthma and healthy children.