Ascaris lumbricoides and Ascaris suum are two closely related parasites that infect humans and pigs. The zoonotic potential of A. suum has been a matter of debate for decades. Here we sought to investigate the potential human infection by A. suum and its immunological alterations. We orally infected five healthy human subjects with eggs embraced by A. suum. The infection was monitored for symptoms and possible respiratory changes, by an interdisciplinary health team. Parasitological, hematological analyses, serum immunoglobulin, cytokine profiles, and gene expression were evaluated during the infection. Our results show that A. suum is able to infect and complete the cycle in humans causing A. lumbricoides similar symptoms, including, cough, headache, diarrhea, respiratory discomfort and chest x-ray alterations coinciding with larvae migration in the lungs. We also observed activation of the immune system with production of IgM and IgG and a Th2/Th17 response with downregulation of genes related to Th1 and apoptosis. PCA (Principal componts analysis) show that infection with A. suum leads to a change in the immune landscape of the human host. Our data reinforce the zoonotic capacity of A. suum and bring a new perspective on the understanding of the immune response against this parasite.

蛔虫和猪蛔虫是感染人类和猪的两种密切相关的寄生虫。几十年来， A. suum的人畜共患潜力一直是争论的焦点。在这里，我们试图调查A. suum的潜在人类感染及其免疫学改变。我们用A. suum 包裹的卵子口服感染了五名健康的人类受试者。跨学科卫生团队监测感染的症状和可能的呼吸道变化。在感染期间评估了寄生虫学、血液学分析、血清免疫球蛋白、细胞因子谱和基因表达。我们的研究结果表明A. suum能够感染并完成人类的循环，导致A. lumbricoides类似的症状，包括咳嗽、头痛、腹泻、呼吸系统不适和胸部 X 射线改变，与幼虫在肺部迁移相吻合。我们还观察到免疫系统的激活与 IgM 和 IgG 的产生以及 Th2/Th17 反应以及与 Th1 和细胞凋亡相关的基因的下调。PCA（主要成分分析）表明感染A. suum会导致人类宿主的免疫环境发生变化。我们的数据加强了A. suum的人畜共患病能力，并为理解针对这种寄生虫的免疫反应带来了新的视角。