New molecular data help clarify the taxonomy of central European avian dicrocoeliidae Looss, 1899 (Trematoda: Plagiorchiida).

Avian Dicrocoeliidae are difficult to identify, even in their adult stages. Molecular analyses have been conducted for only a few species, complicating the accurate identification of juvenile stages. The taxonomy of the family is unresolved, and the status of many dicrocoeliid species is uncertain. Sequences of nuclear and mitochondrial DNA loci of Central European avian Dicrocoeliidae were generated and analyzed. These included representatives of the genera Lyperosomum, Platynosomum, Stromitrema, Brachylecithum, Brachydistomum, and Lutztrema. All the sequences were obtained from morphologically identified adult specimens of dicrocoeliids isolated from avian hosts. Molecular support was obtained to validate Lyperosomum turdia, confirm the rejection of Lyperosomum dujardini and Lyperosomum alagesi, and resurrect Lyperosomum longicauda and Lyperosomum collurionis. The identity of European Platynosomum illiciens from avian hosts with American vouchers of the same species from avian and mammalian hosts was confirmed. Brachylecithum fringillae is not considered valid; the individuals that matched its diagnosis were subadult Brachydistomum ventricosum. Descriptions and comparative data for five new species are provided. These are Lyperosomum hirundinis sp. n., Lyperosomum tenori sp. n., Lyperosomum atricapillae sp. n., Stromitrema acrocephali sp. n., and Lutztrema atricapillae sp. n.. Based on the molecular data, suggestions are provided regarding the validity of dicrocoeliid species that parasitize Central European birds. Further research should address the polyphyletic status of Brachylecithum.

Morishitium polonicum (Machalska, 1980) is a junior synonym of Morishitium dollfusi (Timon-David, 1950) (Trematoda: Cyclocoeliidae).

Species of the genus Morishitium Witenberg, 1928 are parasites of the body cavity, air sacs, and lungs of birds. At least 14 species are considered valid, but molecular confirmation of their status is lacking. Here, we provide the first molecular data on Morishitium dollfusi isolated from their type host Pica pica, compared them with previously reported molecular data from Morishitium polonicum isolated from their type and paratype hosts, Turdus merula and Turdus philomelos, and performed extensive measurements of 511 individuals of Morishitium spp. across a broad host spectrum, at multiple infection intensities, and year-round. We analyzed the molecular phylogenetics of Morishitium spp. adults isolated from bird hosts of Czech origin and provide comparative measurements of the analyzed specimens. Based on the molecular examination of morphologically identified specimens of M. dollfusi and M. polonicum (CO1, ND1, and ITS2 markers), we propose synonymization of Morishitium dollfusi (Timon-David, 1950) with Morishitium polonicum (Machalska, 1980) (isolates of European origin). The three markers were either identical (CO1, ITS2) or formed haplotypes shared by the two species (ND1). Morphological analyses revealed a continuum of key identification features for the two above-named species, although we used specimens matching the original descriptions and isolated them from the type hosts. Therefore, Morishitium polonicum is a junior synonym of Morishitium dollfusi. Attention is needed regarding the status of East Asian isolates identified previously as M. polonicum (or M. polonicum malayense). The molecular analysis revealed that these isolates form a distinct clade, and further research is needed to produce data allowing the likely separation of the malayense clade as a separate species.

Mitogenomic phylogenies suggest the resurrection of the subfamily Porrocaecinae and provide insights into the systematics of the superfamily Ascaridoidea (Nematoda: Ascaridomorpha), with the description of a new species of Porrocaecum.

BACKGROUND: The family Toxocaridae is a group of zooparasitic nematodes of veterinary, medical and economic significance. However, the evolutionary relationship of Porrocaecum and Toxocara, both genera currently classified in Toxocaridae, and the monophyly of the Toxocaridae remain under debate. Moreover, the validity of the subgenus Laymanicaecum in the genus Porrocaecum is open to question. Due to the scarcity of an available genetic database, molecular identification of Porrocaecum nematodes is still in its infancy. METHODS: A number of Porrocaecum nematodes collected from the Eurasian marsh harrier Circus aeruginosus (Linnaeus) (Falconiformes: Accipitridae) in the Czech Republic were identified using integrated morphological methods (light and scanning electron microscopy) and molecular techniques (sequencing and analyzing the nuclear 18S, 28S and ITS regions). The complete mitochondrial genomes of the collected nematode specimens and of Porrocaecum (Laymanicaecum) reticulatum (Linstow, 1899) were sequenced and annotated for the first time. Phylogenetic analyses of ascaridoid nematodes based on the amino acid sequences of 12 protein-coding genes of mitochondrial genomes were performed using maximum likelihood and Bayesian inference. RESULTS: A new species of Porrocaecum, named P. moraveci n. sp., is described based on the morphological and genetic evidence. The mitogenomes of P. moraveci n. sp. and P. reticulatum both contain 36 genes and are 14,517 and 14,210 bp in length, respectively. Comparative mitogenomics revealed that P. moraveci n. sp. represents the first known species with three non-coding regions and that P. reticulatum has the lowest overall A + T content in the mitogenomes of ascaridoid nematodes tested to date. Phylogenetic analyses showed the representatives of Toxocara clustered together with species of the family Ascarididae rather than with Porrocaecum and that P. moraveci n. sp. is a sister to P. reticulatum. CONCLUSIONS: The characterization of the complete mitochondrial genomes of P. moraveci n. sp. and P. reticulatum is reported for the first time. Mitogenomic phylogeny analyses indicated that the family Toxocaridae is non-monophyletic and that the genera Porrocaecum and Toxocara do not have an affinity. The validity of the subgenus Laymanicaecum in Porrocaecum was also rejected. Our results suggest that: (i) Toxocaridae should be degraded to a subfamily of the Ascarididae that includes only the genus Toxocara; and (ii) the subfamily Porrocaecinae should be resurrected to include only the genus Porrocaecum. The present study enriches the database of ascaridoid mitogenomes and provides a new insight into the systematics of the superfamily Ascaridoidea.

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.

BACKGROUND: Central 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. METHODS: From 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. RESULTS: We 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. CONCLUSIONS: The 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.

Long-term dynamics of trematode infections in common birds that use farmlands as their feeding habitats.

BACKGROUND: The biodiversity of farmland habitats is witnessing unprecedented change, mostly in declines and simplification of assemblages that were established during centuries of the use of traditional agricultural techniques. In Central Europe, conspicuous changes are evident in populations of common farmland birds, in strong contrast to forest birds in the same region. However, there is a lack of information on longitudinal changes in trematodes that are associated with common farmland birds, despite the fact that diversity of trematodes is directly linked to the preservation of long-established food webs and habitat use adaptations of their hosts. METHODS: We analyzed the population trends of trematodes for the period 1963-2020 in six bird species that use Central European farmlands as their predominant feeding habitats. Namely, we examined Falco tinnunculus, Vanellus vanellus, winter populations of Buteo buteo, Ciconia ciconia, extravilan population of Pica pica, and Asio otus, all originating from the Czech Republic. RESULTS: We observed dramatic population losses of all trematode species in C. ciconia and V. vanellus; the changes were less prominent in the other examined hosts. Importantly, the declines in prevalence and intensity of infection affected all previously dominant species. These included Tylodelphys excavata and Chaunocephalus ferox in C. ciconia, Lyperosomum petiolatum in P. pica, Strigea strigis in A. otus, Neodiplostomum attenuatum and Strigea falconis in B. buteo (χ2 test P < 0.001 each), and Echinoparyphium agnatum and Uvitellina adelpha in V. vanellus (completely absent in 2011-2000). In contrast, the frequency and spectrum of isolated records of trematode species did not change to any large extent except those in V. vanellus. CONCLUSIONS: The analysis of six unrelated common bird species that use farmlands as their feeding habitats revealed a previously unreported collapse of previously dominant trematode species. The previously dominant trematode species declined in terms of both prevalence and intensity of infection. The causes of the observed declines are unclear; of note is, however, that some of the broadly used agrochemicals, such as azole fungicides, are well known for their antihelminthic activity. Further research is needed to provide direct evidence for effects of field-realistic concentrations of azole fungicides on the survival and fitness of trematodes.

Morphological and complete mitogenomic characterisation of the acanthocephalan Polymorphus minutus infecting the duck Anas platyrhynchos.

Morphological characteristics of the acanthocephalan Polymorphus minutus (Goeze, 1782), which was collected from the duck Anas platyrhynchos Linnaeus in the Czech Republic, are described. The mitochondrial (mt) genome of P. minutus was sequenced, with a total length of 14,149 bp, comprising 36 genes including 12 protein coding genes (PCGs), 22 transfer RNA (tRNA) genes and two ribosomal RNA genes (rrnL and rrnS). This genome is similar to the mt genomes of other syndermatan species. All these genes were encoded on the same DNA strand and in the same orientation. The overall nucleotide composition of the P. minutus mt genome was 38.2% T, 27.3% G, 26.2% A, and 8.3% C. The amino acid sequences of 12 PCGs for mt genomes of 28 platyzoans, including P. minutus, were used for phylogenetic analysis, and the resulting topology recovers P. minutus as sister to Southwellina hispida (Van Cleave, 1925), and the two taxa form a sister clade to Centrorhynchus aluconis (Müller, 1780) and Plagiorhynchus transversus (Rudolphi, 1819), which are all species in the Palaeacanthocephala, thus supporting the monophyly of this class.

Morphological and genetic characterization of Porrocaecum angusticolle (Molin, 1860) (Nematoda: Ascaridomorpha) from the common buzzard Buteo buteo (Linnaeus) (Accipitriformes: Accipitridae) in Czech Republic.

Porrocaecum angusticolle is a nematode species mainly parasitic in the birds of Accipitriformes and Strigiformes. However, some aspects of the morphology of P. angusticolle remain insufficiently known. In the present study, the detailed morphology of P. angusticolle was studied using light and, for the first time, scanning electron microscopy, based on newly collected specimens from the common buzzard Buteo buteo (Linnaeus) (Accipitriformes: Accipitridae) in Czech Republic. Some previously unreported morphological features of taxonomic significance were observed. The nuclear and mitochondrial DNA markers, including partial large ribosomal DNA (28S), complete internal transcribed spacer (ITS-1 + 5.8S + ITS-2), cytochrome c oxidase subunit 1 (cox1) and subunit 2 (cox2) of P. angusticolle were sequenced for molecular identification of this species. There was no intraspecific genetic variation detected in the 28S and ITS regions among different individuals of P. angusticolle, but low level of intraspecific nucleotide divergence was found in the cox1 (0.26-0.78%) and cox2 regions (1.0%). The 28S and cox2 of P. angusticolle were sequenced for the first time. Our molecular evidence supported the validity of both P. angusticolle and P. depressum. The newly obtained genetic data are helpful for further studies of DNA-based taxonomy, population genetics and phylogeny of the genus of Porrocaecum.

Cryptic speciation among Tylodelphys spp.: the major helminth pathogens of fish and amphibians.

Larvae of Tylodelphys Diesing, 1950 are major digenean pathogens of fish and amphibians. Tylodelphys spp. may induce mass mortality of fish and increase their susceptibility to predation. Even though Tylodelphys spp. cause substantial damage to aquaculture systems, surprisingly little is known regarding the taxonomy of this commercially important genus with a limited number of visible autapomorphic identification features. The authors obtained the DNA sequences and analyzed the molecular phylogenetics of Tylodelphys spp. adults isolated from bird hosts of Czech origin and provide comparative measurements of the analyzed species. They identified a previously unknown species complex that is subject to cryptic speciation and was previously morphologically identified as Tylodelphys excavata (Rudolphi, 1803) sensu lato. This species complex consists of three morphologically similar but genetically well-separated species. Tylodelphys excavata sensu stricto remains the dominant Tylodelphys isolated from Ciconia ciconia, which also serves as a satellite host of Tylodelphys circibuteonis Odening, 1962, which is the resurrected species for which birds of prey serve as core hosts. The authors describe Tylodelphys nigriciconis sp. n. Heneberg & Sitko as a new species identified in Ciconia nigra. By providing the first sequences of Tylodelphys podicipina Kozicka and Niewiadomska, 1960, they also show that Tylodelphys immer Dubois, 1961 is a junior synonym of T. podicipina. Further research is needed to match the provided molecular data with the DNA of larval Tylodelphys from outbreaks in commercially exploited fish species.

Emerging helminthiases of song thrush (Turdus philomelos) in Central Europe.

Turdus philomelos is a common Western Palearctic thrush species of forests and agricultural landscapes, where it relies on the presence of hedgerows, patches of trees, and shrubs. In the present study, we address long-term changes in component communities of trematodes in T. philomelos across the timespan of over half a century. Based on our preliminary observations, we hypothesized that component communities of trematodes in T. philomelos in the study area are more diverse and species-rich compared with several decades ago. In the 1961-2019, we performed full-body necropsies of T. philomelos, which originated from the southern Czech Republic, and examined them for the presence of trematodes. We compared the trematode species richness and diversity of the analyzed component communities. The number of trematode species per host steadily increased in time in adult females and males. In juveniles, the highest numbers of trematode species per host were reached already in 1961-1990, then dropped and slowly raised up again in the latter time periods. The newly accumulated evidence suggests that trematodes with intermediate hosts previously restricted to T. philomelos wintering grounds increased in abundance in the study area. Some of them (Morishitium polonicum, Psilotornus confertus) sporadically appeared in juveniles or first-year birds, from which they were previously completely absent. Some of the spreading species, such as Lutztrema attenuatum, are present in high prevalence and high intensities of infection. Yet unknown part of observed changes could be related to changes in food composition; however, direct evidence for changes in T. philomelos diet is lacking despite clear evidence for a decline in earthworms in agricultural landscapes.

Systemic collapse of a host-parasite trematode network associated with wetland birds in Europe.

As host community diversity decreases, parasite diversity may also decline. The life cycles of trematodes involve multiple hosts from different orders, with many trematodes displaying narrow host specialization. In the 1960s and 2010s, we performed full-body necropsies of juvenile or first-year birds of four wetland bird species, Anas platyrhynchos, Aythya fuligula, Fulica atra, and Chroicocephalus ridibundus which originated from the southern Czech Republic, and examined them for the presence of trematodes. We compared the trematode species richness and diversity of the analyzed component communities. We found complete disintegration of host-parasite networks, which led to declining populations and local extinctions of the majority of trematode species, particularly those with narrow host preferences. For example, in black-headed gulls, 67% of trematode species recorded in the 1960s were absent in gulls that were examined in the 2010s. In contrast, we did not identify any trematode species that were absent in the 1960s but present in the 2010s. This collapse provides new insight into the recent debate regarding whether human-caused extinctions should be considered a problem when locally extinct host species are replaced by an equal or even higher number of nonnative species, thus maintaining local alpha diversities but leading to biotic homogenization and consequently reducing beta diversity. By documenting the collapse of the host-parasite network, we provide a strong argument that biodiversity cannot be assessed by simple measures alone, as only local-scale conservation measures allow the preservation of host-pathogen interactions and nutrient cycles and thus prevent the loss of low-visibility species, such as helminths.

GEOGRAPHIC AND ECOLOGIC ASPECTS OF THE COMMUNITY STRUCTURE OF TREMATODES OF MALLARDS (ANAS PLATYRHYNCHOS) IN NORTHERN POLAND AND THE CZECH REPUBLIC.

Trematode infestation of Mallards (Anas platyrhynchos) varies between northern Poland and the Czech Republic. We determined the trematode fauna of juvenile and adult Mallards from Poland in 2010-16 (n=79 Mallards) and from the Czech Republic in 1964-2001 (n=296). Infracommunity diversity of trematodes from juvenile Mallards, defined by the Brillouin index and mean number of species, was significantly greater in Poland than it was in the Czech Republic. There were more species and greater biodiversity in the trematode communities of Mallards from Poland, where the environment is more natural and less altered by human activity than it is in the Czech Republic. In the trematode community of juvenile Mallards, the Simpson's index of biodiversity was higher in the Czech Republic than it was in Poland. The Berger-Parker dominance index was comparable in both countries. In terms of prevalence, the structure of the trematode fauna was hierarchic, and trematode species had different positions in this hierarchy in the two countries. Statistically significant differences in the epidemiologic indices between infection of juvenile Mallards from Poland and the Czech Republic were noted for Bilharziella polonica, Echinostoma miyagawai, Echinostoma revolutum, Prosthogonimus cuneatus, Prosthogonimus ovatus, Notocotylus attenuatus, Echinoparyphium recurvatum, Australapatemon minor, Apatemon gracilis, Cyathocotyle prussica, Hypoderaeum conoideum, Metorchis xanthosomus, Psilochasmus oxyurus, and Cotylurus cornutus.

Paraphyly of Conodiplostomum Dubois, 1937.

Adult trematodes of the genera Conodiplostomum Dubois, 1937 and Neodiplostomum Railliet, 1919 (Trematoda: Diplostomidae) parasitize the intestines of birds of prey, owls and, rarely, passeriform birds. Although the family is taxonomically unsettled, molecular phylogenetics have not been applied to analyze Conodiplostomum and Neodiplostomum and the reference DNA sequences from adult Diplostomidae are scarce and limit studies of their indistinct larval forms. We analyze the Conodiplostomum and Neodiplostomum spp. found during the examination of Czech birds performed from 1962 to 2017, and we provide comparative measurements and host spectra, including prevalence and intensity; we also provide and analyze the sequences of four DNA loci from eight diplostomid species. Molecular phylogenetic analysis suggested that Conodiplostomum spathula (Creplin, 1829), the type species of this genus, is nested in Neodiplostomum. Thus, we suggest the rejection of Conodiplostomum spathula (Creplin, 1829) and the resurrection of Neodiplostomum spathula (Creplin, 1829) La Rue, 1926 and reclassification of all species of Conodiplostomum with the neodiplostomulum type of metacercariae to Neodiplostomum as well. Conodiplostomum canaliculatum (Nicoll, 1914) is reclassified as Neodiplostomum spathulaeforme (Brandes, 1888). The molecular analysis suggested that Conodiplostomum perlatum (Ciurea, 1911), the species with the neascus type of metacercariae, belongs to Crassiphialinae Sudarikov, 1960. We erect the genus Ciureatrema gen. nov. Heneberg & Sitko and reclassify Conodiplostomum perlatum (Ciurea, 1911) as Ciureatrema perlatum (Ciurea, 1911) and establish it as a type species of Ciureatrema gen. nov. Further research should focus on the evolution of the neascus and neodiplostomulum types of metacercariae, as well as the evolution of the genital cone and pseudosuckers in Diplostomidae.

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.

Massive infection of a song thrush by Mesocestoides sp. (Cestoda) tetrathyridia that genetically match acephalic metacestodes causing lethal peritoneal larval cestodiasis in domesticated mammals.

BACKGROUND: Peritoneal larval cestodiasis induced by Mesocestoides Vaillant, 1863 (Cyclophyllidea: Mesocestoididae) is a common cause of severe infections in domestic dogs and cats, reported also from other mammals and less frequently from birds. However, there is a limited knowledge on the taxonomy of causative agents of this disease. RESULTS: In the present study, we investigated a massive, likely lethal, infection of a song thrush Turdus philomelos (Passeriformes: Turdidae) by Mesocestoides sp. tetrathyridia. We performed combined morphological and phylogenetic analysis of the tetrathyridia and compared them with the materials obtained previously from other birds and mammals. The metrical data fitted within the wide range reported by previous authors but confirmed the limited value of morphological data for species identification of tetrathyridia of Mesocestoides spp. The molecular analyses suggested that the isolates represented an unidentified Mesocestoides sp. that was previously repeatedly isolated and sequenced in larval and adult forms from domestic dogs and cats in Europe, the Middle East and North Africa. In contrast to the present study, which found encysted tetrathyridia, four of the five previous studies that identified the same species described infections by acephalic metacestodes only. CONCLUSIONS: The tetrathyridia of the examined Mesocestoides sp. are described in the present study for the first time. However, the possible match with the species that were previously reported to infect birds remains uncertain. The phylogenetic analyses also suggested the rejection of two cases that were previously identified as Mesocestoides corti as they were likely caused by the same species as in the presently reported infection case. The newly provided DNA sequences should allow the assignment to species in the future, when adults of the genus Mesocestoides are more thoroughly sequenced.

Air sac trematodes: Morishitium polonicum as a newly identified cause of death in the common blackbird (Turdus merula).

Necropsy of two free-ranging common blackbirds (Turdus merula) found dead in central Italy revealed the presence of a high number of cyclocoelid flukes in the coelomatic cavity. Cyclocoelid flukes primarily infect avian respiratory system. Histologically, air sac walls were covered with a fibrinous exudate containing degenerate heterophils, many trematodes and some colonies of Gram-positive cocci. The superficial bronchi and parabronchi were markedly distended, and the adjacent pulmonary parenchyma was congested and collapsed. Trematodes, surrounded by a mild suppurative to pyogranulomatous inflammatory reaction, were also observed on the pericardial, intestinal, kidney and hepatic serosal surfaces. The death of the two examined birds was likely due to the high parasite load and associated severe lesions. At parasitological examination, flukes showed a tongue-shaped elongate body, tapered anteriorly and rounded posteriorly, of 2,088-2,314 µm in width and 8,268-11,830 µm in length. The mouth was slightly oval and sub-terminal, with a small oral sucker. The oval pharynx measured 250-309 µm, and the two caeca joined posteriorly. Two large (550-702 µm × 450-520 µm) globular testes were situated obliquely to each other, whereas an oval (250 × 300 µm in mean) or round (about 334 µm in diameter) intertesticular ovary was placed in a longitudinal straight line with the testes. The ootype was about 110 µm in diameter, while the brown-yellow eggs measured 131.5 × 73.9 µm in mean. The genital pore was post-pharyngeal, while the symmetrically arranged vitelline glands were not confluent posteriorly. Morphoflogical diagnosis led to the identification of Morishitium polonicum, a cyclocoelid fluke species that typically inhabits the air sacs of blackbirds. The morphological diagnosis was corroborated by molecular phylogenetic analysis of the mitochondrial (CO1, ND1) DNA loci. The present study provides the first report of pathological lesions and death caused by M. polonicum in birds.

Molecular phylogeny provides new insights on the taxonomy and composition of Lyperosomum Looss, 1899 (Digenea, Dicrocoeliidae) and related genera.

Lyperosomum Looss, 1899 is one of the largest genera of the Dicrocoeliidae and is one of the best examples of the systematic complexity and taxonomic instability within this family. We present the molecular analyses based on novel sequences of nuclear and mitochondrial genes obtained from 56 isolates of adult flukes and larval stages of dicrocoeliids belonging to Lyperosomum, Skrjabinus, Zonorchis as well as previously available sequence data. According to obtained results we propose to return Zonorchis clathratus and Z. petiolatus into Lyperosomum, and to recognize L. alagesi as a synonym of L. petiolatum. Our study shows that L. petiolatum commonly occurs in Europe in corvids as well as in several species of migratory songbirds, e.g. Sylvia atricapilla. At the same time, the Turdidae appear to host a distinct species of Lyperosomum. The phylogenetic analysis has clearly demonstrated the paraphylepic nature of Lyperosomum and indicated the need of its thorough revision preferably using specimens from type hosts and type territories of nominal species. In addition, inclusion of numerous not yet sequenced dicrocoeliid genera into future phylogenetic studies is necessary to clarify the interrelationships of taxa within the family and stabilize its system.

Central European Strigeidae Railliet, 1919 (Trematoda: Strigeidida): Molecular and comparative morphological analysis suggests the reclassification of Parastrigea robusta Szidat, 1928 into Strigea Abildgaard, 1790.

Strigeidae Railliet, 1919 are digenean parasites of birds and mammals that are characteristic by their cup-shaped forebody and bilobed holdfast organ. Despite that the family is taxonomically unsettled, particularly due to a very limited number of visible autapomorphic identification features, molecular phylogenetics have never been applied to analyze the relationships among European members of Strigeidae except for the genus Ichthyocotylurus. Here, we analyze the Strigeidae found during the examination of Czech birds performed from 1962 to 2017, and we provide comparative measurements and host spectra, including prevalence and intensity; we also provide and analyze sequences of four DNA loci of 12 of the Strigeidae species. We suggest the reclassification of Parastrigea robusta Szidat, 1928 as Strigea robusta (Szidat, 1928) Heneberg and Sitko, 2018 comb. n. The genera Strigea Abildgaard, 1790 and Parastrigea Szidat, 1928 appear paraphyletic, and morphological diagnostic features of genera within Strigeini Dubois, 1936 are invalid. The mute swan Cygnus olor hosts two Cotylurus spp., Cotylurus syrius Dubois, 1934 and a second species with molecular identification features shared in part with Cotylurus cornutus (Rudolphi, 1808) and Cotylurus gallinulae Lutz, 1928. New host records are provided for seven species. Analyses of non-European genera of the Strigeidae are needed to provide an updated key to Strigeini.

Chronic lead intoxication decreases intestinal helminth species richness and infection intensity in mallards (Anas platyrhynchos).

Lead (Pb) pollution of aquatic habitats is a known threat to vertebrate health. Depending on Pb dosage, resulting symptoms can be chronic (sublethal) or acute (lethal). While acute exposure results in death of the animal, chronic sublethal exposure can also have consequences, reproduction, antioxidant defense and immunity being the most affected traits. While a great deal is known about Pb intoxication on avian health, relatively little is known about how intoxication impacts parasites dependent on their avian hosts. The effect of Pb on intestinal helminth species richness and infection intensity was investigated in mallards (Anas platyrhynchos, n = 100) from German waters. Coracoid bones were used to measure chronic Pb exposure. Intestinal helminths were characterized morphologically. Molecular approaches were also applied to identify poorly morphologically preserved parasites to obtain sequence data (cox1 gene) for species identification and future parasitological studies. Parasite species richness and infection intensity was found to be significantly lower in birds with higher chronic Pb levels suggesting both host and parasites respond to Pb exposure. Altered immune modulation in the avian host may be the underlying mechanisms of Pb triggered decrease of parasites. However, it also likely reflects differences in the susceptibility of different helminths to Pb. Cestode and acanthocephala species richness were particularly impacted by Pb exposure. We conclude that, Pb intoxication may both negatively impact avian host and parasite diversity in aquatic habitats.

An outbreak of philophthalmosis in Larus michahellis and Larus fuscus gulls in Iberian Peninsula.

Trematodes of the genus Philophthalmus Loos, 1899 are the eye parasites of birds and mammals, which use freshwater snails as their first intermediate hosts. Here we examined the presence of philophthalmids in a total of 1515 gulls (589 Larus fuscus and 926 Larus michahellis) admitted between January 2010 and October 2016 for rehabilitation at Olhão (Portugal), by the use of combined morphological and molecular analysis. We recorded the first infected L. fuscus and L. michahellis in July and November 2015, respectively. The philophthalmids were located in the conjunctival sac or under the nictitating membrane. Gulls infected with Philophthalmus lucipetus Rudolphi, 1819 presented no clinical signs, while those infected with Philophthalmus lacrymosus Braun, 1902 presented serious eye damage in the same host species. The prevalence of P. lucipetus reached 3.6% in L. fuscus and 0.8% in L. michahellis; the prevalence of P. lacrymosus reached 0.3% and 0.0%, respectively. The outbreak of P. lucipetus likely started in a narrowly defined area, since the first six cases, found between July and October 2015, originated from a single municipality, and only later more cases started to be retrieved from other municipalities of Portugal. These findings represent the first records of both philophthalmids in the Iberian Peninsula, their first records in L. michahellis and the first record of P. lacrymosus in L. fuscus. Further follow-up of the outbreak and the identification of intermediate hosts are needed.