The global expansion of South American camelid farming contrasts with the limited knowledge of the pathogens that can infect them. This study investigated the presence of multiple infectious agents, including Anaplasmataceae, Bartonella sp., hemotropic Mycoplasma, piroplasmids, trypanosomatids, and gastrointestinal parasites, in 10 surviving llamas sampled following an outbreak of clinical anemia. Ehrlichia sp. was molecularly detected in 1/10 animal, hemotropic Mycoplasma sp. in 4/10, and 7/10 were infected with apicomplexans, while parasitological stool analysis showed that 6/9 were infected with Strongyloides sp. Co-infections were detected in 4/10 of the positive animals. All samples tested negative for Anaplasma sp., A. marginale, Bartonella sp., and trypanosomes. Genetic sequencing indicated that the detected Ehrlichia sp. was closely related to 'Candidatus Ehrlichia regneryi', the hemotropic Mycoplasma sp. showed high identity to 'Candidatus Mycoplasma haemolamae', and the apicomplexans were identified as Babesia bovis and Sarcocystis masoni. These findings constitute the first report of B. bovis-like and an Ehrlichia species molecularly detected in llamas, highlighting the diverse range of agents that can circulate in these animals and underscoring the need for a greater understanding of pathogen epidemiology in camelid production.

Malaria is an infection caused by protozoa of the genus Plasmodium, responsible for more than 282 million cases annually. Despite the availability of antimalarial drugs, controlling the disease remains a challenge due to resistance and the lack of compounds effective at various stages of the parasite's life cycle. Bi-triazole derivatives are emerging as a growing class in the development of new antimalarials. The compound 4RJ, for example, has demonstrated activity against the asexual stages of resistant Plasmodium falciparum strains in previous studies. However, its effects on field isolates against the sexual forms (transmission blockade) of both species, as well as its interaction with the reference drug, have not yet been reported, and such data are fundamental to consolidating the antimalarial profile of this class. In this study, we evaluated the activity of 4RJ against the asexual and sexual stages of P. falciparum and P. vivax using compound combination studies, ex vivo evaluation of field isolates collected from malaria patients in Porto Velho, Rondônia, Brazil, exflagellation analysis, and ookinete formation assays. 4RJ significantly inhibited asexual parasite growth in field isolates of P. falciparum and P. vivax (IC50 6.95 and 8.85 μM, respectively), suppressed microgametocyte exflagellation (≥80%), and inhibited ookinete formation (46-89%), also revealing an additive interaction profile (FIC50 = 1) with the reference drug. These results broaden the antimalarial profile of 4RJ and reinforce its potential as a candidate for the development of antimalarials.

The genus Myxobolus comprises cnidarians belonging to the subphylum Myxozoa. These parasites have great pathogenic potential in animals, mainly in teleost fish worldwide, where studies have demonstrated great diversity, but with a high possibility of novelty in the face of the existing ichthyofauna. In this context, the present work characterizes morpho-molecularly Myxobolus cajueiroi n. sp. infecting the gills of the estuarine species of great socioeconomic importance Pellona castelnaeana from the district of Mosqueiro, Belém, Pará, Brazilian Amazon. Thirty specimens captured in the Cajueiro River between April 2024 and May 2025 were analyzed. Whitish cysts were observed in the gill arches in all specimens (prevalence of 100%). In the inner region of the cysts, ovoid myxospores measuring 10.6 ± 0.5 (10.3-11.3) μm in length by 8.0 ± 0.4 (7.6-8.4) μm in width, and 5.7 ± 0.4 (5.3-6.1) μm in thickness were observed, with two symmetrical pear-shaped polar capsules, each measuring 4.0 ± 0.3 (3.8-4.6) μm in length and 2.3 ± 0.1 (2.3-2.3) μm in width. Histopathology revealed significant lesions, such as hyperplasia and the formation of fibrous capsules around the cysts. Molecular identification was performed by amplification and sequencing of small subunit ribosomal RNA gene, obtaining a nucleotide sequence of 1935 base pairs. These results allowed the description of Myxobolus cajueiroi n. sp. and reinforce the relevance of integrative studies in characterizing parasites in commercially important fish, in addition to providing new data on parasitic diversity in the Amazonian ichthyofauna.

We report two new monorchiids from two species of goatfishes (Mullidae), Mulloidichthys flavolineatus (Lacépède) and Mulloidichthys vanicolensis (Valenciennes), from off Lizard Island, northern Great Barrier Reef. Morphological and molecular analyses indicate that the two species belong in the previously monotypic genera Obscuromonorchis Wee, Cribb, Miller & Cutmore, 2025 and Lobucirruatus Wee, Cribb & Cutmore, 2022. Obscuromonorchis brittanyae n. sp. is reported from both mullid species and differs from Obscuromonorchis ranae Wee, Cribb, Miller & Cutmore, 2025, in the possession of a less-developed ventral sucker, a noticeably shorter oesophagus, and an ascending uterine coil that enters the terminal organ in the anterior half rather than at its posterior end. Lobucirruatus hasturi n. sp. is also reported from both mullid species, and differs from Lobucirruatus infloresco Wee, Cribb & Cutmore, 2022 in the possession of an unlobed or single-lobed ovary and less prominent lobation of the cirrus. Morphological distinctions for both species are supported by significant differences in three gene markers, the ITS2 and 28S ribosomal DNA regions, and cox1 mitochondrial DNA region. Ovarian form is typically considered a genus-level character for monorchiid genera; the two species of Lobucirruatus differ in this character and the generic diagnosis is thus amended.

Haemonchus contortus shifts from free-living larval stages on pasture to parasitic, blood-feeding stages in the host abomasum, but the coordinated gene programs that underlie this transition remain incompletely resolved. We aimed to construct a stage-resolved developmental co-expression atlas of H. contortus using public RNA-seq data and to integrate it with a 2025 developmental proteome atlas. We assembled 42 RNA-seq libraries spanning ten life-cycle stages from egg to adult and built a signed weighted gene co-expression network on 10,485 genes, which resolved 18 co-expression modules whose eigengenes followed an ordered developmental progression. Several modules were strongly associated with individual stages and showed functional enrichment matching that stage biology. Integration with the proteome atlas gave positive transcriptome-proteome concordance at every matched stage, supporting the modules at the protein level. A differential-expression contrast across the free-living to parasitic boundary identified 4286 genes that were differentially expressed between the two phases: free-living stages were associated with sensory and neuronal programs, whereas parasitic stages showed metabolic, gut and adult, and parasite-associated programs. These co-expression modules and stage-associated programs suggest coordinated stage-associated expression remodeling at host entry, although they do not by themselves demonstrate direct regulation. The atlas provides a reusable, systems-level framework for parasite developmental biology and a prioritized starting point for future functional studies in H. contortus and related nematodes.

Giardiasis is caused by the widespread intestinal parasite Giardia lamblia. The characterization of immunogenic proteins in G. lamblia has been investigated to identify potential vaccine targets, including members of the giardin family, variant-specific surface proteins (VSPs), cyst wall proteins (CWPs) and heat shock protein (HSP). The immunoglobulin-binding protein (BIP) is a HSP that has been described as immunogenic antigen; however, its role in this protozoan remains poorly characterized, particularly regarding its involvement in the humoral immune response activation, critical for parasite clearance. In this study, we evaluated the capacity of BIP to promote an antibody-mediated response through oral administration in mice. Additionally, we identified B-cell epitopes by integrated experimental and immunoinformatic approach. In mice, oral administration of BIP alone, without adjuvants, induced a specific humoral immune response at both systemic and mucosal levels, as well as, during Giardia infection, demonstrating its ability to disrupt the tolerogenic environment of the gut. Immunogenic regions of BIP were identified. A fragment around 7 kDa was recognized by specific-BIP polyclonal and monoclonal antibodies. This fragment contains two potential linear epitopes (the amino acids 64-132 and 176-190 of BIP protein) that are conserved in HSPs of other pathogens. Furthermore, in silico analyses identified additional B-cell epitopes distributed throughout the BIP sequence, reinforcing its antigenic potential. These findings support the ability of BIP to induce an efficient humoral immune response via the oral route, a key feature in infections such as giardiasis, thereby highlighting its potential as a target for vaccine development against Giardia.

This study investigated the prevalence and genetic diversity of tick-borne pathogens in the forested suburbs of Gifu in central Japan, where human cases of Japanese spotted fever and severe fever with thrombocytopenia syndrome (SFTS) have recently been reported. A total of 130 ticks representing eight species were analyzed for spotted fever group Rickettsia (SFGR) and viruses in the family Phenuiviridae using PCR and reverse transcription-PCR, respectively. While the causative agents of Japanese spotted fever (Rickettsia japonica) and SFTS were not detected in this study, SFGR-specific genes were identified in 35 specimens. Candidatus Rickettsia jingxinensis was the predominant species, primarily associated with Haemaphysalis longicornis ticks. Multiple lineages related to Rickettsia monacensis and other uncharacterized species were also identified, reflecting a highly diverse rickettsial population. Dabieshan tick virus (DTV), a member of the family Phenuiviridae, was detected in 11H. longicornis specimens, marking its first identification in central Japan. Notably, these strains form a genetically unique clade distinct from previously detected DTV strains in Japan. Although the pathogenicity of the microorganisms detected in this study remains unclear, our findings highlight the diversity of tick-borne microorganisms in this area. The substantial diversity, characterized by multiple rickettsial lineages and the presence of a unique DTV clade, underscores the importance of continuous surveillance to understand this complex microbial landscape and its potential implications for public health.

Fasciolosis, caused by Fasciola hepatica, is a snail-borne zoonotic disease of major veterinary importance, responsible for significant economic losses in livestock. Its transmission is strongly influenced by environmental and climatic conditions. In northwestern Argentina, particularly in Salta and Jujuy provinces, the disease is endemic; however, the environmental and spatial determinants of its distribution remain incompletely understood. This study aimed to identify environmental risk factors and spatial patterns associated with F. hepatica infection in herbivores to better understand its epidemiological dynamics and support targeted control strategies. A retrospective analysis was conducted using coproparasitological records from 1994 to 2025 from livestock in both provinces. A total of 12,465 fecal samples from multiple host species were analyzed. The infection status was related to climatic variables, topography, and edaphic characteristics. Temporal variability and clear seasonal patterns were observed, with higher positive frequency in late winter-early spring. In the multivariate analysis, higher soil pH, sand and silt content, and cation exchange capacity were positively associated with infection, while bulk density and soil organic carbon were negatively associated. Spatial analysis identified nine significant clusters, including a main high-risk cluster in the central-western region of Salta and the central-southern region of Jujuy provinces, as well as several smaller focal clusters with increased relative risk. These findings demonstrate that fasciolosis distribution is non-random and driven by the interaction between soil properties, climate, host species, and spatial heterogeneity. The results provide a basis for risk-based surveillance and targeted control strategies adapted to local environmental conditions.

From September 2023 to September 2024, the potential intermediate hosts of Angiostrongylus cantonensis (Nematoda: Angiostrongylidae) were investigated on northern Okinawa Island, Japan, where infection of endangered rodent species is a conservation concern. Third-stage larvae of A. cantonensis were detected in Tanychlamys indica (Stylommatophora: Ariophantidae), a globally invasive terrestrial snail species recently established on Okinawa Island. Notably, infected T. indica were primarily collected from forest edges, indicating a potential ecological interface between this invasive host and native forest ecosystems. These findings highlight the necessity to monitor the spread of T. indica from both the conservation and public health perspectives.

The present study aimed: (i) morphologically describe and molecularly characterize a novel Lankesterella species infecting anurans collected in the Pará state, Brazil; (ii) to record Dactylosoma infection in Rhinella marina, with phylogenetic information about the Dactylosoma species clade in Brazil; (iii) to record Hemolivia stellata infection in R. marina, providing the first genetic sequence of this parasite species from amphibians. The samples were collected between March 2023 and December 2024 in three localities of Pará state: Mosqueiro beach district, Natura Ecoparque and Treviso Farm. Thirty-six specimens of R. marina were captured through active search and blood samples were collected by cardiac puncture. A few drops of blood were used to prepare blood smears for microscopical analysis, and another aliquot was stored in ethanol for further molecular analyses. For molecular analyses, only microscopy positive samples were considered. Eight specimens were positive for hemoparasites: Dactylosoma sp. (n = 6), H. stellata (n = 3), and Lankesterella sp. (n = 2). The total number of infected hosts and the number of parasite records are not identical because co-infections occurred. Combining morphological analysis and molecular data, we described Lankesterella amazonica n. sp. We also provided the first molecular characterization of H. stellata in R. marina from the Brazilian Amazon. This study expands the known occurrence area and hosts of Lankesterella species in amazonian region bufonids, while also providing information about other blood parasites of Brazilian Amazon anurans.

The early transcribed membrane protein 4 (ETRAMP4) is one of 14 predicted members of the ETRAMP family in the malaria parasite Plasmodium. All characterized ETRAMP proteins localize to the parasitophorous vacuole membrane (PVM) and associated membranous structures during the early stages of parasite infection of erythrocytes; and are thought to participate in host-parasite material transport, which is critical for parasite development. In this study, we investigated the stage-specific expression and subcellular localization of ETRAMP4 during the asexual and gametocyte intraerythrocytic stages. Indirect immunofluorescence assays revealed that ETRAMP4 is prominently detected in immature stage I and II gametocytes; whereas no detectable signal was observed in stage III to V gametocytes or in asexual blood-stage parasites under our experimental conditions. Immunoelectron microscopy demonstrated that ETRAMP4 predominantly localizes to the PVM and PVM-derived membranous structures extending into the host erythrocyte cytoplasm, suggesting a potential role in membrane dynamics during early gametocyte development.

Elucidating the life cycles of trematodes is essential for understanding their ecology and evolution. However, it is often difficult due to morphological similarities among closely related species, particularly at larval stages, and the distinct morphologies among different life stages of a single trematode species. Here, we used molecular genetics to differentiate morphologically similar species and to link their different life stages within a single species. We dissected 2152 snails, which serve as the first intermediate hosts of trematodes, and 396 individuals of their potential second intermediate hosts, such as fish, crustaceans, and insects. Using molecular genetics, we identified 25 trematode species in those hosts. We investigated the life cycles of these trematodes using the obtained sequences and identified the first and second intermediate hosts for two species. By integrating our sequences with information from the associated publications, we further inferred first and second intermediate host links for an additional 14 species. Among these, five species also had potential definitive host information at the species level. Nine species were found only in either the first or the second intermediate host. While the current study could not elucidate the life cycles of these 9 species, we consider that the accumulation of trematode DNA sequences, along with host information, in public databases will facilitate future identification of their life cycles. This study highlights the usefulness of molecular approaches to infer trematode life cycles.

Microsporidia are obligate intracellular parasites that infect diverse animals. Budding yeast has long been used to define core molecular pathways and inhibitors that target them. To test whether these compounds can target conserved pathways in the microsporidian Nematocida parisii, we assessed 15 inhibitors with defined yeast targets that had not previously been tested for effects on infection of Caenorhabditis elegans. Most showed little activity against N. parisii, except tunicamycin. These results identify tunicamycin as a potential tool for studying endoplasmic reticulum stress in microsporidia, while indicating that many yeast-targeted inhibitors are largely ineffective in this system.

The tick Haemaphysalis hystricis is believed to be a vector of several infectious diseases such as severe fever with thrombocytopenia syndrome and Japanese spotted fever. This tick species is distributed across many Asian countries, including Japan. Recently, the distribution of H. hystricis has been expanding northward, probably due to migratory birds and climate change. In Hokkaido, the northernmost island prefecture of Japan, we collected two adult H. hystricis ticks, one in 2021 and another in 2026, that were identified based on their morphological features and mitochondrial 16S rDNA and COI sequences. To our knowledge, this is the northernmost record of occurrence of this tick species. The fact that unfed adults were collected in July and August, following the arrival period of migratory birds from southern areas, implies that engorged nymphs carried by these birds molted into adults after arrival at Hokkaido. While the immediate establishment of a local population is unlikely under the current subarctic climate of Hokkaido, our findings highlight a potential risk for future colonization, especially under ongoing climate change. This study provides important insights into the distribution of H. hystricis, raising awareness of the northward range expansion of this medically important tick species.