Bullard S A, Frasca S, Benz G W
Department of Coastal Sciences, The University of Southern Mississippi, Ocean Springs 39564, USA.
J Parasitol. 2000 Jun;86(3):618-22. doi: 10.1645/0022-3395(2000)086[0618:SLCBDP]2.0.CO;2.
Skin lesions caused by the ectoparasite Dermophthirius penneri Benz, 1987 (Monogenea: Microbothriidae) on 2 wild-caught blacktip sharks (Carcharhinus limbatus) from the northern Gulf of Mexico were studied using light and scanning electron microscopy. Grossly, lesions appeared as multifocal, well-demarcated, ovoid or irregularly shaped, light gray patches of skin. Scanning electron microscopy of lesions revealed gaps between placoid scales apparently created by detachment and loss of placoid scales, rotated and tilted placoid scales with blunt distal tips and shallow ridges, and a frayed epithelium that covered some placoid scales and filled some spaces between placoid scales. Light microscopy of lesions revealed epithelial hyperplasia accompanied by dermal infiltrates of moderate numbers of loosely arranged lymphocytes interposed between collagen bundles in the superficial layers of the stratum compactum. This report provides the first details of microbothriid skin lesions on wild sharks. Our results indicate that D. penneri caused chronic skin lesions not associated with bacterial infection or severe, debilitating, skin disease in the studied sharks.
利用光学显微镜和扫描电子显微镜，对从墨西哥湾北部捕获的2条野生黑鳍鲨（Carcharhinus limbatus）身上由外寄生虫彭氏皮蝇（Dermophthirius penneri Benz，1987年）（单殖吸虫纲：微双盘吸虫科）引起的皮肤损伤进行了研究。肉眼可见，损伤表现为多灶性、界限清晰、卵圆形或不规则形状的浅灰色皮肤斑块。对损伤部位进行扫描电子显微镜观察发现，盾鳞之间出现间隙，显然是由于盾鳞脱落和丢失造成的；盾鳞旋转并倾斜，远端尖端钝圆，有浅脊；上皮细胞磨损，覆盖了一些盾鳞，并填充了盾鳞之间的一些空隙。对损伤部位进行光学显微镜观察发现，上皮细胞增生，同时在致密层表层的胶原束之间有中等数量松散排列的淋巴细胞浸润真皮。本报告首次详细描述了野生鲨鱼身上微双盘吸虫引起的皮肤损伤。我们的结果表明，彭氏皮蝇在研究的鲨鱼身上引起了慢性皮肤损伤，与细菌感染或严重的、使人衰弱的皮肤病无关。
