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Information on species of parasitic helminths native to Poland is provided by the Pasozytnicze helminty Polski. Gatunki. Zywiciele. Białe Plamy. Until the middle of 2007, there were 1205 species of recorded helminths including 126 species of Monogenea, 338 of Trematoda (Digenea), 279 of Cestoda, 427 of Nematoda and 35 of Acanthocephala. They represented 32.9% of the species recorded in Europe (i.e., registered in the Fauna Europaea database). During the following three years up to the middle of 2010, 64 new species of Polish helminths were detected: 7 Monogenea, 15 Trematoda (Digenea), 21 Cestoda, 20 Nematoda and one Acanthocephala. Most hosts of the new helminth species were reported from birds (40 species), but also from fish (13 species) and mammals (10 species). Only one new species of helminth was detected in amphibians.

A new species of Ergasilus von Nordmann, 1832 (Copepoda: Ergasilidae) parasitic on the gills of two gobiid fishes Boleophthalmus dussumieri Valenciennes and Bathygobius fuscus (Rüppell, 1930) from Shatt Al-Basrah Canal, Iraq, is described. The new species differs from all its congeners by a combination of character states including the shape of the body, and the structure and armature of the swimming legs.

In this study 47 leech species from Poland are listed. They belong to two orders, two suborders, five families and 17 genera. The checklist also includes the information about hosts, distribution in Poland and references concerning the leech species discussed in this study.

Two trichodinid species were identified from freshwater fishes, Mystus bleekeri and Glossogobius giuris, in the Shitalakshya River of Gazipur district, Bangladesh. Trichodina acuta Lom, 1961 is found for the first time in Bangladesh. Trichodina shitalakshyae sp. n. is characterized by having an undivided clear central area in the adhesive disc with a rounded or slightly undulated perimeter containing a few dark granules which form patches; elongated and rectangular blade with large interblade space and blunt tangent point; indistinct anterior blade apophysis and a shallow apex at the base of blade that never extends beyond the Y+1 axis; moderately wide and triangular central part with blunt point; and space between tip of ray and central clear area forms a wide impregnated ring. Based on these characters and the unique shape and absence of variability of the denticles among the silver impregnated specimens of the present species, it resembles Trichodina porocephalusi Asmat, 2001.

This paper lists 127 monogenean species belonging to 2 subclasses, 3 orders, 6 families and 13 genera reported from Polish freshwater and marine fishes. This checklist provides information also on the hosts, distribution in Poland and respective literature sources.

Gyrodactylus latus Bychowsky, 1933 (Monogenea, Gyrodactylidae) was found on fins of Cobitis elongatoides Bacescu et Maier, 1969 (Teleostei, Cobitidae) from tributaries of the Stobrawa River (Odra Basin, Silesia, Poland). It is new to the Polish parasite fauna; its description, measurements, and figures are presented.

Introduction of the host is the main reason behind introduction of the parasite, e. g., nematodes. The introduction of the Japanese eel (Anguilla japonica) in Europe in the 1980s resulted in expansion of the swimbladder nematode Anguillicola crassus which soon invaded not only populations of the European eel (A. anguilla), but also other local fish. The raccoon (Procyon lotor) is native to North America. It is the specific host of Strongyloides procyonis and Baylisascaris procyonis. More than 90 species of wild and domestical bird and mammal species, including humans, have been infected with B. procyonis larvae. The larvae enter various organs of paratenic hosts, particularly the central nervous system and eye, causing severe diseases and death. Asthworthius sidemi--a blood-succking, abomasal nematode, a specific parasite of the Asiatic sika deer (Cervus nippon) and sambar deer (C. unicolor)--was first introduced with its hosts into countries adjacent to Poland. A. sidemi is especially dangerous to the European bison (Bison bonasus) which is its new host. The bison populations, in both Białowieza Primaeval Forest and the Bieszczady Mts, sometimes show a 100% prevalence and mass infection intensity. Imported animals, sold in pet shops or available from private breeding firms, often carry non-native parasites. For example, the red-eared tortoise (Trachemys scripta elegans) and Afgan tortoise (Agrionemys horsfieldii) carry nematodes Angusticaecum holopterum, Tachygonetria lobata and T. robusta. Migratory birds in their wintering grounds are often infected with parasites which are usually not constant components of the native fauna, but sometimes nematodes could find a suitable conditions to complete their life cycle. E.g. Cyathosoma microspiculum, species specific to cormorants (Phalacrocorax carbo) and previously recorded only from Asia and the Asian-European boudary, was able complete the life cycle in Poland. The increasingly frequent travels to countries with different climatic conditions contribute to introduction of non-native nematodes: Dirofilaria immitis--in dogs, D. repens or Ancylostoma brasiliense--in humans.

Elaphostrongylus cervi is a parasite of the family Protostrongylidae, occurring in cervids in Eurasia. This nematode has hitherto been recorded in some woodland areas in Poland. The current distribution of E. cervi in Poland was studied in the frames of the presently reported thesis. The above-mentioned nematode was found in deer in eight additional voivodeships, and in all thirteen forest management units examined. The prevalence values ranged from 66.7% to 100%. The above facts justify the statement that that E. cervi is a common parasite species in Poland. The dynamics of the larval shedding (L I) by deer was monitored and it turned out that there were two peaks--the first in February and the second in December. The identity of the intermediate hosts--terrestrial snails--has been established, as well as the prevalence and the infection intensity of their natural infections. The intermediate hosts of E. cervi are Succinea putris, Bradybena fruticum, Perforatella bidens, and Zonitoides nitidus. It was determined that the prevalence of snails, S. putris, infected with E. cervi larvae maintained a constant level from June to August and it decreased in September and October. Snails, B. fruticum, showed the highest prevalence in July--and it decreased in subsequent months. In the case of P. bidens the prevalence of E. cervi infection was the lowest in August, and than it increased, to reach the highest value in October. The prevalence of spontaneous infections of different snail species ranged from 7.6% to 20.6%. For the first time the highest prevalence of spontaneous infection was found in P. bidens. Till now the most infected species of snail has always been S. putris. The highest intensity of infection--242 larvae--was found in B. fruticum, and little lower--202 in S. putris. In two other species the intensity ranged from 1 to 23 larvae. The most significant role in spreading of E. cervi in the Białowieza Forest is performed by S. putris and B. fruticum, because of their high abundance and P. bidens, because of their highest infection intensity. Also the penetration of the first stage larvae of E. cervi into the intermediate host and their development there throughout the third infective stage were studied. The first stage larvae of E. cervi enter the body of snail through the muscle of foot. The period of their development to the second stage is 7 to 9 days, and to the third stage is 21 to 28 days. E. cervi is a parasite that under intensive infections is very dangerous for domestic ruminants in which in evokes neurological symptoms or even death. Because huge numbers of E. cervi larvae are shed by dear into the environment, homeothermic vertebrates, birds and wild boars can accidentally infect themselves with infective larvae of this parasite. To explain the course of such infections, fish, chickens, and Vietnamese pigs were experimentally infected. In fish and chickens the infective larvae of E. cervi were not able to cross the intestinal barrier, arrested their development, and were digested. Infected pigs produced no clinical symptoms of the infection. In those animals larvae were retained in mesenteric lymphatic nodes and were not able to cross the mesenteric barrier. None of the experimentally infected animals became paratenic hosts and their meat poses no threat to human health.

Acetylcholinesterase (AChE) activity in the tissues of host and the parasite and the impact of carbofuran, a carbamate pesticide on the AChE activity in A. simplex larvae was investigated. Generalized linear models (GLM) were used for modeling enzymatic activity in herring and A. simplex nematodes.

Paratrichodina Lom, 1963 comprises more than ten species. Paratrichodina has been found so far in various freshwater, marine fishes and amphibians worldwide. This report provides the first record of Paratrichodina from freshwater fishes in China. Smears with trichodinids were air-dried and then the slides with trichodinid ciliates were impregnated with Klein dry silver impregnation technique in order to reveal details of the adhesive disc. All measurements are presented in micrometres and follow the system proposed by Lom. Detailed descriptions of the denticles are presented in accordance with the method proposed by Van As and Basson. Denticulate ring of the studied specimens is constituted by loosely arranged denticles and the adoral ciliary spiral is between 180 to 200 degrees. So the studied specimens were assigned to Paratrichodina. The presently described trichodinid resembles P. erectispina Lom et Haldar, 1977 and P. voikarensis Kashkovsky et Lom, 1979, but it is clearly distinguished from P. erectispina by the shape of denticle and some other measurements. Based on its unique characteristics, a new Paratrichodina species is erected, and named Paratrichodina yangtzeus sp. n.

Elaphostrongylus cervi is a parasite of skeletal muscles and central nervous system of wild and farm red deer in Europe and Asia. Numerous species of terrestrial snails can be its intermediate hosts. Considering the fact that invasive larvae of E. cervi are released by deer to the external environment in huge numbers, fishes and birds can be accidentally infect by them. In this study the development of larvae E. cervi in those nonspecific hosts was discussed. It was determined that invasive larvae of E. cervi in the digestive tract of fish do not penetrate the intestinal wall, do not develop any further, and are probably digested. Similarly, those larvae given to chicken are also incapable of breaking the gut barrier and are digested. In all infected animals, the phenomenon of parathenia has not been observed and the meat of the animals studied poses not threat to humans.

Models relating infection intensity with Anisakis simplex larvae to the fish length and weight were developed and applied to estimate the asymptotic size of herring. Generalized linear models (GLM) were used to analyse the prevalence and intensity of infection as dependent on time and area of sampling and the biological parameters of fish. For the characterization of herring populations in the southern Baltic, two complementary approaches were used: morphometric and meristic analyses to quantify the body shape of herring and the presence of parasites as fish migration tags.

The body form of leeches, which becomes a modeling object, is a valid ectosomatic feature. It describes borders, in which, we can find internal organs of an individual. The range of realization of the body form, proposed for different groups of leeches, characterize their life spaces. These life spaces are distinct in term of position of body of leeches to the host and to the environment. Individuals originated from the Caspian Sea, Baikal Lake, and from fresh waters of Italy, Finland, Russia, Germany and Poland. Over 1200 individuals, belonging to 11 genera were measured. The measurements have been made according to the model of the leech body form.

This paper presents the distribution of Monogenea among Polish fish and amphibians as well as their location on the host body. Out of 127 Monogenea species recorded in Poland, 126 were found in fish, and only one in amphibians. Dactylogyridae were found in 3, Diplozoidae in 2, whereas Ancyrocephalidae in 6, and Gyrodactylidae in 9 fish families. Most Monogenea are closely attached to their location (topospecificity). Some species of fish parasites are found on gills, where they may occupy various microhabitats, while others (especially Gyrodactylidae) were found on fins, skin, gills, and rarely in the oral or nasal cavity.

Antarctic fishes are represented by sharks, skates (Chondrichthyes) and bony fishes (Teleostei). Teleosts play an important role in the completion of life cycles of many helminth species. They serve as either definitive or intermediate and paratenic hosts. Chondrichthyes are definitive hosts only. Seventy three helminth species occur as the adult stage in fishes: Digenea (45), Cestoda (14), Nematoda (6), Acanthocephala (8), Also, 11 larval stages of Cestoda (7) and Nematoda (4) are known, together with 7 species of Acanthocephala in the cystacanth stage. One digenean species, Otodistomum cestoides, matures in skates. Among cestodes maturing in fishes only one, Parabothriocephalus johnstoni, occurs in a bony fish, Macrourus whitsoni. Antarctic Chondrichthyes are not infected with nematodes and acanthocephalans. Cestode larvae from teleosts belong to Tetraphyllidea (parasites of skates), and Tetrabothriidae and Diphyllobothriidae (parasites of birds and mammals). Larval nematodes represent Anisakidae, parasites of fishes, birds and mammals. Acanthocephalan cystacanths mature in pinnipeds and birds. The majority of parasites maturing in Antarctic fishes are endemics. Only 4 digenean and one nematode species, Hysterothylacium aduncum, are cosmopolitan. All acanthocephalans, almost all digeneans, the majority of cestodes and some nematodes occur mainly or exclusively in benthic fishes. Specificity of the majority of helminths utilizing teleosts as intermediate and/or paratenic hosts is low. Among parasites using fishes as definitive hosts, all Cestoda, most Digenea and Nematoda, and almost all Acanthocephala have a range of hosts restricted to one order or even to 1-2 host species.

The monogenean ectoparasite genera Dactylogyrus and Gyrodactylus are hyperdiverse, and yet monogenean communities infecting freshwater fish in the northern Holarctic are variable and often impoverished. This is a result of extinctions during periods of glaciation when the host fishes experienced range contraction. Fish species recolonised northern Europe by one of three routes; stenohaline fishes recolonised from the Black Sea basin via Danube-Rhine or Dnieper-Dniester-Vistula connections. These fish retain complex rich monogenean faunas with numerous species of Dactylogyrus and Paradiplozoon. Anadromous fishes, recolonising via marine migrations along the coast, and cold-water fishes surviving in refugia close to the ice sheets, have impoverished monogenean faunas, characterised by gyrodactylid and ancyrocephalid species. However, there may be great complexity, due to the evolution of new host-parasite interactions within specific watersheds before, during and after the Last Glacial Maximum (LGM). This is demonstrated using examples from the sticklebacks (Gasterosteus aculeatus) and the bullheads (Cottus gobio). Finally, the evolution of Gyrodactylus salaris from a clade of G. thymalli is described, and the role of glaciation in stimulating the evolution of numerous clades of the latter is discussed. This latter example represents a unique opportunity to study speciation by host shift in real time.

Paratenic hosts, especially of nematodes, play a major role in spreading many parasite species. The phenomenon of "paratenic parasitism" is illustrated by examples of development of Syngamus trachea and Proteocephalus longicollis. Moravec introduced a concept of "natural paratenic host" for P. longicollis infecting common sculpion, Cottus gobio, in Europe. According to Kennedy, paratenic host richness of Anguillicola crassus is an adaptation to new environmental conditions. New studies, involving laboratorial experiments, have shown that the nematodes parasitizing fishes, with a single intermediate host in their life cycles, acquired numerous paratenic hosts. It also evident that a paratenic host can be present or absent in the life cycles of related (congeneric) parasite species (Bothriocephalus gregarious and B. barbatus; Halipegus occidentalis and H. ovocaudatus; Dracunculus insignis and D. medinensis). Sometimes infective larvae of parasites are reported in accidental hosts, which do not occur in the food chain of the definitive host. Paratenic host is more an ecological than a physiological phenomenon in the transmission of helminths. Under extreme environmental conditions the transmission of parasites is faciliated mainly by paratenic hosts (e.g., Toxascaris leonina or Toxocara sp. occurring in zoological gardens where sanitation is rigorously observed).

A total 89 fish and lamprey species has been recorded from Polish freshwater habitats. Twenty-seven of them (30.3%) have not been surveyed for parasitic helminthes. Some of the latter fishes are either rare or not easily accessible. Other live only in specific habitats in scattered localities. An important obstacle for studying parasite faunas of some fishes may be their status on an endangered species. Among the non-surveyed fishes, are those which have been relatively recently introduced to Poland or migrated there on their own. The present paper attempts to review all hitherto not studied helminthologically fish species, their habitats, localities and current protection status.

Background: Enzymatic activity is an indicator of an organism's metabolic rate which depends on, i.e., environmental conditions, developmental stage, physiological stage, and sex. The API ZYM test was applied to compare activities of 19 hydrolases of female and male Hysterothylacium aduncum., Material and Methods: Sexually mature nematodes were isolated from eelpout individuals caught in the Gulf of Gdańsk. Enzymatic activity of the hydrolases and the protein content was determined in nematode extracts using API ZYM and Bradford's method, respectively., Results: The females and males tested showed a total of 13 enzymes to be active. The males showed additionally the presence of alpha-fucosidase. Acidic and alkaline phosphatases had very high activities in both sexes; short-chain fatty acid esterases, leucine and valine aminopeptidases, alpha-glucosidase, and N-acetylglucosaminidase were highly active. H. aduncum showed no trypsin- and chymotrypsin-specific activities; similarly, no activity of alpha-galactosidase, alpha-mannosidase, and beta-glucuronidase was revealed. Except for lipase (C14), hydrolases were more active in females than in males, which is related to metabolic rate being higher in females due to their reproductive function., Conclusion: Comparison of the results obtained with earlier data produced with API ZYM allowed suggesting that the hydrolase pattern may be more affected by habitat in the host than by the taxonomic affiliation of nematode.

Paper deals with the results of systematic-ecological investigations of host-parasite relationships in the context of 45 year history of the Parasitological Department at the University of Wrocław. Achievements are concentrated on the presentations of new taxonomic units and rearrangement of classification of parasitic protozoans and tapeworms (J. Janiszewska), nematodes (A. Okulewicz), lice (J. Złotorzycka, E. Lonc, M. Modrzejewska). Faunistic and biometrical data of parasitic commities of fishes, birds and mammals, mainly rodents as well as the vector role of ticks and mosquitoes at Wroclaw area are also discussed. Localities of those parasites and their hosts, collected mainly from the Lower Silesia region are rearranged according to new system of physicogeographic differentiation of Poland and its regional position at biogeographical map of world.

Background: A study was carried out in a shallow, eutrophic Oświn Lake, within Seven Islands Reserve (north-eastern Poland), in order to determine the infection of fish with monogeneans as sensitive indicators of water quality. This paper presents comparative analysis of the occurrence of Monogenea in fishes from two, distinctly separated pools of the lake, differing in environmental conditions. The impact of fish size and sampling season on the infection parameters was also analyzed., Material and Methods: In 1998 and 1999, a total of 1091 fish representing 8 dominant species were examined. Samples were collected four times a year (in May, July, August, and October) simultaneously from the eastern and western parts of the lake., Results: 16 species of Monogenea (and some unidentified specimeus) occurred in the fish examined, most of them from the Dactylogyridae family: Dactylogyrus sphyrna, D. auriculatus, D. intermedius, D. anchoratus, D. falcatus, D. tincae, D. wunderi, D. zandti, D. difformis, D. nanus, D. distinguendus, D. crucifer, D. caballeroi. Furthermore, Tetraonchus monenteron (Tetraonchidae), Gyrodactylus elegans (Gyrodactylidae), and Paradiplozoon megan (Diplozoidae) were detected. Monogenea occurred abundantly on the gills of pike, roach, rudd, white bream, carp bream and crucian carp, but rather sporadically in tench and perch. The highest species variety and diversity of monogenean guilds were detected in carp bream and roach. It was proved that D. crucifer and D. difformis were significantly more abundant in the western pool compared to the eastern one. Infection of fish with Dactylogyridae was season-dependent, contrary to the infection of pike with T. monenteron. Intensity of infection of white bream with D. sphyrna and roach with D. crucifer increased with fish body length; such a relationship did not appear for the other monogeneans and their hosts., Conclusion: Presence of common Monogenea in the fish examined, lack of rare species, poor diversity of monogenean guilds and relatively low infection rate could be connected with the low stability of the lake environment. Location-dependent occurrence of D. crucifer and D. difformis indicated that the exchange between fish groups from the eastern and western parts of the lake is limited.

The probabilities of completing the life cycle of Hysterothylacium aduncum and Contracaecum rudolphii at the water of Vistula Lagoon was considered. Hysterothylacium aduncum is a parasite of some fish species from Vistula Lagoon and Contracaecum rudolphii is common parasite of cormorant Phalacrocorax carbo from colony of Katy Rybackie.

Diphyllobothrium latum typically occur in the subarctic and temperature zones of the Eurasian Continent, however it is also observed in the Arctic Region and Australia. Raw fish meat and raw shell-fish containing plerocercoids is the main source of human infections. Humans are the principial final host of D. latum. Under primitive conditions human excrements with immature tapeworm eggs are deposited anywhere. After embrionic development which occurs in the water, the eggs are transformed into coracidia. Two intermediate hosts (cyclop and fish) are needed for further development. The free-swimming coracidium must enter the stomach of different species of Copepoda. After contact with the intestinal juice of the cyclop, the coracidium loses its ciliated envelope and the hooks become mobile. The metamorphosis of the oncosphere to the procercoid occurs. The discovery of the procercoid done by Janicki and Rosen in 1917 implied that the missing link in the cycle of the broad tapeworm had been found. The copepod including the procercoid is consumed by the second intermediate host. The larvae escape from the digestive tract of the fish and are transformed into a plerocercoid. The plerocercoids develop slowly in the fish, and they must reach a certain degree of maturity to be capable of infecting the final host. Today the life cycle of the tapeworm is well recognized and well illustrated in parasitological textbooks and websites. In this paper the history of the exploration of the D. latum life cycle is described. Additionally the main scientific researches carried out on life stages of the broad tapeworm have been reviewed.

A total of 142 individuals of Gasterosteus aculeatus L. and 22 individuals of Pungitius pungitius (L.) from several areas of the coastal waters of the Gdańsk Bay both brackish- and freshwater were examined for parasites. The survey was carried out within 1988-1991. Six parasite species, namely: Gyrodactylus arcuatus, Apatemon gracilis, Sphaerostomum bramae, Phyllodistomumfolium, Neoechinorhynchus rutili, and Argulus foliaceus were recovered from sticklebacks caught in freshwater habitats; while the other 4 parasites: Apatemon annuligerum, Bothriocephalus sp., Schistocephalus solidus, Proteocephalus percae occurred only in fish from brackish-water areas. Additional 5 parasites: Trichodina domerguei, Diplostomum pungitii, Diplostomum spathaceum, Rhaphidascaris acus, and Thersitina gasterostei were recorded in fishes from both habitats.

The occurrence of parasitic Metazoa of bream in Poland was analyzed. Three types of reservoirs were studied--lakes, lakes heated with thermal effluents and artificial reservoirs. The estimated model S = 3.367 * ln(N)--1.192 described relationship between sample size and richness of the component community of bream parasites in lakes. On the basis of this model the confidence intervals for each artificial reservoir and thermally affected lake were computed. The richness of the component communitites of bream did not depend on the type of reservoir (natural vs. artificial). It was affected by the thermal effluents (richer communities in heated lakes), geographical isolation of the reservoir, and young age of the reservoir. Most spectacular influence of the artificial origin of the reservoir was found in Monogenea (group missing in 5-year old reservoir) and Acanthocephalus anguillae (present in 1 out of 4 artificial reservoirs).

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.

This work consisted in studying the frequency of deformations of the attachment organ in specimens representing the family Diplozoidae, occurring in roach, common bream, and white bream from five different water bodies. These water bodies differed in morphometric parameters, levels of eutrophication, and character of their pollution. The presence of three types of deformation was stated. The most common were deformations of type II (morphological changes of clamps, such as sclerite deformation, incomplete sclerite separation or sclerites missing altogether in a clamp), while less frequent were those of types I (changes in the size of clamps not associated with the structural changes) and III (missing clamps in a set). Most frequently anomalies of the attachment organ were stated in polluted Lyna River, polluted Wulpińskie Lake, and in dystrophic Warniak Lake. Less frequent were anomalies in less eutrophied lakes Dgal Wielki and Ukiel. Also the prevalence values of those parasites were the highest in the polluted water bodies. The present study supports believes of other authors, that both infection parameters of Diplozoidae affecting fishes and deformations of monogeneans' attachment apparatus can be treated as indicators of environmental pollution.

The cultivation was done on Eagle's media as well as Eagle's media enriched with the supplement of 10 and 20% of bovine serum. In the media without serum the larvae lived significantly shorter and did not get through molting. They lived the longest and came through molting the fastest in the media with pH 2.0 supplemented with 20% SB. In the media with the pH 4.0 and 7.3 the larvae lived significantly shorter and only a small proportion reached stage IV.

alpha-Amylase is present in the third (L3) and in the fourth-stage (L4) of larvae from Anisakis simplex. The enzymes from both sources differ in some of their properties. alpha-Amylase from L3 showed a maximum at pH 7.8, enzyme from L4 stage at pH 6.5. The alpha-amylase from L3 was mainly lysosomal enzyme. The enzyme from L4 was located in the microsomal fraction. The L3 alpha-amylase showed the inhibition by EDTA and by -SH reagent iodoacetic acid. These agents did not change the activity of L4 enzyme. Both izoenzymes were unaffected by calcium and magnesium ions. Generally the alpha-amylase from L4 stage had higher activity (3.71 u/mg) than L3 one (2.29 u/mg).

Pulmonate and prosobranch snails, being necessary hosts for parthenogenetic generations of digenetic trematodes, participate in transmission of all trematodoses important from medical point of view. Role of particular gastropods in epidemiology of these diseases is discussed in details. Invasion of land snails and slugs is mainly passive by eggs containing developed miracidia, while enter of these larvae into snails inhabiting fresh-water environments is usually active. Generations in the snail host between miracidia and cercariae vary considerable, depending upon the fluke species. Generally, the cercaria is produced by the sporocyst or the redia. Cercariae usually actively penetrate out of the infected snail and enter water. Leaving out of account cases of encystation of cercariae in external environment (liver flukes of the family Fasciolidae) and active penetration into the final host (blood flukes of the family Schistosomatidae), encystation of these larvae takes place in the second intermediate host. Cercariae of medically important flukes may develop into metacercariae in tissues of fish (liver flukes - Opisthorchis felineus, Clonorchis sinensis, intestinal flukes--Heterophyes heterophyes, Metagonimus yokogawai, Troglotrema salmincola), as well as in crustaceans (pulmonary flukes of the genus Paragonimus), insects (the bipathogenic liver fluke Dicrocoelium dendriticum and other species of the family Plagiorchiidae incidentally found in man), and gastropods (flukes of the family Echinostomatidae, among them perhaps the best known is the Oriental species--Echinostoma ilocanum). In prevention and control of human trematodoses, especially in endemic foci, elimination of snail hosts is a great importance. Using molluscides may be objectionable from the stadpoint of environmental modification through their toxicity to other organisms. Biological control of snail hosts is more attractive. It includes introduction and management of predators, parasites, or pathogens, and intramolluscan competition. Moreover, certain slugs and terrestrial snails participate in transmission of nematode larval stages, including species known as pathogenic for man - the strongylid nematodes of the genus Angiostrongylus). Such infections may be prevented by abstanding from eating raw or inadequately cooked molluscs in endemic areas.

Piscicola brylinskae n. sp. is described from the lake Vechten in the village of Bunnik (Prov. Utrecht), The Netherlands. The characteristic features of this leeches allow to conclude that this species is a member of the subfamily Piscicolinae, probably a parasite of fish.

The objective of the experiment was to compare the growth rate in two groups of Siberian sturgeon fry, one of which was infested with metacercariae of Diplostomum, the infestation degree was from 1 to 160/fish. The fish fed on natural as well as artificial food; the latter was given at the rate sufficient to cover 50% of the fish requirements. The average initial body weight in the control group was 16.8 +/- 1.9g, and in the group with Diplostomum - 28.4 +/- 3.6 g. During the period of favorable temperatures, viz. for about 90 days, the fry was showed satisfactory growth, but the growth rate became inhibited as the temperatures decreased to below 12 degrees C, so that throughout the wintering period the fish weight decreased by some 10%. Fish from the control group showed a higher growth rate than the infested ones, and by the end of the experiment the controls weighted 7.5% more than the infested group in spite of their lower initial weight.

The aim of the study was to determine leeches found on the lake fishes. From the lake Ukiel, 213 roaches (R. rutilus) and from the lake Wulpińskie 202 were examined between Nov. 1988 and Dec. 1999. From the Warniak 258 roaches and 9 tenches (Tinca tinca) were examined between May 1998 and Nov. 1999. Warniak on roach (R. rutilus) 4 Piscicola geometra and Hemiclepis marginata on the fish body were found, tench (Tinca tinca) P. geometra were found on gills. Ukiel on roach Piscicola pojmanskae on gills were found. Wulpińskie on roach P. pojmanskae and Piscicola sp. as well as 2 Caspiobdella fadejewi on gills were found. Prevalence and intensity of fish infection with leeches was low in all lakes. C. fadejewi and P. pojmanskae are the first recorded on the lake fishes. Further investigations are necessary since they can result in informations concerning inhabitation of new microhabitants with P. geometra gills.

Now in the time especially intensive development of industry the question of environment pollution became very important. According to review of the problem heavy metals are one of the most hazardous constituents of xenobiotics. Their toxic effects, among other, are manifested directly on the elements of the immune system as well on the modification of the immune response. The influence of heavy metals on the host-parasite system is rather poorly recognized and here we are discused about it, according to literature and own experience. Special attention is paying to their impact on the immune response of infected and treated with lead, cadmium or mercury host and on the parasite. The definitive host eg. fishes and their some parasite can be used as potential accumulation indicators of aquatic environment of heavy metal pollution.

A parasitological investigation was made at 420 fishes from 10 species: Perca fluviatilis L., Gymnocephalus cernuus (L.), Gobio gobio (L.), Tinca tinca (L.), Leuciscus idus (L), Noemacheilus barbatulus (L.), Lota lota (L.), Leucaspisus delineatus (HECKELL 843), Blicca biorkna (L.) and Rhodeus sericeus amarus (BLOCH 1782). The fishes were caught over one year period (1995-1996) in the Mała Panew river drainage basin (South Poland). In examined fishes the following parasite species were found: Diplostomum spathaceum (RUDOLPHI 1819)--metacercaria; Tylodelphys podicipina KOZICKA et NIEWIADOMSKA, 1960--metacercaria, Asymphyllodora tincae (MODER 1790); Bunodera luciopercae (MULLER 1776); Triaenophorus nodulosus (PALLAS 1781)--plerocercoid; Proteocephalus cernue (GMELIN 1790); Camallanus lacustris (ZOEGA 1776); Neoechinorhynchus rutili (MULLER 1780); Echinorhynchus borealis (LINSTOW 1901); Acanthocephalus lucii (MULLER 1776) and Pomphorhynchus laevis (MULLER 1776). One species of tapeworm: P. cernue appeared as a new in the parasitefauna of Poland.

The studies on the reproductive system of P. respirans, based on 115 specimens, have revealed its considerable variability. Two main types of the system can be distinguished: 1) ovaries reaching the first pair of testes, ejaculatory ducts symmetrical, no seminal vesicles (juvenile individuals), 2) ovaries reaching the first pair of testes, ejaculatory ducts symmetrical, seminal vesicles reaching the ends of ovaries (adults individuals). The structure of the reproductive system is correlated with the individual size and age. Because the reproductive system of P. respirans as described by BRUMPT (1900) and SKET (1968) based on type specimens designated by them, is found only in a small fraction (c. 4-8%) of specimens, a redescription of the species is necessary, best based on a neotype series.

Siberian sturgeon fry coming from three different ponds has been examined. 1. "Dgał" - fish culture conerete-terrestrial pond beloning to D.O.Z. Dgał Inland Fisheries Institute in Olsztyn supplied with fresh water from Great Dgał Lake; 2. "Grzmieca" - fish culture pond terrestrial, natural belonging to fishing farm Grzmieca near Brodnica; 3. "Konin" - fish culture pond near Konin supplied with water utilized by near heat and power generating plant. Total of 80 sturgeons fry with parameters: length 17.5 cm - 38.5 cm, weight 21 g - 134 g, age 0+1+ has been examined. The examinated group of sturgenos had metacercariae Diplostomum sp. in their lenses. Prevalence of infection of sturgeon with metacercariae Diplostomum sp. was high in all this three ponds. Intensity of infection was also high in ponds "Dgal" and "Grzmieca", but low in "Konin". In ponds "Dgal" and "Konin" we have obtained high positive correlation ("Dgal" - r = 0,606, p < 0,05; "Konin" - r = 0,743, p < or = 0,01) between number of metacercariae in sturgeon and temperature of water. Our study confirmed observations other authors susceptibility sturgeon fry on the Diplostomum sp. invasion.

Piscicola geometra (L.), Piscicola respirans Troschel, 1850, and Caspiobdella fadejewi (Epshtein, 1968) find their hosts (fishes) by reacting to their shadow. Eye-like spots whose number ranges from 8 to 16 depending on a species, located on the posterior sucker are the main receptors perceiving the decrease in light intensity and thus enabling an immedaite reaction to the host's shadow. They are distributed on the perimeter of the sucker, are absent only from the section that is constantly shaded by the leech body. Experiments with a simulated shadow reveled considerable differences in the threshold light doses between the studied species: P. geometra - 12 lux, P. resprans - 4 lux and C. fadejewi - 2.5 lux. Below these values the leeches do not perceive the decrease in light intensity and do not make host-searching movements. The smallest decreases in light intensity, at which the leeches still make host-searching movement, are: P. geometra - 5 lux, P. resprans - 2 lux, and C. fadejewi- 1.5 lux. In case of P. respirans and C. fadejewi such small decreases in light intensity (2 - 1.5 lux) may be caused only by small fishes which, according to the results of the experiment, should not be infested. This is confirmed by field observations - small fishes are mostly free from parasites. Large fishes (casting a large shadow) have much more numerous leeches.

A brief description of the fish condition indices is provided together with proper formulae, and examples of their application in parasitological studies. Author argues that, since some indices react comparatively slowly upon parasite-induced stress, and some respond quite rapidly, a whole set of indices should be used in order to provide researchers with complete picture of fish-parasite interactions.

In the study, an attempt was undertaken to compare the most common species of tapeworms' larvae in fish: N. cheilancristrotus and T. nodulosus on the basis of histoenzymatic examination of 3 enzymes: alkaline phosphatase (AP), acid phosphatase (APh) and nonspecific esterase (EN-alpha). The high activity of AP and APh in the cuticle and subcuticular cells, and the lack of EN-alpha activity in these structures was stated. Besides, an intensive AP and EN-alpha activity took place in the N. cheilancristrotus scolex, compared to the appropriate T. nodulosus segment in which the reaction was slight.

Parasitological examinations comprised above 20,000 fish which were searched for parasitic nematoda of Anisakidae. It was evidenced that herring were infected with anisakid larvae in 8%, cod and flatfish in 4% and the eelpouts in as many as in 52%. The species that prevails in these fish were: Anisakis simplex, Contracaecum osculatum C, Hysterothylacium auctum and Pseudoterranova decipiens, respectively. In direction of the bacteria pathogenic to man 765 fish were examined; in 38% there were found pathogenic strains such as coagulase-positive staphylococci, even Salmonella and Shigella. Besides there were cultivated 109 strains of bacteria pathogenic to fish belonging to the genera: Aeromonas, Pseudomonas, Acinetobacter and Moraxella Virological evaluation comprised 527 fish, in that number Enteroviruses (Coxsackie, ECHO) were identified in 31% fish and viral agent, likely to be pathogenic to fish in 8% specimens. Not a one case of infection with Ichthyophonus hoferi fungus in the herring hitherto examined was noted.

One specimen of III larval stage of Anisakis simplex was found in body cavity of female stickleback Gasterosteus aculeatus caught in Southern Baltic, in Kołobrzeg. In stickleback from Baltic Sea A. simplex was noted for the first time. It usually occurs in many other species of fish.

Freshwater bream Abramis brama inhabiting warm-water discharge canal of the "Dolna Odra" Power Plant (Poland) were surveyed within 1983-1986 for their copepod parasites Tracheliastes maculatus. A total of 812 bream was studied and 561 females and 7 males of the parasite were recovered. The overall prevalence (for the whole survey) was 23.3% and the overall abundance was 0.69. T. maculatus were prevalent and abundant in winter while in summer they were encountered sporadically. The seasonality of the parasite exhibited consistent pattern within the studied period and it showed no signs of rise beyond the natural balance limits.