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Emerging infectious diseases represent a key problem for the survival of amphibian populations. Declines related to infections of the chytrid fungus Batrachochytrium dendrobatidis and Ranavirus have been described in several areas of Northern Spain, including protected areas. Co-infection—the simultaneous infection of a host by multiple pathogen species—can increase the susceptibility to subsequent infections. Here, we describe a case of triple dermocystid-ranavirus-chytrid fungus co-infection in a specimen of palmate newt (Lissotriton helveticus) from a protected wetland of North-western Spain. Five palmate newts and one Bosca’s newt (Lissotriton boscai) were found dead, and tissue samples were analysed by using qPCR methods. Ranavirus was detected in four out of five L. helveticus and in the L. boscai individual, whereas Bd was detected only in one of the five L. helveticus. Four out of six specimens tested positive for Dermocystidium. Sequencing was performed to double-check the presence of Dermocystidium in a qPCR-positive sample for that pathogen.

The Rio Negro floodplain (tributary of the Amazon River) is a natural habitat of the cardinal tetra Paracheirodon axelrodi. In home aquaria, this species has high vulnerability to superficial infetions and is affected by the protist Dermocystidium. Protist cysts were located in the dermis causing lesions reaching in the epidermis. We observed that a few weeks after the introduction of new wild ornamental fish (mostly Hemigrammus sp. or Hyphessobrycon sp.) into established home aquaria, the cardinal tetra fish became infected, suggesting that the new fish could have acted as carriers., Facultad de Ciencias Veterinarias, Centro de Estudios Parasitológicos y de Vectores

SUMMARYOutbreaks of cutaneous infectious disease in amphibians are increasingly being attributed to an overlooked group of fungal-like pathogens, the Dermocystids. During the last 10 years on the Isle of Rum, Scotland, palmate newts (Lissotriton helveticus) have been reportedly afflicted by unusual skin lesions. Here we present pathological and molecular findings confirming that the pathogen associated with these lesions is a novel organism of the order Dermocystida, and represents the first formally reported, and potentially lethal, case of amphibian Dermocystid infection in the UK. Whilst the gross pathology and the parasite cyst morphology were synonymous to those described in a study from infectedL. helveticusin France, we observed a more extreme clinical outcome on Rum involving severe subcutaneous oedema. Phylogenetic topologies supported synonymy between Dermocystid sequences from Rum and France and as well as their distinction fromAmphibiocystidiumspp. Phylogenetic analysis also suggested that the amphibian-infecting Dermocystids are not monophyletic. We conclude that theL. helveticus-infecting pathogen represents a single, novel species;Amphibiothecum meredithae.

Perkinsus (= Dermocystidium) marinus is a major cause of mortality in eastern oysters, Crassostrea virginica. Because initiation of infection and progression of disease are favored by high temperature and high salinity, we hypothesized that climatic cycles influence cycles of disease. Analyses of a 10-y time series of disease prevalence and intensity, chlorophyll a, suspended sediments, water temperature and salinity from a Louisiana site, using a wavelet technique, show a teleconnection between the El Nino-Southern Oscillation (ENSO) and oyster disease in the northern Gulf of Mexico. Salinity increases precede increased disease prevalence by several months. The changes in salinity that trigger changes in disease prevalence and intensity are strongly driven by ENSO events. Interannual variation is important in the initiation and intensification of disease, and salinity is the primary driving factor. The patterns in the environmental and disease time series suggest that epizootics can be initiated...

A species of Dermocystidium was discovered on the skin and fins of reared southern catfish Silurus meridionalis Chen. The parasite only appeared and caused disease in juvenile catfish at a water temperature of 18 to 23 degrees C. Marked external macroscopical clinical signs of the disease were sluggish movement of the fish, and the appearance of white filiform dermal cysts varying in size (3-20 mm in length and 0.15-0.35 mm in width). Examination of both fixed and fresh mounts for light microscopy and of samples for transmission electron microscopy (TEM) showed spherical spores (3.2-15 microm in diameter) with a peripheral nucleus (1.1-1.8 x 0.5-1.6 microm in diameter) and a prominent refractile body (2.08-10.83 microm in diameter) which occupied most of the volume of a mature spore. Three types of spore were identified, and are presumed to represent various developmental stages. Meanwhile, TEM showed the remnant nuclei in the residual plasmodium of a cyst, revealing its degenerative process. This paper represents the first observation and description of Dermocystidium sp. parasitizing catfishes.

We report the enigmatic parasite Dermocystidium ranae in a green frog population (Solomeo, Umbria, Italy) of the Rana esculenta complex, consisting of the parental species R. lessonae (L) and hybrid form R. esculenta (E). In this population a rapid 50% decline of the parental form L was observed. Large dermal U-shaped cysts of D. ranae were found primarily on the ventral aspect of infected individuals, with a significantly higher incidence of infection in the parental species com- pared to the clonal hybrid. In each form, however, there was little pathological change associated with infection, and the cause of the recent declines of R. lessonae at this site remains unknown. In this paper we present the first ultrastructural description of an amphibian Dermocystidium sp. and we review the taxonomy of Dermocystidium, Dermosporidium and Dermomycoides spp. from amphib- ians. We conclude that Dermosporidium multigranulare Bro= & Kulda, 1954 is synonymous with Der- mocystidium ranae Guyenot & Naville, 1922 and, due to lack of sufficient differences between gen- era and significant dissimilarities with fish Dermocystidium spp., the 3 amphibian genera are synonymous. We propose that they should be designated to a new genus, Amphibiocystidium n. gen., and Dermocystidium retained for those species parasitic in fish.

In autumn 2011 in cyprinid farms located in Iasi on the Jijia river, several infections with bacterial strains and macroscopical external cysts on the skin were diagnosedwhich developed as a result of the stress induced by biotic and abiotic factors. On the examination of the cyst contents the presence of numerous spores was observed, mostly of the Dermocystidium spgenusThe samples were taken from the common carp (Cyprinus carpio) and crucian carp (Carassius auratus gibelio)species from the fish farm as well as from the Jijia River. 35 fish were examined, all of them showing cysts, fragmentation of their dorsal fin and congestion of the gills. Histological examination of the skin showed a field of multiple dermal cysts with round light eosinophilic formations (14-16µm) containing a central refractable body similar to that reported for Dermocystidium sp.Gills samples were taken from the affected areas for the SEM examination with the purpose of evaluating not only aspects of normal morphology, but also aspects of some modifications of the affected areas as well as the presence of the etiologically incriminated bacteria Pseudomonas fluorescens. The isolates were identified through phenotypic methods. All the strains that showed mobility and oxidase-positivity were tested using API 20 NE strip. Consequently, they were taxonomically grouped into the species Pseudomonas fluorescens.The scanning electron microscope (SEM) was used for the first time in the characterization of the bacterial lesions produced by Pseudomonasstrains on Cyprinus carpioand Carassius auratus gibeliogills. The diagnosis of septicemia with conditional pathogen species of Pseudomonas fluorescens was correlated with the results of the physico-chemical investigations of water and the data concerning the breeding conditions of the investigated livestock.

In autumn 2011 in cyprinid farms located in Iasi on the Jijia river, several infections with bacterial strains and macroscopical external cysts on the skin were diagnosedwhich developed as a result of the stress induced by biotic and abiotic factors. On the examination of the cyst contents the presence of numerous spores was observed, mostly of the Dermocystidium spgenusThe samples were taken from the common carp (Cyprinus carpio) and crucian carp (Carassius auratus gibelio)species from the fish farm as well as from the Jijia River. 35 fish were examined, all of them showing cysts, fragmentation of their dorsal fin and congestion of the gills. Histological examination of the skin showed a field of multiple dermal cysts with round light eosinophilic formations (14-16µm) containing a central refractable body similar to that reported for Dermocystidium sp.Gills samples were taken from the affected areas for the SEM examination with the purpose of evaluating not only aspects of normal morphology, but also aspects of some modifications of the affected areas as well as the presence of the etiologically incriminated bacteria Pseudomonas fluorescens. The isolates were identified through phenotypic methods. All the strains that showed mobility and oxidase-positivity were tested using API 20 NE strip. Consequently, they were taxonomically grouped into the species Pseudomonas fluorescens.The scanning electron microscope (SEM) was used for the first time in the characterization of the bacterial lesions produced by Pseudomonasstrains on Cyprinus carpioand Carassius auratus gibeliogills. The diagnosis of septicemia with conditional pathogen species of Pseudomonas fluorescens was correlated with the results of the physico-chemical investigations of water and the data concerning the breeding conditions of the investigated livestock. No outono de 2011, em fazendas de ciprinídeos localizadas em Iasi, no rio Jijia, diversas infecções bacterianas e cistos externos macroscópicos na pele se desenvolveram como resultado do estresse induzido por fatores bióticos e abióticos. No exame do conteúdo dos cistos, a presença de diversos esporos foi observada, a maioria do gênero Dermocystidium sp. As amostras foram colhidas das seguintes espécies: carpa comum (Cyprinus carpio) e carpa cruciana (Carassius auratus gibelio) de fazenda piscícola, além do rio Jijia. Assim sendo, 35 peixes foram examinados, todos demonstrando cistos, fragmentação da barbatana dorsal e congestão das guelras. O exame histológico da pele mostrou um campo de múltiplos cistos dérmicos com formações circulares claras eosinofílicas (14-16µm) contendo corpo central refratado similar ao relatado para Dermocystidium sp. Amostras de guelras foram retiradas das áreas afetadas para exame MEV, com o propósito de se avaliar não apenas os aspectos da morfologia normal, mas também os aspectos de algumas modificações das áreas afetadas, além da presença da bactéria etiologicamente incriminada: Pseudomonas fluorescens. Os isolados foram identificados por meio de métodos fenotípicos. Todas as amostras que mostraram mobilidade e positividade-oxidase foram testadas usando-se fita API 20 NE. Consequentemente, estas foram taxonomicamente agrupadas na espécie Pseudomonas fluorescens. O microscópio eletrônico de varredura (MEV) foi usado pela primeira vez na caracterização de lesões bacterianas produzidas por Pseudomonas nas guelras de Cyprinus carpio e Carassius auratus gibelio. O diagnóstico de septicemia com espécies condicionais de patogênico de Pseudomonas fluorescens foi correlacionado com os resultados das investigações físico-químicas da água e de dados sobre as condições de reprodução dos animais investigados.

For the past 100 years the phylogenetic affinities of Rhinosporidium seeberi have been controversial. Based on its morphological features, it has been classified as a protozoan or as a member of the kingdom Fungi. We have amplified and sequenced nearly a full-length 18S small-subunit (SSU) ribosomal DNA (rDNA) sequence from R. seeberi . Using phylogenetic analysis, by parsimony and distance methods, of R. seeberi ’s 18S SSU rDNA and that of other eukaryotes, we found that this enigmatic pathogen of humans and animals clusters with a novel group of fish parasites referred to as the DRIP clade ( Dermocystidium , rossete agent, Ichthyophonus , and Psorospermium ), near the animal-fungal divergence. Our phylogenetic analyses also indicate that R. seeberi is the sister taxon of the two Dermocystidium species used in this study. This molecular affinity is remarkable since members of the genus Dermocystidium form spherical structures in infected hosts, produce endospores, have not been cultured, and possess mitochondria with flat cristae. With the addition of R. seeberi to this clade, the acronym DRIP is no longer appropriate. We propose to name this monophyletic clade Mesomycetozoa to reflect the group’s phylogenetic association within the Eucarya .

Sequences of nuclear-encoded small-subunit rRNA genes have been determined for representatives of the enigmatic genera Dermocystidium, Ichthyophonus, and Psorospermium, protistan parasites of fish and crustaceans. The small-subunit rRNA genes from these parasites and from the "rosette agent" (also a parasite of fish) together form a novel, statistically supported clade. Phylogenetic analyses demonstrate this clade to diverge near the animal-fungal dichotomy, although more precise resolution is problematic. In the most parsimonious and maximally likely phylogenetic frameworks inferred from the most stably aligned sequence regions, the clade constitutes the most basal branch of the metazoa; but within a limited range of model parameters, and in some analyses that incorporate less well-aligned sequence regions, an alternative topology in which it diverges immediately before the animal-fungal dichotomy was recovered. Mitochondrial cristae of Dermocystidium spp. are flat, whereas those of Ichthyophonus hoferi appear tubulovesiculate. These results extend our understanding of the types of organisms from which metazoa and fungi may have evolved.

The pathogen of frogs Amphibiocystidium ranae was recently described as a new genus. Due to its spherical shape, containing hundred of endospores, it was thought to be closely related to the pathogens of fish, mammals, and birds known as Dermocystidium spp., Rhinosporidium seeberi , and Sphaerothecum destruens in the Mesomycetozoea, but further studies were not conducted to confirm this relationship. To investigate its phylogenetic affinities, total genomic DNA was extracted from samples collected from infected frogs containing multiple cysts (sporangia) and endospores. The universal primers NS1 and NS8, used to amplify the 18S small-subunit rRNA by PCR, yielded ≈1,770-bp amplicons. Sequencing and basic local alignment search tool analyses indicated that the 18S small-subunit rRNA of A. ranae from both Rana esculenta and Rana lessonae was closely related to all of the above organisms. Our phylogenetic analysis placed this pathogen of frogs as the sister group to the genus Dermocystidium and closely related to Rhinosporidium . These data strongly supported the placement of the genus Amphibiocystidium within the mesomycetozoeans, which is in agreement with the phenotypic features that A. ranae shares with the other members of this class. Interestingly, during this study Dermocystidium percae did not group within the Dermocystidium spp. from fish; rather, it was found to be the sister group to Sphaerothecum destruens . This finding suggests that D. percae could well be a member of the genus Sphaerothecum or perhaps represents a new genus.

Dermocystidium koi sp. nov. This species is found as a parasite; in one case it is parasiting to the integument and in another to the muscle of each separate Cyprinus carpis L. The specimen of the former was captured at the Yamada Fish Culture Farm (Locality-Yamada Village, Hyogo Pref., Date-July 23, 1940), and that of the latter obtained from the Seto Fish Culture Farm. (Locality-Vicinity of Odawara City, Kanagawa Pref., Date-May 11, 1959). In the case of integumentary parasitim, the parasites grow between the epidermis and the cutis in uarious places of the body surface without scales; and the characteristic lesions a e formed arising from the integument, due to the increase of the parasites and host's tissues such as fibrous connective tissueand blood vessels. (see text-fig. 1 and 2, A, B.) The muscular parasitism occurs when the parasites are parasitic to the scaley host; and in this case the parasites grow in the muscle near the body surface; on the infected parts, the large and hard tumor like inflammatory swelling arise from the increase of the parasites and the same host's tissues as the former. The parasite is filiform in external character; its transuerse section is round; the diameter 0.04-0.30mm., and it contains innumerable spares. Spare subspherical, 6-14μ in diameter; the diameter of the large characteristic spherical enclosure is 4.5-10.0μ. The details are compiled in the table 1. The spares are figured in text-fig. 3, NOS. 1-9. The present species is distinguishable from all other known species, in external form of the parasite or the cyst, the modus parasitic, and the dimension of the spare etc. The lesions may be ruptured naturally in a certa'n period; and the contents fall out from them; and then they seem to be healed gradually. Therefore, the host should not suffer great influence from the parasite. But the histological reactions of the host are marked, which are chiefly proliferocis inflammation, rarely accompanied with phagocytosis. (Text.-fig. 3, No. 10).

PAGE INTRODUCTIONa. Studies in the Gulf of Mexicox. Discovery of Dermocystidiumn marinurm in Virginia 2 METHODS OF STUDY 2 The Thioglycollate Culture Technique 2 Rating the Intensity of Infections 3 Definitions of Terms 3 THE OCCURRENCE OF Dermocystidium marinuim IN LIVE OYSTERS 3 Seasonal Incidence of Infections 3 Intensity of Infections 5 Recapitulation ........ 6 THE OCCURRENCE OF Der-mocystidium marinumn IN GAPERS 6 Collection of Gapers 6 Seasonal Incidence ..... 6 Incidence in Gapers from Outlying Trays and Natural Habitats ..... 8 Recapitulation ........ 8 DISTRIBUTION OF Dermocystidium marinum IN CHESAPEAKE BAY 11 FUNGUS INFECTIONS IN RELATION TO AGE AND SouRCE OF OYSTEST.11 Data from Live Oysters . ..... 11 Data from Gapers ......... 12 Recapitulation. 13 EXPERIMENTAL INFECTION OF OYSTERS 14 Infection of Old Oysters ...... 14 Infection of Young Oysters I ........ 14 PAGE

MSX, a pathogen of oysters (Crassostrea virginica), produced a drastic epizootic in high—salinity areas of Chesapeake Bay from 1959 to 1963. The patterns of infection and mortality were determined by imports from disease—free seed—oyster areas. Winter and spring imports became infected in early summer and began dying in late summer. Late—summer imports apparently became infected promptly but infections remained subclinical until the following May. Death rates were highest during warm months but losses occurred throughout the year. MSX was assigned as the cause of a high percentage of deaths by sampling live and dead oysters. Mortality for the first and second years after import was usually 50 to 60% annually. A fungus disease caused by Dermocystidium marinum was also prevalent in some areas. Prevalence of MSX did not decline as oyster populations were decimated; hence nearly half of Virginia's private beds have been forced out of production.

Dermocystidium Gasterostei n. sp., A Parasite of Gasterosteus Aculeatus L. and Gasterosteus Pungitius L.

10 páginas, 3 tablas, 5 figuras, Parasites identified as Perkinsus atlanticus have been reported infecting carpet shell clams in Galicia (northwest Spain). We have sequenced the 18S ribosomal RNA gene of in vitro cultured Perkinsus atlanticuslike or hypnospores from diseased clams, and compared it with the same genomic region from P. marinus and Perkinsus sp. We have also compared the sequence of internal transcribed spacer (ITS) 1, ITS 2, and 5.8S rRNA from our isolate with the P. atlanticus GenBank sequence. The phylogenetic analysis of our cultured parasite based on the 18S gene led us to conclude that this isolate is not related to the genus Perkinsus but to the protists Anurofeca, Ichthyophonus, and Psorospermium, located near the animal-fungal divergence. These last two genera have been included, together with Dermocystidium, in the newly described DRIPs (Dermocystidium, rossete agent, Ichthyophonus, and Psorospermium) clade, recently named Mesomycetozoa., This work was partially funded by the Commission for Cultural, Educational and Scientific Exchange between the United States and Spain.

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.

THE examination and control of oyster (Crassostrea virginica Gmelin) pathogens have received much impetus in recent years with the recognition of Haplosporidium costale Wood and Andrews, ‘MSX’ an undescribed haplosporidian, and Dermocystidium marinum Mackin, Owen and Collier along the Atlantic and Gulf coasts of the United States. Research in the problems of isolation, identification and control of oyster pathogens could bo facilitated if techniques for the culture of oyster cells were available.

Zoospores were obtained from a protist, parasitic in the clamMacoma balthica. It has been previously suggested that the parasite is either a closely related species or is the same species asLabyrinthomyxa marina (Dermocystidium marinum), which is found in the oysterCrassostrea virginica. The demonstration of zoosporulation and the description of zoospore micromorphology are here offered as evidence of similarity between the two parasites. The zoospores were biflagellated, pyriform cells with mastigonemes along one side of the anterior flagellum. Negative staining revealed substructure in the mastigonemes.

Dermocystidium marinum is a pathogen which kills oysters in Chesapeake Bay from July through October. The fungus proliferates readily only at temperatures above 25°C but overwinters in oysters as sub-clinical cases. Experiments were conducted in Nature to demonstrate the effects of proximity of infected oysters on epizootiology in isolated disease-free populations. Prevalence ofDermocystidium in the York River was moderate in 1957, heavy in 1959, and extremely low in 1963. In 1957, with 40 feet of isolation, groups mixed with infected oysters showed large increases in deaths and prevalences over controls. In 1959, the fungus was so widely prevalent in York River during a long hot summer that relatively minor reductions in death rates were obtained by 50 feet of isolation. In 1963, with the fungus nearly absent, a failure in laboratory infection techniques caused late timing of the experiment, and results were inconclusive. A new disease caused by “MSX”, a protistan parasite, developed high prevalences in the 1963 lots. This organism, by destroying oyster, populations in high-salinity waters (above 15‰ in late summer) has effectively reducedDermocystidium to a minor role as an oyster pathogen in lower Chesapeake Bay. Losses fromDermocystidium in Chesapeake Bay are dependent upon duration of warm seasons and survival of cases through winter. MSX, is slightly more sensitive to low salinities but much more tolerant of low temperatures thanDermocystidium. The decline ofDermocystidium with the disappearance of oyster populations suggests that the pathogen may be dependent solely upon transmission from oyster, to oyster.