
Corsac foxes (Vulpes corsac) mainly distributed in Eastern Asian and Central Asian. To date, there are limited reports on Taenia and Mesocestoides infections in corsac foxes. This study aimed to identify the taxonomic species of 288 tapeworms from two road-killed corsac foxes in northwestern China. Morphological observation indicated that 10 Taenia and 278 Mesocestoides were primarily identified. Furthermore, 25 representative tapeworms were molecularly identified through two genetic markers, the partial cytochrome c oxidase subunit I gene (445bp) and 16S rDNA gene (557bp). Phylogenetic tree analysis indicated that the Mesocestoides species in corsac foxes was the closest to Mesocestoides sp. isolates from red fox in China (accession number: MZ475884) and Kazakhstan (OQ924334), and their identities only shared 89.50% (341/381) and 90.29% (344/381). Taenia species in this study was most closely related to Taenia polyacantha from red foxes in Turkey (PV023876 and PV023884) and Iran (PP658436), sharing 93.93% (418/445) and 94.38% (420/445) identities, respectively. The 16S rDNA sequences showing comparable genetic distances (81.11% (455/561) identity with Mesocestoides sp. from Israel and 93.87% (521/555) with Taenia tianguangfui from China). While a formal taxonomic description is precluded due to the immature nature of the specimens, the loss of rostellar hooks from freeze-thaw cycles, and the limited sample size, our combined morphological and molecular evidence strongly suggests that the Taenia and Mesocestoides isolates found in corsac foxes represent potentially novel species. This study provides a valuable contribution to the understanding of parasite diversity in wildlife and underscores the need for further comprehensive investigations.
Blastocystis, a common eukaryotic symbiont, has gained interest as a potential pathogen affecting animals and humans worldwide. However, there is limited data on Blastocystis prevalence in wildlife animals, especially in Malaysia. To fill this gap, our study aimed to discover the genetic diversity of Blastocystis in captive animals from Taiping Zoo in Perak, Malaysia. We cultured 182 faecal samples from various animal groups using modified Jones medium, incubated at 37°C for warm-blooded animals and 25°C for cold-blooded animals with an incubation period within 48 to 72hours. DNA barcoding was then performed for subtype identification of samples found positive by in-vitro cultivation. Our findings showed an overall Blastocystis sp. prevalence of 19.2% (35/182) with Rodents had the highest prevalence of (50.0% - 3/6) while Artiodactyla had the least (7.7% - 4/52) whereas no Blastocystis was detected in Perissodactyla and Proboscidea. Our study identified various Blastocystis subtypes in different animals including ST1 in wallabies, ST2 in Bornean orangutans, ST3 in African lions, ST4 in ostriches, ST5 in chimpanzees, ST7 in African grey birds, green peafowl, red-billed tree ducks, whooper swans, and small-clawed otters, and ST8 in green peafowls whereas ST37 was found in African spurred tortoise. ST7 was the dominant subtype, while ST1-5, ST8 and ST37 were less common. There were seven Blastocystis subtypes identified as potentially zoonotic (ST1-ST5, ST7 & ST8), highlighting the possible role of captive wild animals as natural reservoirs for human infection.
Vector-borne hemoparasitic diseases pose a significant threat to the health and productivity of small ruminants, particularly in tropical regions characterized by high humidity and elevated temperatures. This study aimed to investigate the dynamic association between climatic indices and the molecular test positivity rates of hemoparasitism in clinically symptomatic goats during the monsoon transition period in the tropical monsoon zone of India. A total of 102 goats hospitalized with non-specific clinical signs from November 2024 to May 2025 were randomly screened for the presence of five major hemoparasite genera, Theileria, Babesia, Anaplasma/Ehrlichia, hemotropic Mycoplasma, and Trypanosoma spp., using both blood smear examination and polymerase chain reaction (PCR). The climatic indices, including average daily temperature (°F), maximum daily temperature (Tmax), minimum daily temperature (Tmin), daily variation in temperature (Tdelta), average relative humidity (%), maximum daily relative humidity (RHmax), minimum daily relative humidity (RHmin), daily variation in relative humidity (RHdelta), temperature-humidity index (THI) and sunshine duration were recorded on each sampling day. Spearman's rank correlation coefficient was applied to assess the association of these climatic variables on the molecular test positivity of hemoparasites. Theileria and Anaplasma/Ehrlichia spp. emerged as the predominant pathogens, with positivity rates of 58.82% and 43.13%, respectively. Among all pathogens, the apicomplexan piroplasms (Theileria and Babesia spp.) demonstrated statistically significant correlations with climatic indices, whereas hemotropic bacteria (Mycoplasma spp.) and Trypanosoma spp. showed no significant associations. Theileria and Anaplasma/Ehrlichia test positivity rates showed similar trends with RH during the monsoon transition period. Concurrent infections were frequently observed in goats positive for Anaplasma/Ehrlichia spp., followed by co-occurrence with Theileria and Babesia spp. This is the first study to quantitatively link climatic indices with PCR-confirmed hemoparasitism in goats during the monsoon transition in tropical India. The findings provide preliminary insights into climate-associated patterns of molecular haemoparasite positivity among hospital-presented goats and may inform future climate-based surveillance and vector-control studies. Validation in community-based goat populations is required before these associations can be used as generalized predictive or early-warning indicators.
Trematode infections are recognized as one of the most economically important helminthic diseases hampering the productivity of domestic ruminants globally. The study aimed to estimate the prevalence, identify the epidemiological risk factors, confirm morphological identifications using ITS-2 and 28S rDNA sequencing and analyze the pathological effects for development of suitable control strategies. Examination of 80 gastrointestinal tracts from locally reared sheep in North Kashmir revealed an overall prevalence of 26.25% (21/80; 95% CI: 16.6-35.9). The five species of trematode parasites identified were Fasciola gigantica, Dicrocoelium dendriticum, Paramphistomum cervi, P. epiclitum and Gastrothylax crumenifer. Prevalence was significantly (p < 0.05) affected by the season, age, and sex of the animal, while the body condition, breed, and sampling area had non-significant effect. Infected organs exhibited hemorrhages, necrotic spots, cellular infiltration, biliary fibrosis, and ruminal papillae atrophy. Molecular characterization and sequencing of eight representative isolates using ITS-2 and 28S rDNA confirmed F.gigantica (ITS-2: 550 bp; 28S: 618 bp), with minor nucleotide variation observed only in the 28S region. Amphistome species (G.crumenifer, P.epiclitum, P.cervi) were validated by amplification of ITS-2 (500 bp) and 28S (1200 bp), showing varying nucleotide polymorphisms, particularly in P. epiclitum. For D. dendriticum, only preliminary ITS-2 (450 bp) and 28S (650 bp) rDNA PCR amplification was achieved. The present study provides the first molecular characterization of P. epiclitum from Kashmir, although the parasite has been reported previously based on morphological identification. Based on seasonal prevalence, strategic deworming during late winter/early spring, early to mid-summer, and mid-to late autumn, along with snail control, is recommended to reduce infection pressure and economic losses. The study demonstrates the reliability of ITS-2 and 28S rDNA markers for species differentiation and reveals genetic variability among trematode isolates, highlighting the need for further investigations using additional molecular markers to better understand population structure and genetic diversity. Overall, the findings enhance understanding of trematode diversity in the region and provide useful insights into the origin and dispersal of flukes in Asia.
Ascaris spp are the most common parasitic helminth infection in the world. After oral ingestion of eggs, Ascaris larvae undergo a larval migratory cycle through the host. During the migratory cycle larvae release proteins known as Excretory-secretory (ES) product that are thought to aid in development and migration. This study characterizes the excretory-secretory (ES) proteome of different Ascaris larval stages (L3-egg, L3-lung, L3-trachea) to identify interventional targets to prevent Ascaris-induced morbidity. Stage-specific larvae were isolated, cultured in vitro and ES-product was collected. Third-stage Ascaris larvae (L3) were isolated from embryonated eggs (L3-egg), from Balb/c mice lungs infected with Ascaris at day 8 post infection (L3-lungs) and isolated from Balb/c mice trachea infected with Ascaris at day 12 post infection (L3-trachea). Proteomic analysis was conducted using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The analysis encompassed peptide identification, scoring, and quantification against an organism-specific database, with subsequent quality control, correlation assessment, and differential abundance determination. A total of 58 unique proteins were identified in the ES products. Fourteen proteins were common across all stages, while others were stage-specific. Principal component analysis revealed distinct protein profiles for each stage. Gene ontology analysis indicated stage-specific enrichment of specific protein classes, such as nuclear proteins in L3-egg ES products and metabolic enzymes in L3-lung and L3-trachea ES products. This study revealed stage-specific differences in the composition of Ascaris ES products. Further investigation into the functional roles of these proteins and their interactions with host immune cells is crucial for developing novel therapeutic strategies to prevent Ascaris larval migration.
Gastrointestinal nematode (GIN) infections represent one of the most significant constraints to the health and productivity of small ruminants worldwide, leading to substantial economic losses and animal welfare concerns. Control of these parasites has historically relied on the extensive use of anthelmintic drugs; however, the rapid emergence and global spread of anthelmintic resistance (AR) have compromised their effectiveness. Resistance is now reported across all major classes of anthelmintics and is particularly prevalent in key species such as Haemonchus contortus. The development of AR is driven by complex mechanisms, including genetic mutations in drug target genes, enhanced drug efflux mediated by transport proteins, alterations in receptor function, and polygenic adaptations. Accurate detection of resistance remains challenging, with conventional methods such as fecal egg count reduction tests and in vitro assays offering limited sensitivity, while molecular diagnostics provide improved specificity but remain constrained by technical and economic factors. Sustainable control of GIN infections requires a shift toward integrated parasite management strategies. Approaches such as targeted selective treatment, maintenance of refugia, improved nutrition, genetic selection for host resistance, and alternative control methods including phytotherapy and biological control have shown promise in reducing reliance on anthelmintics. In conclusion, a multidisciplinary and sustainable approach is essential to mitigate the impact of AR and ensure long-term effectiveness of parasite control strategies in small ruminant production systems.
Stable transfection of Trypanosoma brucei remains a cornerstone for functional genetic studies in this model parasite. Although the Amaxa Nucleofector II system dramatically improved transfection efficiency in both monomorphic and pleomorphic bloodstream forms, the more recent 4D Nucleofector platform offers enhanced programmability and buffer flexibility that have yet to be systematically evaluated for T. brucei. Here, we benchmark a range of 4D Nucleofector programs to determine optimal parameters for transfection efficiency, cell viability, and reproducibility in bloodstream forms. Using a CRISPR/Cas9 expressing cell line, we compare stable transfection efficiencies across programs. We further demonstrate the advantages of the 16-well Nucleocuvette™ Strip format, enabling simultaneous processing of multiple experimental conditions in 20 µL reactions, reducing DNA, cell, and reagent requirements while increasing experimental throughput. Our results provide a standardized framework for future genetic manipulation of T. brucei using the 4D-Nucleofector X Unit, facilitating robust and reproducible transfection across life-cycle stages and strains.
To counter the threat of drug-resistant malaria parasites, drug discovery efforts should be focused on compounds with novel modes of action. Furthermore, drug candidates acting on vulnerable targets should be triaged as they are most likely to be fast-acting antimalarials and have a lower propensity to resistance. Vulnerable targets can be identified by phenotypic assessment of conditional loss of function mutants. Here, we edited 16 Plasmodium falciparum genes to epitope-tag the target protein and control target expression with the glmS ribozyme tool. Target localization was assessed by confocal microscopy. Conditional knockdown to generate loss of function mutants was assessed by transcriptomic RNA sequencing and western blotting. Target vulnerability assay of the mutants identified UGT1, DHFS-FPGS, and GAT as new vulnerable targets.
Plasmodium falciparum is the major human malaria parasite and its treatment remains challenging, with current artemisinin-based combination therapies increasingly compromised by emerging resistance in several regions. Although the pre-erythrocytic vaccines, Mosquirix and R21, are recommended only for children under five years of age in highly endemic African regions, their protective efficacy is moderate and wanes over time, underscoring the continued need for effective antimalarial drugs. Epigenetic mechanisms play a central role in regulating the parasite genome in response to diverse host environments, with methyltransferases acting as key components that dynamically modulate chromatin structure to control stage-specific gene expression. These epigenetic factors critically shape parasite fate by governing the expression of surface antigens, including var, RIFINs and STEVORs, thereby enabling immune evasion and the establishment of chronic infections. To date, no therapeutics specifically targeting histone lysine methyltransferases (HKMTs) have reached clinical use, although BIX-01294 has been explored as a candidate antimalarial in preclinical studies. This review synthesizes current knowledge on Plasmodium HKMTs, highlighting their biochemical activities, regulatory roles, and contributions to virulence. While evaluating emerging epigenetic inhibitors as potential antimalarial agents. We further discuss the main challenges in developing such therapies, emphasizing the necessity of detailed structural characterization, optimized pharmacological properties and rigorous validation of candidate compounds across Plasmodium species to enable successful translation.
Colorectal cancer develops through complex interactions among genetic alterations, immune responses, and the intestinal microenvironment. Increasing evidence suggests that intestinal parasites may also contribute to colorectal carcinogenesis (CRC). Blastocystis sp. (Blastocystis) is one of the most common intestinal protozoans worldwide. Although its role in disease remains controversial, it has been associated with chronic inflammation and disruption of normal gut homoeostasis. Therefore, this systematic review aimed to summarise the current experimental evidence on the immunomodulatory effects and potential role of Blastocystis solubilized antigens (BSA) in CRC. A systematic literature search was conducted following PRISMA guidelines in PubMed, Scopus, Web of Science, and CINAHL. Six eligible experimental studies investigating the effects of BSA on colorectal cancer cell lines (HCT116 and HT-29) and peripheral blood mononuclear cells (PBMCs) were included. The included studies demonstrated that BSA influences several biological processes associated with CRC. Symptomatic isolates, particularly Subtype 3 (ST3), showed the strongest biological effects by promoting colorectal cancer cell proliferation, increasing the expression of pro-inflammatory and tumour-associated mediators, and reducing p53 gene expression. BSA also increased the gene expression of NF-κB and Nrf2 and reduced the effectiveness of the chemotherapeutic agent 5-fluorouracil (5-FU). In addition, BSA altered cytokine production in PBMCs, with chemotherapy-treated colorectal cancer patients exhibiting reduced immune responsiveness compared to healthy individuals. Overall, the available evidence suggests that Blastocystis, particularly ST3, may contribute to CRC through immune modulation, activation of tumour-related cellular pathways, and reduced chemotherapy sensitivity. However, the limited number of available studies highlights the need for further experimental and clinical investigations to clarify the role of Blastocystis in CRC and its impact on treatment outcomes.
Plasmodium falciparum is the only human-infective species within the Laverania subgenus. In order for Plasmodium falciparum merozoites to invade erythrocytes, parasite ligands interact with a number of erythrocyte surface proteins, several of which are modified with sialic acids. These sialic acids differ between humans, which can synthesise only Neu5Ac sialic acids, and apes which express an enzyme absent in humans that converts Neu5Ac to Neu5Gc, resulting in their surface sialoglycoproteins predominantly being modified with Neu5Gc. This difference between apes and humans has been previously proposed to play a role in the specificity of ligand-receptor interactions between Laverania species. In this study we used biochemical and experimental genetic approaches to explore the molecular preferences of one specific invasion ligand, EBA-140. Recombinant EBA-140 ligands from P. falciparum (human-infective), P. praefalciparum (gorilla-infective) and P. reichenowi (chimpanzee-infective), were all able to bind both sialic acids, but all showed a clear preference for Neu5Gc. Using CRISPR/Cas9 to swap the receptor-binding region of P. falciparum EBA-140 with the same region from Laverania orthologues had no effect on parasite growth or invasion in chimeric transgenic lines. There is therefore no evidence that Neu5Ac/Neu5Gc specificity plays a role in host preference for EBA-140 orthologues.
The polymorphism of major histocompatibility complex (MHC) class II classical genes is closely related to pathogen resistance, among which the second exon of the DRB gene has the highest variability. In this study, we analyzed exon 2 of the MHC class II DRB gene in 32 captive Amur tigers (Panthera tigris altaica) using a cloning-based sequencing approach to assess genetic diversity and its association with infection by Enterocytozoon bieneusi. A total of 16 DRB alleles were identified, including six novel variants. One allele (Pati-DRB*02) showed a significant positive association with infection (P < 0.05), whereas no significant relationship was detected between heterozygosity and infection status. Phylogenetic analysis revealed that Amur tiger DRB alleles clustered with those from other felid species, supporting trans-species polymorphism. These results indicate that the DRB gene in Amur tigers exhibits a high degree of polymorphism, and that DRB*02 may be a susceptibility gene for E. bieneusi.
Amazonian biodiversity is an underexploited source of bioactive natural products with potential relevance to drug discovery for neglected diseases. Here, we characterized the chemistry and multi-target in vitro activity of an ethyl acetate extract from Dinizia excelsa wood. Extraction yielded 4.84 ± 0.10% and produced a phenolic-rich fraction with high total phenolics (501.8 ± 1.0 mg GAE/g extract), flavonoids (172.4 ± 0.8 mg QE/g), flavonols (49.7 ± 0.3 mg QE/g), and hydrolyzable tannins (229.4 ± 1.2 mg TAE/g). LC-HRMS dereplication annotated 19 metabolites, dominated by glycosylated flavonoids (rutin, isoquercetin), phenolic acids (ferulic and ellagic acids), ellagic derivatives (urolithins), and galloylated hydrolyzable tannins. The extract showed moderate-to-low antioxidant capacity across complementary assays (IC₅₀ 78.38-161.99 µg/mL) and a favorable safety profile, with moderate/low cytotoxicity in mammalian cell lines (IC₅₀ 364-700 µg/mL) and minimal hemolysis (<6% up to 1000 µg/mL). In murine splenocytes, the extract preserved membrane integrity, induced dose-dependent proliferation, and promoted a broad but controlled cytokine response (↑IL-2, IL-4, IL-10, IL-12, IFN-γ, IL-17, TNF-α; regulated TGF-β), alongside reduced NO, mild cytosolic ROS modulation, and stable mitochondrial membrane potential. Notably, it displayed strong antiparasitic activity against Trypanosoma cruzi (IC₅₀ 2.37-3.94 µg/mL) and Leishmania spp. (IC₅₀ 1.83-6.43 µg/mL), with additional activity against Schistosoma mansoni (IC₅₀ 114.83-247.0 µg/mL) and Plasmodium falciparum 3D7 (IC₅₀ 5438.27 ng/mL). Antibacterial MICs ranged 16-512 µg/mL and antifungal MICs 16-256 µg/mL, consistent with bacteriostatic/fungistatic effects.
Plasmodium falciparum merozoites invade erythrocytes using various ligand-receptor interactions. Important ligands encoded by the eba and Rh gene families have varying expression levels in different parasite isolates, affecting their vaccine candidacy. Analyses of clinical isolates from endemic areas in Africa have indicated that most variation in these expression profiles exists within each local area, and only minor differences are seen between areas, although comparisons with non-African populations have not previously been performed. To enable this, relative transcript levels of three eba genes and five Rh genes have been analysed in new population samples, Malaysian isolates sampled from Sabah State in Borneo prior to endemic malaria elimination, and Gambian isolates, cultured under the same conditions to harvest schizonts for reverse transcription quantitative PCR assays. Significant differences between these populations were seen for three of the ligand genes, levels of eba175 being higher in Malaysia, while levels of eba181 and Rh2b were lower in Malaysia. The variation in gene transcript profiles was not associated with having single or multiple genotypes within each isolate. The distinctness of the Malaysian population expression profile was also supported by comparing previous data on clinical isolates from Ghana. In tests for correlation with previously determined parasite multiplication rates, eba181 transcript levels correlated positively among Malaysian isolates but not among Gambian isolates. These findings suggest that expression of three P. falciparum merozoite ligands involved in invasion may be regionally differentiated, and further analysis of Asian parasite populations would be important if vaccines based on these candidates are to be considered for future use.
Chagas disease (CD), caused by Trypanosoma cruzi, is a significant problem of public health. The infection induces inflammatory processes in tissues, leading to metabolic changes similar to the Warburg Effect (WE). To evaluate the presence of WE during the progression of CD in mice, 72 male Swiss mice were divided in two groups: one group with 36 mice was infected with 5.0 × 10⁴ trypomastigote forms of T. cruzi QM2 strain, and another group with 36 mice was the control. Every week the mice were weighed, glycemia was measured and lactate was determined biweekly. At the end of each experimental period: 30, 60 and 120 days post-infection, the animals were euthanized for blood collection to analyze TBARS, LDH, urea, creatinine, PCR, pO2 and pCO2. Parasitemic peak was reached in 17th day, when blood glucose was lowered. Glycemia was significantly lower in the infected group, with high lactate dehydrogenase (LDH) activity, suggesting the occurrence of WE, despite normal lactate and pH levels in this group. Neither TBARS nor C-reactive protein showed significant difference across the groups studied. Urea levels did not show significant differences between the groups, but the decrease in its concentration in the infected group may be due to the use of its precursors for the production of nitric oxide. It is concluded that hypoglycemia and increased LDH activity during the acute phase of CD led to a metabolic shift towards glycolysis, suggesting the presence of WE. Further studies are necessary to validate this metabolic shift in CD.
Leishmania donovani exists in two distinct environments to complete its life cycle. It exists as a non-motile infective amastigote state in humans and as a motile promastigote state in the sandfly gut. Although the differences in gene expression between life-cycle stages have been extensively studied, the contribution of variability of gene expression to parasite adaptation remains poorly understood. Here, we have explored transcriptional changes in L. donovani using bulk RNA-seq data, using the amastigote as a reference. After the differential expression analysis, we calculated the gene-wise Wasserstein distance to capture shifts in the expression distribution across the stages. We found that amastigotes show overall lower transcriptional changes than promastigotes, but greater heterogeneity in genes related to stress responses, membrane proteins, and regulation. Importantly, we identified a subset of genes exhibiting high distributional shifts despite minimal changes in mean expression, which were not detected by conventional differential expression analysis. This suggests that deeper regulatory mechanisms may be masked by mean-based differential expression analyses. Furthermore, the poorly annotated genes in both stages were annotated, and many were found to have specific roles that help the parasite survive within host cells and vectors. Overall, our results provide exploratory insights into gene expression variability, revealing genes with stable mean expression but altered distributional patterns across life stages of L. donovani. Together, these findings suggest that transcriptional heterogeneity may constitute an underappreciated regulatory layer that contributes to parasite adaptation during the transition between vector and host environments.
Leishmania donovani ADSL is a tetrameric protein involved in the purine metabolism where the active site is formed from residues belonging to three different subunits. In this study, the amino acid residues- E334, N335 and R370 of LdADSL were studied for their contribution to the enzyme catalysis and inter-subunit binding. Mutating these residues resulted in reduced activity, stability and affinity towards the substrate, SAMP/AMP as shown by enzyme kinetics, fluorescence spectroscopy and thermal stability studies. MD simulation studies also supported this. Structural analysis points to disrupted interactions with the catalytic base, H196, reduced hydrogen bonds and electrostatic interactions between the substrate and the enzyme, C3-loop conformational changes and altered conformation of active site residues as reasons for reduced activity and stability. Incubation of pairs of the mutant enzymes restored partly the functional active site by subunit complementation. Our study highlighted the critical role of inter-subunit residues in maintaining both structural stability and proper active-site architecture in enzymes whose functional catalytic site is formed at interfaces of different subunits. This knowledge can be used to design more specific anti-leishmanials by targeting the inter-subunit interface of LdADSL.
Schistosoma mansoni, a parasitic flatworm, causes schistosomiasis. Approximately 250 million people are infected and require drug treatment. Currently, Praziquantel is the only available drug, but it is ineffective against early infective stages. The development of new drugs is urgently needed. Posttranslational modifications (PTM) of histones are crucial for the parasite's life cycle, making them a suitable drug target. However, many of these modifications are conserved between humans and parasites, posing a risk of severe side effects for patients. Identifying schistosome-specific histone PTMs is essential. We employed a bottom-up mass spectrometry method combining first-time Data Independent Acquisition (DIA) and Data Dependent Acquisition (DDA) to quantify histone peptides and assess histone proteins across three S. mansoni stages. We selected 18 main posttranslational modifications (PTMs) for peptide searches and identified 150 PTMs across peptides from H3, H4, H1/H5, and H2A of S. mansoni. We further refined with more stringency, given the complexity of the mass spectrometry data and our commitment to reliable data generation, we focused on quantifying H3 PTMs,which are well characterized in other species. For histone H3 PTMs, we identified peptides with high abundance and confidence: K27(1-methyl1-methyl)SAPATGGVK, K27(Dimethyl)SAPATGGVK, K9(acetyl)STGGK, and K9 (Dimethyl)STGGK. Notably, both K27(Dimethyl)SAPATGGVK and K9(acetyl)STGGK showed higher abundance in schistosomula. Furthermore, we observed a positive correlation between the expression of the gene Smp_053140 and the abundance of the peptide K9(acetyl)STGGK in 3-day schistosomula. We then knocked down this gene, which affected schistosomula morphology, highlighting the significance of histone posttranslational modification and histone-modifying enzymes in S. mansoni development.