Ectocommensal and ectoparasites in goldfish Carassius auratus (Linnaeus, 1758) in farmed in the State of São Paulo / Ectocomensais e ectoparasitas em kinguios Carassius auratus (Linnaeus, 1758) criados em fazenda no Estado de São Paulo

Concomitant infections by several parasitic genera are rare, very debilitating and often lethal to fish reared under commercial breeding conditions. Were describe a multiple and concurrent parasite infestation in cultured goldfish Carassius auratus with skin damage (nodules and/or ulceration). Fish with skin lesions underwent necropsy, and the skin and gills were scraped and examined. Histopathological examination with Hematoxylin-Eosin and Giemsa stain, and an ultrastructure study using transmission and scanning electron microscopy were conducted. In the skin, we identified multiple-parasite infestations by Gyrodactylidae, Epistylis sp., Trichodina sp., Ichthyophthirius multifiliis, Tetrahymena sp. and Ichthyobodo necator,associated with epithelial cell hyperplasia and epidermal sloughing. Although no gross lesions were observed, were identified a large number of parasites in the gills (Epistylis sp., Piscinoodinium sp., Ichthyophthirius multifiliis, Trichodina sp., Apiosoma sp., Hexamitasp. and cysts of a trematode digenean). The observed trematodes were not identified. The associated microscopic lesions were epithelial hypertrophic and hyperplasic and exhibited fusion of secondary lamellae and epithelial cell detachment. This is the first description of a protozoan Vorticella sp. parasitizing goldfish in Brazil. Multiple ectoparasitism by protozoa and Platyhelminthes, with or without apparent tissue damage, can be fatal for goldfish raised on farms with poor management.

A infestação concomitante por vários gêneros de parasitas é uma condição rara, debilitante e letal para os peixes e está geralmente associada aos problemas ambientais e de manejo. Com o objetivo de descrever os ectoparasitos presentes em kinguios Carassius auratus com lesões cutâneas, cultivados em fazenda comercial, foram analisados 30 exemplares de peixes por esfregaços de pele lesionada e de brânquias; exame histopatológico de tecidos corados pela técnica de Hematoxilina-Eosina e Giemsa e estudo ultraestrutural por microscopia eletrônica de transmissão e varredura de tecidos coletados após necropsia. Nas lesões cutâneas, foram observados os parasitos: Gyrodactylidae, Epistylis sp., Trichodina sp., Ichthyophthirius multifiliis, Tetrahymena sp. e Ichthyobodo necator, associados à hiperplasia epitelial, descamação epidérmica e presença de infiltrado inflamatório. A infestação das brânquias, mesmo sem lesão macroscópica, evidenciou Epistylissp., Piscinoodinium sp., I. multifiliis, Trichodina sp., Apiosoma sp., Hexamita sp. e cistos de trematódeo associados à hipertrofia e hiperplasia epitelial, fusão de lamelas secundárias, descamação epitelial e presença de infiltrado inflamatório. Os trematódeos observados não foram identificados. É a primeira descrição do protozoário Vorticella sp. parasitando kinguios no Brasil. O ectoparasitismo múltiplo por protozoários e platelmintos, com ou sem lesão aparente, pode ser fatal em peixes cultivados em condições ambientais precárias.

Acanthamoeba sohi, n. sp., a pathogenic Korean isolate YM-4 from a freshwater fish

A new species of Acanthamoeba was isolated from a freshwater fish in Korea and tentatively named Acanthamoeba sp. YM-4 (Korean isolate YM-4). The trophozoites were 11.0-23.0 micrometer in length and had hyaline filamentous projections. Cysts were similar to those of A. culbertsoni and A. royreba, which were previously designated as Acanthamoeba group III. Acanthamoeba YM-4 can survive at 40 degrees C, and its generation time was 19.6 hr, which was longer than that of A. culbertsoni. In terms of the in vitro cytotoxicity of lysates, Acanthamoeba YM-4 was weaker than A. culbertsoni, but stronger than A. polyphaga. On the basis of the mortality of experimentally infected mice, Acanthamoeba YM-4 was found to be highly virulent. The isoenzymes profile of Acanthamoeba YM-4 was similar to that of A. royreba. An anti-Acanthamoeba YM-4 monoclonal antibody, McAY7, was found to react only with Acanthamoeba YM-4, and not with A. culbertsoni. Random amplified polymorphic DNA marker analysis and RFLP analysis of mitochondrial DNA and of 18S small subunit ribosomal RNA, placed Acanthamoeba YM-4 in a separate cluster on the basis of phylogenetic distances. Thus the Acanthamoeba Korean isolate YM-4 was identified as a new species, and assigned as Acanthamoeba sohi.