RESUMO: A ictiofitiríase em peixes tem distribuição mundial e forte impacto econômico na piscicultura de água doce devido às altas taxas de mortalidade associadas. Este estudo avaliou o uso do peróxido de hidrogênio (H2O2) e do dióxido e cloro (ClO2) no controle do parasito protozoário Ichthyophthirius multifiliis em jundiá. A concentração letal mediana (CL50, 96h) de cada agente químico foi estabelecida, assim como a concentração mínima inibitória do peróxido de hidrogênio para a fase larval infecciosa do parasito (teronte). Os agentes foram testados assincronicamente em alevinos parasitados na forma de banhos de curta e longa duração, nas seguintes concentrações e tempos de exposição: 1. Peróxido de hidrogênio: (T1) banho contínuo - 30ppm e (T2) 50ppm; (T3) banho curto - 150ppm com duração de 1h e (T4) 250ppm com duração de 1h, além de um grupo controle (sem a adição do agente químico). 2. Dióxido de cloro: (T1) banho contínuo - 4ppm; (T2) banho contínuo - 20ppm; (T3) banho curto - 200ppm, com duração de 1min; (T4) banho curto - 400ppm, com duração de 1min, além de um grupo controle. A análise dos dados indicou a concentração de 82,54ppm do produto comercial utilizado (ou 24,76ppm do princípio ativo) como a Cl50, 96h de H2O2 e de 38,4ppm produto (ou 2,68ppm do princípio ativo) para o ClO2. A concentração de H2O2 que causou 100% de mortalidade dos terontes em 1h foi de 25ppm (do produto, ou 7,5ppm do princípio ativo). Ao final do quarto dia de experimento curativo, 98% dos animais morreram devido à ictiofitiríase. Nenhum dos tratamentos foi efetivo frente à parasitose.

ABSTRACT: Ichthyophthiriasis is a worldwide fish disease with great financial impact on freshwater fish farming due to its associated high mortality rates. Current study assesses the parasiticidal capacity of hydrogen peroxide (H2O2) and chlorine dioxide (ClO2) against the causative agent, Ichthyophthirius multifiliis, in jundiá. Median lethal concentration (LC50, 96h) of each chemical agent was established, as well as the minimum inhibitory concentration of hydrogen peroxide for the parasite´s infectious larval phase (theront). Products were tested asynchronously in parasitized fingerlings for short and long baths at the following concentrations and exposure times: 1. Hydrogen peroxide: (T1) continuous bath - 30ppm and (T2) 50ppm; (T3) short bath - 150ppm, during 1h and (T4) 250ppm during 1h; control group (without any chemical agent). 2. Chlorine dioxide: (T1) continuous bath - 4ppm and (T2) 20ppm; (T3) short bath - 200ppm, during 1min; (T4) short bath - 400ppm, during 1min and control group. Data analysis demonstrated a concentration of 82.54ppm of the commercial product (or 24.76ppm of the active chemical agent) as LC50, 96h of H2O2 and 38.4ppm product (or 2.68ppm of the active chemical agent) for ClO2. Hydrogen peroxide concentration causing 100% mortality rate of theronts in 1h was 25ppm (product, or 7.5ppm of the active chemical agent). At the end of the fourth day of curative experiment, 98% of the animals died by ichthyophthiriasis. No treatment was effective against the parasite.

ABSTRACT Monogenoidea pathogenic activity can elicit various histological responses in fish. Species of Ligophorus are specific parasites of mullets, and its relationship with host fish may result in a moderate pathogenic action. In order to ascertain this relationship, estuarine mullets (Mugil liza) were collected in an estuary, reared in laboratory, for three weeks, and forwarded for histological and parasitological analyses. Ligophorus uruguayense (Monogenoidea) infestation in the gills of the mullets was identified. The severe infestation by only one species of Monogenoidea may result from the specificity of these parasites to mullets. Mullets submitted to histological analysis exhibited respiratory epithelium detachment; mild, moderate and severe hyperplasia of the respiratory epithelium; atrophy; and telangiectasia of the gills. This is the first study reporting that mullets highly infested by Monogenoidea can show mild (100%) to severe (20%) gill changes with a distinct frequency of occurrence. Because of the high prevalence of mild alterations observed, it is possible to accept that L. uruguayense is moderately pathogenic to M. liza, even during high prevalence and intensity of infestation, as a result of its specificity.

ABSTRACT This study aimed to characterize the metazoan parasitic fauna associated with freshwater farmed ornamental fish in Southern Brazil. Between July 2014 and January 2015, a total of 423 fish belonging to nine species were examined: Pterophylum scalare, Betta splendens, two varieties of Carassius auratus, Danio rerio, Xiphophorus helleri, two varieties of Xiphophorus maculatus, Poecilia sphenops, Tanichthys albonubes and Puntius sachsii. In each fish collection, the water quality parameters were measured. Specimens were obtained from three ornamental fish farms located in three micro-regions in the State of Santa Catarina (Araquari, Biguaçu and Camboriú). Parasitological indexes were obtained after qualitative and quantitative parasitological analysis. Monogenean parasites, nematodes, and cestodes were found in all facilities. Nevertheless, nematodes and monogeneans presented 100% of prevalence in P. scalare from Araquari. From the analyzed species, P. scalare showed the highest parasite richness.

O filo Protozoa reúne diversos organismos evolutivamente distintos que podem atuar como ecto ou endoparasitos de peixes em todo o mundo, sendo responsáveis por doenças as quais, por sua vez, podem ocasionar impactos econômico e social nos diferentes países. Apesar dos recentes avanços no campo de diagnóstico de doenças em peixes no Brasil, ainda pouco se conhece sobre a fauna de protozoários parasitos de peixes e suas relações com o ambiente e hospedeiro. Esta revisão apresenta os mais importantes protozoários parasitos encontrados em peixes cultivados no Brasil, não apenas com ênfase no seu diagnóstico, biologia, transmissão e relação hospedeiro-parasito, mas também algumas informações que podem ser úteis para pesquisadores para o correto diagnóstico em pisciculturas.

The Phylum Protozoa brings together several organisms evolutionarily different that may act as ecto or endoparasites of fishes over the world being responsible for diseases, which, in turn, may lead to economical and social impacts in different countries. Apart from the recent advances for the diagnosis of fish diseases in Brazil, little is known on the protozoan parasites and their relationship with environment and host. This revision presents the most important protozoan parasites found in farmed fish from Brazil, not only with emphasis on its diagnosis, biology, transmission and host-parasite relationship, but also on some information that may be useful to researchers in determining the correct diagnosis in fish farms.

Este estudo caracterizou morfologicamente Trichodina heterodentata Duncan, 1977 de alevinos de "pirarucu" Arapaima gigas cultivados no Peru. Esfregaços do corpo e brânquias foram secos à temperatura ambiente, impregnados com nitrato de prata e/ou corados com tricrômico de gômori. A prevalência foi de 100%. Trichodina heterodentata foi considerada um tricodinídeo de tamanho médio com diâmetro médio do corpo de 56,0+ 5,25 (47,3-76,0) μm, anel denticulado 28,21± 2,71 (20,0-34,7) μm, disco adesivo 45,7±3,8 (37,1-57,3) μm de diâmetro e número de dentículos de 20,7± 2,6 (12-24). O presente estudo registra não somente a primeira ocorrência de T. heterodentata no Peru mas também o primeiro registro do tricodinídeo parasitando A. gigas. Tabelas comparativas biométricas de todos os registros de T. heterodentata também são apresentados.

This study characterized morphologically Trichodina heterodentata Duncan, 1977 from cultivated fingerlings of "pirarucu" Arapaima gigas in Peru. Body and gill smears were air-dried at room temperature, impregnated with silver nitrate and/or stained with gomori trichromic. Prevalence was 100%. Trichodina heterodentata was considered a medium-sized trichodinid with mean body diameter of 56.0+ 5.25 (47.3-76.0) μm, denticulate ring 28.21± 2.71 (20-34.7) μm, adhesive disc 45.7±3.8 (37.1-57.3) μm diameter and number of denticles of 20.7± 2.6 (12-24). The present study reports not only the first occurrence of T. heterodentata in Peru but also the first record of this trichodinid infesting A. gigas. Camparative tables of all reports of T. heterodentata are also presented.