The white grunt, Haemulon plumierii (Lacepède, 1801) as paratenic and definitive host of two acanthocephalan species, with the description of a new species of Dollfusentis (Palaeacanthocephala: Leptohynchoididae) from the Yucatán Peninsula, Mexico.

Acanthocephalans are a group of obligate endoparasites that alternate between vertebrates and invertebrates to complete their life cycles. Occasionally, the same individual host acts as a definitive or paratenic host for different acanthocephalan species. In this study, acanthocephalans were sampled in marine fish in three localities of the Yucatán Peninsula; adults and cystacanths were recovered from the intestine and body cavity, respectively, of Haemulon plumierii from off the coast of Sisal, Yucatán. Ribosomal DNA sequences (small and large subunits) were used to test the phylogenetic position of the species of the genus Dollfusentis, whereas the mtDNA gene cox 1 was used for assessing species delimitation. The cox 1 analysis revealed an independent genetic lineage, which is recognized herein as a new species, Dollfusentis mayae n. sp. The new species is morphologically distinguished from the other six congeners by having a cylindrical proboscis armed with 22-25 longitudinal rows bearing 12 hooks each. The cystacanths were morphologically identified as Gorgorhynchus medius by having a cylindrical trunk covered with tiny irregular spines on the anterior region, and a cylindrical proboscis armed with 17-18 longitudinal rows of 21 hooks each; small and large subunit phylogenetic analyses yielded G. medius within the family Isthomosacanthidae, suggesting that Gorgorhynchus should be transferred to this family from Rhadinorhynchidae where it is currently allocated.

Gastrointestinal helminths infection of free-roaming cats (Felis catus) in Southeast Iran.

BACKGROUND: Cats in Iran are definitive hosts for several zoonotic intestinal helminths, such as Toxocara cati, Dipylidium caninum, Toxascaris leonina, Physaloptera praeputialis and Diplopylidium nolleri. OBJECTIVE: This study aimed to determine the prevalence of intestinal helminth infection in free-roaming cats in southeast Iran, a region with a high free-roaming cat population. METHODS: From January 2018 to December 2021, 153 cadavers of free-roaming cats from Southeast Iran were necropsied for intestinal helminth infections. The carcasses were dissected, and the digestive systems were removed. The esophagus, stomach, small intestine, caecum and colon were tightly ligated. All adult helminths were collected, preserved and identified. RESULTS: The prevalence of gastrointestinal helminth infections was 80.39% (123/153). Of the cats from Kerman, 73% (73/100) were infected with at least one helminth, including D. caninum 70% (70/100), T. leonina 8% (8/100) and P. praeputialis 17% (17/100). Concurrent infection with two helminth species was found in 16% (16/100) and of three species infections was found in 3% (3/100) of the cats. Of the cats from Zabol, 94.33% (50/53) were infected with at least one of the helminths, including D. caninum 69.81% (37/53), T. leonina 11.32% (6/53), P. praeputialis 37.73% (20/53) and T. cati 5.66% (3/53). Concurrent infection with two helminth species was found in 28.3% (15/53), and three species were found in 1.88% (1/53) of the cats. Helminth infections were more prevalent in older cats. There was no association between sex and infection rate. CONCLUSION: Based on the very high prevalence of zoonotic intestinal helminth infections in free-roaming cats in southeast Iran, the potential public health risk emphasizes the need for intersectoral collaboration, particularly the provision of health and hygiene education to high-risk populations, such as pre-school and school-age children.

Morphology, genetic characterization and phylogeny of Moniliformis tupaia n. sp. (Acanthocephala: Moniliformidae) from the northern tree shrew Tupaia belangeri chinensis Anderson (Mammalia: Scandentia).

A new species of Moniliformis, M. tupaia n. sp. is described using integrated morphological methods (light and scanning electron microscopy) and molecular techniques (sequencing and analysing the nuclear 18S, ITS, 28S regions and mitochondrial cox1 and cox2 genes), based on specimens collected from the intestine of the northern tree shrew Tupaia belangeri chinensis Anderson (Scandentia: Tupaiidae) in China. Phylogenetic analyses show that M. tupaia n. sp. is a sister to M. moniliformis in the genus Moniliformis, and also challenge the systematic status of Nephridiacanthus major. Moniliformis tupaia n. sp. represents the third Moniliformis species reported from China.

Survey of intestinal parasites in swine farms raised in Western Nepal.

BACKGROUND: Pigs (Sus scrofa domesticus), an important domestic livestock, are generally affected by helminth and protozoan parasites. Rearing pigs in rural regions in Nepal is a common practice for subsistence farming. A cross-sectional survey was conducted to determine the occurrence of gastrointestinal parasites (GIPs) in pigs raised in Western Nepal. METHODS: A total of 200 faecal samples from commercial and smallholder farms were examined by wet mounts, flotation, sedimentation and staining techniques. RESULTS: The results revealed that overall 86.5% of samples were found shedding oocysts or eggs of one or more GIPs. Three species of protozoa [Eimeria sp. (26%), Entamoeba coli (25.5%) and Coccidia (29%)] and nine species of helminths parasites (Ascaris suum (32.5%), Trichuris suis (30%), strongyle-type nematode (27.5%), hookworm (26%), Fasciola sp. (17.5%), Physaloptera sp. (17.5%), Strongyloides sp. (17.5%), Metastrongylus sp. (8%) and Oesophagostomum sp. (5.5%)] were identified. Female pigs were found to have higher protozoan infection than males, but such a difference was not noticed with regard to helminth parasites. Strongyles and Oesophagostomum infection were higher in commercial farms compared to smallholder farms, whereas the prevalences of E. coli and other protozoans were higher in smallholder farms. Among the contextual factors evaluated for association, weight and gender of pigs, and annual income and gender of managers/caretakers were significantly (p < 0.05) associated with the prevalence of GIPs in pigs. The overall prevalence of certain helminths such as strongyle-type nematode and A. suum was significantly (p < 0.05) associated with the weight of pigs after adjusting other contextual factors. CONCLUSIONS: This study detected relatively high prevalence of intestinal parasites in domestic pig facilities. Molecular epidemiological studies are essential to verify the exact zoonotic potential of parasites carried by pigs in the region. An effective periodic monitoring of GIPs of pigs needs to be carried out to minimize their further dissemination.

Helminth community structure of the white-bellied woolly mouse opossum Marmosa constantiae Thomas, 1904 in Central-West Brazil.

Marmosa constantiae is a species of marsupial restricted to the central portion of South America. In Brazil, it occurs in the northwestern region including five states of the Amazon, Cerrado, and Pantanal biomes. However, there is no study of the helminth fauna or helminth community structure for this marsupial. The aims of this study were to describe the species composition and to analyse the structure of the helminthic community of M. constantiae in an area of the Amazon Arc in Sinop, north of the state of Mato Grosso, Brazil. Parasites were searched in 53 specimens of this marsupial, among which 44 were infected with at least one helminth species. Parasitic helminths were counted and identified. Nine species were collected: seven nematodes, one cestode, and one acanthocephalan. The most abundant species were Gracilioxyuris agilisis, Travassostrongylus scheibelorum, Pterygodermatites sinopiensis, and Subulura eliseae. These species were the only dominant ones in the component community. No significant differences were observed in the abundance and prevalence of helminths between male and female hosts. Host body size significantly influenced helminth abundance in males. The pattern of community structure considering the infracommunities in this locality indicated more species replacement than species loss along the environmental gradient. This is the first study to report the helminth fauna and the helminth community structure of M. constantiae.

Squamata reptiles as a potential source of helminth infections when preyed on by companion animals.

BACKGROUND: Squamate reptiles cohabiting with companion animals may represent a source of helminth infections, especially through predation by dogs and cats with an outdoor lifestyle. METHODS: In order to assess the role of reptiles as intermediate/paratenic hosts of trophically transmitted helminths, synanthropic reptiles (n = 245) captured from different ecological settings (i.e., households, dog shelters, urban, peri-urban and rural areas or natural parks) of southern Italy were examined for endoparasites. Parasitic cysts (i.e., larval forms of acanthocephalans, cestodes and nematodes) and free helminths (i.e., adult nematodes and digeneans) were morphologically and molecularly identified, and statistical analysis was carried out to evaluate the correlations between reptiles, infections, and ecological settings. RESULTS: Overall, 31% of reptiles were positive for at least one helminth, with Podarcis siculus (18.7%) and Tarentola mauritanica (8.1%) being the most frequently infected species. Among the parasites of medical interest, Joyeuxiella echinorhyncoides showed the highest prevalence (19.7%), followed by Diplopylidium acanthotetra (10.5%), Joyeuxiella pasqualei, Mesocestoides lineatus (5.6%) and Physaloptera sp. (3.9%). Macracanthorhynchus hirudinaceus was detected once. Podarcis siculus and T. mauritanica were associated with cestode infections. CONCLUSIONS: The wide range of helminths detected here in reptiles living in sympatry with pets and the fact that many of these helminth species are parasitic and may infect companion animals (e.g., J. pasqualei, J. echinorhyncoides, D. acanthotetra, Physaloptera sp.) and humans (i.e., Macracanthorhynchus hirudinaceus, Mesocestoides lineatus) indicate the potential health risk associated with pets preying on these small vertebrates. Our results indicate the need for complementary investigations of trophically transmitted parasites in dogs and cats living in sympatry with reptiles.

A molecular and ecological study of Macracanthorhynchus ingens (von Linstow, 1879) (Acanthocephala: Archiacanthocephala), in its paratenic and definitive hosts in southeastern Mexico and the Eastern USA.

The acanthocephalan Macracanthorhynchus ingens (von Linstow 1879) (Acanthocephala: Archiacanthocephala) is a parasite that infects the gut of carnivores (racoons, coyotes, wolves, foxes, badgers, skunks, opossum, mink and bears) as an adult and the body cavity of lizards, snakes, and frogs as a cystacanth in the Americas. In this study, adults and cystacanths of M. ingens from southeastern Mexico and southern Florida, USA, were identified morphologically by having a cylindrical proboscis armed with 6 rows of hooks each with 6 hooks. Hologenophores were used to sequence the small (SSU) and large (LSU) subunits of ribosomal DNA and cytochrome c oxidase subunit 1 (cox 1) from mitochondrial DNA. Phylogenetic analysis of the new SSU and LSU sequences of M. ingens placed them in a clade with other sequences available in GenBank identified as M. ingens. The cox 1 tree showed that the nine new sequences and six previously published sequences of M. ingens from the USA form a clade with other sequences previously identified as M. ingens from GenBank. The intraspecific genetic divergence among isolates from the Americas ranged from 0 to 2%, and in combination with the phylogenetic trees confirmed that the isolates belonged to the same species. The cox 1 haplotype network inferred with 15 sequences revealed 10 haplotypes separated from each other by a few substitutions. Rio Grande Leopard Frogs and Vaillant´s Frogs harbored cystacanths with low prevalence, 28% and 37% respectively, in Mexico. Brown Basilisks, an invasive lizard in Florida, USA, had high values of prevalence, 92% and 93% in males and females, respectively. Females harbored more cystacanths than males (0-39 vs 0-21) for unknown reasons that may, however, be related to ecological differences.

FIRST RECORD OF A PARASITE, DACTYLOGYRUS CF. SKRJABINI (MONOGENOIDEA: DACTYLOGYRIDAE), INFECTING INVASIVE SILVER CARP, HYPOPHTHALMICHTHYS MOLITRIX (VALENCIENNES, 1844) (CYPRINIFORMES: XENOCYPRIDIDAE) IN NORTH AMERICA.

The parasites infecting invasive carps in North America (all Cypriniformes: Xenocyprididae: grass carp, Ctenopharyngodon idella [Valenciennes, 1844]; silver carp, Hypophthalmichthys molitrix [Valenciennes, 1844]; bighead carp, Hypophthalmichthys nobilis [Richardson, 1845]; and black carp, Mylopharyngodon piceus [Richardson, 1846]) are little studied, and no parasite has been reported from silver carp there. We herein surveyed silver carp from Barkley Reservoir and Cheatham Reservoir (Cumberland River, Tennessee; June and December 2021) and the White River (Arkansas; May 2022) and collected numerous monogenoid specimens infecting the pores on the outer face of the gill raker plate. We heat-killed, formalin-fixed, and routinely stained some specimens for morphology and preserved others in 95% ethanol for DNA extraction and sequencing of the large subunit ribosomal DNA (28S). We identified our specimens as Dactylogyrus cf. skrjabini because they had a dorsal anchor deep root that is much longer than the superficial root, an approximately parallel penis and accessory piece, and a relatively large marginal hook pair V. No type specimen of Dactylogyrus skrjabiniAkhmerov, 1954 (type host and locality is silver carp, Amur River, Russia) is publicly available, but we borrowed several vouchers (NSMT-Pl 6393) that infected the gill rakers of silver carp captured in the Watarase River, Japan. The original description of D. skrjabini was highly stylized and diagrammatical, differing from the specimens we studied from North America and Japan by the dorsal anchor having a superficial root and shaft that comprise a strongly C-shaped hook (the superficial root curves toward the dorsal anchor point) (vs. superficial root straight, at ∼45° angle to deep root and directed away from the dorsal anchor point), a single, much reduced transverse bar that is narrow for its entire breadth (vs. dorsal and ventral transverse bars robust and broad, having an irregular outline), an accessory piece that lacks digitiform projections (vs. accessory piece with 4 digitiform projections), and an accessory piece that lacks a half cardioid-shaped process (vs. accessory piece having a half cardioid-shaped process). Our 28S sequences (generated from 4 specimens of D. cf. skrjabini: 2 from Tennessee [763 base pairs (bp)] and 2 from Arkansas [776 bp]) were identical to 1 ascribed to D. skrjabini from Japan. The present study is the first verifiable and credible report of a parasite from silver carp in North America and the first nucleotide information for a parasite from silver carp in North America.

Temporal variation in helminth infracommunities of the Gafftopsail pompano, Trachinotus rhodopus (Pisces: Carangidae) off the Pacific coast of Mexico.

Temporal variation of the helminth infracommunity structure in the Gafftopsail pompano Trachinotus rhodopus was studied during bi-monthly revisions of samples collected offshore from Puerto Ángel, Oaxaca (Mexican Pacific) in 2018. In total, 110 specimens of T. rhodopus were subjected to a parasitic review. Helminths found were identified to the lowest possible taxonomic level (six species and three genera) by means of morphological and molecular data. Attributes of the helminth infracommunities are described through statistical analyses, showing stability in terms of their richness throughout the year. However, variations were found in helminth abundance related to the seasonality of samplings, which may be associated with the life cycles of the parasites, the host species' gregarious behavior, the availability of intermediate hosts, and/or the diet of T. rhodopus.

Parasite-host relations and new reports of helminths for Rhinella dorbignyi (Duméril & Bibron, 1841) (Anura: Bufonidae) from Neotropical region.

This study aimed to analyze helminth assemblage in Rhinella dorbignyi regarding host gender, size and mass in two sampling sites in southern Brazil, and to report new parasite associations. Anurans (n = 100) were collected in two localities from Rio Grande do Sul (RS) state, Brazil, from 2017 to 2020. Nineteen taxa (adults and larval forms) belonging to Nematoda, Acanthocephala, Digenea, and Cestoda were found in different infection sites. Cosmocercidae gen. spp., Physaloptera liophis, Catadiscus sp., and Cylindrotaenia americana were the dominant taxa in helminth assemblage. Female anurans showed higher helminth species richness than males considering the total sample (two localities) or one of the two localities. However, prevalence and mean intensity of infection did not show any significant difference between genders. Mean intensity of infection was significantly higher (19.52) in Laranjal locality. Host body size does not influence helminth abundance, as infections did not show significant correlation snout-vent length (SVL) nor body mass (BM) of anurans. The findings reveal anurans of R. dorbignyi may be intermediate, paratenic and definitive host for these parasites. Plagiorchioidea helminths (Digenea), Physaloptera liophis, larvae of Acuariidae and Spiroxys sp. (Nematoda), and cystacanth of Lueheia sp. (Acanthocephala) constitute new records for R. dorbignyi. Additionally, this is the first record of Cylindrotaenia americana larvae in this host species. Resulting information increases the knowledge on biodiversity and parasite-host relations and may help future conservation programs developed in ecosystems in the extreme south of Brazil.

Refugia or reservoir? Feral goats and their role in the maintenance and circulation of benzimidazole-resistant gastrointestinal nematodes on shared pastures.

Gastrointestinal nematodes threaten the productivity of grazing livestock and anthelmintic resistance has emerged globally. It is broadly understood that wild ruminants living in sympatry with livestock act as a positive source of refugia for anthelmintic-susceptible nematodes. However, they might also act as reservoirs of anthelmintic-resistant nematodes, contributing to the spread of anthelmintic resistance at a regional scale. Here, we sampled managed sheep and cattle together with feral goats within the same property in New South Wales, Australia. Internal transcribed spacer 2 (ITS-2) nemabiome metabarcoding identified 12 gastrointestinal nematodes (Cooperia oncophora, Cooperia punctata, Haemonchus contortus, Haemonchus placei, Nematodirus spathiger, Ostertagia ostertagi, Teladorsagia circumcincta, Oesophagostomum radiatum, Oesophagostomum venulosum, Trichostrongylus axei, Trichostrongylus colubriformis and Trichostrongylus rugatus). Isotype-1 ß-tubulin metabarcoding targeting benzimidazole resistance polymorphisms identified 6 of these nematode species (C. oncophora, C. punctata, H. contortus, H. placei, O. ostertagi and T. circumcincta), with the remaining 3 genera unable to be identified to the species level (Nematodirus, Oesophagostomum, Trichostrongylus). Both ITS-2 and ß-tubulin metabarcoding showed the presence of a cryptic species of T. circumcincta, known from domestic goats in France. Of the gastrointestinal nematodes detected via ß-tubulin metabarcoding, H. contortus, T. circumcincta, Nematodirus and Trichostrongylus exhibited the presence of at least one resistance genotype. We found that generalist gastrointestinal nematodes in untreated feral goats had a similarly high frequency of the benzimidazole-resistant F200Y polymorphism as those nematodes in sheep and cattle. This suggests cross-transmission and maintenance of the resistant genotype within the wild ruminant population, affirming that wild ruminants should be considered potential reservoirs of anthelmintic resistance.

Top-down and bottom-up effects and relationships with local environmental factors in the water frog-helminth systems in Latvia.

Semi-aquatic European water frogs (Pelophylax spp.) harbour rich helminth infra-communities, whose effects on host population size in nature are poorly known. To study top-down and bottom-up effects, we conducted calling male water frog counts and parasitological investigations of helminths in waterbodies from different regions of Latvia, supplemented by descriptions of waterbody features and surrounding land use data. We performed a series of generalized linear model and zero-inflated negative binomial regressions to determine the best predictors for frog relative population size and helminth infra-communities. The highest-ranked (by Akaike information criterion correction, AICc) model explaining the water frog population size contained only waterbody variables, followed by the model containing only land use within 500 m, while the model containing helminth predictors had the lowest rank. Regarding helminth infection responses, the relative importance of the water frog population size varied from being non-significant (abundances of larval plagiorchiids and nematodes) to having a similar weight to waterbody features (abundances of larval diplostomids). In abundances of adult plagiorchiids and nematodes the best predictor was the host specimen size. Environmental factors had both direct effects from the habitat features (e.g., waterbody characteristics on frogs and diplostomids) and indirect effects through parasite-host interactions (impacts of anthropogenic habitats on frogs and helminths). Our study suggests the presence of synergy between top-down and bottom-up effects in the water frog-helminth system that creates a mutual dependence of frog and helminth population sizes and helps to balance helminth infections at a level that does not cause over-exploitation of the host resource.

SPATIAL VARIATION IN HELMINTH PARASITE COMMUNITIES OF THE FRENCH GRUNT, HAEMULON FLAVOLINEATUM (TELEOSTEI: HAEMULIDAE), FROM THE YUCATAN PENINSULA.

The French grunt, Haemulon flavolineatum, is an abundant fish and a good model for studying parasite communities. Specimens were collected at 4 localities between the Campeche Bank (within the Gulf of Mexico) and the Mexican Caribbean Sea to describe and compare the differences and similarities between localities and regions in the communities of parasitic helminths. Thus, we calculated the Hill numbers associated with species richness (q = 0) and the dominance estimator (q = 2) using rarefaction and extrapolation curves to provide asymptotic estimators of diversity. A 2-way PERMANOVA was used to determine whether there was a significant difference in parasite assemblage structure between localities or regions. A total of 11 helminth taxa (species level) were recorded in 104 individuals of H. flavolineatum, consisting of 8 digenean trematodes species, 2 acanthocephalan species, and 1 nematode species. Our findings include new reports of 7 parasite taxa and new geographical records for some parasites in H. flavolineatum. The highest dissimilarities in parasite composition were observed between the most distant locations (Banco Chinchorro vs. Cayo Arcas) that were each located in different regions. Species richness was similar between regions, although the most dominant helminths were Postmonorchis orthopristis and Dollfustrema sp. in the Mexican Caribbean and Campeche Bank regions, respectively. Future studies should explore how patterns in parasite community structure are affected by currents running south to north by the Yucatan Current through the Yucatan Channel and easterly to Campeche Bank.

Specific Diversity of Helminth Parasites of the Edible Frog Hoplobatrachus occipitalis (Günther, 1858) in Agricultural Landscapes in the South-East of Ivory Coast, Africa.

OBJECTIVE: This study describes the specific diversity of Helminth parasites of the edible frog Hoplobatrachus occipitalis (Günther, 1858) to assess the rate of infestation in three types of plantations (coconut, palm and banana plantations) in the south-east of Africa. METHODS AND RESULTS: A total of 156 frog specimens were collected in November 2019 from all the plantations and ten parasitic Helminth taxa were recorded. The overall prevalence (93.6%) showed a high infestation of the frog in these anthropized environments. The banana plantations that use the most fertilizers and pesticides had the highest prevalence (95.2%) suggesting pollution-related parasitic load. The number of parasites was higher in female frogs than in males, suggesting a sex-specific immune resistance. This study also highlights the parasite specificity and the sites of Helminth infestations. Trematodes of the genus Haematoelochus and Diplodiscus showed strict specificity in the lungs and large intestine/rectum of the host. The other parasites colonized the digestive tract with a more or less marked specificity. CONCLUSION: Our study provides several elements of response on the population of Helminth parasites of the edible frog Hoplobatrachus occipitalis, with a view to better knowledge, management, conservation and protection.

Influence of habitat alteration on the structure of helminth communities in small mammals: a systematic review and critical appraisal of theory and current evidence.

Despite the extensive information on the effects of habitat alteration on the structure of helminth communities in small mammals, the evidence is still inconclusive. A systematic review was carried out using the PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analysis) guideline to compile and synthesize available literature on the influence of habitat alteration on the structure of helminth communities in small mammals. The aim of this review was to describe the variation in infection rates of helminth species associated with habitat alteration and to discuss the theoretical framework that may explain such changes in relation to parasite, host, and environmental features. Twenty-three scientific articles published between 2005 and 2022 were reviewed, 22 of which investigated parasite prevalence, 10 parasite burden, and 14 parasite richness in both altered and natural habitats. Information in assessed articles suggests that the structure of helminth communities in small mammals can be impacted by anthropogenic habitat alteration in various ways. Infection rates of monoxenous and heteroxenous helminths may increase or decrease in small mammals depending on whether their hosts (definitive and intermediate) are available, and environmental and host conditions modify the survival and transmission of parasitic forms. Also, given that habitat alteration may favor inter-species contacts, transmission rates of low host-specific helminths could be increased due to exposure to new reservoir hosts. In a continually changing world, it is essential to assess the spatio-temporal variations of helminth communities in wildlife inhabiting altered and natural habitats to determine potential impacts on wildlife conservation and public health.

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 6 years 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.

Helminth parasites of the wood mouse Apodemus sylvaticus in Southern England: levels of infection, species richness and interactions between species.

Helminth parasites of the wood mouse, Apodemus sylvaticus (n = 440), were surveyed in five localities, comprising woodland and grassland sites, in Southern England. Seven species of helminths were identified, among which Heligmosomoides polygyrus and Syphacia stroma were dominant (prevalence = 79.1% and 54.1%, respectively). Less common species were the trematode Corrigia vitta (14.8%), cestodes Catenotaenia pusilla (8.4%), Hydatigera taeniaeformis (4.1%) and Microsomacanthus crenata (3.4%) and the nematode Aonchotheca murissylvatici (0.2%). Differences in prevalences between localities were found for H. polygyrus, H. taeniaeformis and M. crenata and in abundances of H. polygyrus, S. stroma and C. vitta. Age-dependent increases in both parameters were identified among species and for helminth species richness. The only species to show significant host sex bias was S. stroma with prevalence values being higher in male mice. A number of different methods for exploiting raw data, and data corrected for significant confounding factors, were used to determine whether there were significant associations (prevalence) between species or quantitative interactions (abundance). The strongest evidence for a positive association was shown in concurrent infections with the trematode C. vitta and the cestode C. pusilla (significant in the whole dataset and evident in each locality, both sexes and both age classes). The abundance of C. pusilla was also higher in mice with C. vitta and vice versa. Overall, however, there was little support for associations or quantitative interactions between species, especially after data had been corrected for significant extrinsic/intrinsic factors, and we conclude that the helminths of wood mice in these communities are largely non-interactive and hence, perhaps better referred to as assemblages.

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.

Survey on helminths of bats in the Yucatan Peninsula: infection levels, molecular information and host-parasite networks.

Helminth species of Neotropical bats are poorly known. In Mexico, few studies have been conducted on helminths of bats, especially in regions such as the Yucatan Peninsula where Chiroptera is the mammalian order with the greatest number of species. In this study, we characterized morphologically and molecularly the helminth species of bats and explored their infection levels and parasite­host interactions in the Yucatan Peninsula, Mexico. One hundred and sixty-three bats (representing 21 species) were captured between 2017 and 2022 in 15 sites throughout the Yucatan Peninsula. Conventional morphological techniques and molecular tools were used with the 28S gene to identify the collected helminths. Host­parasite network analyses were carried out to explore interactions by focusing on the level of host species. Helminths were found in 44 (26.9%) bats of 12 species. Twenty helminth taxa were recorded (7 trematodes, 3 cestodes and 10 nematodes), including 4 new host records for the Americas. Prevalence and mean intensity of infection values ranged from 7.1 to 100% and from 1 to 56, respectively. Molecular analyses confirmed the identity of some helminths at species and genus levels; however, some sequences did not correspond to any of the species available on GenBank. The parasite­host network suggests that most of the helminths recorded in bats were host-specific. The highest helminth richness was found in insectivorous bats. This study increases our knowledge of helminths parasitizing Neotropical bats, adding new records and nucleotide sequences.

Morphological and Molecular Characterization of Two New and Two Already Known Species of the Genus Pallisentis (Acanthocephala: Quadrigyridae) from India with an Update in Key to the Species.

To date, 31 species assigned to the genus Pallisentis Van cleave, 1928 have been reported from India. The present study includes morphological and molecular descriptions of two new species of Pallisentis Van Cleave, 1928, namely P. himachalensis and P. longus from the fresh water fishes Channa punctata (Bloch, 1793) and C. marulius (Hamilton, 1822), respectively, procured from Himachal Pradesh and Chandigarh, India. Of total 35 fishes, 17 were found infected with acanthocephalan parasites. The prevalence of infection was 42.85 and 52.38% for C. punctata and C. marulius, respectively. The morphological characters of P. himachalensis n. sp. include proboscis with 4 circles of hooks with 810 hooks per circle, which gradually decline in size. The trunk in male comprises 1516 circles of collar spines and 2737 circles of trunk spines ending above the anterior testis with syncytial cement gland having 2629 nuclei. The trunk in female comprises of 1418 circles of collar spines and 5573 circles of trunk spines present till the anterior end of reproductive system with additional 34 circles at the posterior end. P. longus n. sp. is the longest species reported in the genus and the length of female reach up to 44 mm. The proboscis comprises 4 circles of proboscis hooks with 910 hooks per circle. In males 1316 circles of the collar spines and 2731 circles of trunk spines are present with syncytial cement gland containing 2025 nuclei. The females are much longer with 1516 circles of collar spines and 6469 circles of trunk spines present till the posterior end. The study also reports two already described species: P. gomtii Gupta and Verma, 1980 from C. punctata and P. nandai Sarkar, 1953 from C. marulius. Total 12 sequences for 4 species have been generated based on 18S, 28S and ITS15.8SITS2 molecular markers. The 18S and ITS15.8SITS2 Bayesian inference trees generated in the present study showed distinct identities of all 4 species. Moreover, the Bayesian inference tree generated in the present study based on 18S showed the clustering of Pallisentis species in three different clades compared to the previous studies in which only two clades within the genus were reported. The molecular analysis showed the monophyletic origin of the genus Pallisentis and does not support subgeneric classification within the genus.