Department of Parasitology, Institute of Biological Sciences, Federal University of Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil.
J Med Entomol. 2011 May;48(3):680-6. doi: 10.1603/me10237.
A laboratory model of myiasis as a result of Dermatobia hominis (L.) larvae was developed using mice as hosts. Mice in three groups were each infested with one newly hatched larva and skin biopsies processed for histopathology at 4, 12, and 20 d postinfestation (dpi). Mice in three other groups were each subjected to implantation of one larva collected from an infested (donor) mouse at 4, 12, and 20 dpi. Skin lesions of these receptor mice were then assessed at 10, 14, and 6 d postimplantation (dpimp), respectively. The inflammatory process in infested mice at 4 dpi was discrete, consisting of a thin necrotic layer around the larva, edema, many neutrophils, few eosinophils, mast cells, and proliferation of fibroblasts. At 12 dpi, there was a thicker necrotic layer, edema, many neutrophils and eosinophils, few mast cells, neoformation of capillaries, proliferation of the endothelium and fibroblasts, and early stages of fibrosis. These histopathological characteristics together with fibrosis were observed over a large area of the lesion at 20 dpi. Mice submitted to larval implantations demonstrated similar skin histopathology to that seen in the infested rodents, 10 dpimp corresponding to 12 dpi and 6 or 14 dpimp to 20 dpi. In all mice, the progressive acute inflammatory process followed a sequence linked to factors such as size of larvae and presence of secretory-excretory products. Both infested mice and those implanted experimentally with D. hominis larvae were shown to be suitable models for the study of the parasite-host relationship in this important zoonotic myiasis.
一种由 Dermatobia hominis（L.）幼虫引起的蝇蛆病的实验室模型是使用老鼠作为宿主开发的。三组老鼠每组都被感染了一只新孵化的幼虫，并在感染后 4、12 和 20 天（dpi）进行皮肤活检以进行组织病理学处理。另外三组老鼠每组都接受了一只从感染（供体）老鼠身上收集的幼虫的植入，时间分别为 4、12 和 20 dpi。然后分别在受体老鼠植入后的 10、14 和 6 天（dpimp）评估这些老鼠的皮肤病变。在感染后 4 dpi 的感染老鼠中，炎症过程是离散的，幼虫周围有一层薄的坏死层、水肿、许多中性粒细胞、少量嗜酸性粒细胞、肥大细胞和成纤维细胞增殖。在 12 dpi 时，坏死层较厚，水肿，大量中性粒细胞和嗜酸性粒细胞，少量肥大细胞，毛细血管新生，内皮细胞和成纤维细胞增殖，以及纤维化的早期阶段。在 20 dpi 时，病变的大面积出现了这些组织病理学特征以及纤维化。接受幼虫植入的老鼠表现出与感染老鼠相似的皮肤组织病理学特征，10 dpimp 对应于 12 dpi，而 6 或 14 dpimp 对应于 20 dpi。在所有老鼠中，渐进性急性炎症过程遵循与幼虫大小和分泌-排泄产物存在等因素相关的顺序。感染 D. hominis 幼虫的老鼠和实验性植入幼虫的老鼠都被证明是研究这种重要的人畜共患蝇蛆病中寄生虫与宿主关系的合适模型。
