Omar M S, Garms R
Tropenmed Parasitol. 1977 Mar;28(1):109-19.
High intakes of microfilariae of a Guatemalan strain of Onchocerca volvulus by Simulium metallicum proved lethal to a considerable proportion of the flies within 24 hours of taking an infecting blood-meal. The gross histopathological changes resulting from infection were compared in groups of moribund and of apparently healthy flies during this period. The marked morbidity of the flies could be related to certain events occurring in the alimentary tract and haemocoele of the fly soon after ingestion of the parasitized blood. The rapid death of the flies may be ascribed to one or more of the following reasons: (i) reverse migration of numerous microfilariae from the expanded- to the tubular-part of the mid-gut, where they cause serious injury and disintegration of the gut epithelium; (ii) abrasive damage to the stomach epithelial cells by the invading microfilariae with occasional release of the gut contents into the haemocoele; (iii) interruption of the formation of the peritrophic membrane, particularly at its anterior and posterior ends, with subsequent failure of the flies to digest the blood in the stomach; (iv) passage of large amounts of parasitized blood from the stomach backwards into the hind-gut, leading to its mechanical obstruction and (v) invasion and injury of various organs of the fly, among them the ventral nerve-cord, brain, optic nerve, eye, halteres, fat-body and flight musculature by excessive numbers of microfilariae.
用危地马拉株盘尾丝虫的微丝蚴大量感染金属蚋，结果表明，相当一部分苍蝇在吸食感染性血餐24小时内死亡。在此期间，对濒死苍蝇组和看似健康的苍蝇组感染后产生的大体组织病理学变化进行了比较。苍蝇明显的发病情况可能与吸食带虫血液后不久在其消化道和血腔中发生的某些事件有关。苍蝇的迅速死亡可能归因于以下一个或多个原因：（i）大量微丝蚴从中肠扩张部分反向迁移至管状部分，在那里它们会对肠上皮造成严重损伤和崩解；（ii）入侵的微丝蚴对胃上皮细胞造成磨损性损伤，偶尔会导致肠内容物释放到血腔中；（iii）围食膜形成中断，特别是在其前端和后端，随后苍蝇无法消化胃中的血液；（iv）大量带虫血液从胃向后流入后肠，导致其机械性阻塞；（v）大量微丝蚴侵入并损伤苍蝇的各种器官，其中包括腹神经索、脑、视神经、眼、平衡棒、脂肪体和飞行肌肉组织。
