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Gross appearance of sockeye salmon fingerling with saprolegniasis. The fungal growth appears adjacent to head and peduncle region (arrows). Scale bar= 1 cm.
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A saprolegniasis occurred in cultured sockeye salmon,Onchorhynchus nerka, raised in Hokkaido, Japan. The lesions were mainly observed in the head, peduncle region and the caudal fin. All strains
isolated were morphologically classified in the genusSaprolegnia. They were identified as a new species in the genus from the characteristics of the sexual...
Citations
... Chile, Canada, Japan, Italy and Scotland, are usually caused by infections of fish eggs and fry with S. parasitica, S. diclina and S. australis (Beakes et al., 1994;Cao et al., 2014;Hussein et al., 2001;Hussein & Hatai, 1999Kitancharoen et al., 1995;Pavić et al., 2021;Sakaguchi et al., 2019;Sarowar et al., 2019;Shahbazian et al., 2010;Stueland et al., 2005;Tedesco et al., 2021Tedesco et al., , 2022Thoen et al., 2011Thoen et al., , 2015Van den Berg et al., 2013;Wood et al., 1988). Our study demonstrated that the most frequently isolated representatives of water moulds in Figure 4). ...
... Lithuanian isolates demonstrated 100% identity both with S. parasitica and S. salmonis strains deposited in GenBank, but taxonomic position of S. salmonis is unclear. Original description of S. salmonis did not included any molecular data (Hussein & Hatai, 1999) and by this reason it is impossible to compare ITS sequences of Lithuanian isolates with the type of material of S. salmonis from Japan. Previously, most species of the genus Saprolegnia (including S. salmonis) were described exclusively from morphological data (Hussein & Hatai, 1999;Johnson et al., 2002;Seymour, 1970). ...
... Original description of S. salmonis did not included any molecular data (Hussein & Hatai, 1999) and by this reason it is impossible to compare ITS sequences of Lithuanian isolates with the type of material of S. salmonis from Japan. Previously, most species of the genus Saprolegnia (including S. salmonis) were described exclusively from morphological data (Hussein & Hatai, 1999;Johnson et al., 2002;Seymour, 1970). Following recent molecular F I G U R E 7 Occurrence of fungus-like stramenopilous organisms (Oomycota) on various species of fish in Lithuanian aquaculture. ...
The present work is the first comprehensive study of fungus‐like stramenopilous organisms (Oomycota) diversity in Lithuanian fish farms aimed at proper identification of saprolegniasis pathogens, which is important for water quality control, monitoring infection levels and choosing more effective treatments for this disease in aquaculture. Pathogenic to fish, Saprolegnia and other potentially pathogenic water moulds were isolated from adult fish, their eggs, fry and from water samples. All detected isolates were examined morphologically and confirmed by sequence‐based molecular methods. A total of eight species belonging to the genera Saprolegnia , Achlya , Newbya and Pythium were identified. Four species ( S. parasitica , S. ferax , S. australis and S. diclina ) were found to be the main causative agents of saprolegniasis in Lithuania. S. parasitica and S. ferax dominated both in hatcheries and open fishponds, accounting for 66.2% of all isolates. S. parasitica was isolated from all farmed salmonid fish species as well as from the skin of Cyprinus carpio , Carassius carassius and Perca fluviatilis . S. australis was isolated from water and once from the skin of Oncorhynchus mykiss , and S. diclina was detected only once on the skin of Salmo salar fish. In addition, Achlya ambisexualis , Saprolegnia anisospora and Newbia oligocantha isolated during this study are noted as a possible source of saprolegniasis. The results of this study are relevant for assessing the risk of potential outbreaks of saprolegniasis or other saprolegnia‐like infection in Lithuanian freshwater aquaculture.
... The species was found to be the most destructive pathogen that caused primary infections in both salmon eggs and fish (Shin et al. 2017;Elameen et al. 2021). However, other species such as S. diclina, S. ferax, S. australis, S. monica, and S. salmonis are also reported from different fishes and geographical areas (Hussein and Hatai 1999;Die´guez-Uribeondo et al. 2007;Ghiasi et al. 2010;Sandoval-Sierra et al. 2014;Liu et al. 2017). ...
... Moreover, 5mm agar plugs with fungal hyphae were excised from the advancing edge of 6 d old colony and incubated with autoclaved hempseed and 5ml SDW in a glass petri dish at 18 and 5 °C for 4 w. The cultures were examined for producing of asexual (zoosporangia, gemmae) and sexual (oogonia and antheridia) organs once a week (Hussein and Hatai 1999). All chemicals used, unless otherwise stated, were obtained from Merck Company (Darmstadt, Germany). ...
... How- ever, based on sequence analysis of the ITS region of the rDNA, the isolates KMG1 and 2 were identified as S. salmonis and the isolate KMG3 was detected as S. parasitica. Contrary to our findings (unattainable sexual reproduction after 28 days of incubation for all isolates), sexual reproduction has been reported by some researchers in both S. salmonis (Hussein and Hatai 1999;Liu et al. 2017) and S. parasitica (Stueland et al. 2005;Eissa et al. 2013). Environmental variables could influence the growth, reproduction, and intensity of water mold infections (Hussein et al. 2001). ...
In the present study, we aimed to identify Saprolegnia spp. from infected rainbow trout eggs in a hatchery in the north (Mazandaran province) of Iran. Morphological identification was conducted by light microscopic observation of various life stages of Saprolegnia. For the molecular characterization, the internal transcribed spacer (ITS) region was amplified by using universal primers ITS 1 and ITS 4. Based on morphological and molecular findings, two Saprolegnia spp. have been identified. i.e., Saprolegnia parasitica (Isolate KMG3, MW819780) and S. salmonis (Isolates KMG1, MW819740 and KMG2, MW819707). It is worth mentioning that the latterS. salmonis-is the first report in Iran. The phylogenetic tree inferred by a Neighbor-Joining model revealed that three representative isolates with a well-supported value together with the known isolates of S. parasitica and S. salmonis formed a well-defined clade. An in vitro experiment was conducted to study the growth of S. salmonis (KMG2) and S. parasitica (KMG3) at various incubation temperatures. Both species showed similar hyphal growth rates at 10 and 18°C after 3 days of incubation (P > 0.05).
... Fish death may be due to either blindness which consequently disable fish to feed or due to the fungal growth over gills causing suffocation. The ulcerative areas over the skin may be attributed to the lytic action of primary bacterial infection as all fungal infections are considered as secondary invader pathogen; these results agreed with many authors (8,23,(32)(33)(34)(35)(36). ...
The present study was carried out to screen the predominant mycotic infections among freshwater fishes (Oreochromis niloticus and Clarias gariepinus) in Kafrelsheikh fish farms; with special focus on the seasonal incidence; as well as, the histopathological changes induced by the detected fungi. 500 specimens of freshwater fishes (400 O. niloticus and 100 C. gariepinus) were investigated for seasonal incidence of mycotic diseases. Mycological examination revealed the isolation of 2148 fungal isolates from 375 diseased and 125 apparently healthy fish samples (1828 mould and 320 yeast isolates), of which 1258 were isolated from O. niloticus and 890 isolates from C. gariepinus. Saprolegnia was the predominant among diseased fishes with highest prevalence in late autumn (10.68%, 6.96%) and winter (6.81%, 7.87%) in O. niloticus and C. gariepinus, respectively. However, Pencillium sp. and Aspergillus sp. were the most predominant fungi isolated from apparently healthy fishes. The highest prevalence of Pencillium sp. were recorded in winter, whileas Aspergillus showed variations between species; Aspergillus flavus, Aspergillus niger were more prevalent in summer (25.44%, 23.22%) and (26.9%, 37.44%) and Aspergillus terrus, Aspergillus fumigatus were more prevalent in autumn (5.98%, 5.67%) and (7.69%, 8.23%) in O. niloticus and C. gariepinus, respectively. Moreover, the highest prevalence of Fusarium species was recorded in spring (11.8%, 5.91%) from O. niloticus, C. gariepinus, respectively. Mucor recorded the highest prevalence in autumn (20.09%) in O. niloticus and winter (29.21%) in C. gariepinus; whileas Rhizopus was highest in summer (7.89%, 5.21%) in O. niloticus and C. gariepinus, respectively. Four genera from yeast were isolated; Candida sp. (28.44%, 36.27%), Rhodotorula sp. (36.24%, 24.51%), Cryptococcus sp. (16.97%, 20.59%) and Trichosporon Sp. (18.35%, 18.63%) in O. niloticus and C. gariepinus, respectively. The histopathological findings revealed severe degenerative changes in skin and gills with presence of fungal hyphae and spores.Key words: Clarias gariepinus; moulds; mycotic diseases; Oreochromis niloticus; yeast
... Fungal diseases involve severe management problems in aquaculture farms and saprolegniasis is known as one of the main types salmonids diseases [1,2] . Saprolegniasis in addition to salmonid fish, has been also reported in crayfish (Astacus leptodactylus) [3] . ...
Saprolegniasis is known as one of the most important fungal diseases of salmonids along with high mortality and economic problems.
One hundred and seven fish suffering from cutaneous Saprolegnia infections and the same number of healthy fish were selected and
blood parameters along with histopathology assay were performed in all ones. The results indicated a significant increase (P≤0.01)
in total sialic acid, malondialdehyde, urea, creatinine, aspartate aminotransferase, total protein in plasma and a decrease in glucose,
catalase, glutathione peroxidase and paraoxonase. Meanwhile, no significant alterations of alanine aminotransferase and superoxide
dismutase were revealed in infected fish. Also, the histopathological findings observed in liver, especially glycogen storage and fatty
inclusion and melanomacrophage centres in spleen. Tubular vascular degeneration along with cystic formation was identified in
kidney. The results suggest that saprolegniasis develops substantial histopathological and blood profile changes in rainbow trout and
recommend to pay more attention on some biochemical profiles such as MDA and TSA, due to cell health and defence against fungus
on the skin respectively, along with hepatocyte function index (aspartate aminotransferase) and nitrogen metabolism (creatinine and
urea) during disease management.
... In fish, fungal pathogens are generally concerned as secondary role infecting host animals that were stimulated by other stimuli such as water quality, poor condition, trauma (rough handling or aggression), or bacterial or/and parasitic infections [17]. Two groups of fungi, including water moulds (Saprolegnia, Achlya, Leptolegnia and Aphanomyces) and anamorphic fungi (Fusarium, Acremonium, Plectosporium, Ochroconis, Phoma and Exophiala) have been mainly reported caused diseases in aquatic species [18][19][20][21][22][23][24][25][26][27][28][29][30][31], among whom Saprolegnia, Achlya, and Fusarium were found to be involved in a typical sign of the swell of swim bladder in cultured striped catfish [14][15][16]. However, the efforts on investigation of the diversifying of fungi in striped catfish and their culture environment in Viet Nam in general and in Mekong Delta in particular still are limited so far. ...
Striped catfish (Pangasianodon hypophthalmus) is a very common aquaculture species in large scale throughout the Mekong Delta of Viet Nam for recent years. Disease occurrence caused by pathogens during culture period has been experienced. Fungi are more seriously and increasingly important pathogen in farmed striped catfish. In this study, the distribution of fungi in farmed catfish and farm water column in Mekong Delta was carried out. The results showed that most fungi were isolated from the water samples (269 isolates) rather than from farmed catfish (129 isolates). Seven fungal genera of Aspergillus, Fusarium, Acremonium, Trichoderma, Penicillium, Culvuclaria and Achlya were identified from the samples. Fusarium, Aspergillus, and Penicillium were dominating among identified fungi, while Culvuclaria was only identified from catfish samples. Moreover, water qualities of cultured ponds were suitable for the habitat of the fungi and surviving of cultured catfish. The study provides basic knowledge of the ecological distribution of fungi in the culture system of striped catfish in the Mekong Delta of Viet Nam.
... An agar plug of 5 mm in diameter, colonized by Saprolegnia hyphae, was cut from the GY plate and transferred to another plate containing GY agar (Hussein & Hatai 1999). To inhibit bacterial growth, the GY agar was supplemented with 200 lg mL À1 chloramphenicol (Fregeneda-Grandes, Rodr ıguez-Cadenas & Aller-Gancedo 2007). ...
Here, we address the morphological changes of eyed eggs of Atlantic salmon, Salmo salar L. infected with Saprolegnia from a commercial hatchery and after experimental infection. Eyed eggs infected with Saprolegnia spp. from 10 Atlantic salmon females were obtained. Egg pathology was investigated by light and scanning electron microscopy. Eggs from six of ten females were infected with S. parasitica, and two females had infections with S. diclina clade IIIA; two Saprolegnia isolates remained unidentified. Light microscopy showed S. diclina infection resulted in the chorion in some areas being completely destroyed, whereas eggs infected with S. parasitica had an apparently intact chorion with hyphae growing within or beneath the chorion. The same contrasting pathology was found in experimentally infected eggs. Scanning electron microscopy revealed that S. parasitica grew on the egg surface and hyphae were found penetrating the chorion of the egg, and re-emerging on the surface away from the infection site. The two Saprolegnia species employ different infection strategies when colonizing salmon eggs. Saprolegnia diclina infection results in chorion destruction, while S. parasitica penetrates intact chorion. We discuss the possibility these infection mechanisms representing a necrotrophic (S. diclina) vs. a facultative biotrophic strategy (S. parasitica).
© 2015 John Wiley & Sons Ltd.
... These organisms are abundant in the environment, where they behave as destructive pathogens in fish (Phillips et al. 2008), Daphnia (Wolinska et al. 2009), insects (Pelizza et al. 2011), amphibians (Fernández-Beneítez 2011, and crayfish (Krugner-Rigby et al. 2010). As such, they are responsible for millions of dollars losses to the worldwide aquaculture industry (van West 2006), with considerable damage to highly valued fish such as salmonids (Hussein & Hatai 1999). They can also threaten endangered wildlife, and cases of local extinctions of amphibian populations due to members of this group have been reported (Bragg 1958(Bragg , 1962, as well as declines of wild fish stocks (van West 2006). ...
The Saprolegnia-Achlya clade comprises species of major environmental and economic importance due
to their negative impact on aquaculture and aquatic ecosystems by threatening fishes, amphibians, and crustaceans.
However, their taxonomy and phylogenetic relationships remain unresolved and suffer from many inconsistencies,
which is a major obstacle to the widespread application of molecular barcoding to identify pathogenic strains with
quarantine implications. We assessed phylogenetic relationships of major genera using three commonly used
markers (ITS, SSU rRNA, and LSU rRNA). A consensus tree of the three genes provided support for nine clades
encompassing eleven documented genera and a new clade (SAP1) that has not been described morphologically.
In the course of this study, we isolated a new species, Newbya dichotoma sp. nov., which provided the only culture
available for this genus. In parallel, we attempted to summarize the evolution of traits in the different genera, but
their successive reversals rendered the inference of ancestral states impossible. This highlights even more the
importance of a bar-coding strategy for saprolegniacean parasite detection and monitoring.
... Uribeondo et al. (2007) found that most Saprolegnia isolates obtained from salmonid lesions contained cysts with bundles of long-hooked hairs and suggested to put them into the same cluster. Curiously, Saprolegnia isolates with the longest hairs (Fregeneda-Grandes et al. 2000 ) (Type I) appeared to be less aggressive pathogens or even non-pathogenic, at least towards salmonid fish, than those with shorter spines (Fregeneda-Grandes et al. 2000) (Type II) and these observations appear to be supported by other studies (Hatai et al. 1990; Hussein and Hatai 1999; Stueland et al. 2005). This could mean that the size and number of hairs might not be directly related to the pathogenicity of the species. ...
... On the skin of both species of fishes Saprolegnia salmonis was found growing. It was first described in Japan on the eggs of sockeye salmon, Oncorhynchus nerka (Walbaum,1792) (Hussein et al., 1999). We recently observed growth of this species on the eggs of lavaret (Coregonus lavaretus, L.,1758) in Mazury (Czeczuga et al., 2004c) and Kaszuby in Poland (Czeczuga et al., 2004a). ...
We investigated the growth of straminipilous organisms on the skin, muscles and liver of herbivorous pirapitinga (Piaractus brachypomus) and carnivorous piranha (Pygocentrus nattereri) in water of three different eutrophication levels. Sixteen straminipilous organism species were found growing on the investigated body parts of both species of fish used as baits. The higher number of species was found on the baits of carnivorous species (15) when compared with the ones from the herbivorous pirapitinga (10 species). The highest number of straminipilous organisms species developed on the skin of both species of fish. The highest number of species of straminipilous organisms was observed growing in the water of the BiaBa river (middle eutrophication), while the lowest number occurred in the baits of vessels with water from the Dojlidy pond (low eutrophication).
... nov. nhiễm ở cá hồi O. nerka (Hussein and Hatai, 1999;Hussein and Hatai, 2002). Nấm Aphanomyces khi nuôi cấy trên môi trường thạch GYA khuẩn lạc có màu trắng. ...
Fungi are popular pathogen in aquatic animals. The aims of this study are to systematize fungal diseases in aquatic animals, to summarize the results of previous studies included isolation, culture and identification in order to apply knowledge for fungal diseases study. There are two groups of fungi that common infected on aquatic animals. The lower fungi have hyphae without septate for examples Saprolegnia, Achlya, Aphanomyces, Branchiomyces, Lagenidium and Haliphthoros and the higher fungi have hyphae with septate included Fusarium, Exophiala, Ochroconis, Acremonium and Plectosporium. Methodology of fungal study for sample collection, wet-mount observation, isolation, single conidium culture, slide culture, asexual reproduction, and identification are described in this paper.
