Allergic bronchial asthma is a long-lasting illness of the respiratory system characterized by
chronic inflammation of the respiratory airways with abnormal Th2-type immune responses to
specific allergens. The accumulation of scientific evidence supports the beneficial effects of
some parasitic infections in animal models of allergic diseases. Thus, the aim of this work was
to discover the influence of infection with T. spiralis on ovalbumin-induced acute allergic airway
inflammation in mice and to investigate whether this effect is correlated to the infection
dose or not. Therefore, the severity of respiratory airways inflammation, the leukocyte counts in
the blood and BALF, immunohistochemistry of FOXP3+CD4+T cells and the levels of IL-6, IL-
13, and IL-10 were assessed. In this experiment, 120 male laboratory bred mice were randomly
divided into six groups: induced asthma, saline control, low dose preventive, high dose preventive,
low dose therapeutic and high dose therapeutic groups. T. spiralis infection attenuated the
intensity of pulmonary inflammation, decreased numbers of eosinophils in BALF and blood,
reduced levels of IL-6 and IL-13 and elevated levels of IL-10 with a significant upregulation of
FOXP3+CD4+T cells expression compared to the uninfected induced asthma group. The preventive
groups showed the best results with no significant difference between effects of the low and
the high doses. In conclusion, T. spiralis infection reduced Th2 type infammation and augmented
regulatory immune response in ovalbumin-induced acute allergic airway inflammation with
better preventive than therapeutic effects. Further investigations are needed to determine the
minimal dose of infection that gives the best influence.