Scabies is a neglected tropical disease caused by the ectoparasitic mite, Sarcoptes scabiei var. hominis (S. scabiei). Common scabies, the most prevalent clinical subtype of scabies, is characterized by pruritus, multiple skin lesions and low mite burden. In contrast, crusted scabies, an extremely contagious variant, is characterized by hyperkeratosis and high mite burden, with or without pruritus. Scabies can be diagnosed based on clinical manifestations, with confirmation obtained through microscopic identification of diagnostic features of S. scabiei. However, owing to the diversity and non-specific nature of its clinical manifestations and insufficient knowledge regarding early-stage clinical manifestations, the diagnosis of crusted scabies continues to be delayed. Herein, we present three cases of scabies with varying degrees of crusting and mite burden. Three patients with physical and microscopic results suggesting scabies were selected for this study. Case 1 had mild crusting and low mite burden, case 2 had severe crusting and high mite burden and case 3 had mild crusting and high mite burden. In this case report, ‘the initial stage of crusted scabies’ refers to the progression from common to crusted scabies. The discussion regarding the diagnostic characteristics of the initial stage of crusted scabies is expected to aid the early diagnosis of crusted scabies.

Avian trypanosomes (Trypanosoma, Kinetoplastea) are successful blood parasites occurring worldwide. These parasites are usually non-pathogenic to their avian hosts, thus neglected in studies regarding their life cycles and vectors. Several families of blood-sucking dipteran insects, including mosquitoes, have been identified as vectors of avian trypanosomes. Mosquitoes have been experimentally confirmed as vectors of Trypanosoma culicavium and Trypanosoma thomasbancrofti. In this study, we describe a third species of avian trypanosomes occurring in mosquitoes, designated as Trypanosoma tertium n. sp. This species can be distinguished from related trypanosome species based on morphology and small subunit rRNA gene sequence. Two isolates of T. tertium n. sp. obtained from a mosquito and a bird host were able to infect two subspecies of laboratory Culex pipiens mosquitoes, with infection rates reaching 60% and heavy infections in 90% of positive females. In infected mosquitoes, trypanosomes occurred as long epimastigotes in the midgut and short epimastigotes and rosettes in the hindgut. Putative infectious stages were detected in the diuretic liquid of infected mosquitoes, suggesting, besides transmission through ingestion of the infected vector, a possible transconjunctival infection. Among wild mosquitoes, avian trypanosomes were detected exclusively in Cx. pipiens with 3.3% total prevalence, while T. tertium n. sp. prevalence was only 0.08% among 1128 dissected Cx. pipiens individuals. In birds, T. tertium n. sp. was detected in 8 species within which the prevalence was 1.3% (686 birds), while it was 0.3% in total (3084 birds). We discuss the relationship of the newly described T. tertium n. sp. with other mosquito-transmitted trypanosomes.

Visceral leishmaniasis (VL) is a tropical disease that can be fatal if acute and untreated. Diagnosis is difficult, the treatment is toxic and prophylactic vaccines do not exist. Leishmania parasites express hundreds of proteins and several of them are relevant for the host's immune system. In this context, in the present study, 10 specific T-cell epitopes from 5 parasite proteins, which were identified by antibodies in VL patients’ sera, were selected and used to construct a gene codifying the new chimeric protein called rCHI. The rCHI vaccine was developed and thoroughly evaluated for its potential effectiveness against Leishmania infantum infection. We used monophosphoryl lipid A (MPLA) and polymeric micelles (Mic) as adjuvant and/or delivery system. The results demonstrated that both rCHI/MPLA and rCHI/Mic significantly stimulate an antileishmanial Th1-type cellular response, with higher production of IFN-γ, TNF-α, IL-12 and nitrite in vaccinated animals, and this response was sustained after challenge. In addition, these mice significantly reduced the parasitism in internal organs and increased the production of IgG2a isotype antibodies. In vivo and in vitro toxicity showed that rCHI is safe for the mammalians, and the recombinant protein also induced in vitro lymphoproliferative response and production of Th1-type cytokines by human cells, which were collected from healthy subjects and treated VL patients. These data suggest rCHI plus MPLA or micelles could be considered as a vaccine candidate against VL.

The Mediterranean and the Middle East represent unique biogeographical regions that significantly shaped the evolutionary history and particular diversity of their associated organisms. However, knowledge on the copepods parasitizing freshwater fishes in these regions is limited. This study aims to investigate the diversity and phylogeny of parasitic copepods in freshwater fishes across the Mediterranean and the Middle Eastern regions. A total of 169 freshwater fish species from the Mediterranean and Middle East were examined for metazoan parasites, yielding over 1000 parasitic copepods. A thorough morphological evaluation combined with molecular analyses of partial fragments of rDNA (18S and 28S) and mitochondrial cytochrome c oxidase subunit I (COI) led to the identification of 7 species of Ergasilidae and 3 species of Lernaeidae. These findings include the descriptions of 2 new species: Ergasilus italicus n. sp. parasitizing South European nase, Protochondrostoma genei (Bonaparte, 1839), in Italy and Pseudolamproglena zahrziensis n. sp. found in yellow barbel, Carasobarbus luteus (Heckel, 1843), in Iraq. New host and geographical records, along with molecular data are provided for 8 previously described species – Ergasilus barbi Rahemo, 1982, Ergasilus briani Markevich, 1933, Ergasilus lizae Krøyer, 1863, Ergasilus rostralis Ho, Jayarajan & Radhakrishnan 1992, Neoergasilus japonicus (Harada, 1930), Paraergasilus longidigitus Yin, 1954, Lamproglena pulchella von Nordmann, 1832 and Lernaea cyprinacea Linnaeus, 1758.

Helminth infection is highly prevalent in indigenous chickens reared in semi-scavenging/ scavenging systems in Bangladesh. Here, we estimated the prevalence of gizzard worm infection in indigenous chickens, the detection of the worm-induced pathologies, the development of ex vivo cultural protocol, and anthelmintic efficacy. We randomly collected and examined 390 chickens and isolated worms from the gizzard and proventriculus. The isolated worms were identified as Cheilospirura hamulosa Diesing, 1861. The overall prevalence of C. hamulosa was 33.1% (129 out of 390). Prevalence of the worm was almost similar in both sexes but significantly (p <0.05) higher in adult chickens (44.3%) and in the summer season (47.1%). In heavy infections, C. hamulosa destroyed the muscular layer of the gizzard. The presence of brown necrotic tissues and curd-like caseous materials was detected in the affected gizzards. In severe cases, the horny lining of the gizzard was inflamed, necrotized and marked by multiple holes and brick-red colored spots. Liquefied, fetid materials oozed out from the muscular layer in extensive cases. Histopathological examination showed marked infiltrations of eosinophils. In serum-supplemented M199 and DMEM, adult C. hamulosa survived well and reproduced. Levamisole (LEV) and ivermectin (IVM) efficiently killed the worm. However, albendazole (ABZ), mebendazole (MBZ) and piperazine (PPZ) did not kill the worms. Our results suggest that C. hamulosa is highly prevalent in semi-scavenging chickens in Bangladesh. LEV and IVM can be used to treat and control the infection in chickens.

Brazil has the richest biodiversity of Ergasilidae on Earth, with 76 species in 19 genera. However, several authors suggested that there is still great potential for discoveries, especially regarding genetic data that are still scarce for ergasilids from this region. To expand our knowledge of this taxon, we conducted an integrative study involving morphological (light and scanning electron microscopy) and molecular analyses of ergasilids from fishes sampled in the Pardo River, São Paulo State, Brazil. Two ergasilid species were found, Gamispatulus schizodontis and Rhinergasilus piranhus parasitizing the nostrils of 5 fish species (native and exotic): (i) R. piranhus from Astyanax lacustris; Cyphocharax modestus; Coptodon rendalli; Psalidodon bockmanni; and (ii) G. schizodontis from Serrasalmus maculatus. Additionally, we redescribed R. piranhus herein based on novelties and discrepancies found in the antennules, antennae, body segments and ornamentation of the swimming legs. Novel molecular data of ribosomal (18S and 28S rDNA) and/or mitochondrial (cox 1) genes were provided for both species and the phylogenetic relationships among the ergasilids were tested. Relationships between species/genera are still uncertain in Ergasilidae, but it was possible to verify the formation of 5 well-supported terminal clades – i.e. including a clade formed only by Neotropical species. More molecular data are needed to test this hypothesis, but the clades observed here represent good targets for future taxonomic revisions. The occurrence of R. piranhus specimens in the introduced fish, Co. rendalli can indicate (for the first time) host switching in this parasite species and spillback from native to introduced hosts.

Eimeria species, the causative agents of avian coccidiosis, are major pathogens in poultry, resulting in substantial economic losses and welfare concerns worldwide. Understanding their complex life cycle, including different developmental stages and host interactions, is essential for advancing control strategies. Traditional cultivation systems, such as primary cell cultures and immortalised cell lines, have provided valuable insights, but they present limitations in supporting complete parasite development, host–pathogen interactions and immune response evaluation. Recent advances in intestinal organoids offer a promising alternative for Eimeria research. Initially developed in human models, intestinal organoids have been successfully adapted to avian systems, replicating the architecture, cellular diversity and physiological functions of the chicken gut epithelium. These 3D models provide now a physiologically relevant platform for studying parasite development, host–pathogen interactions, immune responses and drug screening in vitro. Complementary tools, such as intestinal explants, could further enhance the experimental repertory available for investigating Eimeria species. Additionally, insights from studies on related apicomplexan parasites support the translational value of these systems. These innovative systems could support significant advances in Eimeria cultivation, enabling more robust and ethical research while reducing the use of experimental animals.

Aplectana membranosa is a cosmocercid nematode that shows affinity with various amphibian and reptile hosts, being considered a generalist species. To date, no studies have investigated the influence of host and locality in the morphological variation of this species. Thus, we analysed morphological and morphometric characters of 260 specimens of A. membranosa collected from 9 host species and 7 different localities. To complement the metric studies, we conducted phylogenetic analyses using the ribosomal genes 28S and internal transcript spacer 1 (ITS1) to determine the phylogenetic position of the species and its divergence. In the present study, it was possible to observe the cloacal papillae pattern of the species through scanning electron microscopy, and we found no morphological variation in the specimens of A. membranosa from various hosts in different localities in Brazil. The study showed low variation in all data. However, despite the low variation, we found that external environmental conditions, such as climate and latitude, influence its variation. Molecular analyses highlighted that the separation of Cosmocercidae members may be related to geographic distribution and population genetic divergence. Thus, the results illustrated in this study reiterate the importance of using integrative data to better elucidate the family’s taxonomic and evolutionary history.

Marine parasites remain understudied in South Africa with little information available on their diversity and the effects these parasites may have on their hosts. This is especially true for parasitic copepods within the family Ergasilidae. Among the 4 genera known in Africa, Ergasilus Nordmann, 1832 is the most speciose with 19 reported species. However, this represents only 12% (19/163) of the global diversity. Furthermore, only 5 known African species are reported from marine environments, and only 1 is reported from the South African coastline. Given the rich biodiversity along this coastline, a high marine parasite diversity could be expected from these shores. As a case study, the Evileye blaasop, Amblyrhynchote honckenii (Bloch), a marine and brackish fish species, was screened for parasites along the South African coastline. This resulted in the discovery of 2 species of Ergasilus new to science (Ergasilus arenalbus n. sp. and Ergasilus chintensis n. sp.), which makes them the second and third ergasilid species reported for tetraodontid pufferfishes worldwide. Although genetically distinct, the 2 newly described species clustered in the same subclade within the Ergasilidae based on 18S rDNA, 28S rDNA and COI mtDNA phylogenies. The newly described species differ morphologically from each other, and their respective congeners based on the size and armature of the antenna; body segmentation; and general ornamentation throughout the entire body. The addition of these 2 new species from a single host species indicates that South Africa's marine fishes contain most probably a hidden parasitic copepod diversity that is worth exploring.

Clestobothrium Lühe, 1899 is a genus of cestodes belonging to the order Bothriocephalidea, which infects marine fish from the Gadiformes order. Herein, a novel species of Clestobothrium is described from the intestine of the European hake Merluccius merluccius (Linnaeus, 1758) in the Ionian Sea (Eastern Mediterranean Sea), through an integrative taxonomic approach that combines morphological and molecular data. The new species, named Clestobothrium brettiae n. sp., can be distinguished from all congeners by its unique ovary shape, and a combination of characters including the arrangement and number of testes. It shares similar morphological characters, with Clestobothrium crassiceps (Rudolphi, 1819) Lühe, 1899, which overlaps in host and geographic distribution. However, morphological differences between Clestobothrium brettiae n. sp. and C. crassiceps also include the arrangement of gladiate spinitriches, as well as a larger scolex, proglottids, testes and cirrus sac, and different ovary morphology. The establishment of Clestobothrium brettiae n. sp. as a novel taxon is supported by detailed morphological description and biometric statistics, in addition to molecular characterisation (based on partial small subunit ribosomal ribonucleic acid [rRNA], partial large subunit rRNA, and internal transcribed spacer region 2), genetic distance, and phylogenetic analyses.

Zoonotic parasites associated with domestic dogs have been well-studied in the majority of Europe. In the Balkan region, however, there is minimal knowledge of the parasites in dogs in shelters for rehoming in other European countries. This study aimed to investigate parasitic infections in dogs from two private shelters in Pristina, Kosovo. Faecal samples were collected, representing both adult dogs (72%) and puppies (28%). Coproscopic analysis revealed that 88% of dogs were infected with at least one parasite, with hookworms being the most common. Amplicon metabarcoding targeting internal transcribed spacer (ITS)-2 rRNA gene confirmed the presence of only Uncinaria stenocephala in 68% of samples apparently susceptible to benzimidazoles. The canonical F167Y and Q134H isotype-1 β-tubulin of U. stenocephala mutations conferring benzimidazole resistance were not detected. No evidence of Ancylostoma caninum was detected. Molecular analysis confirmed Giardia duodenalis in 18% of samples, with assemblages B, D and C detected. Other parasites detected included Cystoisospora spp. (18%), Toxocara canis (4%), Toxascaris leonina (6%), Trichuris vulpis (32%), Eucoleus aerophilus (10%) and Dipylidium caninum (2%). Co-infections were identified in 48% of the samples. These findings demonstrate a high frequency of gastrointestinal parasites in shelter dogs. The presence of U. stenocephala and T. vulpis points to the challenges with monitoring and managing these parasitic infections in such settings, as these are likely translocated with the rehomed dogs. The frequency of detection of hookworms emphasizes the need for further research into the distribution of hookworms in Europe because of the emerging benzimidazole resistance on other continents.

Coccidiosis, caused by Eimeria spp., leads to substantial economic losses in the poultry industry globally. These protozoan parasites invade the intestinal epithelium of birds, impairing nutrient absorption, causing diarrhoea and potentially leading to mortality. The complex endogenous life cycle of Eimeria spp., particularly the gametogony phase, presents significant challenges for in vitro cultivation. This study aimed to develop mature chicken intestinal organoids as an in vitro model capable of supporting the complete endogenous life cycle of Eimeria tenella. Two commercially available culture media, 3dGRO L-WRN conditioned medium (L-WRN) and IntestiCult™ Organoid Growth Medium (OGM), were evaluated for their ability to support chicken intestinal organoid development. The results demonstrated that basolateral-out organoids embedded in Matrigel and cultured in the L-WRN medium expanded more rapidly. In contrast, those apical-out organoids in the OGM developed more microvilli structures on enterocytes. Apical-out organoids, initially cultured in L-WRN medium and subsequently matured in OGM, were selected as the optimal host for the Eimeria infection model. Sporozoites of E. tenella successfully invaded the organoids and progressed through both the schizogony and gametogony phases. Moreover, the parasites produced a new generation of oocysts in this study. The presence of schizonts, gametocytes, and sporulated oocysts confirmed that the model can support the full endogenous life cycle of the parasite in vitro. This organoid-based infection model serves as a promising platform for studying host–pathogen interactions and developing novel interventions to control avian coccidiosis.

Toxoplasma gondii non-archetypal strains have distinct virulence profiles and immunological activation in the host when compared with archetypal strains. The present work aims to perform an analysis of the inflammatory profile during acute and early chronic infection by T. gondii atypical strain in an experimental murine model. After euthanasia, blood was collected for the quantification of specific IgG antibodies and their subtypes (IgG1/IgG3) by ELISA; bronchoalveolar lavage (BAL) was realized and immunophenotyping of lymphocytes population was performed at 12- and 30-days post infection (dpi); the levels of IFN-γ, IL-12, IL-10, TNF-α, IL-6, IL-17, nitric oxide and total proteins were determined in the BAL supernatant. Tissue cyst burden was determined in the brain homogenate, and the parasite load in the lungs was assessed by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Infection with the CK4 strain induced a lower brain cyst load similar parasite burden in the lungs, and higher levels of IgG1 and IgG3, when compared to ME49. The group infected with the CK4 strain presented higher levels of systemic IFN-γ, and both infected groups displayed similarly elevated levels of systemic TNF-α, IL-6 and IL-17 at 30 dpi, as well as higher numbers of CD4+ and CD8+ T lymphocytes in the acute stage of infection, followed by higher numbers of central and effector CD4+ T cells. IFN-γ levels in the BAL fluid were significantly higher in animals infected with the CK4 strain in both the acute and early chronic stage of infection, highlighting the involvement of the lung environment.

Schistosomiasis is a parasitic disease that imposes a significant burden on society. The eggs are the primary pathogenic factor in schistosomiasis, and their accumulation in liver could lead to the formation of granulomas and liver fibrosis. However, the metabolic changes in liver resulting from schistosomiasis remain poorly understood. We established a mouse model of schistosomiasis japonica, where the eggs accumulate in the liver and form egg granulomas. We used mass spectrometry imaging to analyze the differences in metabolites among various liver regions, including the liver tissue from normal mice, the liver area outside the granulomas in schistosomiasis mice, and the granuloma region in schistosomiasis mice. There were significant differences in metabolites between different liver regions, which enriched in metabolic pathways such as the biosynthesis of unsaturated fatty acids, taurine and hypotaurine metabolism, glycerophospholipid metabolism, glycolysis/gluconeogenesis, purine metabolism, arachidonic acid metabolism, and bile secretion. In normal liver tissue, higher concentrations of oleic acid (FA (18:1)), eicosapentaenoic acid (FA (20:5)), and L-glutamine were observed. In liver regions outside the granulomas, D-glucose and pyruvic acid were elevated compared to those in normal mice. Taurine increased in the liver of schistosomiasis. Meanwhile, there were elevated uric acid and spermidine in the egg granulomas. We employed mass spectrometry imaging technology to investigate metabolic reprogramming in liver of Schistosoma japonicum-infected mice. We explored the spatial distribution of differential metabolites in liver of schistosomiasis including unsaturated fatty acids, taurine, glutamine, spermidine, and uric acid. Our research provides valuable insights for further elucidating metabolic reprogramming in schistosomiasis.

Tritrichomonas foetus causes bovine trichomonosis, a venereal disease that reduces productivity in naturally mated cattle. Its high prevalence in Northern Australian herds underscores the need for a locally made strain-specific vaccine. This study developed and tested a whole-cell killed T. foetus vaccine using the Queensland isolate TfOz5 (vaccine strain) and TfOz-N36 (Northern Territory isolate) as the challenge strain. The heat-inactivated vaccine, adjuvanted with Montanide ISA 61 VG, was administered subcutaneously in 2 doses (5 × 10⁷ cells/dose) at a 1-month interval to mature bulls (n = 6) (4–7 years old), while controls (n = 6) (4–8 years old) received adjuvant with PBS. Bulls were experimentally challenged intrapreputially with live cultures of T. foetus at 2- and 6-months post first vaccination. A therapeutic trial with T. foetus-positive, persistently infected mature bulls (n = 10) (4–7 years old) used the same vaccine regime without the subsequent T. foetus challenges. The vaccine was found to be safe, causing only mild local reactions. The vaccine challenge experiment demonstrated similar duration of T. foetus positivity, confirmed by quantitative polymerase chain reaction (qPCR), compared to controls (94 vs. 106 days, P = 0.73). In the therapeutic experiment, 2/10 treated bulls tested negative for T. foetus at the end of the trial, while the remaining eight remained positive. Vaccinated bulls in both experiments showed significantly elevated serum anti-T. foetus IgG antibody levels, confirming the vaccine’s immunogenicity. These findings demonstrate that the experimental vaccine is safe and capable of eliciting a specific immune response in mature bulls.

This study investigated the prevalence and genetic diversity of Hydatigera parva in 341 native rodents in a riparian habitat in the Mediterranean part of Spain. Polycephalic larvae were found in 32% of wood mice (Apodemus sylvaticus; n = 84) and 0.4% of Algerian mice (Mus spretus; n = 257) examined, with a significantly higher prevalence in the former. No significant differences in infection prevalence in wood mouse were found between sex and age groups, habitats (agricultural vs natural) or seasons. Genetic analysis of 25 cysts using cox1 sequences revealed low nucleotide (0.00110) and haplotype diversity (0.380), suggesting limited genetic variation. Phylogenetic analysis showed that the studied H. parva isolates were genetically distinct from other species within the genus Hydatigera. The results indicate a lower genetic diversity in European than in African populations, supporting the hypothesis that H. parva was introduced to Europe from Africa, possibly with its final host, the common genet (Genetta genetta), an abundant predator in the study area. This study is the first population genetic study of H. parva in the Iberian Peninsula. It provides insights into the population structure of the parasite and its interaction with rodent hosts, and thereby constitutes an example of the potential identification of an introduction route of a parasite with its definitive host. It also confirms the importance of the wood mouse as an intermediate host for the maintenance of the parasite’s life cycle in Europe and forms the basis for further studies on the distribution and genetic diversity of H. parva.

Ectoparasites are ubiquitous and are often harmful to host fitness. Whereas protective responses to ectoparasitism in vertebrate hosts are well documented, our understanding of such defences in invertebrates remains limited. Here, we examined attachment-resistance in adult Drosophila to their naturally co-occurring ectoparasitic mites, Gamasodes pachysetis (Parasitidae). Significant differences in mite attachment duration were documented among 6 species of Drosophila, providing evidence for interspecific differentiation in attachment-resistance. Experiments with D. malerkotliana, a species exhibiting a relatively high rate of mite detachment, revealed that pre-infesting flies significantly reduced mite attachment duration compared to naïve controls, indicating a priming effect. In contrast, a reduction in attachment duration was not observed in D. malerkotliana after experimentally wounding the abdominal cuticle. These results suggest that the priming effect is not simply a response to cuticle damage, and that its activation may depend on mite-specific factors. Eight genes were individually tested for their effects on the rate of mite detachment from adult flies by deploying the GAL4-UAS gene knockdown system in D. melanogaster. Knockdown of heat shock protein 70Ba (Hsp70Ba) and prophenoloxidase 2 (PPO2), which underlie general stress and melanization responses, respectively, significantly prolonged mite attachment duration, implicating their involvement in host attachment-resistance to mites. Together the results support the existence of inducible protective mechanisms mediating parasitism by mites in a naturally occurring invertebrate host–ectoparasite symbiosis.

Dioctophyme renale, the giant kidney worm, is a nematode related to Trichuris sp and is distributed worldwide. These parasites locate in the kidney of their definitive hosts (mainly belonging to the order Carnivora) and have an indirect life cycle with an annelid as the main intermediate host. Humans are rarely affected, but in those that are, 1 or both kidneys are destroyed. In South America, D. renale is widespread in riparian regions where changing climatic conditions, environmental degradation, and compromised sanitation are increasing the risk of distribution of this parasite, including humans. Here, we provide the descriptions of the genetic diversity of the parasite in the region by analysing 73 adult D. renale samples collected from domestic and wild carnivores. The most common hosts were (Canis lupus familiaris) and maned wolf (Chrysocyon brachyurus Fam. Canidae) among domestic and wild carnivores, respectively. This work shows the descriptions of the genetic diversity of this parasite complementing molecular methods and classical and probabilistic phylogeography. Our results strongly suggest that this parasite has been present on the continent long enough to develop local genetic variants. Also, the phylogenies show transmission between localities and bidirectional transmission between domestic and wild species. We now have new tools to understand the ecological dynamics of this parasite such as molecular markers to study its genetic diversity as well as for identification and reporting in cryptic cases.