Histopathological changes induced by Hysterothylacium deardorffoverstreetorum larvae (Nematoda: Raphidascarididae) in Priacanthus arenatus Cuvier, 1829 (Actinopterygii)

Abstract Priacanthus arenatus is a fish that occurs in the waters of the western Atlantic Ocean and has few records of parasitism. This study aimed to report histological changes caused by the larvae of Hysterothylacium deardorffoverstreetorum. Between July and December, 2013, 30 samples of P. arenatus were obtained from fish markets in the cities of Niterói and Rio de Janeiro, state of Rio de Janeiro, Brazil. Fragments of spleen, liver, stomach wall and mesentery tissues containing nodules and free parasites were extracted to histopathological study. Through histological analysis it was verified that these nodules consisted of connective tissue capsules, in which the parasites were located, with granulomatous inflammation mainly comprised of macrophages and lymphocytes. These nodules also consisted of a central portion of acellular amorphous material, formed by concentric layers, which was slightly basophilic and contained tunnels and, sometimes, parasite debris. The presence of tunnels in acellular amorphous material suggests that the larvae are initially located at the center of the nodules and then they migrate to the surface.

摘要：大西洋大眼鲷（Priacanthus arenatus）是一种栖息于西大西洋海域的鱼类，目前其寄生相关记录较为匮乏。本研究旨在报道德氏宫线虫（Hysterothylacium deardorffoverstreetorum）幼虫寄生所引发的组织病理学变化。2013年7月至12月期间，研究人员从巴西里约热内卢州尼特罗伊市与里约热内卢市的鱼市采集了30尾大西洋大眼鲷样本。研究人员切取带有结节与游离寄生虫的脾脏、肝脏、胃壁及肠系膜组织片段，用于组织病理学研究。经病理组织学分析确认，这些结节为包裹寄生虫的结缔组织囊，伴随以巨噬细胞与淋巴细胞为主要成分的肉芽肿性炎症反应。结节内部还存在由同心层状结构构成的无细胞无定形物质，该物质呈轻度嗜碱性，内部可见隧道样结构，有时还存在寄生虫残骸。无细胞无定形物质中的隧道样结构提示，幼虫最初定位于结节中心，随后逐渐迁移至结节表面。