Helminth Component Communities Research Articles

Helminth Communities of Common Fish Species in the Coastal Zone off Crimea: Species Composition, Diversity, and Structure.

In this paper, we analyzed the diversity and structure of helminth communities of 12 common fish species from the coastal zone of Crimea. A total of 53 helminth species were found. The total number of parasite species per host fish ranged from 3 to 18. Species richness at the infracommunity and component community levels were from 1.4-4.2 to 1.7-7, respectively. The Brillouin index for the infracommunites was 0.1-1, while the Shannon index for the component communities was 0.3-1.2. Component communities demonstrated a bi- or tri-modal distribution of the parasite prevalence and positive correlations between the prevalence and log-transformed abundance indices, thus following the "core-satellite" conception. Overall, the prevalence and abundance index of the dominant parasite in the component communities ranged from 18 to 80% and from 0.6 to 61.5 ind. per fish, respectively. The structure of the helminth component communities demonstrated good accordance with the nestedness mode where the rarest species occurred in the most diverse infracommunities, while the poorest infracommunities were composed of a few dominating species. More than two-thirds of the studied helminth species had an aggregated distribution indicating well-structured and developed communities. Our data provide a basis for further research and may be used for fish resource monitoring and management.

Infection patterns of helminth community in black rockcod Notothenia coriiceps in West Antarctica over a 6-year term.

Patterns of the rockcod Notothenia coriiceps infection with helminths were analysed to understand the dynamics of parasite communities in this Antarctic fish and to test their stability over time. The study was performed using helminth samples collected from 183 N. coriiceps in 2014-2015 and 2020-2021 in the vicinity of the Ukrainian Antarctic station (UAS) "Akademik Vernadsky", Galindez Island, Argentine Islands, West Antarctica. Overall, 25 helminth taxonomical categories (nine trematodes, four cestodes, five nematodes, and seven acanthocephalans) were subjected to analysis. A direct comparison of the helminth population characteristics showed that nine species significantly changed their infection parameters during the 6years between the samples. Seven of them (Pseudoterranova sp., Contracaecum sp., Ascarophis nototheniae, monolocular metacestodes, bilocular metacestodes, Metacanthocephalus rennicki, and Diphyllobothrium sp.) were found to have a significant impact on the differences between helminth infracommunities in 2014-2015 and 2020-2021. Most studied patterns of helminth component community appeared to show a stable tendency, and observed fluctuations were close to the steady trend. Slight but significant changes in the infection patterns observed in this study might have been caused by changes in the populations of intermediate, paratenic, and definitive hosts of helminths (marine invertebrates, mammals, and birds), which participate in helminth transmission in Antarctic ecosystems.

Long-term study reveals central European aerial insectivores as an unusual group of hosts that harbor mostly helminths that are unable to complete life-cycles in the nesting quarters of their hosts

BackgroundCentral European aerial insectivores are long-distance migrants that winter in sub-Saharan Africa. Most of them employ the fly-and-forage migrating strategy and differ in their food composition. The composition and structure of helminth component communities of these hosts are poorly understood, and information regarding seasonality and long-term changes is unavailable.MethodsFrom 1963 to 2022, we analyzed the population trends of helminths in five aerial insectivore species. Namely, we examined Apus apus, Hirundo rustica, Delichon urbicum, Riparia riparia, and Ficedula albicollis; all originated from the Czech Republic.ResultsWe identified central European aerial insectivores as hosts that are parasitized mostly by helminths that cannot complete their life-cycles in the nesting quarters of their hosts. This phenomenon is unknown in other bird host species. In contrast, only a single dominant trematode species that completes its life-cycle locally colonized the central European aerial insectivores. All other dominant species of Trematoda, all Nematoda, and all Acanthocephala were dependent on intermediate hosts unavailable in the nesting quarters of the examined bird hosts. Surprisingly, these helminths transmitted from winter quarters or migratory routes were diverse, and many of them were abundant in terms of both prevalence and intensity of infection. The helminth component communities of aerial insectivores were dynamic systems. During the study period, three species became new and regularly encountered members of helminth fauna of examined hosts, and other species gradually increased or decreased their intensity of infection. In contrast to other groups of bird hosts, the dominant helminth species of aerial insectivores did not experience local extinctions or rapid population losses.ConclusionsThe analysis of helminths of five central European aerial insectivores revealed component communities that heavily rely on completing host–parasite cycles at migration routes or wintering grounds. The composition of the analyzed component communities changed dynamically during the 60-year-long study period, but there was no evidence of large-scale declines in abundance or prevalence.Graphical

Wintering Rooks, Corvus frugilegus (Aves, Corvidae) and Their Helminths in Poltava and Kyiv, Ukraine

Observations of wintering rook populations were carried out from late October till early March in 2020–2021 and 2021–2022 in the cities of Poltava and Kyiv. In Poltava, rooks made up 95 % of the approximately 50,000 wintering corvids, and in Kyiv, more than 93% of the approximately 90,000 corvids. Up to 10 % of the rooks observed in Poltava were juveniles; no juvenile rooks were observed in Kyiv. Forty-six dead rooks (24 in Poltava and 22 in Kiev) collected on the ground at roosting sites were used for parasitological studies. We found 13 helminth species in the two samples of rooks, 10 species were recorded in each sample. In both samples, nematodes predominated by their infection prevalence and abundance. At the levels of helminth populations and infracommunities, the differences between the two samples were mostly influenced by the infection parameters of the nematodes Acuaria anthuris, Baruscapillaria resectum, Diplotriaena tricuspis, Eucoleus frugilegi, Microtetrameres spp., and the cestode Spiniglans affinis. In the helminth component community from Poltava, the evenness and diversity indices were comparatively higher than in the component community from Kyiv; Microtetrameres spp. was the predominat taxon. In the component community from Kyiv, E. frugilegi predominated by its infection prevalence and abundance.

Helminth biocoenosis of Lepus europaeus meridiei (Hilzheimer, 1906) from Pianosa island, Italy.

Pianosa is a 10 km2 Italian island in the Tyrrhenian Sea which is part of the Tuscan Archipelago National Park. In this island lives a brown hare population which, according to the literature, belongs to the ancestral taxon Lepus europaeus meridei that offers a unique opportunity to observe how the parasite biocoenosis shapes in condition of isolation, limited space availability and high population density. The aim of this work is to describe the helminth component community of a non-managed, isolated, and dense hare population, evaluating host-parasite relationship and parasite community structure. All 26 analyzed hares (13 males and 13 females) were in good physical conditions, and all of them harboured exclusively the nematode Protostrongylus oryctolagi only. This is the first report of this lungworm species in Italy. The estimated overall abundance was 48.15 worms per examined hare (range 3–258, median 50) and the parasites were unevenly distributed across host population, with few hosts having most parasites (aggregated or overdispersed distribution). No significant relationship was detected between the number of isolated parasites and hare sex and weigh. The effect of the isolation of Pianosa's hare population seems to have acted reducing parasite richness, while the high host density is probably the cause of the high prevalence and abundance of the single helminth species collected.In conclusion, despite the low impact of parasites confirmed also by the overdispersed parasite distribution, the low diversity of the studied parasite community sounds a warning for the management of the hare population and the whole Pianosa's ecosystem.

Analysis of the helminth community of Notothenia coriiceps (Actinopterygii: Nototheniidae) collected in the water area of the Argentine Islands, West Antarctica

Helminth community of the Antarctic black rockcod, Notothenia coriiceps, was examined using the fish samples collected in 2014—2015 (106 specimens) and 2020—2021 (78 specimens) in the water area of the Argentine Islands, West Antarctica. In total, 30,951 helminth specimens were collected and identified. We analyse the helminth infra- and component communities and investigate possible changes in the main parameters of helminth communities of N. coriiceps during the six-year period. Thirty species of helminths from five taxonomic groups were recorded: one species of Monogenea, 5 of Nematoda, 4 of Cestoda, 9 of Trematoda, and 11 of Acanthocephala. Notothenia coriiceps was found to be the definitive host of 18 helminth species; 12 species parasitize it in the larval stage using N. coriiceps as the second intermediate or paratenic host. The proportion of larval helminths in the samples was lower in 2014—2015 (73.4%) than in 2020—2021 (81.4%). The number of dominant helminth species (infection prevalence >50%) increased from seven in 2014—2015 to nine in 2020—2021. In helminth infracommunities, the species richness was similar in two samples. On the other hand, we found significantly higher helminth abundance in the infracommunities from the sample collected in 2020—2021. In the helminth component community, the diversity indices (Shannon, Simpson, Pielou, Berger-Parker) evidenced higher evenness and lower domination in the sample collected in 2014— 2015 compared to the sample collected in 2020—2021. Lower evenness in 2020—2021 was due to the larger relative abundance of larval Pseudoterranova sp. and Corynosoma spp. We suggest a deeper investigation of the role of separate helminth species in the component community changes, as well as further monitoring of component community parameters as prospective directions for future studies of helminth communities of N. coriiceps in West Antarctica.

Gleasonian structure in the helminth metacommunity of the opossumDidelphis albiventrisin two extremes of the Atlantic Forest

Didelphis albiventris is the opossum with the largest geographic distribution in Brazil and has a wide spectrum of helminth parasites. This study aimed to describe the species composition and analyse the structure of helminth communities of D. albiventris in two extremes of the Atlantic Forest in Brazil. The influence of host sex, body mass, age, helminth species richness and locality on the abundance and prevalence of the most prevalent helminth species was investigated. Ninety-five per cent of the animals were infected with at least one species. Nine helminth species were found: the nematodes Aspidodera raillieti, Cruzia tentaculata, Trichuris didelphis and Trichuris minuta in the large intestine; Turgida turgida in the stomach; Travassostrongylus orloffi and Viannaia hamata; and the trematodes Brachylaima advena and Rhopalias coronatus in the small intestine. Three helminth morphospecies were also recovered: the nematodes Hoineffia sp. and Viannaia sp. and a cestode in the small intestine. Cruzia tentaculata and V. hamata were the species with the highest mean abundances and intensities, while the most prevalent species were A. raillieti, C. tentaculata, T. turgida and V. hamata, forming the central nucleus of the helminth component community. The analysis of the helminth metacommunity structure indicated a Gleasonian pattern for the total set of infracommunities, corroborating the beta diversity indices, which indicated more species replacement than loss between localities and infracommunities, although at a low level. The results indicated a stronger influence of host attributes than geographical distance on the community structure.

Helminths of the Antarctic dragonfish, Parachaenichthys charcoti (Perciformes, Notothenioidei, Bathydraconidae) Studied near Galindez Island (Argentine Islands, West Antarctica).

The Antarctic dragonfish, Parachaenichthys charcoti is a notothenioid teleost fish endemic to the Southern Ocean surrounding Antarctica. It is a relatively rare fish species; therefore, published data on the parasite communities of P. charcoti are limited. The present study was performed on the Ukrainian Antarctic Station "Akademik Vernadsky", Argentine Islands, West Antarctica and the purpose was to examine the species diversity of the parasites of P. charcoti and to identify the parameters of helminth infection and helminth component community. Fifteen specimens of P. charcoti were caught at a depth of 10-30 m and examined using standard parasitological techniques. All helminths (6251 specimens) were collected manually, fixed in 70% ethanol and identified based on their morphology. All examined specimens of P. charcoti were found to be infected with helminths; each fish harboured 10-20 helminth species (mean 13.2; median 13) and 237-804 helminth specimens (mean 417; median 401). Twenty-seven helminth species were found, including nine species of trematodes, 4 of cestodes, 4 of nematodes and 10 of acanthocephalans. P. charcoti is the definitive host for 11 out of 27 helminth species recorded. In the helminth component community, the diversity indices were 2.03 (Shannon's index) and 0.79 (Simpson's index); Pielou evenness index was 0.61, and Berger-Parker dominance index was 0.38. Our results indicate a high species diversity and complex structure of the helminth community in Antarctic dragonfish P. charcoti in the Argentine Islands.

Host–parasite relationship in Magellanic Penguins (Spheniscus magellanicus) during their long northward journey to the Brazilian coast

The Magellanic Penguin Spheniscus magellanicus is one of the main seabird predators in the western South Atlantic. This species presents an opportunist feeding behaviour and its diet, as well as its parasite fauna, varies geographically depending on available prey and intermediate hosts. Despite thousands of Magellanic Penguins being found dead every year in southern Brazil, little attention has been given to their parasite–host interactions in this area. In this context, the aim of the present study was to assess the relationship between Magellanic Penguin diets and gastrointestinal helminth fauna at different age classes and body conditions in southern Brazil. To this end, the gastrointestinal tracts of 63 Magellanic Penguins found dead in 2013 and 2014 were examined. All individuals were parasitized by at least one species and only one penguin did not contain any food remains. A total of 138,209 helminths comprising eight species were found. Moreover, 12 prey species were recorded, including six fish and six cephalopod taxa. The helminth component community composition of juvenile penguins was similar to that of adults but the structure differed according to penguin age class. Cephalopod and crustacean prey species were significantly more frequent in juveniles compared to adults. Adults preyed mainly upon fishes. It was evident that lean individuals, both juveniles and adults, are more intensely infected in southern Brazil. Therefore, the high abundance of helminth parasites and the consumption of less energy-efficient prey cannot be ruled out as contributory factors to the high mortality of this species, mainly lean juveniles, in this area.

Variation in Helminth Parasite Component Communities of Gambusia affinis.

In north-central Texas streams, seasonal changes in ambient temperature and rainfall result in dynamic variation in microhabitat structure, affecting the distribution and abundance of hosts. Since the complex life cycles of parasites require the presence and interaction of multiple hosts, the seasonal variations in microhabitats could influence parasite component communities within these ecosystems. Gambusia affinis (western mosquitofish) serves as a host for a variety of larval and adult parasites. Factors that affect helminth component communities in populations of mosquitofish from the Paluxy River were investigated in this study. Gambusia affinis individuals were collected from 3 sites monthly from June 2015 through August 2016. All helminth parasites were collected during necropsy and subsequently identified. From 495 mosquitofish, 5,283 helminths were collected. Component community diversity varied among collection sites and collection dates and was positively influenced by river flow. These results indicate that helminth assemblages infecting mosquitofish in the Paluxy River vary through time and space, as well as in response to environmental variation (i.e., changes in water flow).

Diversity of helminth parasites of eight siluriform fishes from the Aguapeí River, upper Paraná basin, São Paulo state, Brazil.

Fishes of the order Siluriformes, known as catfishes, have a global distribution with more than 3,600 valid species of which 2,087 occur in the Neotropical region. Despite being highly diverse, abundant, and of economic importance as food and ornamental fishes, knowledge about the diversity and distribution of their helminth parasites is fragmentary and scarce. Eight species of catfishes (Pterodoras granulosus, Trachydoras paraguayensis, Pimelodella avanhandavae, Loricariichthys platymetopon, Pterygoplichthys ambrosettii, Rhinelepis aspera, Hemisorubim platyrhynchos, and Sorubim lima) from the Aguapeí River, Upper Paraná River basin, municipality of Castilho, São Paulo State, Brazil, were surveyed for helminth parasites.Collected fishes were weighed, measured, and examined for helminth parasites following standard methodology. Fifty helminth parasite taxa (23 monogeneans, 13 digeneans, 11 nematodes, and three cestodes) were found from a total of 405 fishes screened. The helminth taxon that showed the highest mean intensity of infection and mean abundance was the nematode Rondonia rondoni from P. granulosus, followed by the nematode Parasynodontisia petterae from R. aspera. The ecological analyses were carried out at the component community level and at the infracommunity level. Trachydoras paraguayensis had the richest helminth component community. Pterygoplichthys ambrosettii had the most diverse helminth component community and R. aspera had the lowest. Both hosts are loricariids and have similar diet. However, the high parasite diversity of P. ambrosettii is due to the number of dactylogyrids species found (10), which are directly transmitted, whereas only three dactylogyrid species were found in R. aspera. At infracommunity level, the nematode species R. rondoni and P. petterae dominated the parasite communities. This study presents 38 new host records, contributing considerably to increase the diffuse knowledge of helminth parasites of Neotropical siluriforms.

Unconventional support for a raptorial niche division between Australaves and Afroaves: The distribution of helminths

Deep evolutionary relationships within raptorial niche have recently been challenged. Little is known as to whether birds of the raptorial niche share congruent or host-switching communities of parasites. Here, we analyzed the helminth component communities associated with birds of prey and owls. From 1962 to 2015, we examined 1731 birds of prey and owls in Czechia, and we provide a meta-analysis based on the available literature. Both the analysis of newly examined birds as well as the meta-analysis of previous studies suggested low similarities in the helminth component communities in Strigiformes relative to those in Accipitriformes (Sørensen similarity indices 0.380 in Czechia and 0.324 worldwide) or Falconiformes (0.341 and 0.328), as well as low similarities in the helminth component communities in Falconiformes to those in Accipitriformes (0.366 and 0.413). Globally, 59.6% of helminth species found in Accipitriformes, 39.5% of those in Falconiformes and 38.3% of those in Strigiformes were obligate specialists that were limited to a single examined bird order. Another 11.5%, 12.8% and 8.3% of species had core hosts in only a single order. Only five helminth species infected all three bird orders at a similar prevalence. The differences in prevalence cannot be explained by differences in food composition. We provide detailed information on the prevalence, seasonality, age- and sex-specificity, intensity and lethality of helminth infections. In conclusion, we provide the first systematically collected evidence on the congruence of the helminth distribution and phylogeny of the raptorial niche, which is consistent with its split into Australaves and Afroaves.

Intra- and interspecific similarity in species composition of helminth communities in two closely-related rodents from South Africa

To reveal factors responsible for spatial variation in parasite community composition we studied patterns of similarity in helminth species composition in two closely-related rodents (Rhabdomys pumilio and Rhabdomys dilectus) that differ in their social and spatial behaviour and live under different environmental conditions across 20 localities in South Africa. We asked whether the two hosts harbour similar assemblages, whether these are more dissimilar between than within hosts and if host social structure, behaviour or environment affects similarity patterns in helminth infracommunities within and among localities. We also investigated whether similarity in species composition of helminth component communities decreases with an increase of geographic distance between host populations. We found that the pattern of space use by the hosts rather than their social behaviour promotes differences in helminth species composition between host species as well as among host populations from different localities. The rate of distance decay of similarity in species composition of helminth component communities differed between the two hosts due to difference in the degree of environmental variation across their geographic ranges. We conclude that patterns of spatial variation in helminth species composition are driven mainly by host spatial behaviour and, to a lesser extent, by environment-associated factors.

Impact of the degree of urbanization on composition and structure of helminth communities in the Mongolian racerunner (Eremias argus) Peters, 1869.

The effects of the degree of urbanization on the composition and mean abundance of helminth species and the structure of helminth communities in the Mongolian racerunner were investigated along a rural-urban gradient in the region of Ulan-Ude city (the Republic of Buryatia, Russia) and neighbouring rural districts. Racerunners were obtained from key areas and categorized into three grades based on the degree of urbanization. In this study, a total of 208 lizards were examined. The helminth communities in the Mongolian racerunner were studied at the infracommunity and component community levels. The nematode Spauligodon pseudoeremiasi was a sensitive bioindicator of the degree of urbanization in our study. All parameters of helminth infracommunities in the Mongolian racerunner were significantly reduced with increasing degree of urbanization of the key areas. Two parameters of helminth component communities (the proportion of hosts infected with parasites and the Shannon index) were significantly reduced with increasing degree of urbanization. The decline recorded in parameters of helminth infracommunities and component communities in the Mongolian racerunner were probably connected with the attenuation of the relationships between helminths, having a complex life cycle with intermediate hosts along the rural-urban gradient.

Helminth parasite communities of two Physalaemus cuvieri Fitzinger, 1826 (Anura: Leiuperidae) populations under different conditions of habitat integrity in the Atlantic Rain Forest of Brazil.

Adults of Physalaemus cuvieri were collected and necropsied between November 2009 and January 2010. This was carried out in order to report and compare the helminth fauna associated with two populations of this anuran species from the Brazilian Atlantic rain forest under different conditions of habitat integrity. The hosts from the disturbed area were parasitized with five helminth taxa: Cosmocerca parva, Aplectana sp., Physaloptera sp., Rhabdias sp., Oswaldocruzia subauricularis (Nematoda) and Polystoma cuvieri (Monogenea) while those from the preserved area had four helminth taxa: C. parva, Aplectana sp., Physaloptera sp., Rhabdias sp., and Acanthocephalus saopaulensis (Acanthocephala). Prevalence, mean intensity of infection, mean abundance, mean richness, importance index and dominance frequency of helminth component communities were similar in both areas. The helminth community associated with anurans from the disturbed area had higher diversity than that from the preserved area. This study is the first to report on the acanthocephalan parasites of Ph. cuvieri, and the similarity between helminth fauna composition of two host populations under different selective pressures.

Helminth community structure in tadpoles of northern leopard frogs (Rana pipiens) and Woodhouse's toads (Bufo woodhousii) from Nebraska.

Currently, little information is available on helminth community structure in tadpoles, the ephemeral, feeding, non-reproductive larva stages of anurans. We examined the helminth community structure in tadpoles of northern leopard frogs, Rana pipiens, and Woodhouse's toads, Bufo woodhousii, from a first-order stream in Western Nebraska. Specifically, we were interested in how species-specific difference in size, time to metamorphosis, and habitat partitioning among larval anurans affect their helminth community structure. From June-July 2009, we collected 30 tadpoles of northern leopard frogs, R. pipiens, and 50 tadpoles of Woodhouse's toads, B. woodhousii, from Cedar Creek, Keith County, NE, USA. The compound helminth community was dominated by trematode metacercarial stages (echinostomatids and plagiorchids) and the nematode Gyrinicola batrachiensis with only a single non-gravid adult trematode, Gorgoderina attenuata, present in low numbers. The helminth component communities were depauperate and isolationist in nature, with a maximum of four helminth species/types per component community. Although no species-specific helminth infections were observed, clear differences were found in overall abundance of nematode versus trematode infections among tadpoles of these two anuran species. The component community of tadpoles of R. pipiens was dominated by nematodes, whereas the component community of tadpoles of B. woodhousii was dominated by trematodes. Although differences in tadpole susceptibility of these two anuran species could not be ruled out, differences in the reproductive strategy of G. batrachiensis in tadpoles of R. pipiens and B. woodhousii and anuran species-specific habitats partitioning among tadpoles of these two anuran species were important factors in structuring their helminth communities. Our study indicates that time to metamorphosis (older tadpoles) play a significant role in structuring helminth communities of tadpoles within species at the infracommunity level with older tadpoles having higher helminth species richness and/or abundances. However, species-specific differences in anuran tadpole habitat partitioning outweighed the effects of differences in time to metamorphosis at the component community level. Finally, our study is the first to report deformities in hind limb development in a tadpole from Nebraska. Of the 30 northern leopard frog tadpoles collected, a single individual contained an extra hind limb and was infected with two plagiorchid metacercariae located in the musculature above the hind limbs.

Patterns of parasite community dissimilarity: the significant role of land use and lack of distance‐decay in a bat–helminth system

Increasing community dissimilarity across geographic distance has been described for a wide variety of organisms and understanding its underlying causes is key to understanding mechanisms driving patterns of biodiversity. Both niche‐based and neutral processes may produce a distance decay relationship; however, disentangling their relative influence requires simultaneous examination of multiple potential drivers. Parasites represent a unique opportunity in which to study distance decay because community dissimilarity may depend on environmental requirements and dispersal capability of parasites as well also those of their hosts. We used big brown bats Eptesicus fuscus and their intestinal helminths to investigate: 1) independent contributions of geographic and environmental distances on dissimilarity of intestinal helminth component communities between populations of big brown bats; 2) which environmental variables best explained variation in community dissimilarity; and 3) whether similar patterns of decay with geographic or environmental distance were observed for within‐host population and within‐individual host parasite communities. We used compositional measures of community dissimilarity to examine how parasite communities may change with geographic distance and varying environmental conditions. Non‐spatial variables strongly influenced compositional parasite community dissimilarity over multiple community scales, and we observed little evidence for spatial processes such as distance decay. Environment surrounding roost sites better predicted helminth community dissimilarity than any other class of variables and landcover classes representing anthropogenic modification consistently explained variation in community structure. Our results indicate that human disturbance drives significant patterns of parasite community dissimilarity, most likely by changing the presence or abundance of intermediate hosts in an area.

Host specificity and seasonality of helminth component communities in central European grebes (Podicipediformes) and loons (Gaviiformes)

Structure and pattern of helminth component communities parasitizing grebes and loons are poorly understood. Here we analyze the prevalence, intensity and diversity of helminths in 505 Czech grebes (Podiceps cristatus, Podiceps nigricollis, Tachybaptus ruficollis) and loons (Gavia arctica, Gavia stellata) collected between 1962 and 2014. The species richness of helminth component communities ranged from 31±8 (P. cristatus) to 50±4 (G. stellata) species, with helminth load similar in all five host species, but with strong differences in prevalence and intensity of infection at a helminth species-specific level. The dominance was low, ranging from 0.11 (P. cristatus and G. stellata) to 0.21 (P. nigricollis). Dominant species (>25% prevalence) in P. cristatus were Confluaria sp., Tylodelphys clavata, Echinochasmus coaxatus, Petasiger neocomense and Ligula colymbi; in P. nigricollis and T. ruficollis: Confluaria sp. and Tatria sp.; in G. arctica and G. stellata: Tetrabothrius microcephalus, Stephanoprora denticulata, Cryptocotyle concava, Diplostomum gavium and Ichthyocotylurus erraticus; in G. stellata only: Echinochasmus (Monilifer) spinulosus. Four (12%) of the grebe digenean species were not locally acquired (with non-sympatric intermediate hosts) despite the fact that they represented 25% of digenean individuals found. In loons, five (28%) of digenean species and striking 38% of individuals found used the non-sympatric intermediate host species. Component communities of grebes were similar to each other (Sørensen similarity index 0.47–0.65) but differed strongly from those hosted by loons (0.00–0.20). We present the first systematically collected evidence of intra-annual changes of helminth component communities in grebes, and provide 20 new host records.

Composition, structure and pattern of helminth assemblages associated with central European storks (Ciconiidae)

The composition, structure and pattern of helminth assemblages associated with the storks (Ciconiidae), ibises and spoonbills (Threskiornithidae) are poorly understood. Here we analyze the prevalence, intensity and diversity of the helminth component communities associated with the white stork Ciconia ciconia and black stork Ciconia nigra, and notice the findings of helminths on Eurasian spoonbill Platalea leucorodia and glossy ibis Plegadis falcinellus obtained in the Czech Republic in years 1962–2013. Comparison with datasets from multiple European countries supports the existence of well-defined local helminth component communities, which are subject to strong geographic variation. The estimated diversity of the helminth component communities reached 11.0±1.6 (C. ciconia) and 12.5±5.4 (C. nigra) species, with the Berger–Parker dominance index reaching only 0.24 and 0.21, respectively. Typically, the dominant species (Chaunocephalus ferox, Tylodelphys excavata and Dictymetra discoidea in C. ciconia, and Cathaemasia hians and Dicheilonema ciconiae in C. nigra) were considered as local, with intermediate host species available onsite. Altogether 10 of the 11 species with known life cycle were capable to complete their life cycle locally, which is in strong contrast with the situation in Czech egrets and herons. In C. ciconia and C. nigra, the highest helminth load was in juveniles, whereas Echinostoma sudanense, absent in the juveniles, was associated with intermediate hosts absent in the study area. Relative prevalence and frequency of helminths associated with male and female C. ciconia was similar to each other. The first systematically collected evidence of the intra-annual changes of the helminth assemblages in storks is provided.

Composition, structure and pattern of helminth assemblages associated with central European herons (Ardeidae)

Helminths parasitizing the ardeid birds are poorly understood, and the majority of studies are limited to checklists and records of novel host–parasite interactions. Here we analyzed the prevalence, intensity and diversity of the helminth component communities associated with an extensive cohort of the five most common Czech herons (Ardea cinerea, Ardea alba, Nycticorax nycticorax, Botaurus stellaris and Ixobrychus minutus) collected in the years 1962–2013. Comparison with Ukrainian datasets supports the existence of local helminth component communities, subject to strong geographic variation. The diversity of the component communities ranged between 37.3±9.6 (A. cinerea) and 2.5±1.1 (I. minutus) species. Similarly, the frequency of particular helminths differed by over one order of magnitude, whereas the helminth load differed by over two orders of magnitude. Typically, the dominant species (Echinochasmus beleocephalus, Uroproctepisthmium bursicola, Posthodiplostomum cuticola, Apharyngostrigea cornu, Desmidocercella numidica and Neogryporhynchus cheilancristrotus) were considered local, with intermediate host species available onsite, as represented by freshwater mollusks. Of the digeneans, 52% of the species likely infected their definitive hosts outside the study area, frequently utilizing invertebrates of salt or brackish waters. For A. cinerea, the largest number of species was in adult males; however the helminth load of the adults was lower than in their juvenile counterparts. This study provides the first systematically collected evidence for the intra-annual changes of the helminth assemblages in herons.