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Sayyaf Dezfuli B, Franchella E, Bernacchia G, De Bastiani M, Lorenzoni F, Carosi A, Lorenzoni M, Bosi G. Infection of endemic chub Squalius tenellus with the intestinal tapeworm Caryophyllaeus brachycollis (Cestoda): histopathology and ultrastructural surveys. Parasitology 2024; 151:157-167. [PMID: 38193283 PMCID: PMC10941047 DOI: 10.1017/s0031182023001233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 11/22/2023] [Accepted: 11/25/2023] [Indexed: 01/10/2024]
Abstract
The endemic chub Squalius tenellus (Heckel, 1843) was introduced more than 100 years ago to Lake Blidinje (Bosnia-Herzegovina). Only 1 species of enteric helminth was found in a sample of 35 chubs, the tapeworm Caryophyllaeus brachycollis (Janiszewska, 1953). The paper includes histopathological investigation with identification of innate immune cells involved in host reaction and molecular data allowed correct designation of the cestode species. Of 35 specimens of chub examined, 21 (60%) harboured individuals of C. brachycollis and a total of 1619 tapeworms were counted, the intensity of infection ranged from 1 to 390 worms per fish (46.2 ± 15.3, mean ± s.e.). Histopathological and ultrastructural investigations showed strict contact between the worm's body and the epithelia and increase in the number of mucous cells, rodlet cells among the epithelial cells. Within the tunica propria-submucosa, beneath the site of scolex attachment, numerous neutrophils and mast cells were noticed. This is the first study of the occurrence of C. brachycollis in chub from Lake Blidinje and on the response of the innate immune cells of S. tenellus to this tapeworm. Interestingly, in 3 very heavily infected chubs, perforation of the intestinal wall was documented; this is uncommon among cestodes which use fish as a definitive host.
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Affiliation(s)
- Bahram Sayyaf Dezfuli
- Department of Life Sciences and Biotechnology, University of Ferrara, St. Borsari 46, 44121 Ferrara, Italy
| | - Emanuela Franchella
- Department of Life Sciences and Biotechnology, University of Ferrara, St. Borsari 46, 44121 Ferrara, Italy
| | - Giovanni Bernacchia
- Department of Life Sciences and Biotechnology, University of Ferrara, St. Borsari 46, 44121 Ferrara, Italy
| | - Morena De Bastiani
- Department of Life Sciences and Biotechnology, University of Ferrara, St. Borsari 46, 44121 Ferrara, Italy
| | - Francesca Lorenzoni
- Department of Chemistry, Biology, and Biotechnology, University of Perugia, St. Elce di sotto 5, 06123 Perugia, Italy
| | - Antonella Carosi
- Department of Chemistry, Biology, and Biotechnology, University of Perugia, St. Elce di sotto 5, 06123 Perugia, Italy
| | - Massimo Lorenzoni
- Department of Chemistry, Biology, and Biotechnology, University of Perugia, St. Elce di sotto 5, 06123 Perugia, Italy
| | - Giampaolo Bosi
- Department of Veterinary Medicine and Animal Science, University of Milan, St. of University 6, 26900, Lodi, Italy
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Abou-Okada M, Rashad MM, Ali GE, Abdel-Radi S, Hassan A. Oxidative stress, gene expression and histopathology of cultured gilthead sea bream (Sparus aurata) naturally co-infected with Ergasilus sieboldi and Vibrio alginolyticus. BMC Vet Res 2023; 19:277. [PMID: 38104092 PMCID: PMC10724927 DOI: 10.1186/s12917-023-03840-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 12/01/2023] [Indexed: 12/19/2023] Open
Abstract
BACKGROUND Parasitic and bacterial co-infections have been associated with increasing fish mortalities and severe economic losses in aquaculture through the past three decades. The aim of this study was to evaluate the oxidative stress, histopathology, and immune gene expression profile of gilthead sea bream (Sparus aurata) co-infected with Ergasilus sieboldi and Vibrio alginolyticus. RESULTS Vibrio alginolyticus and Ergasilus sieboldi were identified using 16 S rRNA and 28 S rRNA sequencing, respectively. The collagenase virulence gene was found in all Vibrio alginolyticus isolates, and the multiple antimicrobial resistance index ranged from 0.286 to 0.857. Oxidant-antioxidant parameters in the gills, skin, and muscles of naturally infected fish revealed increased lipid peroxidation levels and a decrease in catalase and glutathione antioxidant activities. Moreover, naturally co-infected gilthead sea bream exhibited substantial up-regulation of il-1β, tnf-α, and cyp1a1. Ergasilus sieboldi encircled gill lamellae with its second antennae, exhibited severe gill architectural deformation with extensive eosinophilic granular cell infiltration. Vibrio alginolyticus infection caused skin and muscle necrosis in gilthead sea bream. CONCLUSION This study described some details about the gill, skin and muscle tissue defense mechanisms of gilthead sea bream against Ergasilus sieboldi and Vibrio alginolyticus co-infections. The prevalence of co-infections was 100%, and no resistant fish were detected. These co-infections imbalance the health status of the fish by hampering the oxidant-antioxidant mechanisms and proinflammatory/inflammatory immune genes to a more detrimental side. Our results suggest that simultaneous screening for bacterial and parasitic pathogens should be considered.
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Affiliation(s)
- Mahmoud Abou-Okada
- Department of Aquatic Animal Medicine and Management, Faculty of Veterinary Medicine, Cairo University, Giza, 12211, Egypt.
| | - Maha M Rashad
- Department of Biochemistry and Chemistry of Nutrition, Faculty of Veterinary Medicine, Cairo University, Giza, 12211, Egypt
| | - Ghada E Ali
- Department of Biochemistry and Chemistry of Nutrition, Faculty of Veterinary Medicine, Cairo University, Giza, 12211, Egypt
| | - Shimaa Abdel-Radi
- Department of Parasitology, Faculty of Veterinary Medicine, Cairo University, Giza, 12211, Egypt
| | - Azza Hassan
- Department of Pathology, Faculty of Veterinary Medicine, Cairo University, Giza, 12211, Egypt
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Sayyaf Dezfuli B, Lorenzoni M, Carosi A, Giari L, Bosi G. Teleost innate immunity, an intricate game between immune cells and parasites of fish organs: who wins, who loses. Front Immunol 2023; 14:1250835. [PMID: 37908358 PMCID: PMC10613888 DOI: 10.3389/fimmu.2023.1250835] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 10/06/2023] [Indexed: 11/02/2023] Open
Abstract
Fish, comprising over 27,000 species, represent the oldest vertebrate group and possess both innate and adaptive immune systems. The susceptibility of most wild fish to parasitic infections and related diseases is well-established. Among all vertebrates, the digestive tract creates a remarkably favorable and nutrient-rich environment, which, in turn, renders it susceptible to microparasites and macroparasites. Consequently, metazoan parasites emerge as important disease agents, impacting both wild and farmed fish and resulting in substantial economic losses. Given their status as pathogenic organisms, these parasites warrant considerable attention. Helminths, a general term encompassing worms, constitute one of the most important groups of metazoan parasites in fish. This group includes various species of platyhelminthes (digeneans, cestodes), nematodes, and acanthocephalans. In addition, myxozoans, microscopic metazoan endoparasites, are found in water-dwelling invertebrates and vertebrate hosts. It is worth noting that several innate immune cells within the fish alimentary canal and certain visceral organs (e.g., liver, spleen, and gonads) play active roles in the immune response against parasites. These immune cells include macrophages, neutrophils, rodlet cells, and mast cells also known as eosinophilic granular cells. At the site of intestinal infection, helminths often impact mucous cells number and alter mucus composition. This paper presents an overview of the state of the art on the occurrence and characteristics of innate immune cells in the digestive tract and other visceral organs in different fish-parasite systems. The data, coming especially from studies employed immunohistochemical, histopathological, and ultrastructural analyses, provide evidence supporting the involvement of teleost innate immune cells in modulating inflammatory responses to metazoan and protozoan parasitic infections.
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Affiliation(s)
- Bahram Sayyaf Dezfuli
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Massimo Lorenzoni
- Department of Chemistry, Biology and Biotechnologies, University of Perugia, Perugia, Italy
| | - Antonella Carosi
- Department of Chemistry, Biology and Biotechnologies, University of Perugia, Perugia, Italy
| | - Luisa Giari
- Department of Environmental and Prevention Sciences, University of Ferrara, Ferrara, Italy
| | - Giampaolo Bosi
- Department of Veterinary Medicine and Animal Science, University of Milan, Lodi, Italy
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Manera M, Castaldelli G, Giari L. Perfluorooctanoic Acid Promotes Recruitment and Exocytosis of Rodlet Cells in the Renal Hematopoietic Tissue of Common Carp. TOXICS 2023; 11:831. [PMID: 37888682 PMCID: PMC10611324 DOI: 10.3390/toxics11100831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Revised: 09/20/2023] [Accepted: 09/29/2023] [Indexed: 10/28/2023]
Abstract
Per- and polyfluoroalkyl substances (PFAS) are ubiquitous environmental contaminants, with perfluorooctanoic acid (PFOA) being a prominent member. PFOA poses a risk to aquatic ecosystems and human health due to its presence in water, environmental persistence, and bioaccumulation. Since rodlet cells (RCs) have emerged as potential biomarkers for chemical stressors, this study aimed to investigate the effects of sub-chronic PFOA exposure on RCs in the renal hematopoietic tissue of common carp. Three groups of fish were used: an unexposed control group and two groups exposed to environmentally relevant (200 ng L-1) and elevated (2 mg L-1) PFOA concentrations. Light and transmission electron microscopy were employed to assess RCs' distribution patterns and exocytosis, while biometry quantified RCs in the hematopoietic tissue. The results showed that, even at environmentally relevant concentrations, PFOA significantly influenced RCs' distribution patterns, leading to increased occurrence and cluster formation, as well as heightened exocytosis activity. This research highlights PFOA's immunotoxicity in fish and suggests the potential of RCs as sentinel cells in the immunological response to environmental contaminants. These findings enhance our understanding of PFAS toxicity and emphasise the importance of monitoring their impact on fish as representative vertebrates and reliable animal models.
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Affiliation(s)
- Maurizio Manera
- Department of Biosciences, Food and Environmental Technologies, University of Teramo, St. R. Balzarini 1, 64100 Teramo, Italy
| | - Giuseppe Castaldelli
- Department of Environmental and Prevention Sciences, University of Ferrara, St. Borsari 46, 44121 Ferrara, Italy; (G.C.); (L.G.)
| | - Luisa Giari
- Department of Environmental and Prevention Sciences, University of Ferrara, St. Borsari 46, 44121 Ferrara, Italy; (G.C.); (L.G.)
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Wu YX, Hu SY, Lu XJ, Hu JR. Identification and characterization of two novel antimicrobial peptides from Japanese sea bass (Lateolabrax japonicus) with antimicrobial activity and MO/MФ activation capability. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2023; 145:104726. [PMID: 37149238 DOI: 10.1016/j.dci.2023.104726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 05/04/2023] [Accepted: 05/04/2023] [Indexed: 05/08/2023]
Abstract
Piscidins participate in the innate immune response of fish, which aims to eliminate recognized foreign microbes and restore the homeostasis of immune system. We characterized two piscidin-like antimicrobial peptides (LjPL-3 and LjPL-2) isolated from Japanese sea bass (Lateolabrax japonicus). LjPL-3 and LjPL-2 showed different expression patterns in tissues. After Vibrio harveyi infection, the mRNA expression of LjPL-3 and LjPL-2 was upregulated in the liver, spleen, head kidney, and trunk kidney. The synthetic mature peptides LjPL-3 and LjPL-2 exhibited different antimicrobial spectra. Furthermore, LjPL-3 and LjPL-2 treatments decreased inflammatory cytokine production while promoting chemotaxis and phagocytosis in monocytes/macrophages (MO/MФ). LjPL-2, but not LjPL-3, displayed bacterial killing capability in MO/MФ. LjPL-3 and LjPL-2 administration increased Japanese sea bass survival after V. harveyi challenge, which was accompanied by a decline in bacterial burden. These data suggested that LjPL-3 and LjPL-2 participate in immune response through direct bacterial killing and MO/MФ activation.
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Affiliation(s)
- Yi-Xin Wu
- School of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 311121, Zhejiang, China; Department of Physiology, and Department of Hepatobiliary and Pancreatic Surgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, Zhejiang, China
| | - Shuai-Yue Hu
- Hangzhou Medical College, Hangzhou, 310013, Zhejiang, China
| | - Xin-Jiang Lu
- Department of Physiology, and Department of Hepatobiliary and Pancreatic Surgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, Zhejiang, China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China.
| | - Jian-Rao Hu
- School of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 311121, Zhejiang, China.
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Jiang S, Huang X. Host responses against the fish parasitizing ciliate Cryptocaryon irritans. Parasite Immunol 2023; 45:e12967. [PMID: 36606416 DOI: 10.1111/pim.12967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 12/05/2022] [Accepted: 01/02/2023] [Indexed: 01/07/2023]
Abstract
The parasitic ciliate Cryptocaryon irritans, which infects almost all marine fish species occurring in both tropical and subtropical regions throughout the world. The disease, cryptocaryonosis, accounts for significant economic losses to the aquaculture industry. This review attempts to provide a comprehensive overview of the biology of the parasite, host-parasite interactions and both specific and non-specific host defense mechanisms are responsible for the protection of fish against challenge infections with this ciliate. Also, this article reflects the current interest in this subject area and the quest to develop an available vaccine against the disease. Due to the high frequency of clinical fish cryptocaryonosis, the study of fish immune responses to C. irritans provides an optimal experimental model for understanding immunity against extracellular protozoa.
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Affiliation(s)
- Shuiqing Jiang
- Fujian Key Laboratory of Developmental and Neural Biology, College of Life Science, Fujian Normal University, Fuzhou, Fujian, China
| | - Xiaohong Huang
- Fujian Key Laboratory of Developmental and Neural Biology, College of Life Science, Fujian Normal University, Fuzhou, Fujian, China
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Bosi G, Maynard BJ, Pironi F, Sayyaf Dezfuli B. Parasites and the neuroendocrine control of fish intestinal function: an ancient struggle between pathogens and host. Parasitology 2022; 149:1842-1861. [PMID: 36076315 PMCID: PMC11010486 DOI: 10.1017/s0031182022001160] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 08/03/2022] [Accepted: 08/11/2022] [Indexed: 12/29/2022]
Abstract
Most individual fish in wild and farmed populations can be infected with parasites. Fish intestines can harbour protozoans, myxozoans and helminths, which include several species of digeneans, cestodes, nematodes and acanthocephalans. Enteric parasites often induce inflammation of the intestine; the pathogen provokes changes in the host physiology, which will be genetically selected for if they benefit the parasite. The host response to intestinal parasites involves neural, endocrine and immune systems and interaction among these systems is coordinated by hormones, chemokines, cytokines and neurotransmitters including peptides. Intestinal fish parasites have effects on the components of the enteric nervous and endocrine systems; mechanical/chemical changes impair the activity of these systems, including gut motility and digestion. Investigations on the role of the neuroendocrine system in response to fish intestinal parasites are very few. This paper provides immunohistochemical and ultrastructural data on effects of parasites on the enteric nervous system and the enteric endocrine system in several fish–parasite systems. Emphasis is on the occurrence of 21 molecules including cholecystokinin-8, neuropeptide Y, enkephalins, galanin, vasoactive intestinal peptide and serotonin in infected tissues.
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Affiliation(s)
- Giampaolo Bosi
- Department of Veterinary Medicine and Animal Science, University of Milan, St. dell'Università 6, 26900 Lodi, Italy
| | - Barbara J. Maynard
- The Institute for Learning and Teaching, Colorado State University, Fort Collins, CO 80523, USA
| | - Flavio Pironi
- Department of Life Sciences and Biotechnology, University of Ferrara, St. Borsari 46, 44121 Ferrara, Italy
| | - Bahram Sayyaf Dezfuli
- Department of Life Sciences and Biotechnology, University of Ferrara, St. Borsari 46, 44121 Ferrara, Italy
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Nikolić D, Poleksić V, Skorić S, Tasić A, Stanojević S, Rašković B. The European Chub (Squalius cephalus) as an indicator of reservoirs pollution and human health risk assessment associated with its consumption. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 310:119871. [PMID: 35940479 DOI: 10.1016/j.envpol.2022.119871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 07/17/2022] [Accepted: 07/25/2022] [Indexed: 06/15/2023]
Abstract
Five reservoirs (Vlasina, Medjuvršje, Zaovine, Perućac, and Garaši) in Serbia were chosen as study sites, which differ by their position, purpose, stages of eutrophication, management policies, and levels of anthropogenic pressure. The objectives of this research were to: determine the concentrations of 26 elements in muscle, gills, and liver of the European chub by inductively-coupled plasma optical emission spectrometry (ICP-OES); determine the concentrations of 17 organochlorine pesticides in fish muscle by gas chromatography with mass spectrometric detection (GC-MS); compare these findings with condition factor (CF) and histopathological (HP) biomarkers; and assess the potential human health risks due to consumption of chub muscle tissue. The highest elemental accumulation was found in the gills. The European chub was not a good indicator of Pb pollution between reservoirs. Concentrations of Hg, As, and Cu were low and did not exceed the proscribed maximum allowed concentrations (MACs). 4,4'-DDE was detected only in individuals from Vlasina, 4,4'-DDD from Perućac and Zaovine, and heptachlor from Zaovine. Low to moderate levels of HP were observed for both gills and liver in all studied reservoirs. HP index for gills was significantly higher for Zaovine compared to Vlasina. Significantly lower HP index for liver and the total HP index value were observed for fish from Vlasina compared to Perućac. No significant human health risks due to the intake of examined pollutants in each reservoir were recorded; women were at higher risk compared to men. A reason for concern is a few muscle samples from Garaši, Vlasina, Perućac, and Medjuvršje in which Cd exceeded the MAC. A reservoir for water supply (Garaši) is generally considered the safest for fish consumption.
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Affiliation(s)
- Dušan Nikolić
- University of Belgrade - Institute for Multidisciplinary Research, Department of Inland Water Biology and Protection, Kneza Višeslava 1, 11030, Belgrade, Serbia.
| | - Vesna Poleksić
- University of Belgrade - Faculty of Agriculture, Institute of Animal Sciences, Nemanjina 6, Zemun, 11080, Belgrade, Serbia
| | - Stefan Skorić
- University of Belgrade - Institute for Multidisciplinary Research, Department of Inland Water Biology and Protection, Kneza Višeslava 1, 11030, Belgrade, Serbia
| | - Aleksandra Tasić
- Institute of Veterinary Medicine of Serbia, Janisa Janulisa 14, 11000, Belgrade, Serbia
| | - Slobodan Stanojević
- Institute of Veterinary Medicine of Serbia, Janisa Janulisa 14, 11000, Belgrade, Serbia
| | - Božidar Rašković
- University of Belgrade - Faculty of Agriculture, Institute of Animal Sciences, Nemanjina 6, Zemun, 11080, Belgrade, Serbia; University of Porto - Institute of Biomedical Sciences Abel Salazar (ICBAS) - School of Medicine and Biomedical Sciences, Department of Microscopy, Laboratory of Histology and Embryology, Rua de Jorge Viterbo Ferreira 228, 4050-313, Porto, Portugal
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Scholz T, Kuchta R, Oros M. Tapeworms as pathogens of fish: A review. JOURNAL OF FISH DISEASES 2021; 44:1883-1900. [PMID: 34529835 DOI: 10.1111/jfd.13526] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 08/20/2021] [Accepted: 08/23/2021] [Indexed: 06/13/2023]
Abstract
Tapeworms (Cestoda) represents a species rich (about 5000 species) group of flatworms (Neodermata) parasitizing all groups of vertebrates including humans, with about 1000 species parasitizing elasmobranchs and almost 500 occurring in teleosts as adults. They are common parasites of cultured fish, both as adults and larvae (metacestodes), but only few adult tapeworms are actually pathogenic for their fish hosts. In contrast, cestode larvae can be harmful for fish, especially plerocercoids migrating throughout their tissue and internal organs. Current knowledge of host-parasite relationships, including immune response of fish infected with tapeworms, is still insufficient to enable adequate control of cestodoses, and most data available were obtained several decades ago. Treatment of fish infected with adult tapeworms is effective, especially with praziquantel, whereas the treatment of metacestodes is problematic. Control measures include interruption of the complex life cycle and prevention of transport of uninspected fish to new region.
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Affiliation(s)
- Tomáš Scholz
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
| | - Roman Kuchta
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
| | - Mikuláš Oros
- Institute of Parasitology, Slovak Academy of Sciences, Košice, Slovakia
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Holzer AS, Piazzon MC, Barrett D, Bartholomew JL, Sitjà-Bobadilla A. To React or Not to React: The Dilemma of Fish Immune Systems Facing Myxozoan Infections. Front Immunol 2021; 12:734238. [PMID: 34603313 PMCID: PMC8481699 DOI: 10.3389/fimmu.2021.734238] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 09/01/2021] [Indexed: 11/13/2022] Open
Abstract
Myxozoans are microscopic, metazoan, obligate parasites, belonging to the phylum Cnidaria. In contrast to the free-living lifestyle of most members of this taxon, myxozoans have complex life cycles alternating between vertebrate and invertebrate hosts. Vertebrate hosts are primarily fish, although they are also reported from amphibians, reptiles, trematodes, mollusks, birds and mammals. Invertebrate hosts include annelids and bryozoans. Most myxozoans are not overtly pathogenic to fish hosts, but some are responsible for severe economic losses in fisheries and aquaculture. In both scenarios, the interaction between the parasite and the host immune system is key to explain such different outcomes of this relationship. Innate immune responses contribute to the resistance of certain fish strains and species, and the absence or low levels of some innate and regulatory factors explain the high pathogenicity of some infections. In many cases, immune evasion explains the absence of a host response and allows the parasite to proliferate covertly during the first stages of the infection. In some infections, the lack of an appropriate regulatory response results in an excessive inflammatory response, causing immunopathological consequences that are worse than inflicted by the parasite itself. This review will update the available information about the immune responses against Myxozoa, with special focus on T and B lymphocyte and immunoglobulin responses, how these immune effectors are modulated by different biotic and abiotic factors, and on the mechanisms of immune evasion targeting specific immune effectors. The current and future design of control strategies for myxozoan diseases is based on understanding this myxozoan-fish interaction, and immune-based strategies such as improvement of innate and specific factors through diets and additives, host genetic selection, passive immunization and vaccination, are starting to be considered.
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Affiliation(s)
- Astrid S Holzer
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czechia
| | - M Carla Piazzon
- Fish Pathology Group, Institute of Aquaculture Torre de la Sal - Consejo Superior de Investigaciones Científicas (IATS-CSIC), Castellón, Spain
| | - Damien Barrett
- Department of Microbiology, Oregon State University, Corvallis, OR, United States
| | - Jerri L Bartholomew
- Department of Microbiology, Oregon State University, Corvallis, OR, United States
| | - Ariadna Sitjà-Bobadilla
- Fish Pathology Group, Institute of Aquaculture Torre de la Sal - Consejo Superior de Investigaciones Científicas (IATS-CSIC), Castellón, Spain
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