Guagliardo Silvia, Viozzi Gustavo, Brugni Norma
Laboratorio de Patología de Organismos Acuáticos- Dep. Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, San Juan, 670, 8000, Bahía Blanca, Argentina.
Laboratorio de Parasitología, INIBIOMA (Universidad Nacional del Comahue-CONICET), Quintral 1250, 8400, Bariloche, Argentina.
Int J Parasitol Parasites Wildl. 2019 Aug 8;10:113-116. doi: 10.1016/j.ijppaw.2019.08.004. eCollection 2019 Dec.
Helminth infections within tissues tend to be subjected to a host response that can include encapsulation and melanization to isolate the parasite. The effectiveness of this response depends on the host species. During a survey of parasites of the native fish, , we found conspicuous, strongly melanized exterior cysts located in the caudal peduncle of the fish. Dissection of these cysts exposed larval nematodes whose morphometrical features allowed their identification as sp. Species of this genus are distributed worldwide. was previously reported as second intermediate host to sp. larvae, and the aquatic bird was cited as definitive host of in Andean Patagonian lakes. The site of infection in the fish, and the host's response are unique among infections by larvae of sp. in fishes, so the objective of this study was to describe the histological injury caused by larvae of the genus parasitizing . Samples of fish were taken near the shore of Gutiérrez lake, in northwestern Patagonia. Some larval morphometric features were described to confirm the identity of larvae to generic level. Histopathological analysis (tissues sectioned at 5-7 μm, stained with Hematoxylin and Eosin, and Masson's Trichrome) of the caudal peduncle revealed almost complete disappearance of the epaxial musculature due to compressive atrophy and a chronic inflammatory response, associated mainly with a dense fibrotic capsule and an intense melanic deposit. This is the first description of the histopathology of an external cyst caused by sp. larvae in fishes.
组织内的蠕虫感染往往会引发宿主反应，其中可能包括包囊形成和黑化，以隔离寄生虫。这种反应的有效性取决于宿主物种。在对本地鱼类寄生虫的调查中，我们发现鱼的尾柄处有明显的、高度黑化的外部囊肿。解剖这些囊肿后发现了幼虫线虫，其形态特征使其被鉴定为 属物种。该属物种分布于世界各地。此前曾报道 是 属幼虫的第二中间宿主，而水鸟 被认为是安第斯巴塔哥尼亚湖泊中 的终末宿主。鱼类的感染部位以及宿主的反应在 属幼虫感染鱼类的情况中是独特的，因此本研究的目的是描述 属幼虫寄生 所引起的组织学损伤。在巴塔哥尼亚西北部的古铁雷斯湖岸边采集了鱼样本。描述了一些幼虫的形态特征，以在属的水平上确认幼虫的身份。对尾柄进行组织病理学分析（组织切片厚度为5 - 7μm，用苏木精和伊红染色以及马松三色染色）发现，由于压迫性萎缩和慢性炎症反应，轴上肌肉组织几乎完全消失，主要与致密的纤维性囊和强烈的黑色素沉积有关。这是首次对鱼类中 属幼虫引起的外部囊肿的组织病理学进行描述。
