We examined the frequency distributions of worm burdens and worm biomass of the dominant gastric nematode, Protospirura muricola, of eastern spiny mice (Acomys dimidiatus) surveyed at 4-year intervals over a period of 12 years in two montane wadis in St. Kathrine's Protectorate in S. Sinai, Egypt. Whilst the frequency distribution of worm burdens differed significantly between the mice from the 2 wadis, variation between years was not significant among mice from each wadi. The frequency distribution of P. muricola worm burdens did not differ significantly between the sexes, despite female mice carrying significantly higher worm burdens, but showed a marked difference between juvenile and mature mice. The biomass of P. muricola carried by individual mice varied considerably, with two mice from Wadi Gharaba carrying biomasses of over 1 gm, representing over 2.5% of total body weight. Biomass showed significant positive covariation with worm burdens, and heavy biomass and worm burdens were most likely among the older mature female mice. The frequency distribution of individual worm weights indicated that frequent low-dose transmission was common, with rarer instances of higher-dose, package transmission from insect vectors of this parasite.

Serpinema currently comprises 12 valid species of nematode parasites of freshwater turtles, distributed across the Neotropical, Oriental and Palearctic regions. Thus, we describe Serpinema yehi n. sp., a parasite of Rhinoclemmys punctularia from the Brazilian Amazon. Species identification was based on light and scanning electron microscopy, and molecular and phylogenetic analyses were performed using partial sequences of the mitochondrial cytochrome c oxidase subunit I and nuclear 18S genes. Serpinema yehi n. sp. can be distinguished from its congeners by the number of ridges in the buccal capsule, the number and arrangement of caudal papillae, the length and morphology of the right spicule, vulvar lip morphology and the number of mucrons on the female tail. Phylogenetic analyses recovered the new species as closely related to Camallanus, but not nested within the Camallanus spp. clade, thereby supporting the recognition of Serpinema as a valid genus. Serpinema yehi n. sp. represents the second species of the genus described from R. punctularia and the eighth species recorded from Brazil.

International collaborations enhance research outcomes by providing partners with increased access to resources, training and multidisciplinary expertise. These partnerships facilitate knowledge exchange and infrastructure development, promoting sustainable research ecosystems. The development of early career researchers (ECRs) is particularly important in strengthening research capacity within international research networks. However, literature regarding their experiences is limited. Here, we present a qualitative study of one international research network, the UK Global Challenges Research Fund-supported Global Network for Neglected Tropical Diseases (2018–2022) and its impact on ECR career development. Semi-structured interviews were conducted with 19 ECRs previously supported by the Network; these were then thematically analysed. Key themes were identified relating to ECR experiences with the Network. Findings indicate that the Network provided valuable opportunities for professional development, knowledge exchange and collaborative research, which participants described as transformative for their careers. However, ECRs stressed that structural barriers such as insufficient funding and job insecurity limited the Network’s longer-term impact, severely affecting ECR retention and development. These results highlight the benefits of international research collaborations and the need for targeted support and sustainable research funding to retain and develop ECRs, particularly in disease-endemic countries.

Freshwater streams in Iraq harbour a remarkable diversity of fish species. A similarly high diversity has also been recorded for diplozoid parasites, which are commonly associated with the cyprinoid fishes. A new species, Paradiplozoon vorax sp. nov., is described from Leuciscus vorax from Al-Gharraf River. This is the 21st Paradiplozoon species recorded from Iraq and presumably the 11th species from this fish host. Phylogenetic analyses based on the ITS2 rDNA region revealed a close relationship between P. vorax sp. nov. and P. pavlovskii, which exhibits a wide geographical range spanning Europe and the Middle East. Although these two species are morphologically similar, they differ in important characters such as the number of folds in the hindbody, the shape of postovarian caecum or the shape of anterior joining sclerite of clamps. It is hypothesized that these two species originated by vicariant speciation from a common ancestor associated with ancestral Aspius-like leuciscids.

In the last decades, different 5-nitroindazole-based compounds have been synthesized and proposed as potential agents for treating the infection caused by Trypanosoma cruzi, i.e. Chagas disease. In previous works, the 1,2-disubstituted 5-nitroindazolinone system has been identified as a promising scaffold to design compounds, among which derivatives with a benzyl moiety at N-2 stand out. Now, we have synthesized 4-, 6- and 7-nitroindazolin-3-ones (19–24), analogues of the previously studied 2-benzyl-1-methyl-5-nitroindazolinone (1) and 2-benzyl-5-nitro-1-propylindazolinone (2), to explore the impact of the nitro group position on their trypanocidal activity. These 8 nitro derivatives were in silico predicted to have good oral bioavailability and no toxicity risks. In vitro assays over bloodstream trypomastigotes (Y strain, DTU TcII) showed an improvement in the lytic profile of 2-benzyl-1-propyl derivatives, when the NO2 group is moved to position 6 of the indazole ring: EC50 = 34.55 µM (23) versus EC50 > 50 µM (2, 22 and 24). Regarding the assays on amastigotes (Tulahuen strain, DTU TcVI), 4-, 6- and 7-nitroindazoles did not display better activity (EC50 from 3.82 to > 20 µM) than 5-nitroindazoles, with EC50 = 2.34 (1) and 3.03 µM (2). The lack of cytotoxicity over cardiac (CC50 > 200 µM) and L929 cells (CC50 > 170 µM) supports selective action, particularly of 5-nitroindazolinones towards intracellular forms: SI > 85.47 (1) and 56.53 (2). Altogether, data indicate that the anti-T. cruzi activity of 4-, 6- and 7-nitroindazolinones is not better than that of 1 and 2, not presenting significant advantages over these two 5-nitroindazolinones.

The helminth communities of owls may provide indirect information on host ecology and long-term changes in trophic interactions. We analysed 645 owl specimens from 10 host species, collected in Central Europe between 1963 and 2026, to test for temporal changes in overall infection probability, helminth abundance and richness, host-dependent trajectories and taxon-specific trends. In total, 22 helminth taxa were recorded, and 262 hosts (40.6%) were infected. The highest observed taxon richness occurred in Strix aluco (15 taxa) and Asio otus (10 taxa), which were also the most frequently sampled hosts. Analyses based on individual-host records showed significant long-term changes in community-level infection metrics and in several common helminth taxa. Cladotaenia globifera, Porrocaecum spirale and Strigea strigis declined over time, whereas Centrorhynchus aluconis increased. The marked decline of S. strigis, a parasite linked to amphibian-mediated transmission pathways, suggests a long-term weakening of these trophic links. Temporal patterns differed among hosts, and the dominant taxa varied markedly among owl species. Synanthropic species, particularly Tyto alba and Athene noctua, showed comparatively depauperate helminth assemblages, consistent with reduced exposure to diverse prey-mediated transmission pathways. These results indicate that long-term change in owl helminth communities is taxon- and host-specific rather than uniform. Owl helminths may therefore serve as informative indicators of changes in prey use and food-web structure in human-modified landscapes.

Tritrichomonas foetus is the causative agent of bovine trichomonosis, a venereal disease that compromises cattle fertility and causes major economic losses. We report a chromosome-scale genome assembly of T. foetus isolate, TfOz5, from Queensland, Australia generated using Oxford Nanopore long-read sequencing and Pore-C chromatin conformation capture. The 137.7 Mb assembly spans 5 chromosomes with an N50 of 24 Mb. Repeat analysis revealed 43.6% repetitive content dominated by DNA transposons. Gene prediction identified 32 104 protein-coding genes of which 98.3% were assigned to orthogroups. Comparative analysis with the KV-1 genome detected 160 structural variants, including deletions (40.6%), insertions (22.5%), duplications (16.3%), inversions (13.1%) and translocations (7.5%). Across 9 Parabasalia species, we observed high gene family conservation and 305 species-specific orthogroups in TfOz5. Phylogenetic analysis confirmed the monophyletic cluster of T. foetus strains (K, KV-1 and TfOz5). Inter-species comparison with the human urogenital parasite Trichomonas vaginalis G3 revealed conserved gene sets between T. foetus TfOz5 and T. vaginalis G3 that were significantly enriched for core cellular functions (translation, cell cycle and mitochondria-related homology hits), while divergent genes highlighted species-specific host interactions. Trichomonas vaginalis G3 showed enrichment for proteolysis, regulation of DNA-templated transcription and symbiont–host adhesion, traits consistent with persistence in the human genital tract. Similarly, T. foetus TfOz5 host interactions align with long-term survival in the bovine reproductive niche. This chromosome-scale assembly provides a valuable genomic framework for investigating parasite evolution, identifying candidate genetic features associated with host adaptation and supporting the development of next-generation recombinant vaccines to control bovine trichomonosis.

Nematodes constitute one of the most diverse and ecologically significant parasite groups in fishes, yet their diversity and host associations remain poorly documented in tropical freshwater systems. In this study, a community-wide survey of 10 fish species from La Mojana wetland was conducted to assess nematode diversity and host associations. The highest infection indices were recorded in Pseudoplatystoma magdaleniatum (Pimelodidae), Sorubim cuspicaudus (Sciaenidae) and Sternopygus macrurus (Sternopygidae). Morphological examination revealed 2 distinct nematode morphotypes corresponding to larval Contracaecum (Anisakidae) and adult camallanids. Molecular analyses based on ITS2, 18S rRNA, 28S rRNA and mitochondrial rrnS markers resolved well-supported lineages corresponding to Contracaecum jorgei Sardella, Mancini, Salinas, Simões & Luque, 2020 and Spirocamallanus sp. The multilocus approach demonstrated the coexistence of phylogenetically distinct nematode groups within the same fish community. Patterns of parasite association revealed a broader host distribution for Contracaecum, whereas Spirocamallanus showed more restricted occurrence. Coinfections reflected the structural complexity of parasite communities in this tropical system. Because fish represent a primary protein source for local communities in La Mojana, the detection of anisakids raises considerations for food safety and public health. This study provides the first multilocus characterization of nematode diversity and host associations in the region, contributing to the understanding of parasite ecology in tropical freshwater ecosystems.

This study aimed to investigate the diversity, prevalence and host specificity of Dictyocaulus lungworms in free-ranging wild ungulates in Lithuania using morphological and molecular approaches. A total of 129 individuals representing 4 host species (red deer, roe deer, moose and European bison) were examined. Four Dictyocaulus species were identified: D. cervi, D. skrjabini, D. capreolus and D. viviparus bisontis. Infection parameters varied markedly among host species. Red deer showed the highest prevalence and parasite diversity, whereas European bison exhibited low prevalence but relatively high infection intensity. Moose displayed intermediate infection levels with a high proportion of co-infections, while roe deer were infected exclusively with the host-specific species D. capreolus. Co-infections involving multiple Dictyocaulus species were common in cervids, indicating complex transmission dynamics. Molecular analyses based on mitochondrial (cox1) and nuclear (SSU rDNA) markers confirmed species identification and revealed clear genetic differentiation among taxa. Phylogenetic incongruences between markers suggest potentially complex evolutionary relationships, possibly influenced by co-infections and host overlap. These findings provide the first comprehensive insight into Dictyocaulus infections in wild ungulates in Lithuania and highlight the importance of combining morphological and molecular methods for accurate parasite identification. The results contribute to a better understanding of lungworm epidemiology and host–parasite interactions in wildlife and emphasize the need for improved surveillance strategies.

Cryptosporidium muris is a gastric species primarily infecting rodents, whereas natural infections in cats are rarely documented and biologically poorly characterized. Oocysts of C. muris were detected in a cat and monitored for 120 days. Molecular characterization was performed on the small subunit rRNA, actin, 70-kDa heat shock protein, Cryptosporidium oocyst wall protein and thrombospondin-related adhesive protein of Cryptosporidium-1 loci. Oocyst morphology was evaluated microscopically. Infectivity and shedding dynamics were assessed in BALB/c mice and compared with C. muris RN66 and C. proliferans. Oocyst integrity during storage at 4°C was monitored for 60 days at 15-day intervals using flow cytometry and viability assays. The infected cat shed oocysts for 97 days, with a maximum intensity of 371 200 oocysts per gram (OPG), yet remained clinically asymptomatic. Developmental stages were confirmed histologically in gastric biopsy specimens. Haematological and biochemical parameters remained within reference ranges, and no concurrent parasitic, bacterial or viral infections were detected; only seropositivity to Toxoplasma gondii was recorded. All analysed loci showed 100% identity with C. muris RN66. Oocyst morphology did not differ from reference isolates. However, oocysts originating from the cat exhibited markedly reduced environmental stability, with a 90% decline in integrity within 60 days. Experimental infection of mice confirmed infectivity, but total oocyst output (32 300 OPG/days) was several orders of magnitude lower than that of C. muris RN66. Although genetically identical to rodent isolates, the feline-derived C. muris displayed altered biological properties, including reduced oocyst stability and transmission fitness. Cats may serve as susceptible but epidemiologically inefficient hosts.

Host age can indicate where avian helminths are acquired, but age patterns may also reflect seasonality, cumulative exposure and parasite persistence. We analysed age-specific prevalence, abundance and infection intensity in our long-term dataset of individually examined birds from the Czech Republic. Helminth taxa were classified statistically according to age and seasonal effects, and, independently, trematodes were assigned a priori to biogeographic groups based on their life cycles and intermediate-host distributions. Among 177 taxa retained for statistical analysis, 34 showed a pronounced adult-biased effect (Category A), 9 showed neither a strong adult effect nor significant seasonality (Category B) and 134 showed significant seasonal effects without meeting the Category A criterion (Category C). The independent biological classification provided clearer evidence of geographic acquisition. Trematodes associated with wintering grounds in southern Europe or Africa occurred in 0.21% of first-year and 3.12% of adult host–taxon associations. In contrast, nonlocal trematodes completing their life cycles elsewhere in Europe or marine taxa occurred in 0.70% and 2.01%, respectively. In contrast, cosmopolitan trematodes and those completing their life cycle locally were more prevalent in first-year associations. Most qualifying nonlocal species showed adult-biased prevalence, although Psilotrema oligoon and Psilotrema simillimum showed the opposite pattern. Several biologically nonlocal taxa were assigned to Category B or C because age and sampling month were strongly confounded, showing that failure to detect an independent age effect does not imply local transmission. Age-structured helminth data, therefore, provide a useful signal of migration-mediated parasite acquisition when interpreted together with parasite life cycles, intermediate-host distributions, seasonality and persistence.