Background: A lower allergy and asthma prevalence in farm children has been described three decades ago in Switzerland. Objective: After years of research into bacterial exposure at farms, the origin of the farm effect is still unknown. We now hypothesize, that there is no such an effect in large industrial cattle farms with slatted floors indoors but in small farms only where animals are grazing outdoors and are having a higher endoparasite load. Methods: We re-analyze an earlier epidemiological study by record-linkage to later agricultural surveys. The Asthma and Allergy Study in 1989/90 was a cross-sectional study of 1714 ten year old children in 63 villages covering ten different districts of Upper Bavaria. The farm effect is defined here as the association of number of cows per villager on lifetime prevalence of allergic rhinitis prevalence in the children of this village. Results: The farm effect is restricted to small villages only. Furthermore, districts with higher Fasciola infection rates of cows, show a significant stronger farm effect than districts with lower infection rates. Conclusion: The results warrant further research into human immune response to endoparasites in livestock.

中文翻译：

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并非所有动物都是平等的-上巴伐利亚行政区的农场生活和过敏

背景：三年前，瑞士描述了农场儿童的变态反应和哮喘患病率较低。目的：经过对农场中细菌暴露的多年研究，农场效应的起源仍然未知。我们现在假设，在室内有板条地板的大型工业化牛场中没有这种影响，而在只有室外放牧和高体内寄生虫负荷的小型农场中没有这种作用。方法：我们通过记录链接到以后的农业调查来重新分析早期的流行病学研究。1989/90年的哮喘和变态反应研究是一项横断面研究，涉及17个10岁的儿童，分布在上巴伐利亚州十个不同地区的63个村庄中。这里的农场效应定义为每个村民的牛数与该村庄儿童过敏性鼻炎患病率的一生之间的关系。结果：农场效应仅限于小村庄。此外，奶牛Fasciola感染率较高的地区比感染率较低的地区表现出明显更强的农场效应。结论：该结果值得进一步研究人类对家畜体内寄生虫的免疫反应。