Dermocystidium sp. infection in farmed striped catfish Pangasianodon hypophthalmus farmed in Ceará state, Northeastern Brazil / Infecção por Dermocystidium no bagre listrado Pangasianodon hypophthalmus cultivado no estado Ceará, nordeste do Brasil

The genus Dermocystidium infects a wide range of animals. The host infection often occurs through the ingestion of endospores. The diagnosis depends on wet mounts and histopathological analysis of the affected tissue. The aim of this study was to investigate the incidence of Dermocystidium sp. infection on the skin of farmed striped catfish (Pangasianodon hypophthalmus) from a fish farm located in Fortaleza, Ceará state, northeastern Brazil. From these observations, we determined that 100% of the analyzed animals were infected with Dermocystidium sp. The wet mount and histopathology of the fish lesions revealed spore-filled cysts between the dermis and epidermis, encapsulated by connective tissue. Owing to a lack of research on the parasite and its prevalence among different fish species in Brazil and the rest of the world, additional studies are required to understand their endemicity in fish farms of Brazil, and consequently develop better disease prevention methods and increase the overall productivity.(AU)

O gênero Dermocystidium infecta uma ampla variedade de espécies de animais, e o hospedeiro pode se infectar pela ingestão de endósporos. O diagnóstico depende de montagem em lâmina a fresco e análise histopatológica dos tecidos afetados. O objetivo deste estudo foi relatar infecção por Dermocystidium na pele do bagre listrado (P. hypophthalmus), cultivado em piscicultura do estado do Ceará, nordeste do Brasil. Foi detectado que 100% dos animais analisados estavam infectados por Dermocystidium sp. A montagem em lâminas a fresco e histopatologia das lesões mostrou cistos repletos de esporos entre a derme e a epiderme, encapsulados por tecidos conectivos. Devido às escassas pesquisas sobre esse parasito, em diferentes espécies de peixes no Brasil e no mundo, estudos adicionais são necessários para entender a endemicidade em diferentes pisciculturas do Brasil, consequentemente, melhorando os métodos de prevenção da doença e aumentando a produção e a produtividade.(AU)

Ichthyophonosis in Peruvian rainbow trout Oncorhynchus mykiss: identification of endemic areas using molecular and histopathological tools.

Ichthyophonus infection was first detected in Peruvian Oncorhynchus mykiss in 1986, but the occurrence of ichthyophonosis disease in the region is unknown. This study investigated the presence and distribution of Ichthyophonus sp. in Peruvian rainbow trout using traditional and DNA sequencing tools. Between 2007 and 2008, 205 rainbow trout from 13 hatcheries in the Mantaro river basin were examined for the presence of Ichthyophonus, and at that time only 3 farms were positive. This early study confirmed the presence of Ichthyophonus sp. in the Tranca Grande lagoon for the first time, at a prevalence of 50%. In 2012, examination of 240 trout from 24 fish farms in 2 Peruvian Departments found 9 infected farms. More recently, in 2018, Ichthyophonus sp. was found in Lake Titicaca, infecting a trout in the Ichu area (in the Department of Puno). Our molecular analysis of the infected trout showed that ichthyophonosis disease in the Peruvian trout was caused by Ichthyophonus sp. Clade C. The finding of this pathogen in Lake Titicaca should be an alert for nearby farms and entities dealing with fish of economic importance in the rivers of Peru.

Dermocystidium sp. in the gills of farmed Oreochromis niloticus in Brazil.

The genus Dermocystidium is very comprehensive in the host and site of infection, however this is the first report of the occurrence of Dermocystidium sp. in the gills of Nile tilapia. This study was carried out in a fish farming located in the state of Santa Catarina, Brazil. No mortalities were reported in the facility studied and the animals were clinically healthy. During the histopathological analysis of the gills, 8.33% of the fish presented spores of Dermocystidium sp. in the gill tissue. The spores reported herein had a mean length and width of 6.206 x 5.233 µm and a refractile body diameter of 1.965 µm and were studied by histopathology and Transmission Electron Microscopy. This study highlights the importance of a new branchial pathogen in farmed tilapia, as well as to its pathogenic potential, considering the outbreaks of mortalities associated with other fish species.

Amphibian parasites of the Order Dermocystida (Ichthyosporea): current knowledge, taxonomic review and new records from Brazil.

Amphibian parasites of the Order Dermocystida (Ichthyosporea) are widespread pathogens known mainly from Europe and North America, which cause primarily a disease of skin and subcutaneous tissue in their hosts. The taxonomy of these organisms has been problematic given their conserved morphology, similar clinical disease and pathology. Currently recognized taxa belong to the three closely related genera, Amphibiocystidium, Amphibiothecum, and Rhinosporidium, whereas species of Dermocystidium and Sphaerothecum destruens include fish parasites. Here, we review the taxonomy of Dermocystida based on a molecular phylogenetic analysis, principally of amphibian parasites, including DNA sequences obtained from amphibian hosts collected in the central-eastern region of South America. A new taxonomic arrangement is proposed, which includes the designation of type material for Dermocystidium pusula, synonymization of Amphibiothecum with Dermocystidium, and the restriction of Amphibiocystidium to its type species A. ranae. We also review the taxonomic status of Dermosporidium hylarum until the present work included in the synonymy of the human and animal pathogen R. seeberi, and considered herein as a valid taxon, however. In addition, a new species of Sphaerothecum parasitic to amphibians is described, being the first record of this genus in the southern hemisphere and in an amphibian host.

Ichthyophonus sp. (Ichthyophonae, Ichthyophonida) infection in a South American amphibian, the hylid frog Hypsiboas pulchellus.

We report infection by Ichthyophonus sp. in a South American amphibian, the hylid frog Hypsiboas pulchellus in Uruguay. This frog had a large subcutaneous mass over the urostyle and dorsal musculature comprised of parasitic cysts with mild granulomatous inflammation but otherwise appeared healthy.

Dermocystid-chytrid coinfection in the neotropical frog Hypsiboas pulchellus (Anura: Hylidae).

We present gross and histologic evidence of coinfection in amphibians by fungal-like parasites of the order Dermocystidia (Amphibiocystidium sp.) and the fungus Batrachochytrium dendrobatidis. The condition was observed in frogs Hypsiboas pulchellus (Hylidae) from Uruguay in 2009 to 2012. This report is the first of dermocystids in Neotropical amphibians since 1940.

Seasonality and prevalence of the protistan trichomycete Enterobryus halophilus (Ichthyosporea: Eccrinales) in the mole crab Emerita portoricensis.

In Puerto Rico the protist Enterobryus halophilus (Ichthyosporea: Eccrinales) has been reported associated with a new host, Emerita portoricensis (Malacostraca: Hippidae). A study on prevalence and abundance in populations of E. halophilus was conducted during 18 mo to determine whether sex-dependent infection exists in Em. portoricensis, as suggested (1958) for the original description of E. halophilus in Em. talpoida. Individuals (1440) of Em. portoricensis were collected and their guts dissected on microscope slides. The thalli of E. halophilus were counted under a microscope with random grid squares. A factorial ANOVA with interaction revealed that the prevalence and the abundance of E. halophilus do not depend on the sex of its host. Furthermore the data indicate that E. halophilus populations undergo seasonal variations in infestation following the population dynamics of the host.