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16 pages, 3073 KiB

Open AccessArticle

Scanning Electron Microscopy and First Molecular Data of Two Species of Lamproglena (Copepoda: Lernaeidae) from Labeo victorianus (Cyprinidae) and Clarias gariepinus (Clariidae) in Kenya

by Nehemiah M. Rindoria, Zipporah Gichana, George N. Morara, Coret van Wyk, Willem J. Smit, Nico J. Smit and Wilmien J. Luus-Powell

Pathogens 2023, 12(8), 980; https://doi.org/10.3390/pathogens12080980 - 27 Jul 2023

Cited by 1 | Viewed by 871

Abstract

A parasitological study carried out in May 2022 and March 2023 in the Nyando River of Lake Victoria Basin, Kenya, disclosed two parasitic lernaeid copepods: Lamproglena cleopatra Humes, 1957, from the gills of a cyprinid, the Ningu Labeo victorianus Boulenger, 1901, endemic to [...] Read more.

A parasitological study carried out in May 2022 and March 2023 in the Nyando River of Lake Victoria Basin, Kenya, disclosed two parasitic lernaeid copepods: Lamproglena cleopatra Humes, 1957, from the gills of a cyprinid, the Ningu Labeo victorianus Boulenger, 1901, endemic to the Lake Victoria drainage system, and Lamproglena clariae Fryer, 1957, from a clariid, the North African catfish Clarias gariepinus (Burchell, 1822). The copepods were studied and supplementary taxonomic information was presented using scanning electron micrographs and genetic data. Scanning electron microscopy (SEM) provided information on the morphology of L. cleopatra’s antennae, oral region, thoracic legs (2–5), and furcal rami not previously reported. Analyses of the partial fragments of 18S and 28S rDNA and cytochrome c oxidase subunit 1 (cox1) of the two parasites showed them to be distinct from all other Lamproglena taxa retrieved from GenBank. This study presents new taxonomic information on morphology using SEM and provides the first ribosomal (18S and 28S rDNA) and mitochondrial (mtDNA) data for these two parasite species. The cox1 data provided are the first for all 38 nominal species of Lamproglena. Notably, the study also provides a new host record for L. cleopatra and extends the geographical information of this species to Kenya. Full article

(This article belongs to the Special Issue Parasitic Diseases of Fish: Identification, Host-Parasite Interactions and Molecular Biology)

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11 pages, 5716 KiB

Open AccessArticle

Limnotrachelobdella hypophthalmichthysa n. sp. (Hirudinida: Piscicolidae) on Gills of Bighead Carp Hypophthalmichthys nobilis in China

by Lin Lin, Houda Cheng, Wenxiang Li, Ming Li, Hong Zou and Guitang Wang

Pathogens 2023, 12(4), 562; https://doi.org/10.3390/pathogens12040562 - 06 Apr 2023

Cited by 1 | Viewed by 1165

Abstract

We describe the characterization of a novel fish leech species found on the gills of bighead carp (Hypophthalmichthys nobilis) from lakes and reservoirs in China. This leech is morphologically similar to Limnotrachelobdella sinensis recorded on goldfish and common carp. However, there [...] Read more.

We describe the characterization of a novel fish leech species found on the gills of bighead carp (Hypophthalmichthys nobilis) from lakes and reservoirs in China. This leech is morphologically similar to Limnotrachelobdella sinensis recorded on goldfish and common carp. However, there are 0–2 pairs of symmetrical or asymmetrical eyes and 10 pairs of pulsatile vesicles in the newly discovered leech, in remarkable contrast to L. sinensis. Except for bighead carp, where it demonstrated a higher than 90% prevalence, and silver carp (H. molitrix), where there was low infection, this leech was not detected on any other fish from the Qiandao reservoir in China that were examined during this investigation. Molecular analyses indicated 87.8% ITS sequence identity with L. sinensis and 85.0 and 86.1% COX1 sequence identity with L. sinensis and L. okae, respectively. The uncorrected p-distance based on the COX1 sequence was found to be 15.1 and 14.0% for L. sinensis and L. okae, respectively, suggesting interspecific variation. Phylogenetic analyses based on the combination of 18S and COX1 sequences showed that the newly discovered leech groups with Limnotrachelobdella species. Histopathological observation indicated that attachment of the leech on the gill rakers and gill arches causes a loss of connective tissue, hemorrhage, and ulceration. Based on the morphology, molecular analyses, and host specificity, we conclude that this leech is a new species of Limnotrachelobdella and named it Limnotrachelobdella hypophthalmichthysa n. sp. Full article

(This article belongs to the Special Issue Parasitic Diseases of Fish: Identification, Host-Parasite Interactions and Molecular Biology)

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18 pages, 2060 KiB

Open AccessArticle

Dual RNA-Seq of Flavobacterium psychrophilum and Its Outer Membrane Vesicles Distinguishes Genes Associated with Susceptibility to Bacterial Cold-Water Disease in Rainbow Trout (Oncorhynchus mykiss)

by Pratima Chapagain, Ali Ali and Mohamed Salem

Pathogens 2023, 12(3), 436; https://doi.org/10.3390/pathogens12030436 - 10 Mar 2023

Cited by 1 | Viewed by 1837

Abstract

Flavobacterium psychrophilum (Fp), the causative agent of Bacterial Cold-Water disease in salmonids, causes substantial losses in aquaculture. Bacterial outer membrane vesicles (OMVs) contain several virulence factors, enzymes, toxins, and nucleic acids and are expected to play an essential role in host–pathogen [...] Read more.

Flavobacterium psychrophilum (Fp), the causative agent of Bacterial Cold-Water disease in salmonids, causes substantial losses in aquaculture. Bacterial outer membrane vesicles (OMVs) contain several virulence factors, enzymes, toxins, and nucleic acids and are expected to play an essential role in host–pathogen interactions. In this study, we used transcriptome sequencing, RNA-seq, to investigate the expression abundance of the protein-coding genes in the Fp OMVs versus the Fp whole cell. RNA-seq identified 2190 transcripts expressed in the whole cell and 2046 transcripts in OMVs. Of them, 168 transcripts were uniquely identified in OMVs, 312 transcripts were expressed only in the whole cell, and 1878 transcripts were shared in the two sets. Functional annotation analysis of the OMV-abundant transcripts showed an association with the bacterial translation machinery and histone-like DNA-binding proteins. RNA-Seq of the pathogen transcriptome on day 5 post-infection of Fp-resistant versus Fp-susceptible rainbow trout genetic lines revealed differential gene expression of OMV-enriched genes, suggesting a role for the OMVs in shaping the host–microbe interaction. Interestingly, a cell wall-associated hydrolase (CWH) gene was the most highly expressed gene in OMVs and among the top upregulated transcripts in susceptible fish. The CWH sequence was conserved in 51 different strains of Fp. The study provides insights into the potential role of OMVs in host–pathogen interactions and explores microbial genes essential for virulence and pathogenesis. Full article

(This article belongs to the Special Issue Parasitic Diseases of Fish: Identification, Host-Parasite Interactions and Molecular Biology)

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12 pages, 7444 KiB

Open AccessArticle

Morphological and Molecular Identification of Dactylogyrus gobiocypris (Monogenea: Dactylogyridae) on Gills of a Model Fish, Gobiocypris rarus (Cypriniformes: Gobionidae)

by Jiangwen Cheng, Hong Zou, Ming Li, Jianwei Wang, Guitang Wang and Wenxiang Li

Pathogens 2023, 12(2), 206; https://doi.org/10.3390/pathogens12020206 - 28 Jan 2023

Cited by 2 | Viewed by 3072

Abstract

The rare minnow Gobiocypris rarus is an ideal model organism for toxicological research. Dactylogyrus species are usually found on the gills of this rare minnow in laboratory farming systems. Dactylogyrid infection may change the sensibility of fish to toxicants and affect toxicological evaluations. [...] Read more.

The rare minnow Gobiocypris rarus is an ideal model organism for toxicological research. Dactylogyrus species are usually found on the gills of this rare minnow in laboratory farming systems. Dactylogyrid infection may change the sensibility of fish to toxicants and affect toxicological evaluations. In the present study, dactylogyrid infection was investigated, and species of Dactylogyrus collected from rare minnows were determined. Based on the observed ‘D. wunderi’ type anchors, with a shorter outer root and elongated inner root, and accessory piece consisting of two parts, the dactylogyrids were identified as D. gobiocypris. A partial 18S-ITS1 rDNA sequence was firstly sequenced, and the highest sequence identity (86.7%) was to D. cryptomeres. Phylogenetic analysis revealed that D. gobiocypris formed a clade with D. squameus, D. finitimus, and D. cryptomeres, all of which have been recorded in the family Gobionidae. Histopathology analysis indicated that a heavy burden of D. gobiocypris caused necrosis of gill filaments. Inflammatory responses, such as tumefaction and hyperaemia, were also observed on gills with severe dactylogyrid infection. Supplementary morphological characteristics and 18S-ITS1 rDNA sequence provided basic data for identification of this parasite species. Full article

(This article belongs to the Special Issue Parasitic Diseases of Fish: Identification, Host-Parasite Interactions and Molecular Biology)

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10 pages, 19716 KiB

Open AccessCommunication

Monogeneans from Catfishes in Lake Tanganyika. II: New Infection Site, New Record, and Additional Details on the Morphology of the Male Copulatory Organ of Gyrodactylus transvaalensis Prudhoe and Hussey, 1977

by Archimède Mushagalusa Mulega, Maarten Van Steenberge, Nikol Kmentová, Fidel Muterezi Bukinga, Imane Rahmouni, Pascal Mulungula Masilya, Abdelaziz Benhoussa, Antoine Pariselle and Maarten P. M. Vanhove

Pathogens 2023, 12(2), 200; https://doi.org/10.3390/pathogens12020200 - 28 Jan 2023

Cited by 2 | Viewed by 1496

Abstract

The ichthyofauna of Lake Tanganyika consists of 12 families of fish of which five belong to Siluriformes (catfishes). Studies on Siluriformes and their parasites in this lake are very fragmentary. The present study was carried out to help fill the knowledge gap on [...] Read more.

The ichthyofauna of Lake Tanganyika consists of 12 families of fish of which five belong to Siluriformes (catfishes). Studies on Siluriformes and their parasites in this lake are very fragmentary. The present study was carried out to help fill the knowledge gap on the monogeneans infesting the siluriform fishes of Lake Tanganyika in general and, more particularly, Clarias gariepinus. Samples of gills of Clarias gariepinus (Clariidae) were examined for ectoparasites. We identified the monogenean Gyrodactylus transvaalensis (Gyrodactylidae). This is the first time this parasite was found infecting gills. We are the first to observe a large spine in the male copulatory organ of this species and to provide measurements of its genital spines; this completes the description of the male copulatory organ, which is important in standard monogenean identification. This is the first monogenean species reported in C. gariepinus at Lake Tanganyika and the third known species on a representative of Siluriformes of this lake. It brings the total number of species of Gyrodactylus recorded in Lake Tanganyika to four. Knowing that other locations where this species has been reported are geographically remote from Lake Tanganyika, we propose a “failure to diverge” phenomenon for G. transvaalensis. Full article

(This article belongs to the Special Issue Parasitic Diseases of Fish: Identification, Host-Parasite Interactions and Molecular Biology)

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12 pages, 8038 KiB

Open AccessArticle

Prevalence, Morpho-Histopathological Identification, Clinical Picture, and the Role of Lernanthropus kroyeri to Alleviate the Zinc Toxicity in Moron labrax

by Attia A. Abou Zaid, Rehab R. Abd El Maged, Nesma Rasheed, Dina Mohamed Mansour, Heba H. Mahboub, Hany M. Abd El-Lateef, Jean-Marc Sabatier, Hebatallah M. Saad, Gaber El-Saber Batiha and Michel De Waard

Pathogens 2023, 12(1), 52; https://doi.org/10.3390/pathogens12010052 - 28 Dec 2022

Cited by 1 | Viewed by 1613

Abstract

The present context is a pioneer attempt to verify the ability of copepod, Lernanthropus kroyeri (L. kroyeri), to uptake and accumulate heavy metals. We primarily assess the prevalence of the parasite in various seasons and its clinical signs, as well as post-mortem changes [...] Read more.

The present context is a pioneer attempt to verify the ability of copepod, Lernanthropus kroyeri (L. kroyeri), to uptake and accumulate heavy metals. We primarily assess the prevalence of the parasite in various seasons and its clinical signs, as well as post-mortem changes in sea bass (Moron labrax). The morphological features of the parasite using a light microscope, the bioaccumulation of heavy metals in the tissues of both L. kroyeri and M. labrax (gills, muscles) using Flame Atomic Absorption Spectrometry, and the histopathological alterations were monitored. Fish (n = 200) were obtained from Ezbet Elborg and examined for the parasite, L. kroyeri. The results revealed that the total infection was recorded at 86%. The infested fish exhibited excessive mucous and ulceration at the site of attachment. The post-mortem lesion in the gills revealed a marbling appearance with destructed filaments. Various heavy metals (Zn, Co, Cu, and Cd) were detected in the tissues of L. kroyeri and M. labrax and, surprisingly, L. kroyeri had the ability to uptake and accumulate a high amount of Zn in its tissues. Infested fish accumulated a lower concentration of Zn in their tissue compared with the non-infested ones. Within the host tissue, the accumulation of Zn was higher in the gills compared with the muscles. The histopathological findings demonstrated scattered parasitic elements with the destruction of the gill lamellae. Taken together, we highlight the potential role of L. kroyeri to eliminate Zn and it can be utilized as a bio-indicator for metal monitoring studies for sustaining aquaculture. Full article

(This article belongs to the Special Issue Parasitic Diseases of Fish: Identification, Host-Parasite Interactions and Molecular Biology)

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8 pages, 1172 KiB

Open AccessCommunication

Outbreak of Parasitic Dinoflagellate Piscinoodinium sp. Infection in an Endangered Fish from India: Arulius Barb (Dawkinsia arulius)

by Arun Sudhagar, Nithianantham Sundar Raj, Sowmya Pazhur Mohandas, Shaji Serin, Konnoth Kuttappan Sibi, Nandiath Karayi Sanil and Thangaraj Raja Swaminathan

Pathogens 2022, 11(11), 1350; https://doi.org/10.3390/pathogens11111350 - 14 Nov 2022

Viewed by 1717

Abstract

Freshwater velvet disease is caused by the dinoflagellate parasite, Piscinoodinium sp. This parasite has been reported in tropical and subtropical fishes, and it can cause devastating losses. Moreover, Piscinoodinium sp. is identified as one of the least studied finfish parasites, and the available [...] Read more.

Freshwater velvet disease is caused by the dinoflagellate parasite, Piscinoodinium sp. This parasite has been reported in tropical and subtropical fishes, and it can cause devastating losses. Moreover, Piscinoodinium sp. is identified as one of the least studied finfish parasites, and the available molecular information about this parasite is meager. Recently, Piscinoodinium sp. was responsible for the 100% cumulative mortality of the captive-bred F1 generation of Arulius barb (Dawkinsia arulius), an endangered freshwater fish native to India. The trophont stages of the parasite were observed in the skin and gills of the affected fish. The total DNA was extracted from the trophonts collected from the affected Arulius barb and the partial nucleotide sequence of the rDNA complex region (2334 bp) was amplified using PCR. The amplified PCR product exhibited a high sequence identity (97.61%) with Piscinoodinium sp. In the phylogenetic analysis of the SSU rDNA, Piscinoodinium sp. emerged as a separate clade from other dinoflagellate species. This is the first report of the infection of Piscinoodinium sp. in Arulius barb and the molecular information generated from this study can serve as a baseline to study the diversity of the parasite in India. Furthermore, the impact of this parasite among wild fish stock is not known, and this parasite needs further research focus to generate more molecular information and to understand the host–pathogen interaction. Full article

(This article belongs to the Special Issue Parasitic Diseases of Fish: Identification, Host-Parasite Interactions and Molecular Biology)

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11 pages, 428 KiB

Open AccessArticle

Application of Phyto-Stimulants for Growth, Survival Rate, and Meat Quality Improvement of Tiger Shrimp (Penaeus monodon) Maintained in a Traditional Pond

by Esti Handayani Hardi, Rudi Agung Nugroho, Maulina Agriandini, Muhammad Rizki, Muhammad Eko Nur Falah, Ismail Fahmy Almadi, Haris Retno Susmiyati, Rita Diana, Nurul Puspita Palupi, Gina Saptiani, Agustina Agustina, Andi Noor Asikin and Komsanah Sukarti

Pathogens 2022, 11(11), 1243; https://doi.org/10.3390/pathogens11111243 - 27 Oct 2022

Cited by 2 | Viewed by 1778

Abstract

The tiger shrimp culture in East Borneo is commonly performed using traditional pond system management. In this work, the objective was to evaluate the application of Boesenbergia pandurata and Solanum ferox extract supplemented as feed additives considering shrimp growth, survival rate, and meat [...] Read more.

The tiger shrimp culture in East Borneo is commonly performed using traditional pond system management. In this work, the objective was to evaluate the application of Boesenbergia pandurata and Solanum ferox extract supplemented as feed additives considering shrimp growth, survival rate, and meat quality culture in a traditional pond. There were three dietary groups that were stocked with 300 shrimp in this study. The shrimp were maintained in a pond, separated with a 3 × 3 m² net. The dietary treatment applied was divided into three types, namely P1, without the extracts; P2, 20 mL kg⁻¹ dietary supplementation; and P3, 30 mL kg⁻¹ dietary supplementation in the diet. The findings revealed that the herb extract influenced the growth rate, feed efficiency, survival rate, and meat quality of the shrimp, mainly the amino and fatty acid contents in the shrimp meat. The 30 mL kg⁻¹ herb extract dose in group 3 showed a higher growth performance and survival rate. In group 3, 98% of the shrimp could survive until the final study period, while 96% of shrimp survived in group 2, and 70% of the shrimp survived in group 1. These findings indicate that the phytoimmune (B. pandurata and S. ferox) extract can be utilized as a feed additive to improve the growth, survival rate, and meat quality of the shrimp. Full article

(This article belongs to the Special Issue Parasitic Diseases of Fish: Identification, Host-Parasite Interactions and Molecular Biology)

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9 pages, 1593 KiB

Open AccessArticle

Host–Parasite Interaction and Phylogenetic of a New Cnidarian Myxosporean (Endocnidozoa: Myxobolidae) Infecting a Valuative Commercialized Ornamental Fish from Pantanal Wetland Biome, Brazil

by Patrick D. Mathews, Omar Mertins, Anai P. P. Flores-Gonzales, Luis L. Espinoza, Julio C. Aguiar and Tiago Milanin

Pathogens 2022, 11(10), 1119; https://doi.org/10.3390/pathogens11101119 - 29 Sep 2022

Cited by 3 | Viewed by 1353

Abstract

Myxozoans are a diverse group of parasitic cnidarians of wide distribution. A new species, Myxobolus matogrossoensis n. sp., is herein described infecting wild specimens of tetra mato-grosso Hyphessobrycon eques, caught in the Pantanal biome, the world’s largest tropical wetland area. Cysts were [...] Read more.

Myxozoans are a diverse group of parasitic cnidarians of wide distribution. A new species, Myxobolus matogrossoensis n. sp., is herein described infecting wild specimens of tetra mato-grosso Hyphessobrycon eques, caught in the Pantanal biome, the world’s largest tropical wetland area. Cysts were found in 3 of the 30 examined fishes. Mature myxospores were ovoid in shape in frontal and measured 6.6 ± 0.4 µm (6.2–7.0 µm) in length and 3.5 ± 0.2 µm (3.3–3.7 µm) in width. The two polar capsules were elongated in shape, equal in size and occupying almost half of the myxospore body. They measured 3.3 ± 0.2 µm (3.1–3.5 µm) in length and 1.8 ± 0.1 µm (1.7–1.9 µm) in width. The polar tubules presented three to four turns. Phylogenetic analysis placed the new species within a clade containing myxobolid species from South American characiforms fish and appears as a close species of Myxobolus piraputangae and Myxobolus umidus. Nevertheless, the sequences of the new species and P. umidus and P. piraputangae have a large genetic divergence of 12 and 12.2% in their 18S rDNA gene, respectively. To the best of our knowledge, this is the first report of a Myxobolus species parasitizing the tetra fish mato-grosso, thus increasing our knowledge of cnidarian myxosporean diversity from South America. Full article

(This article belongs to the Special Issue Parasitic Diseases of Fish: Identification, Host-Parasite Interactions and Molecular Biology)

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10 pages, 1535 KiB

Open AccessArticle

Morphological and Molecular Characterization of a New Myxozoan, Myxobolus grassi sp. nov. (Myxosporea), Infecting the Grass Carp, Ctenopharyngodon idella in the Gomti River, India

by Naireen Fariya, Harpreet Kaur, Mahender Singh, Rehana Abidi, Mansour El-Matbouli and Gokhlesh Kumar

Pathogens 2022, 11(3), 303; https://doi.org/10.3390/pathogens11030303 - 28 Feb 2022

Cited by 7 | Viewed by 2474

Abstract

Myxosporeans are well-known parasites infecting food fishes in fresh and marine water around the globe. Grass carp (Ctenopharyngodon idella), a freshwater food fish commonly cultured in India with has significant economic importance. Herein, the study focuses on the description of a new [...] Read more.

Myxosporeans are well-known parasites infecting food fishes in fresh and marine water around the globe. Grass carp (Ctenopharyngodon idella), a freshwater food fish commonly cultured in India with has significant economic importance. Herein, the study focuses on the description of a new myxosporean species, Myxobolus grassi sp. nov. from the gills as primary site and liver as secondary site of infection in grass carp. Both organs (gill and liver) were infected concurrently in the host and the prevalence of grass carp infection was 4.05% in gill filaments and liver, respectively. Identification of species was based on the morphological and morphometric features of the myxospore as well as 18S rDNA sequence data. A smear from gill and liver exhibited hundreds of morphologically similar myxospores. BLAST search revealed 98% sequence similarity and 0.03 genetic distance with M. catlae (KM029967) infecting gill lamellae of mrigal carp (Cirrhinus cirrhosus) from India and 98–84% sequence similarity with other myxobolids in India, China, Japan, Malaysia, Turkey and Hungary. Phylogenetically, it clustered with other myxobolids infecting gills and related organs (i.e., vital organ) of Indian cyprinid carp species. On the basis of myxospore morphology and 18S sequence, we propose M. grassi sp. nov. Full article

(This article belongs to the Special Issue Parasitic Diseases of Fish: Identification, Host-Parasite Interactions and Molecular Biology)

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11 pages, 2162 KiB

Open AccessArticle

First Molecular Identification of Caligus clemensi on Cultured Crimson Snapper Lutjanus erythropterus on Jerejak Island, Penang, Peninsular Malaysia

by Zary Shariman Yahaya, Mohd Nor Siti Azizah, Luay Alkazmi, Rajiv Ravi and Oluwaseun Bunmi Awosolu

Pathogens 2022, 11(2), 188; https://doi.org/10.3390/pathogens11020188 - 29 Jan 2022

Cited by 1 | Viewed by 2639

Abstract

Fish parasites such as Caligus clemensi are a serious concern for cultured fish in many regions of the world, including Malaysia. This study was designed to elucidate the parasites’ prevalence and intensity coupled with the morphology and molecular identification of C. clemensi on [...] Read more.

Fish parasites such as Caligus clemensi are a serious concern for cultured fish in many regions of the world, including Malaysia. This study was designed to elucidate the parasites’ prevalence and intensity coupled with the morphology and molecular identification of C. clemensi on cultured Lutjanus erythropterus in Jerejak Island, Penang, Peninsular Malaysia. The study was carried out on 200 fish specimens of cultured L. erythropterus obtained from the GST group aquaculture farm. Parasites were collected from the infested part of L. erythropterus fish, and their prevalence and intensity were determined. The parasites were identified morphologically using a field emission scanning electron microscope. Molecular studies were performed through PCR amplification and sequencing. MEGA 5 was used to construct a phylogenetic tree using the pairwise distance method. The results showed that only the C. clemensi parasite was found prevalent on L. erythropterus fish with a prevalence and mean intensity (S.D) of 198 (99%) and 36.4 ± 12.2, respectively. The prevalence varied significantly with respect to fish length (p < 0.05). The nucleotide BLAST sequence for 18S ribosomal RNA partial sequences showed 97% with 100% query similarity, E-value 0 with C. clemensi with the accession number DQ123833.1. Conclusively, C. clemensi remains a major parasite of L. erythropterus in the study area. Full article

(This article belongs to the Special Issue Parasitic Diseases of Fish: Identification, Host-Parasite Interactions and Molecular Biology)

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15 pages, 2344 KiB

Open AccessArticle

Prevalence and Intensity of Cardicola spp. Infection in Ranched Southern Bluefin Tuna and a Comparison of Diagnostic Methods

by Cecilia Power, Shannon Evenden, Kirsten Rough, Claire Webber, Maree Widdicombe, Barbara F. Nowak and Nathan J. Bott

Pathogens 2021, 10(10), 1248; https://doi.org/10.3390/pathogens10101248 - 27 Sep 2021

Cited by 4 | Viewed by 1886

Abstract

The parasitic blood flukes Cardicola forsteri and C. orientalis are an ongoing health concern for Southern Bluefin Tuna Thunnus maccoyii (SBT) ranched in Australia. In this study we compared the effect of treatment, company, and ranching year on blood fluke infections in ranched [...] Read more.

The parasitic blood flukes Cardicola forsteri and C. orientalis are an ongoing health concern for Southern Bluefin Tuna Thunnus maccoyii (SBT) ranched in Australia. In this study we compared the effect of treatment, company, and ranching year on blood fluke infections in ranched SBT. SBT were sampled during the 2018 and 2019 ranching seasons from praziquantel (PZQ) treated pontoons and untreated pontoons managed by two companies. Severity of infection was diagnosed by several criteria including adult fluke counts from hearts, egg counts from gill filaments and the use of specific quantitative polymerase chain reaction (qPCR) for detection of C. forsteri and C. orientalis ITS-2 DNA in SBT hearts and gills. PZQ treatment remains highly effective against C. forsteri infection. Prevalence and intensity of Cardicola spp. infection was lower in 2019 than 2018 for Company A in treated pontoons at week 12 and week 17 of ranching, and lower for Company A than Company B in untreated pontoons at month 5 of ranching. Results indicate re-infection may be less likely in the environment near Company A pontoons, and consistent years of treatment may have lowered the parasite load in the environment. qPCR demonstrated higher sensitivity when comparing diagnostic methods for C. forsteri in heart, and higher specificity when comparing diagnostic methods for Cardicola spp. in gills. Continuing to monitor blood fluke infections in ranched SBT can help to detect changes in drug efficacy over time and help industry to develop a best practice for treatment. Full article

(This article belongs to the Special Issue Parasitic Diseases of Fish: Identification, Host-Parasite Interactions and Molecular Biology)

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11 pages, 796 KiB

Open AccessArticle

Proteins of the Ciliated Protozoan Parasite Ichthyophthirius multifiliis Identified in Common Carp Skin Mucus

by Mona Saleh, Abdel-Azeem S. Abdel-Baki, Mohamed A. Dkhil, Mansour El-Matbouli and Saleh Al-Quraishy

Pathogens 2021, 10(7), 790; https://doi.org/10.3390/pathogens10070790 - 22 Jun 2021

Cited by 7 | Viewed by 2395

Abstract

The skin mucus is the fish primary defense barrier protecting from infections via the skin epidermis. In a previous study, we have investigated the proteome of common carp (Cyprinus carpio) skin mucus at two different time points (1 and 9 days) [...] Read more.

The skin mucus is the fish primary defense barrier protecting from infections via the skin epidermis. In a previous study, we have investigated the proteome of common carp (Cyprinus carpio) skin mucus at two different time points (1 and 9 days) post-exposure to Ichthyophthirius multifiliis. Applying a nano-LC ESI MS/MS technique, we have earlier revealed that the abundance of 44 skin mucus proteins has been differentially regulated including proteins associated with host immune responses and wound healing. Herein, in skin mucus samples, we identified six proteins of I. multifiliis associated with the skin mucus in common carp. Alpha and beta tubulins were detected in addition to the elongation factor alpha, 26S proteasome regulatory subunit, 26S protease regulatory subunit 6B, and heat shock protein 90. The identified proteins are likely involved in motility, virulence, and general stress during parasite growth and development after parasite attachment and invasion. Two KEGG pathways, phagosome and proteasome, were identified among these parasite proteins, mirroring the proteolytic and phagocytic activities of this parasite during host invasion, growth, and development, which represent a plausible host invasion strategy of this parasite. The results obtained from this study can support revealing molecular aspects of the interplay between carp and I. multifiliis and may help us understand the I. multifiliis invasion strategy at the skin mucus barrier. The data may advance the development of novel drugs, vaccines, and diagnostics suitable for the management and prevention of ichthyophthiriosis in fish. Full article

(This article belongs to the Special Issue Parasitic Diseases of Fish: Identification, Host-Parasite Interactions and Molecular Biology)

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25 pages, 3226 KiB

Open AccessOpinion

Are We Ready to Get Rid of the Terms “Chalimus” and ”Preadult” in the Caligid (Crustacea: Copepoda: Caligidae) Life Cycle Nomenclature?

by Wojciech Piasecki, Balu Alagar Venmathi Maran and Susumu Ohtsuka

Pathogens 2023, 12(3), 460; https://doi.org/10.3390/pathogens12030460 - 14 Mar 2023

Cited by 2 | Viewed by 1483

Abstract

In view of recent studies, we suggest that the term “preadult” should not be used in scientific reports on Copepoda parasitic on fishes as having no explicit meaning or further justification. Consequently, the term “chalimus” with its use currently restricted in the Caligidae [...] Read more.

In view of recent studies, we suggest that the term “preadult” should not be used in scientific reports on Copepoda parasitic on fishes as having no explicit meaning or further justification. Consequently, the term “chalimus” with its use currently restricted in the Caligidae to at most two instars in the life cycles of species of Lepeophtheirus, also becomes redundant. In our new understanding, both the chalimus and preadult stages should be referred to as the respective copepodid stages (II through V, in integrative terminology). The terminology for the caligid copepod life cycle thereby becomes consistent with that for the homologous stages of other podoplean copepods. We see no justification for keeping “chalimus” and “preadult” even as purely practical terms. To justify this reinterpretation, we comprehensively summarize and reinterpret the patterns of instar succession reported in previous studies on the ontogeny of caligid copepods, with special attention to the frontal filament. Key concepts are illustrated in diagrams. We conclude that, using the new integrative terminology, copepods of the family Caligidae have the following stages in their life cycles: nauplius I, nauplius II (both free-living), copepodid I (infective), copepodid II (chalimus 1), copepodid III (chalimus 2), copepodid IV (chalimus 3/preadult 1), copepodid V (chalimus 4/preadult 2), and adult (parasitic). With this admittedly polemical paper, we hope to spark a discussion about this terminological problem. Full article

(This article belongs to the Special Issue Parasitic Diseases of Fish: Identification, Host-Parasite Interactions and Molecular Biology)

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Parasitic Diseases of Fish: Identification, Host-Parasite Interactions and Molecular Biology

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