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.