The genus Micipsella comprises three species of filariae to date identified in lagomorphs only, whereas the other genera belonging to the subfamily Splendidofilariinae are described as parasites of birds, reptiles and mammals. In the present study seven specimens of Micipsella numidica (Seurat, 1917), collected from the hare Lepus europaeus in Italy, were characterized genetically by molecular amplification of the mitochondrial genes (12S rDNA; cox1) and the 5S rDNA gene spacer region. Phylogenetic trees inferred using available sequences from filariae and those identified in this study evidenced a close relationship between M. numidica and Splendidofilariinae of other mammals and reptiles (Rumenfilaria andersoni and Madathamugadia hiepei). The present findings, apart from adding new data about the hosts in Italy, support the taxonomic position of M. numidica and highlight the substantial biological and molecular differences existing between Splendidofilariinae and other Onchocercidae. The study also contributes to our knowledge of the molecular/genetic diagnosis of filarial parasites of veterinary and medical concern in any vertebrate or invertebrate host.

It was shown that maintenance of cercariae of S. mansoni and S. haematobium at low (10°C) and high temperatures (40°C) markedly increased their mortality during penetration of mammalian host skin. These increased losses in the skin accounted for the known decrease in infectivity, as measured by adult worm recovery, of cercariae kept at low or high temperatures.

During the summer of 1961 an opportunity arose which enabled us to study the incidence of certain helminth parasites in pigs slaughtered at Roath Abattoir, Cardiff. The studies were undertaken primarily because of the apparent lack of incidence figures concerning the helminth parasites in pigs from the southern part of the Principality. Some information was available for other regions of the Principality as Morgan (1924), Jones (1926) and Lewis (1930) have published reports on helminth parasites of pigs from Central and North Wales. Unfortunately none of these papers provided any comparative data on incidence of the various helminths, the numbers of each species in each infection and the proportion of sexes for each helminth in a given population.

Some preliminary experiments on the effects of potato root excretions in stimulating the larvæ of H. schachtii to hatch and emerge from the cyst, and the neutralisation of this stimulating factor by the root excretions of mustard seedlings, have already been described. Since chemical treatment of infected soil as a means of controlling the eelworm has been the subject of investigation in Europe for the past fifty years without yielding any results of practical value, investigations into the reactions of the paiasites to the root excretions of plants were undertaken in the hope that some result might be attained which would point to a solution of the eelworm problem on biological lines. The high degree of specialisation shown by the British potato-strain rendered it peculiary suitable for investigations of this character.

Morphological variations in Onchocerca armillata and O. gutturosa, from buffalo and cattle, with special reference to male tail and cuticular ornamentation, have been studied from a large collection of worms available from the infected aortae and ligamentum nuchae, procured from slaughter houses at 3 different localities in Uttar Pradesh, India. Seven variations in the disposition of caudal papillae in males in O. armillata and 14 in O. gutturosa are described. The prevalence of these two Onchocerca species in bubaline and bovine populations appears to be widespread.

Analysis of mitotic and meiotic chromosome spreads of Aspidogaster conchicola (Trematoda: Aspidogastrea) reveals a diploid number of 10 for this species. Haploid sets containing 5 bivalents confirm the diploid number. The karyotype consists of one pair of comparatively long subtelocentric chromosomes and four pairs of shorter acrocentric elements. The results are discussed in comparison with existing data on chromosomes of aspidogastrean species and other related helminth groups.

Exposure of encysted metacercariae of Clinostomum complanatum to UV light (254 nm) for 60 min reduced their development into adult worms in buff-backed herons (95.7% reduction in worm burden). Metacercariae that succeeded in developing into adult worms, showed low fecundity levels. Furthermore, 30% of eggs laid showed abnormal shape; however, all normal and abnormal eggs failed to hatch into miracidia. The effectiveness of UV-irradiated metacercariae as a vaccine was investigated. Compared to control unvaccinated herons, the vaccinated group showed a significantly high protection rate (73.8%) against challenge. In vitro, worm development after challenge showed decreased fecundity and increased egg abnormalities, where only 1.5% of all eggs produced hatched into miracidia. A passive haemagglutination test revealed increased antibody titres against soluble adult worm antigen in both vaccinated and vaccinated-challenged birds. It was concluded that vaccination of herons using encysted metacercariae UV-irradiated for 60 min can protect them against challenge infection.

Cephalobus parasiticus Sandground, 1939, reported from the stomachs of monkeys, is shown to resemble the sour paste eelworm, Turbatrix rediviva, so closely as to be identical with it.

It is suggested that the monkeys probably acquired the nematodes by consuming fruit, or some other vegetable substance, on which the worms were living saprophagously; having been brought to the food by visiting flies.

Regular monthly examination of lungs of donkeys, with a total of 423 in a year, revealed that in Morocco Dictyocaulus arnfieldi infection is present throughout the year with an annual incidence of 47.8% (range 30 to 62.2%). The monthly mean number of worms per animal varied from 19.4 to 69.6 (annual average 39.5) with a maximum of 1000 worms in a donkey. October, February and June are the months when peaks of infections were observed. The ratio of worms in lungs to larvae per g in faeces (L.P.G) ratio varied from 1:0.57 to 1:1.33 (average 1:0.97) and although this relation was significant, cases with high worm burden and no larvae in faeces were observed.

Few studies have examined vertebrate models of invasive species to explore parasite release as a proposed mechanism through which host species might become invasive. In this study, we examined evidence for parasite release in invasive American bullfrogs (Rana catesbeiana/Lithobates catesbeianus) from five sites in Victoria, British Columbia, Canada. We examined helminth species richness, as well as the prevalence, intensity and abundance of lung and kidney fluke infections. These flukes are expected to impose costs on host survival, growth and reproductive output. We compared measures of these parasite taxa with bullfrogs from Ontario and New Brunswick where they are endemic. Helminth species richness in bullfrogs from the Victoria sites was lower than in Ontario bullfrogs, but comparable to reported indices for other endemic populations. The prevalence of lung flukes (Haematoloechus spp.) in bullfrogs from Victoria was twice as high as was observed in the Ontario bullfrogs, and higher than has been reported from other endemic locations. In four of the five study sites in Victoria, numbers of Echinostoma spp. kidney cysts were lower than observed in endemic populations; however, the fifth site had uncharacteristically high numbers of cysts. In this study, there did not appear to be clear evidence to support parasite release using either parasite species numbers, or infection by specific parasite taxa. Instead, the invasive bullfrogs demonstrated high parasite species richness and high levels of infection for parasites known to be harmful to their hosts.

The superfamily Pronocephaloidea Looss, 1899 comprises digeneans occurring in the gut and respiratory organs of fishes, turtles, marine iguanas, birds and mammals. Although many life cycles are known for species of the Notocotylidae Lühe, 1909 maturing in birds and mammals, relatively few are known for the remaining pronocephaloid lineages. We report the cercariae of five pronocephaloid species from marine gastropods of the Queensland coast, Australia. From Lizard Island, northern Great Barrier Reef, we report three cercariae, two from Rhinoclavis vertagus (Cerithiidae) and one from Nassarius coronatus (Nassariidae). From Moreton Bay, southern Queensland, an additional two cercariae are reported from two genotypes of the gastropod worm shell Thylacodes sp. (Vermetidae). Phylogenetic analysis using 28S rRNA gene sequences shows all five species are nested within the Pronocephaloidea, but not matching or particularly close to any previously sequenced taxon. In combination, phylogenetic and ecological evidence suggests that most of these species will prove to be pronocephalids parasitic in marine turtles. The Vermetidae is a new host family for the Pronocephaloidea.

Acanthogyrus (Acanthosentis) maroccanus (Dollfus, 1951), an insufficiently described quadrigyrid acanthocephalan of cyprinid fishes from Northwest Africa, is redescribed based on recently collected specimens from the Algerian barb Luciobarbus callensis (Valenciennes) in Algeria. Newly observed morphological features for A. (A.) maroccanus include the arrangement of proboscis hooks (not in regular circles), the male reproductive structures extending into the copulatory bursa and the presence of a para-receptacle structure and vaginal sleeve. The mechanism of copulation of this acanthocephalan is described based on several copulating pairs. The phylogenetic position of A. (A.) maroccanus within Eoacanthocephala was assessed based on partial 28S rDNA sequences. Maximum likelihood and Bayesian inference analyses placed A. (A.) maroccanus in a clade with Palliolisentis (Demidueterospinus) ophiocephalus (Thapar, 1931), both species included in the Quadrigyridae, the only family within the Gyracanthocephala.

Neoechinorhynchus is one of the most speciose genera of acanthocephalans, with approximately 116 described species. A recent study, aimed at establishing the genetic diversity of Neoechinorhynchus in Middle American freshwater fishes, validated nine species molecularly and morphologically and revealed the existence of 10 putative candidate species. Neoechinorhynchus golvani, a parasite commonly found in cichlids throughout Middle America with an allegedly large intraspecific morphological variability, was found to represent a species complex; species delimitation methods uncovered three additional genetic lineages. Here, we re-analyse the morphological and molecular data for N. golvani species complex infecting cichlids in that geographical area. A multivariate analysis of variance (MANOVA) was conducted particularly for the length of apical, middle and posterior hooks of the species/lineages of Neoechinorhynchus in cichlids, revealing morphological variation in the length of apical hooks for Lineage 8, although no morphological distinction was observed for Lineages 9 and 10. A new concatenated phylogenetic analysis of one mitochondrial and two ribosomal DNA genes was used to further corroborate the species delimitation among lineages; Neoechinorhynchus Lineage 8 was found to be morphologically and genetically distinct from its sister taxa, N. golvani and other two undescribed genetic lineages, and is formally described as a new species. Neoechinorhynchus costarricense n. sp. is described from the intestines of eight species of cichlids in Costa Rica. The new species is distinguished from the other species/lineages of Neoechinorhynchus in cichlids mainly by the size of the apical hooks of the proboscis.

Dirofilaria repens is a zoonotic mosquito-borne filarioid that parasitizes in the subcutaneous tissues of carnivores, that has been incriminated in the great majority of human dirofilariasis cases reported throughout the Old World. From the Republic of Uzbekistan, recent data showed that this parasite is endemic in domestic and wild carnivores. In contrast, information regarding human infection is scarce and mostly outdated, with a single case report being published during the last decades. The present paper reports a case of recurrent autochthonous infection with D. repens in a patient living in the rural area of the Sirdaryo Region of Uzbekistan and having no international travel history. The first diagnosis was in 2019, when the patient presented with what was suspected to be a tumour of the left breast. Three years later, in 2022, she presented for a consultation after experiencing redness, occasional swelling and persistent itching in the umbilical region of the abdomen. The ultrasound indicated the presence of a living, motile nematode. Following anthelmintic therapy, the parasite was surgically removed and identified as a female D. repens. The present report highlights the possibility of human re-infection with D. repens and further underlines the necessity of raising public awareness and implementing of solid control strategies in carnivores.

Species-specific microenvironmental preferences and interactions between parasite species have been the focus of many ecological studies. Here, we studied the distribution of ectoparasite species within the gill apparatus of bream (Abramis brama) from Lake Lubāns (Latvia) to establish whether digenean metacercariae: (1) prefer specific patches within the gill apparatus; (2) co-occur in the same patches with monogeneans and copepods within a host individual; and (3) interact with monogeneans and copepods. We recorded all parasites on gill arches of the same host species and used null models to analyse co-occurrences of digenean metacercariae, monogeneans and copepods. Zero-inflated mixture models were used to define the preferred patches of parasites. We found that digenean metacercariae (Bucephalus polymorphus) prefer specific patches of the gill apparatus to encyst, and shared these preferences with monogeneans and copepods, but did not interact with them. We concluded that digenean metacercariae have a species-specific microenvironmental preference to encyst in the gill apparatus and their occurrence (even in high numbers) does not reduce the success of attachment of monogeneans and copepods in the same gill patches.

Very little is known about parasitic diseases of eastern box turtles (Terrapene carolina carolina). The objective of this study was to examine the parasitic fauna of eastern box turtles collected from southern Indiana, USA. Turtles (n = 40) were salvaged mostly as road kills from southern Indiana between May and October 2009. Seven species of helminths in total were found parasitizing the gastrointestinal tract, including two digenean trematodes (Brachycoelium salamandrae and Telorchis robustus) and five nematodes (Oswaldocruzia pipiens, Cosmocercoides dukae, Falcaustra affinis, F. chelydrae and Serpinema trispinosus). We report prevalence, abundance and mean intensity of infection for all helminths. Helminths were not found in any other organs examined (heart, gonads, liver, heart, kidney and urinary bladder) and no ectoparasites were found. Overall, mean intensity of infections was low (1–14 parasites/host), suggesting that these parasites are unlikely to be associated with negative health impacts. This constitutes the first study of this kind for Indiana.

Based on morphometric, morphological and molecular characterization using partial small subunit 18S ribosomal DNA (rDNA) and the D2/D3 domain of large subunit 28S rDNA, we described a new species Mononchoides kanzakii collected from manure, and the known species Mononchoides composticola Steel, Moens, Scholaert, Boshoff, Houthoofd and Bert, 2011, isolated from the dung beetle Oniticellus cinctus (Fabricius, 1775). Phylogenetic trees based on the evolutionary model (GTR + I + G) were inferred by Bayesian inference algorithms. Mononchoides kanzakii sp. n. is characterized by 28–32 longitudinal ridges, discontinuous at level of stoma; amphidial apertures inconspicuous; metastegostom armed with thorn-shaped dorsal tooth; a flattened, claw-like right subventral tooth, and left subventral denticulate ridge with 12–14 fine denticles delimited by a group of five denticles in females vs. triangular, flattened right subventral tooth, 5–8 prominent denticles at left subventral sector in males; cloacal lips with a distinct rim; and gubernaculum with cuticularized, proximal and distal extensions of equal length, each constituting half of the length of the wider part of gubernaculum.

Furcocercariae of the genus Neodiplostomum Railliet, 1919 (Diplostomidae Poirier, 1886) were found in freshwater snails Helicorbis sujfunensis Starobogatov, 1957 (Planorbidae Rafinesque, 1815) collected from three localities in the Russian southern Far East. For the trematodes from each locality, frogs played the role of the second intermediate host, and rats were the definitive host. Chickens were insusceptible to infection. The morphological and molecular data obtained for these trematodes indicated they were representatives of the same species. The experimentally-derived adult individuals were morphometrically similar to the East Asian Neodiplostomum seoulense (Seo, Rim, Lee, 1964), Neodiplostomum oriolinum Oschmarin, 1963, Neodiplostomum leei Chai and Shin, 2002, and Neodiplostomum boryongense Shin et al., 2008. Analysis of available data on the life cycle, developmental stage morphology, and molecular genetic characteristics of East Asian Neodiplostomum revealed a lack of information for objective assessment of the species status of neodiplostomula found in the East Asia region. Based on the considerations above and the data for the cox1 marker, we named the trematode Neodiplostomum cf. seoulense (Seo, Rim, Lee, 1964) sensu Pyo et al., 2014. In a phylogenetic reconstruction based on nuclear and mitochondrial markers, neodiplostomulas clustered into geographically related groups: South American, North American, European, and East Asian, with the former occupying an external position in the tree, which may indicate South America as a center of Neodiplostomum speciation.

The yellow-necked mouse, Apodemus flavicollis, can be considered as a model for genetic polymorphism produced by the frequent presence of supernumerary or B chromosomes (Bs). Host genetic background is rarely taken into account in studies of parasite sex ratio. The main aim of this study was to investigate the range of infrapopulation sex ratios for nematode parasites of the yellow-necked mouse and to determine which factors most influence variation in parasite sex ratios. Six nematode species found in the collected yellow-necked mice were analysed. We confirmed the predominant pattern of female-biased sex ratios in vertebrate parasite infrapopulations. The presence of B chromosomes in host genomes played an important role in infrapopulations of Heligmosomoides polygyrus, Syphacia stroma and Trichuris muris, as hosts with B chromosomes carried a higher proportion of males. The relative increase of males in infrapopulations could result from a shift in parasite life history strategy, induced by adaptation to the specific host genotypes (Bs present). In a meta-analysis with previously published data, the sex determination system was demonstrated to play a significant role in nematode sex ratio variation, as well as specific life history patterns, such as the place of egg hatching.