The gill monogenean Sciadicleithrum variabilum induces histomorphological alterations in the gill tissues of the discus Symphysodon aequifasciatus.

High mortality is among the most serious problems and challenges in the ornamental fish trade. Examination of the discus Symphysodon aequifasciatus from ornamental fish hatchery revealed infestation with the monogenean Sciadicleithrum variabilum. Gill infestation with this monogenean induced serious damage to the gill lamellae, including clavate lamellae, vascular congestion in the peripheral blood vessels, lamellar blood sinus dilation, and other structural anomalies. Light and transmission electron microscopy showed that in all infested hosts the interlamellar cell mass (ILCM) completely filled the interlamellar space. The monogenean-associated damage combined with the ILCM led to severe impairment of respiratory efficiency of the gill. Anti-parasitic treatment was applied during breeding (hatchery), which was followed by almost complete regression of the ILCM seen in the fish. A single point of ILCM hyperplasia was observed in only one specimen at the site of parasite attachment to the gill filament. The ILCM covering the gill lamellae protected the discus against infestation with this monogenean, but considerable reduction in the gaseous exchange surface and serious damage to the gill lamellae contributed to the increased mortality of the fish in the hatchery, which reached 90%.

First case of human anisakiasis in Poland.

Consumption of raw or inadequately processed marine fish may result in anisakidosis - a zoonotic disease caused by larvae of the parasitic nematodes of the family Anisakidae (anisakiasis when caused by members of the genus Anisakis (Nematoda: Anisakidae)), commonly found in a variety of marine fish species all over the world. Most cases of anisakidosis have been detected in the residents of Japan and South Korea, which results from the tradition of eating raw and semi-raw fish dishes. However, the disease is now increasingly often diagnosed in other parts of the world, including Europe (mainly in Spain and Italy). In Poland, no cases of human infection with anisakid nematodes have been detected so far. In this study, we report the first case of gastric anisakiasis in Poland, in a 59-year-old female patient, after eating raw Atlantic salmon (Salmo salar). The parasite was identified as the third-stage larva of Anisakis simplex sensu stricto on the basis of morphology and molecular analysis. The larva was still alive and causing pain until it was removed, which occurred more than 5 weeks after infection. The described case prove that anisakiasis should be considered as a potential cause of gastrointestinal tract ailments following the consumption of seafood in countries where no cases of this zoonosis have been reported to date.

A Novel Method for Predicting Anisakid Nematode Infection of Atlantic Cod Using Rough Set Theory.

Atlantic cod ( Gadus morhua L.) is one of the most important fish species in the fisheries industries of many countries; however, these fish are often infected with parasites. The detection of pathogenic larval nematodes is usually performed in fish processing facilities by visual examination using candling or by digesting muscles in artificial digestive juices, but these methods are both time and labor intensive. This article presents an innovative approach to the analysis of cod parasites from both the Atlantic and Baltic Sea areas through the application of rough set theory, one of the methods of artificial intelligence, for the prediction of food safety in a food production chain. The parasitological examinations were performed focusing on nematode larvae pathogenic to humans, e.g., Anisakis simplex, Contracaecum osculatum, and Pseudoterranova decipiens. The analysis allowed identification of protocols with which it is possible to make preliminary estimates of the quantity and quality of parasites found in cod catches before detailed analyses are performed. The results indicate that the method used can be an effective analytical tool for these types of data. To achieve this goal, a database is needed that contains the patterns intensity of parasite infections and the conditions of commercial fish species in different localities in their distributions.

Species richness and diversity of the parasites of two predatory fish species - perch (Perca fluviatilis Linnaeus, 1758) and zander (Sander lucioperca Linnaeus, 1758) from the Pomeranian Bay.

Pomeranian Bay as an ecotone is a transition zone between two different biocenoses, which is characterized by an increase in biodiversity and species density. Therefore, Pomeranian Bay is a destination of finding and reproductive migrations of fish from the rivers entered the area. The aim of the study was to compare parasitic fauna of two predatory fish species from the Pomeranian Bay, collected from the same fishing grounds at the same period. A total of 126 fish studied (53 perches and 73 zanders) were collected in the summer 2013. Parasitological examinations included: skin, fins, gills, vitreous humour and lens of the eye, mouth cavity, body cavity and internal organs. Apart from the prevalence and intensity of infection (mean, range) the parasite communities of both fish species were compared. European perch and zander were infected with parasites from five different taxonomic units. The most numerous parasites were Diplostomum spp. in European perch and Bucephalus polymorphus in zander. The prevalence of infection of European perch ranged from 5.7% (Diphyllobothrium latum) to 22.3% (Diplostomum spp.) and for zander from 1.4% (Ancyrocephalus paradoxus, Hysterothylacium aduncum) to 12.3% (Bucephalus polymorphus). Different composition of the parasitic fauna is likely due to the different biology of both fish species.

Morphological and molecular characterization of Ceratomyxa gurnardi sp. n. (Myxozoa: Ceratomyxidae) infecting the gallbladder of the grey gurnard Eutrigla gurnardus (L.) (Scorpaeniformes, Triglidae).

The myxosporean specimens were noted in grey gurnard Eutrigla gurnardus (L.) from the area near the Shetland Islands. The structure and dimensions of its vegetative stage differ from earlier descriptions. A sequence of small subunit ribosomal RNA gene obtained during the current study differs from other Ceratomyxa spp. available in GenBank. A phylogenetic position of parasite based on the 18S rDNA fragment was estimated. The proposed name for this myxosporean is Ceratomyxa gurnardi sp. n.

Collarinema eutriglae n. sp. (Nematoda: Cystidicolidae), a new gastric parasite of the scorpaeniform fish Eutrigla gurnardus (Osteichthyes: Triglidae) in the North Sea, with remarks on the systematic status of Collarinema Sey, 1970.

A new species of parasitic nematode, Collarinema eutriglae n. sp. (Cystidicolidae), is described from the stomach of the marine scorpaeniform fish Eutrigla gurnardus (Linnaeus), the grey gurnard (Triglidae), collected in the North Sea in the vicinity of the Shetland Islands (61°12'N, 00°30'E) during March, 2011. The new species, studied using both light and scanning electron microscopy, is characterised mainly by the structure of the mouth (small pseudolabia with terminal projections, submedian labia and well-developed sublabia not exceeding the labia externally), very small simple deirids, the length of the spicules (405-423 and 117-135 µm) and non-filamented eggs. Collarinema Sey, 1970 is considered a valid genus and an amended diagnosis is provided. Ascarophis collaris Petter, 1970 is transferred to Collarinema as C. collaris (Petter, 1970) n. comb.

The state of health of the river lamprey Lampetra fluviatilis (L.) from Lake Dabie compared to the pathogens hitherto found in this host.

The objective of the study was to check the health status of the anadromic river lamprey Lampetra fluviatilis (L.), the most frequently recorded lamprey species in Poland caught in Lake Dabie, connected with the Odra river estuary. The species composition of parasitofauna of the river lamprey from the Polish waters was compared to the pathogens of this host noted so far. The skin and fins, eyes, oral cavity and nasal mucus of 36 lamprey specimens were examined. After decapitation the brains and gills were analysed. A single gonad, liver and the kidney wet microscopic preparations were made and examined. Examination was also made of the contents of the straight alimentary tract, the body cavity and muscles from the dorsal area. The pathogens known of the river lamprey are mostly the parasites of a very low extensity. No monogeneans were found among the parasites recorded. The reasons of such species composition of the parasitic fauna are discussed against the background of the anatomy, physiology and biology of the host. In the alimentary tract of one lamprey single larva of the nematode Anisakis simplex (Rudolphi, 1809) was found, not noted yet in this host in Poland and Europe. The parasite was noted in any of the lamprey species occurring in neither fresh nor saline waters in Europe. Such a low prevalence and intensity of the infection pointed that this nematode as many other species of parasites was swallowed accidentally.

Parasitic nematodes of pumpkinseed sunfish (Lepomis gibbosus L., 1758) from warm-water canal of a power plant in Szczecin, Poland.

Parasitological examination of 273 pumpkinseed sunfish, caught in the warm water channel at the Dolna Odra Power Plant in Stare Czarnowo near Szczecin was carried out. The total lengths of the fish ranged from 6.8 to 18.1 cm (13.3 cm means), infected fish 9.8 to 17.5 cm. In 48 individuals the presence of nematodes representing 4 species has been found: Schulmanela petruschewskii, Raphidascaris acus, Spiroxys contortus and Contracaecum sp. In total the number of nematodes found was 319, the mean intensity of infection was 6.64. The greatest number of fish infected with parasites was caught in June and April. The most frequently noted has been S. petruschewskii, found in adult forms as well as in larval stage in the liver, intestine, stomach and peritoneum in 40 specimens. In total the number of this nematode found was 305. The least frequent has been S. contortus, rarely found in Poland and for the first time noted in sunfish. Usually one fish was invaded by one species of nematodes.

Characteristics of the peripheral blood of the Anguillicola crassus (Kuwahara, Niimi et Tagaki, 1974) and Trypanosoma granulosum Laveran et Mesnil, 1902 infested eel (Anguilla anguilla L.) ascending the River Rega (north-western Poland).

UNLABELLED: The study was aimed at characterising the peripheral blood of eel (Anguilla anguilla L.) ascending the River Rega and infested with Anguillicola crassus (Kuwahara, Niimi et Itagaki, 1974) and Trypanosoma granulosum Laveran et Mesnil, 1902. MATERIAL AND METHODS: Haematological assays were performed on 58 eel individuals caught in August and September 2001 and in July 2002. The nematode Anguillicola crassus was identified in the swim bladder lumen of 44 eel individuals. The mean infestation intensity amounted to 3.2, from 1 to 11 nematodes being found in a single host. Values of the basic haematological indices were determined from May-Grünwald-Giemsa (MGG)-stained blood smears. The data were subjected to statistical treatment involving the analysis of variance (ANOVA) and Kruskal-Wallis test (STATISTICA 6.0). RESULTS: Microscope slides showed the eel to be infested by Trypanosma granulosum Laveran and Mesnil, 1902 occurring at a prevalence of 100%. Significant differences between the months of fish capture were revealed in the mean haematocrit, MCHC, and MCV values of all the eel, regardless if they were infested with Anguillicola crassus or not. On the other hand, there were no significant differences in the values of the parameters studied (E, Hb, Ht, L), including the haematological indices (MCH, MCHC, MCV), between the Anguillicola crassus-infested individuals and those free of the parasites, throughout the period of study. The relative and absolute leukograms showed a substantial domination of lymphocytes over other blood cells of the leukocyte line. The qualitative characteristics of the peripheral blood of the Anguillicola crassus-affected and -free eel were similar. The results indicate that some haematological parameters could be related to the season of capture. Effects of Trypanosoma granulosum on the blood seems to be distinct, but requires further, detailed studies, including research on the infestation intensity and taking into account characteristics of the parasite's morphological forms.

Comparative description of males of two species of Achtheres von Nordmann, 1832 (Copepoda: Siphonostomatoida: Lernaeopodidae) infecting zander and European perch.

Achtheres percarum von Nordmann, 1832 and Achtheres sandrae Gadd, 1901 (Lernaeopodidae) are common parasitic copepods infecting fishes in Eurasia. The former is specific to perch, Perca fluviatilis L., while the latter, to zander, Sander lucioperca (L.). Until recently these copepods have been regarded a single species. The present study was intended to analyse details of male morphology and provide their complete descriptions with differential diagnosis. Males of A. percarum and A. sandrae were collected from perch and zander at Lake Dabie (north-western Poland). The males of A. sandrae are larger than those of A. percarum. They also differ in proportions of the first antenna, mandibular denticulation, structure of the first maxilla, and the armament of caudal ramus. The reported differences in male morphology constitute a conclusive confirmation of the separate identity of the two species.

Nematodes of the intestine and swimbladder of the European eel Anguilla anguilla (L.) ascending Pomeranian rivers.

The study focused on the eel (length and weight averaging 23.1 cm and 13.7 g, respectively) ascending Pomeranian rivers in summers of 1999 - 2003. The swim bladder was examined in 322 individuals, the intestine being examined in 272 fish. Anguillicola crassus was present in the swim bladder of 184 fish. Infection prevalence varied between the rivers, the highest prevalence being recorded in the eel caught in the Radew (65.6%) and the lowest in the Wieprza (41.7%). The intensity of infection was generally low, the mean values varying from 2.1 in the Rega to 1.3 in the Wieprza. The coefficient of infection was low (0.11 to 0.12). Spinitectus inermis was present, with low intensity, in the intestine of 18 fish (6.6%). The nematode had not been recorded in the eel in Poland for 70 years. In addition, the intestine of the eel under study was found to house Raphidascaris acus and Paraquimperia tennerima, each present as a single larva. This is the first record of the latter in Poland. The infection of eel from the Radew river that stayed in the fresh water for a longer time was higher than that of the eel found in the Rega and Wieprza.

Parasite fauna of selected fish species of Lake Miedwie.

A total of 136 fishes, representing 9 species (perch, Perca fluviatilis L.; pike, Esox lucius L.; European eel, Anguilla anguilla (L.); common bream, Abramis brama (L.); roach, Rutilus rutilus (L.); tench Tinca tinca (L.); European whitefish, Coregonus lavaretus (L.); vendace, Coregonus albula (L.); and zander, Sander lucioperca (L.)), from Lake Miedwie were studied within 1997-1999. The necropsies yielded 41 parasite species (taxa). The most diversified were parasite faunas of pike (19 parasite species) and perch (16 species). The parasites found represented 13 higher taxa: Monera, Fungi, Protista, Myxozoa, Monogenea, Cestoda, Digenea, Nematoda, Acanthocephala, Branchiura, Copepoda, Mollusca, and Acarina. The parasites affecting fishes of Lake Miedwie exhibited diversified host-specificity. The most fish species were infected by metacercariae of Diplostomum spp. (8 fish species) and Tylodelphys clavata (7). Three fish species harboured: Ichthyocotylurus platycephalus, Ergasilus sieboldi, and glochidia Unionidae gen. sp. while Dermocystidium sp., Trichodinella epizootica, Henneguya psorospermica, Triaenophorus nodulosus, Posthodiplostomum cuticula, and Camallanus lacustris parasitised two host species. The remaining parasites were found in single fish species.