Aquatic Parasitology Laboratory and Southeastern Cooperative Fish Parasite and Disease Laboratory, Auburn University, 559 Devall Drive, Auburn, AL, 36832, USA.
Department of Zoology, School for Environmental Sciences and Development, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa.
Parasitol Res. 2022 Aug;121(8):2307-2323. doi: 10.1007/s00436-022-07570-z. Epub 2022 Jun 27.
Variable platyfish, Xiphophorus variatus (Meek, 1904) (Cyprinodontiformes: Poeciliidae) and eastern mosquitofish, Gambusia holbrooki Girard, 1859 (Poeciliidae) from earthen ponds in west central Florida were examined for parasitic infections. At necropsy, we observed myriad nematodes (adults and eggs), which we identified as Huffmanela cf. huffmani, infecting the swim bladder, gonad, and visceral peritoneum. Nucleotide sequences (small subunit ribosomal DNA, 18S) of H. cf. huffmani from variable platyfish and eastern mosquitofish were identical; likewise for newly obtained 18S sequences of Huffmanela huffmani Moravec, 1987 from the swim bladder of red breast sunfish, Lepomis auritus (Linnaeus, 1758) (Centrarchiformes: Centrarchidae) and warmouth, Lepomis gulosus (Cuvier, 1829) from the San Marcos River (type locality for Huffmanela huffmani Moravec, 1987), Texas. The sequences of H. huffmani and H. cf. huffmani differed by 7 (1%) nucleotides. Pathological changes comprised proliferation of the tunica externa of the swim bladder in low-intensity infections in addition to inflammation, proliferation, and tissue necrosis of swim bladder, peritoneum, and gonad in high-intensity infections. The lesion was severe, affecting the cellular constituents of the swim bladder wall and reducing the size of the swim bladder lumen; potentially reducing swim bladder physiological efficiency. The present study is the first record of a freshwater species of Huffmanela Moravec, 1987 from beyond the San Marcos River, first record of a species of Huffmanela from a livebearer, first nucleotide sequences and phylogenetic analysis for Huffmanela, and first evidence that an infection by a species of Huffmanela causes pathological changes that could impact organ function.
从佛罗里达州中西部的土池塘中采集的变异平鳍鱼（Xiphophorus variatus）（鲤形目：胎生鱂科）和东部食蚊鱼（Gambusia holbrooki）（胎生鱂科）进行寄生虫感染检查。在剖检时，我们观察到无数的线虫（成虫和卵），鉴定为感染鳔、性腺和内脏腹膜的Huffmanela cf. huffmani。来自变异平鳍鱼和东部食蚊鱼的 H. cf. huffmani 的核苷酸序列（小亚基核糖体 DNA，18S）完全相同；同样，从红胸太阳鱼（Lepomis auritus）（鲈形目：太阳鱼科）鳔中获得的新 Huffmanela huffmani Moravec，1987 的 18S 序列和来自德克萨斯州圣马科斯河（Huffmanela huffmani Moravec，1987 的模式产地）的温暖口鱼（Lepomis gulosus）的 18S 序列也完全相同。H. huffmani 和 H. cf. huffmani 的序列差异为 7（1%）个核苷酸。在低强度感染中，病变主要为鳔外膜增生，在高强度感染中，还伴有鳔、腹膜和性腺的炎症、增生和组织坏死。病变严重，影响鳔壁的细胞成分，缩小鳔腔的大小；可能会降低鳔的生理效率。本研究首次记录了 San Marcos 河以外的淡水 Huffmanela Moravec，1987 种，首次记录了从活胎生鱼中分离出的 Huffmanela 种，首次提供了 Huffmanela 的核苷酸序列和系统发育分析，以及首次证明由 Huffmanela 种感染引起的病理变化可能会影响器官功能。
