Comparison of the infectivity of Trypanosoma cruzi insect-derived metacyclic trypomastigotes after mucosal and cutaneous contaminative challenges

Trypanosoma cruzi infects humans when infected triatomine vector excreta contaminate breaks in skin or mucosal surfaces. T. cruzi insect-derived metacyclic trypomastigotes (IMT) invade through gastric mucosa after oral challenges without any visible inflammatory changes, while cutaneous and conjunctival infections result in obvious local physical signs. In this study we compared the infectivity of T. cruzi IMT in mice after cutaneous and oral contaminative challenges simulating natural infections. The 50% infective dose (ID50) for oral challenge was 100 fold lower than the ID50for cutaneous challenge, indicating that oral mucosal transmission is more efficient than cutaneous transmission.

克氏锥虫（Trypanosoma cruzi）可通过受感染锥蝽媒介的排泄物污染皮肤破损或黏膜表面的途径感染人类。经口攻毒时，虫源循环后期锥鞭毛体（insect-derived metacyclic trypomastigotes, IMT）可通过胃黏膜侵入宿主，且无可见炎症变化；而皮肤与结膜感染则会出现明显的局部体征。本研究模拟自然感染场景，分别经皮肤污染途径和经口污染途径感染小鼠，对比了克氏锥虫虫源循环后期锥鞭毛体的感染活性。经口攻毒的半数感染量（ID50）较皮肤攻毒低100倍，表明经口黏膜传播的效率高于皮肤传播。