The study for the relationship between the quantity of Ascaris antigen in the house dust and asthma symptoms of children living in the rural area of Bangladesh

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So-called hygiene hypothesis means that better hygienic environment introduce less allergic diseases. This hypothesis is still controversial especially in the developing country where the ascaris infection is mostly endemic. We had published a paper concerning the epidemiological data which showed the morbidity of wheezing is about 16% in Bangladeshi children. The morbidity of ascaris infestation is over 70% in the rural area in Bangladesh. Our data threw the issue against the hygiene hypothesis. We had also showed that high amount of anti-ascaris IgE antibody significantly correlated to the morbidity of wheezy episodes, diagnosed as the bronchial asthma. We hypothesized there might be ascaris antigen in the house-dust which worked as the inhalant allergen. We surveyed the same field in the rural Bangladesh as the one surveyed in 2001.ISAAC questionnaire was used. Sixty one children out of 142(43%) who were wheezy group in 2001 showed wheezing episode yet after 10 years and 79 out of 97(81%) who were not wheezy showed no wheezing episode. This difference was statistically significant by chi square test(p<0.0001). House dust was collected from the bedding of these two groups. Higher amount of ascaris antigen(5.25μg/g dust, 1.15～ 9.36, 95% CI) was detected in the house dust of the wheezy group than the non-wheezy group(2.54μg/g dust, 1.67～ 3.41, 95% CI), although statistically not significant. The newly developed method for detecting ascaris antigen has some limitation, because something was detected from the dust which was collected from Japanese housing. Our result suggested that there might be cross-reactive materials other than ascaris antigen in those house dust collected from two countries. Further research is needed.