Human Parasite Research Articles

Reduced efficacy of selection on a young Z chromosome region of Schistosoma japonicum

Abstract Sex-linked and autosomal loci experience different selective pressures and evolutionary dynamics. X (or Z) chromosomes are often hemizygous in males (or females), as Y (or W) chromosomes often degenerate. Such hemizygous regions can be under greater efficacy of selection, as recessive mutations are immediately exposed to selection in the heterogametic sex leading to faster adaptation and faster divergence on the X chromosome (the so-called Faster-X or Faster-Z effect). However, in young non-recombining regions, Y/W chromosomes often have many functional genes, and many X/Z-linked loci are therefore diploid. The sheltering of recessive mutations on the X/Z by the Y/W homolog is expected to drive slower adaptation for diploid X/Z loci, i.e. a reduction in the efficacy of selection. While the Faster-X effect has been studied extensively, much less is known empirically about the evolutionary dynamics of diploid X or Z chromosomes. Here, we took advantage of published population genomic data in the female-heterogametic human parasite Schistosoma japonicum to characterize the gene content and diversity levels of the diploid and hemizygous regions of the Z chromosome. We used different metrics of selective pressures acting on genes to test for differences in the efficacy of selection in hemizygous and diploid Z regions, relative to autosomes. We found consistent patterns suggesting reduced Ne, and reduced efficacy of purifying selection, on both hemizygous and diploid Z regions. Moreover, relaxed selection was particularly pronounced for female-biased genes on the diploid Z, as predicted by recent theoretical work.

Is Parasitic Contamination of Soil in the Southern United States Related to Poverty and Does It Represent a Human Health Threat? A Perspective.

In recent years, multiple reports have emerged describing real-time quantitative polymerase chain reaction (qPCR) detection of DNA derived from human parasite species in environmental soil samples. In one such report, sampling was focused in impoverished areas of the southeastern United States, and a link between poverty and the presence of parasite DNA in soil was proposed. Whether transmission of certain parasitic diseases persists in the United States in association with poverty remains an important question. However, we emphasize caution when reviewing interpretations drawn solely from qPCR detection of parasite-derived environmental DNA without further verification. We discuss here the limitations of using qPCR to test environmental DNA samples, the need for sampling strategies that are unbiased and repeatable, and the importance of selecting appropriate control areas and statistical tests to draw meaningful conclusions.

Utilisation of an in vivo malaria model to provide functional proof for RhopH1/CLAG essentiality and conserved orthology with P. falciparum

BackgroundMalaria parasites establish new permeation pathways (NPPs) at the red blood cell membrane to facilitate the transport of essential nutrients from the blood plasma into the infected host cell. The NPPs are critical to parasite survival and, therefore, in the pursuit of novel therapeutics are an attractive drug target. The NPPs of the human parasite, P. falciparum, have been linked to the RhopH complex, with the monoallelic paralogues clag3.1 and clag3.2 encoding the protein RhopH1/CLAG3 that likely forms the NPP channel-forming component. Yet curiously, the combined knockout of both clag3 genes does not completely eliminate NPP function. The essentiality of the clag3 genes is, however, complicated by three additional clag paralogs (clag2, clag8 and clag9) in P. falciparum that could also be contributing to NPP formation.MethodsHere, the rodent malaria species, P. berghei, was utilised to investigate clag essentiality since it contains only two clag genes, clagX and clag9. Allelic replacement of the regions encompassing the functional components of P. berghei clagX with either P. berghei clag9 or P. falciparum clag3.1 examined the relationship between the two P. berghei clag genes as well as functional orthology across the two species. An inducible P. berghei clagX knockout was created to examine the essentiality of the clag3 ortholog to both survival and NPP functionality.ResultsIt was revealed P. berghei CLAGX and CLAG9, which belong to two distinct phylogenetic clades, have separate non-complementary functions, and that clagX is the functional orthologue of P. falciparum clag3. The inducible clagX knockout in conjunction with a guanidinium chloride induced-haemolysis assay to assess NPP function provided the first evidence of CLAG essentiality to Plasmodium survival and NPP function in an in vivo model of infection.ConclusionsThis work provides valuable insight regarding the essentiality of the RhopH1 clag genes to the NPPs functionality and validates the continued investigation of the RhopH complex as a therapeutic target to treat malaria infections.

Hatching of whipworm eggs induced by bacterial contact is serine-protease dependent.

Whipworms (Trichuris spp) are ubiquitous parasites of humans and domestic and wild mammals that cause chronic disease, considerably impacting human and animal health. Egg hatching is a critical phase in the whipworm life cycle that marks the initiation of infection, with newly hatched larvae rapidly migrating to and invading host intestinal epithelial cells. Hatching is triggered by the host microbiota; however, the physical and chemical interactions between bacteria and whipworm eggs, as well as the bacterial and larval responses that result in the disintegration of the polar plug and larval eclosion, are not completely understood. Here, we examined hatching in the murine whipworm, Trichuris muris, and investigated the role of specific bacterial and larval structures and molecules in this process. Using scanning and transmission electron microscopy, we characterised the physical interactions of both fimbriated (Escherichia coli, Salmonella typhimurium and Pseudomonas aeruginosa) and non-fimbriated (Staphylococcus aureus) bacteria with the egg polar plugs during the induction/initiation stage, and visualised the effects of structural changes in the polar plugs, leading to larval eclosion. Further, we found that protease inhibitors blocked whipworm hatching induced by both fimbriated and non-fimbriated bacteria in a dose-dependent manner, suggesting the partial involvement of bacterial enzymes in this process. In addition, we identified the minimal egg developmental timing required for whipworm hatching, and transcriptomic analysis of T. muris eggs through embryonation revealed the specific upregulation of serine proteases (S01A family) in fully embryonated eggs containing 'hatch-ready' L1 larvae. Finally, we demonstrated that inhibition of serine proteases with the serine-protease inhibitor Pefabloc ablated T. muris egg hatching induced by bacteria. Collectively, our findings unravel the temporal and physicochemical bacterial-egg interactions leading to whipworm hatching and indicate serine proteases of both bacterial and larval origin mediate these processes.

Search for and functional annotation of multi-domain PLA2 family proteins in flatworms

The phospholipase A2 (PLA2) is a superfamily of hydrolases that catalyze the hydrolysis of phospholipids and play a key role in many molecular processes in the cells and the organism as a whole. This family consists of 16 groups divided into six main types. PLA2 were first isolated from venom toxins and porcine pancreatic juice. The study of these enzymes is currently of great interest, since it has been shown that a number of PLA2 are involved in the processes of carcinogenesis. PLA2 enzymes were characterized in detail in model organisms and humans. However, their presence and functional role in non-model organisms is poorly understood. Such poorly studied taxa include flatworms, a number of species of which are human parasites. Several PLA2 genes have previously been characterized in parasitic flatworms and their possible role in parasite-host interaction has been shown. However, no systematic identification of the PLA2 genes in this taxon has been carried out. The paper provides a search for and a comparative analysis of PLA2 sequences encoded in the genomes of flatworms. 44 species represented by two free-living and 42 parasitic organisms were studied. The analysis was based on identification of orthologous groups of protein-coding genes, taking into account the domain structure of proteins. In flatworms, 12 of the 13 known types of animal A2 phospholipases were found, represented by 11 orthologous groups. Some phospholipases of several types fell into one orthologous group, some types split into several orthogroups in accordance with their domain structure. It has been shown that phospholipases A2 of the calcium-independent type, platelet-activating phospho­lipases from group G8 and lysosomal phospholipases from group G15 are represented in all large taxa of flatworms and the vast majority of the species studied by us. In free-living flatworms PLA2 genes have multiple copies. In parasitic flatworms, on the contrary, loss of genes occur specifically in individual taxa specifically for groups or sub­families of PLAs. An orthologous group of secreted phospholipases has been identified, which is represented only in Digenea and this family has undergone duplications in the genomes of opisthorchids. Interestingly, a number of experimental studies have previously shown the effect of Clonorchis sinensis proteins of this orthogroup on the cancer transformation of host cells. Our results made it possible for the first time to systematically identify PLA2 sequences in flatworms, and demonstrated that their evolution is subject to gene loss processes characteristic of parasite genomes in general. In addition, our analysis allowed us to identify taxon-specific processes of duplication and loss of PLA2 genes in parasitic organisms, which may be associated with the processes of their interaction with the host organism.

Blastocystis ST1: Protein Profile and Specific Serum Immunoglobulin in Irritable Bowel Syndrome (IBS) Patients.

Blastocystis sp. is a common enteric human parasite, which recently has been linked to gastrointestinal disorders i.e. Irritable Bowel Syndrome (IBS) and symptomatic patients (non IBS). Analyzing antibodies level in these patients could help in differential diagnosis. The current study aimed to identify the protein profile of the Blastocystis ST1 (Syrian strain: OR537347) lysates and to investigate the differences in IgG serum immunoglobulin between patients with IBS and non IBS. Twenty two IBS (Rome III) and nineteen patients suffering from different gastrointestinal disorders (non IBS), positive for Blastocystis were enrolled in this study. SDS-PAGE was used to identify the protein profile of the Blastocystis ST1 lysates and immunoblotting using sera from patients was used for reactivity compared to known Blastocystis protein targets. The crude protein profile of Blastocystis ST1 showed 24 protein bands ranged between 10 and 130kDa. Western blot demonstrated that the proteins (27-29);32;(39-42);(50-51) kDa had similar immunogenicity characteristic in IBS and non IBS patients while the proteins (60-95kDa) only interacted with IBS patients' sera. Our results highlighted the importance of Blastocystis proteins 60-95kDa (probably a metalloproteases) in IBS patients compared to non IBS, suggesting that these metalloproteases may be important Blastocystis antigens and can be used as a serologic test tool or as a biomarker for differential diagnosis.

Transcriptome of Arabidopsis thaliana Plants Exposed to Human Parasites Cryptosporidium parvum and Giardia lamblia

Pathogen infection in animals and plants is recognized in a relatively similar manner by the interaction of pattern recognition receptors on the host cell surface with pathogen-associated molecular patterns on the pathogen surface. Previous work demonstrates that animal pathogenic bacteria can be recognized by plant receptors and alter transcriptome. In this work, we have hypothesized that exposure to human parasites, Cryptosporidium parvum and Giardia lamblia, would also trigger pathogen response in plants, leading to changes in transcriptome. Detached Arabidopsis leaves were exposed for one hour to heat-inactivated Cryptosporidia or Giardia. The transcriptome profile showed large changes in gene expression with significant overlap between two parasites, including upregulated GO terms “cellular response to chitin”, “response to wounding”, “response to oomycetes”, “defense response to fungus”, “incompatible interaction”, and “activation of innate immune response”, and downregulated GO terms “positive regulation of development”, “cell surface”, “regulation of organ growth”, “wax biosynthetic process”, “leaf and shoot morphogenesis”. Uniquely downregulated GO terms in response to Cryptosporidia were GO terms related to chromatin remodelling, something that was not reported before. To conclude, it appears that while Cryptosporidia or Giardia are not pathogens of Arabidopsis, this plant possesses various mechanisms of recognition of pathogenic components of parasites.

Nation-wide surveillance of tick (Acari: Ixodidae) infestations of humans in Singapore.

Ticks are an increasingly important threat to public health in Southeast Asia, due to the role of many tick species as parasites of humans and as vectors of zoonotic pathogens. Singapore is a densely populated Southeast Asian nation with a rich tick fauna and a significant mosaic of city and greenspace. However, apart from occasional case reports, the human-biting ticks in Singapore have received little attention from researchers. Based on an ongoing nationwide tick surveillance program beginning in 2018 and literature records (since 2002), we present data from 51 cases of tick infestation in humans in Singapore involving 128 individual ticks of 11 species. The genera Dermacentor, Haemaphysalis, Ixodes, and Amblyomma were all found to bite humans in Singapore. The most common species infesting humans in Singapore was Dermacentor auratus which was responsible for more than half of all infestations. The first records of Haemaphysalis papuana in Singapore are also presented, with 3 cases of human infestation by this tick species. Finally, we highlight the Singapore National Tick Reference Collection (SNTRC) as an invaluable resource for the identification and study of ticks in Singapore.

Public Health Evaluation of Prisoners' Demographics and Awareness of Communicable Diseases in Correction Center in South-South Nigeria

Communicable diseases are a significant public health concern in Nigerian custodial centers. This study evaluated the public health implications of prisoners’ demographics and their awareness of communicable diseases in a correctional center in South-South Nigeria. A structured questionnaire was used to gather data on inmates' demographic characteristics and knowledge of six communicable diseases. Two hundred and nine (209) inmates who consented were randomly selected and self-administered the questionnaire. The data were tabulated and analyzed descriptively. Demographic data, including age, sex, marital and educational status, pre-incarceration occupation, residence, and duration in prison, aligned with the prison registry. Results indicated that all inmates (100.0%) were aware of communicable diseases. Information sources included hospitals/health workers (48.3%), family/friends/inmates (37.3%), books/magazines/newspapers (11.0%), and radio/TV/internet (3.3%). Inmates demonstrated good knowledge of communicable diseases, with 87.1% identifying causes and 56.6% recognizing modes of transmission. Awareness levels were high for HIV/AIDS (100.0%), hepatitis (81.3%), COVID-19 (100.0%), malaria (100.0%), human intestinal parasite infections (66.0%), and tuberculosis (73.2%). Most respondents correctly identified the etiologic agents, though some incorrectly attributed HIV/AIDS (9.3%) and hepatitis (17.1%) to spiritual causes. Regarding prevention, all inmates (100.0%) knew the methods for HIV/AIDS, COVID-19, and malaria. Awareness of hepatitis B prevention was 81.3%, while 66.0% and 73.2% identified preventive methods for human intestinal parasite infections and tuberculosis, respectively. This study highlights commendable awareness of communicable diseases among inmates, however, it revealed some misconceptions about its causes, control, and prevention., offering valuable insights for public health programs in correctional facilities.

Nucleotide-resolution Mapping of RNA N6-Methyladenosine (m6A) modifications and comprehensive analysis of global polyadenylation events in mRNA 3' end processing in malaria pathogen Plasmodium falciparum.

Plasmodium falciparum is an obligate human parasite of the phylum Apicomplexa and is the causative agent of the most lethal form of human malaria. Although N6-methyladenosine modification is thought to be one of the major post-transcriptional regulatory mechanisms for stage-specific gene expression in apicomplexan parasites, the precise base position of m6A in mRNAs or noncoding RNAs in these parasites remains unknown. Here, we report global nucleotide-resolution mapping of m6A residues in P. falciparum using DART-seq technology, which quantitatively displayed a stage-specific, dynamic distribution pattern with enrichment near mRNA 3' ends. In this process we identified 894, 788, and 1,762 m6A-modified genes in Ring, Trophozoite and Schizont stages respectively, with an average of 5-7 m6A sites per-transcript at the individual gene level. Notably, several genes involved in malaria pathophysiology, such as KAHRP, ETRAMPs, SERA and stress response genes, such as members of Heat Shock Protein (HSP) family are highly enriched in m6A and therefore could be regulated by this RNA modification. Since we observed preferential methylation at the 3' ends of P. falciparum transcripts and because malaria polyadenylation specificity factor PfCPSF30 harbors an m6A reader 'YTH' domain, we reasoned that m6A might play an important role in 3'-end processing of malaria mRNAs. To investigate this, we used two complementary high-throughput RNA 3'-end mapping approaches, which provided an initial framework to explore potential roles of m6A in the regulation of alternative polyadenylation (APA) during malaria development in human hosts.

Identification of a New Pentafluorosulfanyl-Substituted Chalcone with Activity Against Hepatoma and Human Parasites.

New drugs are required for the treatment of liver cancers and protozoal parasite infections. Analogs of the known anticancer active and antileishmanial 2',4',6'-trimethoxychalcone SU086 were prepared and investigated. The chalcones were prepared according to the Claisen-Schmidt condensation protocol and analyzed. They were tested for activity against two liver cancer cell lines (HepG2 and HuH-7) and protozoal parasites (Toxoplasma gondii and Leishmania major). Unspecific toxicity and expression of Hsp90 and Hsp70 upon treatment were analyzed in liver cancer cells. A new chalcone, 2',4',6'-trimethoxy-3-pentafluorosulfanylchalcone (246TMP-3SF5), with a pentafluorosulfanyl (SF5) substituent showed pronounced activities against liver cancer cells and T. gondii parasites which were superior to the activities of the parent chalcone SU086 in these models. In contrast, SU086 and its anthracene analog 2',4',6'-trimethoxy-9-anthracenylchalcone (246TMP-Anth) were most active against L. major promastigotes. The new SF5-substituted chalcone behaved like the known Hsp90 inhibitor 17-AAG and upregulated Hsp70 expression in liver cancer cells. The SF5-substituted SU086 analog has potential to become a new drug for the therapy of hepatoma and toxoplasmosis.

Cannabinoids as cytotoxic agents and potential modulators of the human parasite Trichomonas vaginalis.

Trichomoniasis, a globally prevalent sexually transmitted infection caused by Trichomonas vaginalis, affects approximately 278 million people each year. It presents a challenge due to resistance to the current treatment, Metronidazole (MTZ), which is also associated with side effects. Cannabis sativa, with more than 100 phytocannabinoids and numerous studies for therapeutic applications, including parasitic infections, has undergone a significant shift in acceptance worldwide, highlighted by legalizations and substantial revenue projections. In this context, the present study delves into the effects of cannabinoids, specifically WIN 55,212-2 (WIN), Cannabivarin (CBV) showcasing their anti-parasitic actions that influence the growth and morphology of T. vaginalis. The analysis extends to encompass the pharmacokinetic properties of these cannabinoids. Among the analyzed cannabinoids, CBV stands out for adhering to Lipinski's rules, indicating its potential suitability for oral drug delivery. They also demonstrated inhibitory effects on the growth of T. vaginalis trophozoites and a reduction in the parasite's adhesion to host cells. Several morphological alterations were observed, such as membrane projections, blebbing, autophagosomes and damaged hydrogenosomes. These results highlight the need for further research to explore the therapeutic potential of cannabinoids and understand their mechanisms of action in T. vaginalis.

Current status of intestinal parasitosis and microsporidiosis in industrialized countries: Results from a prospective study in France and Luxembourg.

Human intestinal parasitosis and microsporidiosis are a global health concern, mostly in endemic areas but should not be neglected elsewhere. Recent nationwide epidemiological data are scarce, especially from primary health care and developed countries. Diagnosis by molecular tools are increasing and several commercial gastrointestinal panel assays including protozoans and/or helminths are now available. These news tools improve the knowledge into real human parasite epidemiology. This study provides an epidemiological update on intestinal parasites found in primary health care in France and Luxembourg. Two thousand fifty-six stools from primary health care patients were analyzed for the presence of intestinal parasites (IPs) during two different seasons of 2022, the winter and the summer, corresponding to more than 1500 patients from all over France and Luxembourg. Parasite detection was performed combining standard microscopy (merthiolate-iodine-formaldehyde and Bailenger concentration procedures) with two molecular panel assays (AMPLIQUICK Fecal Pretreatment, AMPLIQUICK Protozoans and AMPLIQUICK Helminths, BIOSYNEX, France). The prevalence of IPs in primary care patients reached 33.2%. Blastocystis sp. and Dientamoeba fragilis were the most frequently detected parasites in 20.5% and 13.1% of patients, respectively. Coinfection with two or more parasites was detected in 9.9% of patients. For some parasites, patterns according to gender, age, geography or season have been observed. The high prevalence of pathogenic IPs (about 7%) underlines the importance of investigating gastrointestinal disorders through parasite examination, even in developed countries. The detection of parasites, pathogenic or not, remains a marker of the faecal-oral route of transmission and results should be interpreted accordingly. Parasites molecular characterization give new insights and should encourage further research as industrialized countries are not exempt of parasitic circulation and a better survey is necessary.

Thermosensory behaviors of the free-living life stages of Strongyloides species support parasitism in tropical environments.

Soil-transmitted parasitic nematodes infect over 1 billion people worldwide and are a common source of neglected disease. Strongyloides stercoralis is a potentially fatal skin-penetrating human parasite that is endemic to tropical and subtropical regions around the world. The complex life cycle of Strongyloides species is unique among human-parasitic nematodes in that it includes a single free-living generation featuring soil-dwelling, bacterivorous adults whose progeny all develop into infective larvae. The sensory behaviors that enable free-living Strongyloides adults to navigate and survive soil environments are unknown. S. stercoralis infective larvae display parasite-specific sensory-driven behaviors, including robust attraction to mammalian body heat. In contrast, the free-living model nematode Caenorhabditis elegans displays thermosensory behaviors that guide adult worms to stay within a physiologically permissive range of environmental temperatures. Do S. stercoralis and C. elegans free-living adults, which experience similar environmental stressors, display common thermal preferences? Here, we characterize the thermosensory behaviors of the free-living adults of S. stercoralis as well as those of the closely related rat parasite, Strongyloides ratti. We find that Strongyloides free-living adults are exclusively attracted to near-tropical temperatures, despite their inability to infect mammalian hosts. We further show that lifespan is shorter at higher temperatures for free-living Strongyloides adults, similar to the effect of temperature on C. elegans lifespan. However, we also find that the reproductive potential of the free-living life stage is enhanced at warmer temperatures, particularly for S. stercoralis. Together, our results reveal a novel role for thermotaxis to maximize the infectious capacity of obligate parasites and provide insight into the biological adaptations that may contribute to their endemicity in tropical climates.

Synthesis of 1,2,3-Triazole-Methyl-Menadione Derivatives: Evaluation of Electrochemical and Antiparasitic Properties against two Blood-Dwelling Parasites.

This study explores the synthesis and evaluation of novel 1,2,3-triazole-methyl-1,4-naphthoquinone hybrids, focusing on their electrochemical properties and antiparasitic efficacies against two human blood-dwelling parasites Plasmodium falciparum and Schistosoma mansoni. Using copper-catalyzed azide-alkyne cycloaddition (CuAAC), a well-established tool in click chemistry, two synthetic routes were assessed to develop a- and b-[triazole-methyl]-menadione derivatives. By optimizing the CuAAC reaction conditions, yields were significantly improved, reaching up to 94% for key intermediates and resulting in the formation of a library of approximately 30 compounds. Biological evaluation of the compounds in antiparasitic drug assays demonstrated notable antischistosomal potencies, while no significant activity was observed for the same series against P. falciparum parasites. Electrochemical and 'benzylic' oxidation studies confirmed that the active 'benzoyl' metabolite responsible for the antiplasmodial activity of plasmodione cannot be generated. These findings highlight the potential of triazole-linked menadione hybrids as promising early candidates for antischistosomal drug development, and provides insights into structure-activity relationships crucial for future therapeutic strategies.

High-Throughput Screening of More Than 30,000 Compounds for Anthelmintics against Gastrointestinal Nematode Parasites.

Gastrointestinal nematodes (GINs) are among the most common parasites of humans, livestock, and companion animals. GIN parasites infect 1-2 billion people worldwide, significantly impacting hundreds of millions of children, pregnant women, and adult workers, thereby perpetuating poverty. Two benzimidazoles with suboptimal efficacy are currently used to treat GINs in humans as part of mass drug administrations, with many instances of lower-than-expected or poor efficacy and possible resistance. Thus, new anthelmintics are urgently needed. However, screening methods for new anthelmintics using human GINs typically have low throughput. Here, using our novel screening pipeline that starts with human hookworms, we screened 30,238 unique small molecules from a wide range of compound libraries, including ones with generic diversity, repurposed drugs, natural derivatives, known mechanisms of action, as well as multiple target-focused libraries (e.g., targeting kinases, GPCRs, and neuronal proteins). We identified 55 compounds with broad-spectrum activity against adult stages of two evolutionary divergent GINs, hookworms (Ancylostoma ceylanicum) and whipworms (Trichuris muris). Based on known databases, the targets of these 55 compounds were predicted in nematode parasites. One novel scaffold from the diversity set library, F0317-0202, showed good activity (high motility inhibition) against both GINs. To better understand this novel scaffold's structure-activity relationships (SAR), we screened 28 analogs and created SAR models highlighting chemical and functional groups required for broad-spectrum activity. These studies validate our new and efficient screening pipeline at the level of tens of thousands of compounds and provide an important set of new GIN-active compounds for developing novel and broadly active anthelmintics.

Comprehensive analysis of the Kinetoplastea intron landscape reveals a novel intron-containing gene and the first exclusively trans-splicing eukaryote

BackgroundIn trypanosomatids, a group of unicellular eukaryotes that includes numerous important human parasites, cis-splicing has been previously reported for only two genes: a poly(A) polymerase and an RNA helicase. Conversely, trans-splicing, which involves the attachment of a spliced leader sequence, is observed for nearly every protein-coding transcript. So far, our understanding of splicing in this protistan group has stemmed from the analysis of only a few medically relevant species. In this study, we used an extensive dataset encompassing all described trypanosomatid genera to investigate the distribution of intron-containing genes and the evolution of splice sites.ResultsWe identified a new conserved intron-containing gene encoding an RNA-binding protein that is universally present in Kinetoplastea. We show that Perkinsela sp., a kinetoplastid endosymbiont of Amoebozoa, represents the first eukaryote completely devoid of cis-splicing, yet still preserving trans-splicing. We also provided evidence for reverse transcriptase-mediated intron loss in Kinetoplastea, extensive conservation of 5′ splice sites, and the presence of non-coding RNAs within a subset of retained trypanosomatid introns.ConclusionsAll three intron-containing genes identified in Kinetoplastea encode RNA-interacting proteins, with a potential to fine-tune the expression of multiple genes, thus challenging the perception of cis-splicing in these protists as a mere evolutionary relic. We suggest that there is a selective pressure to retain cis-splicing in trypanosomatids and that this is likely associated with overall control of mRNA processing. Our study provides new insights into the evolution of introns and, consequently, the regulation of gene expression in eukaryotes.

Operational Risk Assessment Tool for Evaluating Leishmania infantum Introduction and Establishment in the United States through Dog Importation1.

International pet travel and commercial operations have increased animal disease importation risks, including for Leishmania infantum, a deadly parasite of humans and domestic dogs. Collaborating as an interdisciplinary working group, we developed an operational tool for veterinary and public health practitioners to assess and manage L. infantum risk in dogs imported to the United States. Overall risk varies by dog, human, and geographic factors but could be high without proper controls. We determined dog risk management strategies should include application of sand fly insecticides and repellents, sterilization, and treatment. US public health authorities can use a One Health approach to manage L. infantum importation risks via infected dogs.

Recognition of parasitic helminth eggs via a deep learning-based platform.

Accurate and rapid diagnosis is crucial for the effective treatment of parasitosis. Traditional etiological methods, especially microscopic examination, are time-consuming, labor-intensive, and prone to false or missed detections. In response to these challenges, this study explores the use of artificial intelligence (AI) for the detection and classification of human parasite eggs through the YOLOv4 deep learning object detection algorithm. Eggs from species such as Ascaris lumbricoides (A. lumbricoides), Trichuris trichiura (T. trichiura), Enterobius vermicularis (E. vermicularis), Ancylostoma duodenale (A. duodenale), Schistosoma japonicum (S. japonicum), Paragonimus westermani (P. westermani), Fasciolopsis buski (F. buski), Clonorchis sinensis (C. sinensis), and Taenia spp. (T. spp.) were collected and prepared as both single species and mixed egg smears. These samples were photographed under a light microscope and analyzed using the YOLO (You Only Look Once) v4 model. The model demonstrated high recognition accuracy, achieving 100% for Clonorchis sinensis and Schistosoma japonicum, with slightly lower accuracies for other species such as E. vermicularis (89.31%), F. buski (88.00%), and T. trichiura (84.85%). For mixed helminth eggs, the recognition accuracy rates arrived at Group 1 (98.10, 95.61%), Group 2 (94.86, 93.28 and 91.43%), and Group 3 (93.34 and 75.00%), indicating the platform's robustness but also highlighting areas for improvement in complex diagnostic scenarios. The results show that this AI-assisted platform significantly reduces reliance on professional expertise while maintaining real-time efficiency and high accuracy, offering a powerful tool for the diagnosis and treatment of parasitosis. With further optimization, such as expanding training datasets and refining recognition algorithms, this AI system could become a key resource in both clinical and public health efforts to combat parasitic infections.

Gastrointestinal Parasitic Infections in Non-Human Primates at Gabon’s Primatology Center: Implications for Zoonotic Diseases

Parasites and infectious diseases pose significant threats to primate populations, especially in captive non-human primates (NHPs). This study aimed to assess the diversity and prevalence of intestinal parasites in NHPs at the CIRMF Primatology Center. A total of 97 fecal samples were analyzed using parasitological techniques, including sodium chloride flotation and modified Baermann sedimentation methods. An overall parasite prevalence of 93.81% (91/97) was observed. Sixteen groups of parasites with zoonotic potential were identified, comprising ten genera of nematodes (Trichuris, Enterobius, Hookworm, Trichostrongylus, Mammomonogamus, Spirure, Oesophagostomum, Schistosoma, Ascaris, and Strongyloides), three genera of protists (Eimeria, Balantioides coli/Buxtonella, and Entamoeba), one genus of cestodes (Hymenolepis), and two genera of trematodes (Dicrocoelium and Paramphistomum). High prevalences were noted for Oesophagostomum spp. (83.5%), Strongyloides spp. (52.58%), and Trichostrongylus spp. (50.52%). These findings underscore the potential role of the CIRMF Primatology Center in maintaining and facilitating the transmission of intestinal parasites with high zoonotic potential. The co-existence of human and NHP parasites in shared environments, such as zoos and research facilities, emphasizes the need for a holistic, One Health approach that addresses the interconnected health of humans, animals, and the environment. This study highlights the urgent need for collaborative strategies to mitigate the risks of zoonotic parasite transmission between NHPs and humans in captive settings.