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Fisheries play a crucial role in aquatic ecosystems, a resource with ecological and economic importance. Measuring parasite prevalence is necessary to assess these fish species' health and well-being. Within the Sistan region, this study sought to estimate the prevalence and intensity of infection with plerocercoid Ligula intestinalis (L. intestinalis) in seven fish species and identify factors such as fish weight, seasonality, and fishing location that might influence infection rates. 2800 fish from seven species were obtained in the Sistan region throughout four seasons. Fish samples from three weight categories (<200gr, 200–400gr, 400gr<) were examined parasitologically. Ligula intestinalis was detected in 96/2800 (3.4%) of fishs. There was a variation in prevalence among fish species. Alburnus charusini (A. charusini), Hypophthalmichthys molitrix (H. molitrix), Hypophthalmichthys nobilis (H. nobilis), and Schizocypris altidorsalis (S. altidorsalis) showed no infection. Schizothorax zarudnyi (S. zarudnyi) showed a prevalence of 1.5% (6/400), Cyprinus carpio (C. carpio) 15% (60/400), and Ctenopharyngodon idella (C. idella) 7.5% (30/400). It was found that infection prevalence was significantly influenced by fish weight in C. carpio and C. idella. A higher prevalence was found in fish with lower weight. Infection rates significantly fluctuated with season across species, but fishing locations had no significant difference. The present study highlights the significant prevalence of L. intestinalis infections in fish populations within Iran's Sistan region, underscoring the need for ongoing monitoring and research to inform effective fishery management strategies. Future studies should focus on long-term monitoring efforts and consider the broader global context of fish parasitology to understand parasite-host interactions better and inform conservation measures worldwide. [ABSTRACT FROM AUTHOR]

Purpose: Ligulosis caused by Ligula intestinalis adversely affects the fisheries carried out in the lakes and ponds, causing economic losses in the fish industry. In this study, it was aimed to reveal the molecular characterization of L. intestinalis isolates obtained from woodfish (Acanthobrama marmid) in Keban Dam Lake in Elazig province of Turkey by using mt-CO1 gene sequences and to determine the genetic differences and haplotypes between the isolates. Methods: In the examination made in terms of L. intestinalis, the intestine of the fish was opened with the help of fine-tipped scissors, the contents were allowed to come out, and the parasites were taken into a petri dish containing phosphate buffered saline (PBS). Then, L. intestinalis plerocercoids were taken into 15 ml falcon tubes containing 70% ethanol and stored at − 20 °C until further analysis. From each isolate, total gDNA was extracted from the plerocercoids. A partial (480 bp) mt-CO1 gene was amplified by PCR and sequenced unidirectionally. The final size of the trimmed sequences was 392 bp for 43 sequences. Sequence and haplotype analyses were performed, followed by phylogenetic analyses. Results: All isolates were confirmed as L. intestinalis by BLAST analysis. In addition, 87 nucleotide mutation positions were determined among 43 CO1 gene sequences. As a result of the haplotype network performed for the mt-CO1 gene region of L. intestinalis isolates; arranged in a star-like configuration with the main haplotype (Hap05), separated from other haplotypes by 1–6 mutation steps, and 29 haplotypes were identified, covering 13.9% (6/43) of the total isolates. Also, 75 variable (polymorphic) sites were determined, 52 of which were parsimony informative sites. Conclusions: The molecular characterization of L. intestinalis in woodfish (A. marmid) was identified for the first time in Turkey. [ABSTRACT FROM AUTHOR]

In this study, the usability of Ligula intestinalis as a bioindicator for pesticide accumulation was investigated. Two different experiments were designed for the detection of pesticide residues and its withdrawal period. In the first experiment, the accumulation of malathion for 10 days was measured in the hybrid fish, Squalius orientalisxAlburnus derjugini sampled from a dam lake. In the next experiment, withdrawal was measured for 15 days. The infected and healthy fish in groups exposed malathion and not exposed malathion were sampled at the end of the first experiment. No malathion residue was found in the control group that was not exposed with malathion. For the second experiment, infected and healthy fish from malathion and without malathion groups were sampled to measure the elimination of malathion on the 1st, 4th, 5th, 8th, 12th, and 15th days. At the end of the first experiment, the presence of malathion was not detected in the control group while accumulation was observed in both fish and L. intestinalis in the experimental group. At the end of the second experiment (15th day), the highest residual value was found in L. intestinalis (1.02 mg/kg) while it was determined as 0.009 mg/kg in infected fish and 0.006 mg/kg in uninfected fish. According to the correlation, malathion accumulation was linear between uninfected fish and infected fish. On the other hand, an inverse correlation was found between L. intestinalis and both malathion and control fish. As a result, it was determined that L. intestinalis can be used as a bioindicator in pesticide accumulation and the pesticide is still detectable in the parasite after withdrawal from fish. [ABSTRACT FROM AUTHOR]

Three subspecies of the ringed seal (Pusa hispida) are found in northeastern Europe: P. h. botnica in the Baltic Sea, P. h saimensis in Lake Saimaa in Finland, and P. h. ladogensis in Lake Ladoga in Russia. We investigated the poorly-known cestode helminth communities of these closely related but ecologically divergent subspecies using COI barcode data. Our results show that, while cestodes from the Baltic Sea represent Schistocephalus solidus, all worms from the two lakes are identified as Ligula intestinalis, a species that has previously not been reported from seals. The observed shift in cestode communities appears to be driven by differential availability of intermediate fish host species in marine vs. freshwater environments. Both observed cestode species normally infect fish-eating birds, so further work is required to elucidate the health and conservation implications of cestode infections in European ringed seals, whether L. intestinalis occurs also in marine ringed seals, and whether the species is able to reproduce in seal hosts. In addition, a deep barcode divergence found within S. solidus suggests the presence of cryptic diversity under this species name.

Microplastic (MP) pollution is currently one of the most serious environmental issues. MPs were investigated in the Kürtün Dam Lake in healthy individuals of the native leuciscid hybrid (Alburnus derjugini x Squalius orientalis) species and individuals infected with the Ligula intestinalis parasite. Although MP abundance appeared to be higher in non-infected fish (NIF) than in L. intestinalis (L) and infected fish (IF), the MP abundance in IF was higher, because the parasite theoretically belongs to IF. In addition to the observation of MPs in the gastrointestinal tract (GIT) of fish, the diffusion of MPs by parasites settled in the body cavity indicates that MPs are not only present in the GIT. Therefore, predation on existing fish by birds causes MP dispersion. In the present study, the most common MP shape was fiber (100% for NIF and IF, 85.7% for L), the MP color was black (57.1% for IF and L) and orange (50% for NIF), and the polymer type was polyamide (57.1% for IF, 50% for NIF) and polyethylene terephthalate (28.5% for L). These MP compositions led us to believe that textile effluents and aquaculture operations in dam lakes could be sources of pollution. Therefore, this study provides insights for future research to elucidate the connection between MP consumption and parasite infection. [Display omitted] • Parasitic infection increased MP accumulation in fish. • Fibers were the most frequently observed MP type in fish and parasites. • Predation of the hybrid fish species by birds may result in MP dispersal. • MP sources from aquaculture activities and textile effluents were likely most important. [ABSTRACT FROM AUTHOR]

Abstract Ligula intestinalis is a cestode parasite that affects freshwater fish in different countries of the world. The current study aims to reveal the phylogenetic, genetic and haplotype diversity of mt-CO1 gene sequences sent to the NCBI database from different countries by using in-silico analysis. The 105 mt-CO1 (371 bp) gene sequences of L. intestinalis obtained from NCBI were used for bioinformatics analyses. Sequences were subjected to phylogenetic and haplotype analysis. As a result of the haplotype analysis of L. intestinalis, 38 haplotypes were obtained from 13 different countries. Hap24 constituted 44.76% of the obtained haplotype network. Changes in nucleotides between haplotypes occurred at 1-84 different points. China and Turkey have highest fixation index (Fst) values of 0.59761, while the lowest (-0.10526) was found between Russia and Turkey. This study provides a baseline for future studies on extensive scale on the epidemiology, ecological aspects, distribution pattern, transmission dynamics and population dispersion of L. intestinalis worldwide.

Endocrine disruption of different host species by their parasites is an oft-neglected topic in the field of ecotoxicology. Several endocrine disrupting chemicals, both synthetic and natural, are reported to influence host-parasite interactions in various ways. This review highlights different aspects of endocrine disruption by a diphyllobothriidean (previously pseudophyllidean) cestode Ligula intestinalis and its effect on its wide range of fish hosts. Although this cosmopolitan cestode with a three-host life cycle can damage the host physiology by reproductive, phenotypic, behavioural, haematological, growth and mortality related alterations, the most significant of these effects is parasitic castration, i.e., reducing the fecundity by damaging the reproductive system. The effects of endocrine disruption by other helminth infections and interactions with polluting agents are also discussed. It is concluded that the potential bioaccumulation of the effects in the hosts at higher trophic levels and consequent threat towards human, especially in Indian context, need to be studied in depth to control or reduce the detrimental effects of parasite-induced endocrine disruption in the hosts. [ABSTRACT FROM AUTHOR]

Three subspecies of the ringed seal (Pusa hispida) are found in northeastern Europe: P. h. botnica in the Baltic Sea, P. h saimensis in Lake Saimaa in Finland, and P. h. ladogensis in Lake Ladoga in Russia. We investigated the poorly-known cestode helminth communities of these closely related but ecologically divergent subspecies using COI barcode data. Our results show that, while cestodes from the Baltic Sea represent Schistocephalus solidus , all worms from the two lakes are identified as Ligula intestinalis , a species that has previously not been reported from seals. The observed shift in cestode communities appears to be driven by differential availability of intermediate fish host species in marine vs. freshwater environments. Both observed cestode species normally infect fish-eating birds, so further work is required to elucidate the health and conservation implications of cestode infections in European ringed seals, whether L. intestinalis occurs also in marine ringed seals, and whether the species is able to reproduce in seal hosts. In addition, a deep barcode divergence found within S. solidus suggests the presence of cryptic diversity under this species name. [Display omitted] • COI barcoding reveals different cestodes in marine and freshwater ringed seals. • Ligula intestinalis is reported for the first time from seals. • A deep barcode divergence is found within Schistocephalus solidus in the Baltic Sea. [ABSTRACT FROM AUTHOR]

Objective of research: Comparative studies of qualitative indexes of meat from healthy fish and fish infected with ligulosis for its further sanitary assessment. Materials and methods: As research material served the breams infected with Ligula and free from them (by 30 ind.) caught by amateur fishermen in reservoirs of Moscow region. Fish invasion was studied by K.I.Skryabin method of incomplete helminthological dissection; age of fish was detected on scale; after that weighing was carried out. Microbiological examination of meat from sick and healthy fishes was conducted according to «The instruction for sanitary and microbiological control of food products from fish and sea invertebrates» (Sazonova A. S., etc., 1991). Determination of free and bound amino acids in a water extract of muscular tissue of fishes was carried out by method of a capillary electrophoresis. Toxic elements in fishes were detected by methods of atomic-emission and absorbing spectrometry. Results and discussion: Growth retardation of breams infected with ligulosis rises with age (intensity of infection 1-2 ind. per head); that is displayed in their weight reduction. All unreplaceable amino acids were found in proteins of muscular tissue of fishes. However, fishes infected with ligulosis had lower levels of amino acids that indicates a decrease in nutrition value of a food product. Microbiological research of fish meat showed that MAFAM (number of mesophilic aerobic and facultative anaerobic microorganisms) was higher in muscular tissue of breams infected with ligulosis (10х105), and in meat of healthy fish - 5,5х103 that did not exceed the maximum allowable concentration values. Bacteria of colibacillus group, staphylococcus, salmonellas and L.monocytogenes in were not determined in all fish samples. In muscle tissue samples isolated from all studied fishes, the levels of lead, cadmium and arsenic did not exceed the maximum allowable concentrations. Mercury wasn’t ever revealed in none of studied samples. The results of our research confirmed the safety of bream meat infected with ligulosis for the consumer.

Ligula intestinalis was found during the parasitological investigations of Pseudorasbora parva specimens collected from Hirfanlı Dam Lake, Turkey. It was found that 8.78% of all specimens were infected with L. intestinalis including 17 female (3.8%) and 22 males (4.95%). It was determined that the length–weight relationship equivalents of infected individuals with population differed from those of non-infected individuals. The b value of the infected individuals was found to be lower than the b value of the non-infected individuals. It is thought that the results obtained in this study will be beneficial in preserving and improving the ecological potential of the lake.

This study is devoted to parasitism caused by the tapeworm Ligula intestinalis (L.) in the roach Rutilus rutilus (L.), an invasive species, in three Algerian dam lakes dependent on three different watersheds. We follow the quantitative parameters of parasitism and the impact of parasitism on the development of fish. From March 2016 to February 2017, we examined 578, 565 and 629 individuals in Sekkak, ghrib and guenitra dams respectively. The rate of infection varies depending on the site (p-value < 5%). The prevalence is 0.86% in Sekkak, 2.22% in Guenitra and 10.26% in Ghrib. Respectively, the mean intensity of infection is equal to 1.2, 5.2 and 1.3. The occurrence of the parasite is higher in all dams during autumn. Major allometric growth was observed in parasitized individuals in the three dams (b = 3.19 for ghrib, b = 3.98 for Sekkak and b = 3.44 for guenitra) and minor allometric growth in non-parasitized individuals (b = 2.98 to ghrib, b = 2.98 to Sekkak and b = 2.92 to guenitra), with a significant difference between parasitized and healthy individuals in the three dams (p < 5%). Overweight fish are influenced by parasitism in ghrib dam (parasitized individuals: Kp = 1.03 ± 0.07 and healthy individuals: Ks = 1.06 ± 0.11 (p < 5%)) contrariwise to Sekkak and guenitra (parasitized individu-als: Kp = 1.09 ± 0.18 in Sekkak, 0.97 ± 0.09 in guenitra; healthy individuals: Ks = 1.04 ± 0.14 in Sekkak, 1.03 ± 0.12 in guenitra) (p > 5%). At ghrib dam, the parasitism varies depending on the groups of both size and age (p < 5%), on the contrary to the condition factor (p > 5%). [ABSTRACT FROM AUTHOR]

The article touches upon the morphological characteristics of Crucian carp Carassius gibelio (Bloch, 1782), Kura chub Alburnoides eichwaldii, Kura nase Chondrostoma cyri, Stone moroko Pseudorasbora parva, Grass carp Ctenopharyngodon idella currently found in the Karnut Reservoir, as well as the extensity and intensity of infection of individual fish species such as Ligula intestinalis with plerocercoid. Based on the conducted studies, it is recommended to increas the fish productivity of the Karnut Reservoir by importing and breeding the most economically valuable fish species, thus contributing to the socio-economic sustainable development of rural communities. [ABSTRACT FROM AUTHOR]

There have been several studies on heavy metals in Lake Naivasha. However, none of them has reported the levels of mercury (Hg), arsenic (As), and chromium (Cr). Moreover, there are no studies on the heavy metals' concentrations in the straightfin barb (Enteromius paludinosus, Peters 1852), a fish species that hosts a parasite (Ligula intestinalis), the latter having been reported to have a high ability to absorb heavy metals from its host. This paper therefore addresses the accumulation of heavy metals, namely arsenic (As), chromium (Cr), lead (Pb), and mercury (Hg) in the tissues of straightfin barb, Enteromius paludinosus (Peters 1852) from the mouth of River Malewa in Lake Naivasha, Kenya. A total of 1307 fish were collected during the month of November 2017. Water samples, sediment samples, 25 fish muscle tissues, and its endoparasite, the cestode Ligula intestinalis, were isolated, and heavy metal concentrations were determined using the thermal-electron atomic absorption spectrophotometer at the Lake Nakuru Water Quality Testing Laboratory. The concentrations of heavy metals in the sediment were below the lowest effect level in sediment, threshold effect concentration in sediment, severe effect concentration in sediment, and the shale values of sedimentary rocks thus showing no sign of pollution. In the muscle tissues of the fish, As, Cr, Pb, and Hg showed high levels with mean concentrations of 5.0696, 22.0854, 45.2108, and 1.5458 mg/kg ww, respectively. Bioconcentration factors further supported the observation that trace element accumulation was higher in fish compared with sediment and water. The target hazard quotients of As, Cr, Pb, and Hg obtained for both the female and male were > 1 indicating a possible health risk associated with the consumption of E. paludinosus. The bioaccumulation factors (BAFs) for L. intestinalis were 2.4093, 2.1873, 5.8601, and 5.1395 for As, Cr, Pb, and Hg, respectively, indicating the potential of the cestode in the accumulation of heavy metals from the host; hence, it can be used as an accumulation bioindicator. [ABSTRACT FROM AUTHOR]

Objective of research: The purpose of the study is to investigate the influence of Ligula intestinalis plerocercoids on linear growth of roach Rutilus rutilus in the Chivyrkuysky bay of thelakeBaikal.Materials and methods. Roach was caught on a permanent station in the Monakhovo creek of Chivyrkuysky bay of thelakeBaikal at the same time interval (June 25-July 5) in 1997-2005. The analysis of roach infection with L. intestinalis plerocercoids was performed based on incomplete parasitological dissections of 807 host specimens at the age of 0+ to 10+. Standard body length (the distance from the tip of the snout to the anterior end of the caudal fin) was used to characterize the linear growth of roach.Results and discussion. L. intestinalis plerocercoids wasn’t found out in underyearlings (0+) of roach. The host began to be infected with this tapeworm at the age of 1+. The maximum infection level with L. intestinalis plerocercoids was observed in roach at the age of 3+. That one was significantly reduced in the age of 4+. The infection level of roach with L. intestinalis continued to decrease in the next age groups, going down to a minimum at the age of 7+. The roach wasn’t infected with this tapeworm at the age of 8+–10+. A significant reduction of the infection level in the roach in the age classes 4+ and older after the maximum at the age of 3+ was probably associated with parasite-induced mortality of the host during the growth of the age group 3+ to 4+. A standard body length of roach specimens infected with L. intestinalis at the age of 1+ and 2+ was greater than that of uninfected ones. In contrast, the standard body length of the roach specimens infected with this tapeworm was less than that of uninfected ones in subsequent age classes (3 + -6 +). Differences of standard body length between roach specimens infected with L. intestinalis and uninfected ones were statistically significant in the above-mentioned age groups (1 + 6 +). The effect of L. intestinalis plerocercoids on the linear growth of the roach in Chivyrkuysky Bay of the lake Baikal was manifested in an increase of body length of infected host specimens compared to uninfected ones in young age groups (1+ and 2+) and, vice versa, in one’s decrease in age groups 3+–6 +. We proposed to call this effect "reversive".

Background: The position of Digramma interrupta remains disputable as it was raised by Cholodkovsky from Ligula alternans. This study aimed to survey the evolutionary relationships and the taxonomic position of D. interrupta and L. intestinalis. It also intended to support or reject the validity of D. interrupt as an independent genus and its correlation with L. intestinalis on the basis of their morphological characteristics and a study on molecular data. Methods: Overall, 1301 fish varieties, including 883 Alburnoides bipunctatus and 418 Abramis brama, were collected from north and north-western parts of Iran. A. bipunctatus samples were obtained from fresh water sources of the Maragheh dam (northwest) and the Ramesar Lake (north). Moreover, samples of A. brama were captured from the Aras Dam (northwest) and the Bandar-e-Anzali lagoon (north). PCR was used to generate a fragment spanning two independent ITS-inclusive parts: ITS1-5.8S and ITS2 with two pairs of primers. Results: Nucleotide variation between L. intestinalis and D. interrupta samples amounts to about 3% to 7%. Between samples of L. intestinalis and GenBank data, and also between D. interrupta specimens and GenBank data, the diversity was seen for about 1% to 3%. Moreover, about 1% to 4% nucleotide variation was seen only in L. intestinalis samples caught from the same host, which could be supplementary to the presence of a species and/or strains in this genus. Conclusion: Maybe D. interrupta was just a rare diplogonadic form of the Ligula species, not a different genus and not synonymous with the Ligula genus, but only another species of the Ligula genus.

Highlights • Fish host infected with parasite differed in behavior from uninfected ones. • Were caught easily, active in swimming and stayed higher up in the water column. • The parasite had a significant impact on the fish host behavior at the infective stage. • Less developed parasite had little effect on the fish host behavior. • This parasite may affect the fish host's behavior and makes it vulnerable to predation. Abstract Ligula intestinalis is a tapeworm using copepods and cyprinid fish as intermediate hosts and fish-eating birds as final hosts. Since some parasites can increase their own fitness by manipulating the behavior of the intermediate host, we explored if this parasite affected predator avoidance, swimming activity and depth preference of the fish intermediate host, Engraulicypris sardella. We found that when L. intestinalis had reached a developmental stage that is able to establish in the bird host, it had a significant impact on E. sardella behavior, while the tapeworm that was not fully developed had little effect and fish hosts showed a behavior more similar to uninfected fish. These results are discussed with respect to two different processes: the manipulation hypothesis and the energy drain hypothesis. [ABSTRACT FROM AUTHOR]

Background: The position of Digramma interrupta remains disputable as it was raised by Cholodkovsky from Ligula alternans. This study aimed to survey the evolutionary relationships and the taxonomic position of D. interrupta and L. intestinalis. It also intended to support or reject the validity of D. interrupt as an independent genus and its correlation with L. intestinalis on the basis of their morphological characteristics and a study on molecular data. Methods: Overall, 1301 fish varieties, including 883 Alburnoides bipunctatus and 418 Abramis brama, were collected from north and north-western parts of Iran. A. bipunctatus samples were obtained from fresh water sources of the Maragheh dam (northwest) and the Ramesar Lake (north). Moreover, samples of A. brama were captured from the Aras Dam (northwest) and the Bandar-e-Anzali lagoon (north). PCR was used to generate a fragment spanning two independent ITS-inclusive parts: ITS1-5.8S and ITS2 with two pairs of primers. Results: Nucleotide variation between L. intestinalis and D. interrupta samples amounts to about 3% to 7%. Between samples of L. intestinalis and GenBank data, and also between D. interrupta specimens and GenBank data, the diversity was seen for about 1% to 3%. Moreover, about 1% to 4% nucleotide variation was seen only in L. intestinalis samples caught from the same host, which could be supplementary to the presence of a species and/or strains in this genus. Conclusion: Maybe D. interrupta was just a rare diplogonadic form of the Ligula species, not a different genus and not synonymous with the Ligula genus, but only another species of the Ligula genus. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine the pathological findings of 30 naturally infected tench (Tinca tinca) with Ligula intestinalis plerocercoids from Golhisar Lake (Burdur) in Mediterranean Area of Turkey. Clinically and macroscopically, poor and irregular swimming, hemorrhages at the bases of fins and around the anus, the presence of the plerocercoids in the viscera together with perivisceral hemorrhages and distension of abdomen were generally observed in the diseased fish. Microscopically, hemorrhages, necrosis and mononuclear cell infiltrations were seen in the viscera invaded by plerocercoids. In conclusion, the cestode Ligula intestinalis plerocercoids' pathological effects on the tench tissues were widely evaluated for the first time in Turkey. [ABSTRACT FROM AUTHOR]

Ligula intestinalis parasite is a cestode that can cause remarkable damages to fishes. SDS-PAGE is one of the methods that can be used to determine the immune serum band polymorphism and immune responses in fishes infested by Ligula intestinalis. This study reports the results of an investigation conducted using SDS-PAGE focusing on immune serum band polymorphism and on the reaction of the immune system in spirlins (Alburnoides bipunctatus) infested by pleurocercoids of Ligula intestinalis parasite. Serum samples from infested spirlins revealed a polymorphism band which differed from that reported in sera of roaches (Rutilus rutilus), a species of the same Cyprinidae family.

Freshwater ecosystems are often impacted by biological invasions, including the introduction of exotic parasites capable of infecting native species. Here, we report the occurrence of the introduced tapeworm Ligula sp. from common bully, Gobiomorphus cotidianus, and quinnat salmon, Oncorhynchus tshawytscha, in Lake Hawea, South Island, New Zealand. This parasite has a complex life cycle, reaching its adult stage in fish-eating birds. Worms recovered from the body cavity of fish hosts reached huge sizes (60-300 mm long); however, their low prevalence in fish populations suggests that infections are rare or localised. Molecular analysis (internal transcribed spacer (ITS)1 and ITS2 sequences) confirms that these specimens belong to the genus Ligula and suggests tentative routes of invasion into New Zealand. Monitoring the spread of this parasite is important, as it can impact fish populations and also, when infection levels are high, those of piscivorous birds. [ABSTRACT FROM AUTHOR]

Chalcalburnus mossulensis from the Cyprinidae family is one of the indigenous fish in many water sources. Ligula intestinalis is one of the infective parasites of this fish. In this study, The effect of this parasite in some biological parameters of this fish like: Weight, Total length, Condition Index (I.C.) and Gonadosomatic Ratio (G.S.R.) was investigated. After random sampling, collected 300 samples from Gheshlagh Lake of Kordestan, Species and age of samples was detected. In 25% of samples the infection was seen. The result of this infection was the negative effect in all biological parameters (p

Le suivi des paramètres quantitatifs du parasitisme par Ligula intestinalis (Cestoda : Diphyllobothridae) a été réalisé par l’examen de 516 spécimens appartenant à deux espèces introduites de poissons d’eau douce : Rutilus rubilio (350 individus) et Scardinius erythrophthalmus (166 individus). Les échantillonnages ont été réalisés dans deux retenues de barrages, Sidi Salem et Nebhana en Tunisie. L’analyse de la composition spécifique de l’avifaune piscivore dans ces deux retenues a révélé l’existence d’espèces d’oiseaux déjà décrites dans la littérature comme étant des hôtes définitifs de la ligule. Le suivi de l’avifaune dans les deux plans d’eau a montré une abondance relative et une fréquence plus élevées dans la retenue de Sidi Salem que dans celle de Nebhana. L’analyse des prévalences, des intensités moyennes et de l’abondance du parasite a révélé des valeurs plus importantes chez le gardon, Rutilus rubilio qui semble donc le second hôte intermédiaire préférentiel de Ligula intestinalis dans ces milieux. L’analyse comparée de la parasitose, dans les deux retenues prospectées, suggère que la ligule présente deux stratégies différentes d’infestation selon le plan d’eau. À Sidi Salem, grande retenue dont la superficie est plus importante que celle de Nebhana et qui de plus abrite une avifaune piscivore plus importante et beaucoup plus diversifiée, le parasite infeste le maximum d’individus hôtes avec des charges parasitaires faibles. En revanche, à Nebhana, petite retenue, le parasite infeste moins d’individus hôtes qu’à Sidi Salem, mais avec des intensités moyennes beaucoup plus élevées. L’analyse de la prévalence en fonction de la taille et de l’âge au niveau de la retenue de Sidi Salem a révélé des valeurs plus élevées dans les grandes classes de taille chez le gardon.

Morphological characteristics and DNA sequencing were used to identify plerocercoids of a Schistocephalus sp. infecting slimy sculpin (Cottus cognatus) from northern New Brunswick and plerocercoids of Ligula intestinalis infecting blacknose dace (Rhinichthys atratulus) in Fundy National Park (FNP, New Brunswick). To our knowledge, no previous publications documented either cestode from New Brunswick, Canada. Blacknose dace represent a new host record for L. intestinalis. Identifications were made based on the presence or absence of segmentation and sequencing partial nicotinamide adenine dinucleotide dehydrogenase subunit 1 (ND1; mitochondrial DNA) and/or partial cytochrome c oxidase subunit 1 (COI; mitochondrial DNA). Plerocercoids from blacknose dace in FNP were identified as Ligula intestinalis based on >99% nucleotide identity with COI for this species in the NCBI GenBank database. Plerocercoids in slimy sculpin from northern New Brunswick were identified as a Schistocephalus sp. based on high nucleotide identity with congenerics in the NCBI GenBank database. The absence of GenBank entries with sufficient high percent identity to our specimens, and potential species hybrids in this genus, prevents species-level identification of Schistocephalus sp. plerocercoids currently. The absence of previous documentation of these cestodes might reflect recent environmental change promoting the transmission of these parasites that can modulate host fish behavior, induce sterility of host fishes, and contribute to epizootics., (© American Society of Parasitologists 2023.)

Infection with Ligula intestinalis was found to be the main cause of fish mortality in Satarkhan Dam of EastAzerbaijan Province. Zooplanktons, fish, water and water birds were sampled and studied for infestation with the parasite. We randomly sampled 100 copepods, fixed them in Chloridric Acid 0.01% for 3-4 minute until tissue became soft and colored by Logol. After washing the sample with distilled water, the parasites were separated and identified perevalance of infection was sixteen (1% male and 15% female Cyclops).

We describe here the mass death of predatory carp, Chanodichthys erythropterus, in Korea induced by plerocercoid larvae of Ligula intestinalis as a result of host manipulation. The carcasses of fish with ligulid larvae were first found in the river-edge areas of Chilgok-bo in Nakdong-gang (River), Korea at early February 2016. This ecological phenomena also occurred in the adjacent areas of 3 dams of Nakdong-gang, i.e., Gangjeong-bo, Dalseong-bo, and Hapcheon- Changnyeong-bo. Total 1,173 fish carcasses were collected from the 4 regions. To examine the cause of death, we captured 10 wondering carp in the river-edge areas of Hapcheon-Changnyeong-bo with a landing net. They were 24.0-28.5 cm in length and 147-257 g in weight, and had 2-11 plerocercoid larvae in the abdominal cavity. Their digestive organs were slender and empty, and reproductive organs were not observed at all. The plerocercoid larvae occupied almost all spaces of the abdominal cavity under the air bladders. The proportion of larvae per fish was 14.6-32.1% of body weight. The larvae were ivory-white, 21.5-63.0 cm long, and 6.0-13.8 g in weight. We suggest that the preference for the river-edge in infected fish during winter is a modified behavioral response by host manipulation of the tapeworm larvae. The life cycle of this tapeworm seems to be successfully continued as the infected fish can be easily eaten by avian definitive hosts. [ABSTRACT FROM AUTHOR]

The dynamics of the emergence, duration, and decline phases in epizootic cycles are well known for humans and some crops, but they are poorly understood for host–parasite systems in the wild. Parasites may be particularly insidious as they are often introduced unintentionally, simultaneously with their hosts, and later transferred to species in the new location. Here we investigate the epizootic dynamics of the tapeworm Ligula intestinalis in the Hamiz reservoir, Algeria, and explore its effects on the cyprinid fish Barbus callensis. Regular sampling was conducted from October 2005 to February 2008 with intermittent surveys carried out until 2010. Five percent of the 566 specimens of B. callensis that were caught were infected, with the maximum number of parasites found in spring. There was no obvious difference in weight between uninfected fish and infected ones, and infection did not affect fish condition. However, infected fish were significantly longer than uninfected fish and had inhibited gonad development. The proportion of infected fish caught was significantly higher in year 1 and by the second winter, infection collapsed to zero. The Ligula infection thus appeared to have minimal ecological effects and be of a temporary nature, thus exhibiting an epizootic cycle. Taken together, our data indicates that this infection declined or even failed during our study period. Failure may be due to the specific genetic strain of Ligula, but invasive carp may also have been influential in both the introduction and subsequent decline of this parasite. [ABSTRACT FROM AUTHOR]

Although Ligula intestinalis (L., 1758) has been recorded in several fish hosts, available data on the parasitization parameters of Ligula intestinalis plerocercoids such as prevalence, mean intensity and parasitic index in tench (Tinca tinca L., 1758) is limited. In this study, totally 272 fishes were investigated for the presence of L. intestinalis plerocercoids. The prevalence value was 40.01% of the whole fish sample and the mean intensity was 2.48. The lower IP values and mean intensity levels may provide some evidence of the strategy of Ligula in order to complete its life cycle. None of the parasitization parameters showed significant differences between the sexes.

Background and Objective: A lot of organisms including parasites cause damages to the fishes. Ligulosis is one of the most common parasitic infections and is economically the most important fish diseases in sweet water. This study was performed to introduce the cases of river whitefishes infected by Ligula intestinalis parasite. Case: 50 river whitefishes (Rutilus rutilus), which had been hunted from Aras dam prepared from Babol fish market and transferred to parasitology department of Babol medical school. For more investigation, the samples were kept in 10% formalin. On average most of these fishes had 4 to 5 numbers of plerocercoid larvae that their size was on average 30±5 centimeters. Conclusion: This parasite has been known to infect aquatic animals especially breeding fishes that many scholars in the world reported it and there are some reports from Iran. The important point is the toxin produced by this parasite, which causes special physiologic side effects in fishes such as infertility, reduction of body weight, pale and etc and this toxin can be harmful for human health.

Background: The tapeworm Ligula intestinalis (Diphyllobothriidea) is one of the most fascinating cestode parasites because it may cause parasitic castration of its second intermediate host, teleost freshwater fishes, due to inhibition of production of fish gonadotropic hormones. Large-sized (length up to 1 m) larvae called plerocercoids develop several months in the body cavity of freshwater fish and affect host behavior to facilitate transmission to the final host, a fish-eating bird. Vitellogenesis, i.e. formation of vitellocytes, is a key process in formation and nutrition of female gametes, oocytes in many flatworms, mainly parasitic Neodermata. The present study provides the first ultrastructural evidence in flatworms (Platyhelminthes) of the process that is interpreted as cytoplasmic-like cell death, i.e. a special case of programmed cell death (paraptosis) in vitellocytes of L. intestinalis. Results: As molecular markers for paraptosis are not yet available, its identification was based on morphological criteria. Electron microscopy analyses revealed evident structural changes in vitellocytes associated with progressive cytoplasmatic vacuolation, swelling of the granular endoplasmic reticulum and mitochondria. In addition, the present study has shown that vitellocytes of L. intestinalis share numerous features in common with the members of other earliest evolved eucestodes. Conclusions: The present study indicates that paraptotic-like cell death may occur in parasitic flatworms (Neodermata). The presence of GER-bodies in mature vitellocytes indicates close relationship between the Diphyllobothriidea, Caryophyllidea and Spathebothriidea, which are considered as the earliest evolved groups of the Eucestoda. Beyond the general similarities, however, a number of differences exist between the morphology, chemical composition and amount of these inclusions which could be due to the variations in their embryonic development, life cycle strategies and definitive host groups. [ABSTRACT FROM AUTHOR]

Introduced species have the potential to outperform natives via the introduction of new parasites to which the native ecosystem is vulnerable. Cryptic diversity within an invasive species can obscure invasion patterns and confound proper management measures. The aim of this study is to use coalescent theory based methodology to trace recent routes of invasion in populations of Ligula intestinalis, a globally distributed fish parasite possessing both native and recently introduced populations in North Africa. Molecular analyses of mitochondrial DNA discerned a pronounced genetic divergence between introduced and native populations. Distribution of mitochondrial haplotypes demonstrated common origin of European populations with North African parasites sampled from introduced fish species in Tunisia. To test the suggested pathway of introduction, microsatellite data were examined in a model-based coalescent analysis using the software MIGRATE, where Europe to Tunisia direction of migration was favoured over alternative hypotheses of gene flow. Specificity of Tunisian populations to different host species was assessed in an epidemiologic survey confirming prevailing host-based division between introduced and native parasites in North Africa. This approach combining advanced analysis of molecular markers with host-specificity data allows revealing the evolution of host-parasite interactions following biological invasion and provides basis for devising future management measurements. [ABSTRACT FROM AUTHOR]

Two mesh sizes (5 and 10 mm) usually used to harvest Rastrineobola argentea in Lake Victoria were assessed from April to September 2001 to determine their suitability. It was observed that 13.2% offish caught in 5 mm and 11.2% caught in 10 mm for April, May, June and July were of a size below maturity (44 mm standard length, fSLJ). Mean size offish caught with the 5 mm mesh was 46.8 ± 1.2 mm and that offish caught with the 10 mm mesh was 46.8 ±0.5 mm (SL). Catches per unit effort (CPUE)from the two meshes were not significantly different, with Haplochromis laparogramma (50.1%) dominating the catch followed by R. argentea (48.9%). Juveniles of Nile Perch, Brycinusjacksonii, Brycinus sadleri, and Barbus spp. (0.9%) were caught in small numbers. About half of the females matured at 43.5 mm and the males at 46.6 mm SL. Fish caught with the 5 mm mesh had on average 1050 ± 400 eggs and those caught with the 10 mm mesh had 918 ± 281 eggs, but the difference was not significant. However, a significant difference was noted between non-infected fish (1050 ± 400 eggs) and fish infected by the cestode Ligula intestinalis (663 ± 316 eggs). Given the absence of differences in key parameters under investigation between the fish caught with the 5 and 10 mm mesh sizes, the two meshes can be used interchangeably. [ABSTRACT FROM AUTHOR]

This prevalence study was conducted between the years 2003 and 2008. The survey aimed at assessing the occurrence of the plerocercoid Ligula intestinalis within five cyprinid populations, cyprinus carpio, carassius gibelio, hypophtalmichthys molitrix, ctenopharingodon idella and abramis brama, from four natural complexes: Sontea-Fortuna, Gorgova-Uzlina, Dunavat-Dranov and Razim-Sinoie. Of the four study sites, the highest frequency of the disease was recorded within the Razim-Sinoie lakes, probably due to an apparently higher number of piscivorous birds and copepods that may have inhabited this area during the study time period. Only A. brama and H. molitrix were found infected by the helminth, with a mean prevalence of the cases in A. brama of 16.31%, and in H. molitrix of 13.06%. [ABSTRACT FROM AUTHOR]

The infection rate by Ligula intestinalis has been studied in 14 fish species ( Varicorhinus beso, Garra dembecha, Labeobarbus intermedius, L. crassibarbis, L. tsanensis, L. megastoma, L. brevicephalus, L. nedgia, L. acutirostris, L. gorgorensis, L. dainellii, L. macrophthalmus, Barbus humilis, and B. tanapelagius) from Lake Tana (Ethiopia). Plerocercoids have been found only in the fishes of gg. Labeobarbus and Barbus. Ligula has been found in seven out of ten studied large barbels. Barbels larger than 23 cm are not infected with ligula. It is revealed that a specific 'synergism' exists between Ligula intestinalis and cestode Khawia sp. parasitizing the intestine of barbels. This synergism is manifested as a regular cooccurrence of these parasites. In juvenile Labeobarbus, fish coparasitized by Khawia sp. and L. intestinalis occurred more often than fish infected with each of this parasite separately. [ABSTRACT FROM AUTHOR]

SUMMARY: Sampling of the fish community was carried out for 20 years in the Mirgenbach reservoir, in North-Eastern France. The prevalence and the mean intensity of Ligula intestinalis (Cestoda) were analysed in roach (Rutilus rutilus) and silver bream (Blicca bjoerkna) populations, the main two infected species. The aim of this study was to investigate the host switch from roach to silver bream and the consequences of L. intestinalis infestation in silver bream, which is an unusual host for this parasite as Ligula parasitism in silver bream appears to be rare. We analysed in detail the relationships between parasitism index (PI), gonadosomatic index (GSI), perivisceral fat abundance (PFA) and condition index (CI) in the silver bream population. In 1998, prevalence of L. intestinalis highlighted a clear host switch from roach to silver bream. In the silver bream population, young fish were the most severely infected and the impact of plerocercoids appeared to be different depending on the host sex. In male silver bream, plerocercoids drew energy from fat reserves even if GSI was also slightly impacted. On the contrary, in females energy was diverted from gonad maturation rather than from perivisceral fat reserves. No significant difference was observed in terms of CI in either sex. [ABSTRACT FROM AUTHOR]

Abstract: Infestation of fish by parasites may influence metal accumulation patterns in the host. However, the subcellular mechanisms of these processes have rarely been studied. Therefore, this study determined how a cyprinid fish (Rastrineobola argentea) partitioned four metals (Cd, Cr, Zn and Cu) in the subcellular fractions of the gut in presence of an endoparasite (Ligula intestinalis). The fish were sampled along four sites in Lake Victoria, Kenya differing in metal contamination. Accumulation of Cd, Cr and Zn was higher in the whole body and in the gut of parasitized fish compared to non-parasitized fish, while Cu was depleted in parasitized fish. Generally, for both non-parasitized and parasitized fish, Cd, Cr and Zn partitioned in the cytosolic fractions and Cu in the particulate fraction. Metal concentrations in organelles within the particulate fractions of the non-parasitized fish were statistically similar except for Cd in the lysosome, while in the parasitized fish, Cd, Cr and Zn were accumulated more by the lysosome and microsomes. In the cytosolic fractions, the non-parasitized fish accumulated Cd, Cr and Zn in the heat stable proteins (HSP), while in the parasitized fish the metals were accumulated in the heat denatured proteins (HDP). On the contrary, Cu accumulated in the HSP in parasitized fish. The present study revealed specific binding of metals to potentially sensitive sub-cellular fractions in fish in the presence of parasites, suggesting interference with metal detoxification, and potentially affecting the health status of fish hosts in Lake Victoria. [Copyright &y& Elsevier]

Abstract: Parasites can impact host reproduction by interfering with host endocrine systems, but the adaptive nature of such effects is disputed. Schistocephalus solidus plerocercoids are parasites of three-spined sticklebacks Gasterosteus aculeatus that are often associated with impaired host reproduction. Here, we relate reproductive behavior and physiology to levels of the androgen 11-ketotestosterone (11KT) in naturally infected and non-infected male sticklebacks from two UK populations. In one population infected males harbored heavy infections and showed uniformly reduced 11KT titres and kidney spiggin (nesting glue protein) content compared to non-infected fish. However in a second population infection levels were more variable and males with smaller infections recorded 11KT and spiggin titres that overlapped those of non-infected fish; among infected males from this population 11KT and kidney spiggin also both correlated negatively with infection severity. Male reproductive behavior correlated closely with 11KT titre in both populations, and infected males with high 11KT levels exhibited normal reproductive behavior. Our results suggest that Schistocephalus infection per se does not block reproductive development in male sticklebacks, and that some male fish may have the ability to breed whilst infected. Our results are not consistent with the hypothesis that Schistocephalus adaptively castrates male hosts via endocrine disruption; rather they support the hypothesis that reproductive disruption is a side effect of the energetic costs of infection. [Copyright &y& Elsevier]