Conference Agenda

Background: Schistosoma mekongi remains a public health concern in Cambodia and Lao PDR despite substantial reductions in prevalence following repeated mass drug administration (MDA). As transmission becomes increasingly localised, sensitive and integrated surveillance approaches are needed to identify residual transmission, animal reservoirs, environmental risk, and behavioural factors that may sustain infection. We conducted a pilot One Health study to inform future schistosomiasis elimination activities by combining household surveys, latrine audits, animal sampling, molecular diagnostics, environmental DNA surveillance, and formative research to guide development of health education.

Methods: A mixed-methods cross-sectional pilot study was conducted in six historically endemic villages in Cambodia and two villages in Lao PDR. Household heads completed structured questionnaires on water use, sanitation, knowledge of S. mekongi, water contact and open defecation. Latrine audits assessed infrastructure, functionality, water availability and soap presence. In selected villages, faecal samples were collected from domestic animals and preserved for microscopy and qPCR. Environmental DNA samples were collected to support identification of potential transmission hotspots. Formative research, including draw-and-write activities, focus group discussions and key informant interviews, was undertaken with school children, parents, teachers and health officials. These data were used to identify knowledge gaps, misconceptions, preferred communication styles and culturally relevant storylines to support development of the Magic Glasses (MG) health education package for schistosomiasis.

Results: River water use remained common, particularly for cooking, washing and latrine water, and recent river contact was frequently reported across study villages in both countries. Latrine access varied between Cambodian villages, with some communities reporting substantial proportions of households without latrines; overall latrine coverage was higher in Lao PDR. Knowledge of S. mekongi was generally high, particularly regarding serious disease, but important gaps remained around transmission, animal reservoirs and the potential for reinfection after treatment. Open defecation and frequent river contact persisted in several villages. Participants strongly supported school-based education and interactive learning activities, informing development of the MG.

Conclusions: This pilot demonstrates the feasibility and value of integrated One Health surveillance for S. mekongi. Combining molecular, environmental, animal and community-based approaches strengthens detection while generating locally grounded formative data for health education.

Paralysis ticks (Ixodes holocyclus) cause a severe, potentially fatal, toxicosis in dogs. A fast and sustained speed-of-kill throughout the dosing interval is a valuable acaricidal characteristic. Lotilaner has the longest half-life (35 days) of the oral isoxazolines¹, and a single dose kills paralysis ticks for over 11 weeks.²

A randomised, blinded, controlled study was conducted to compare the speed-of-kill of the monthly-dosed combination isoxazoline products Credelio™ PLUS (lotilaner, milbemycin oxime), NexGard Spectra^® (afoxolaner, milbemycin oxime) and Simparica^® Trio (sarolaner, moxidectin, pyrantel) against Ixodes holocyclus. Dogs (n=7/group) were treated (or left as untreated controls) on Day 0 and infested with 10-12 unfed adult female ticks on Days -2, 21, 28 and 35. Tick counts were performed 12, 18 and 24 hours post-treatment and post-reinfestation.

The initial speed-of-kill efficacy (12 h post-treatment) was rapid and similar for lotilaner and sarolaner (>80%), and significantly greater than afoxolaner (50%; P<0.004). On Day 21, efficacies of lotilaner, sarolaner and afoxolaner were 95.6%, 66.1% and 26.0%, respectively, 12 hours after reinfestation, with lotilaner and afoxolaner exceeding 97% and sarolaner nearly reaching 95% by 24 hours. On Day 28, efficacies of lotilaner, sarolaner and afoxolaner were 86.4%, 21.6% and 3.6%, respectively, 12 hours after reinfestation, with all products exceeding 96% and lotilaner reaching 100% by 24 hours. On Day 35, efficacies of lotilaner, sarolaner and afoxolaner were 76.6%, 23.4% and 6.9%, respectively, 12 hours after reinfestation. Lotilaner exceeded 95% efficacy already by 18 hours, sarolaner by 24 hours, while afoxolaner remained below 90%.

Lotilaner killed reinfesting ticks faster (P<0.01 at 12 hours) than sarolaner and afoxolaner and sustained its rapid speed-of-kill and efficacy beyond the label claim of one month. This offers reassurance to veterinarians and dog owners, addressing concerns about the potential increased risk of tick paralysis towards the end of the dosing interval of acaricides.

References:

¹ Toutain CE., et al. The intravenous and oral pharmacokinetics of lotilaner in dogs. Parasit Vectors. 2017;10(1):522.

² Baker, K., et al. Laboratory evaluations of the 3-month efficacy of oral lotilaner (Credelio™) against experimental infestations of dogs with the Australian paralysis tick, Ixodes holocyclus. Parasit Vectors. 2018;11(1):487.

Recently published whole-genome analyses of the two closely related parasites, Plasmodium ovale curtisi and P. ovale wallikeri, which cause human ovale malaria, provide compelling evidence that the nuclear genomes of these two organisms do not recombine and are therefore perfectly dimorphic at all loci examined. The same pattern is observed when comparing the two 4.3 kb mitochondrial genomes. Here, we present an analysis of new sequencing data from the tufa locus, encoded in the plastid-derived apicoplast organelle, that provides evidence that this third parasite genome is also dimorphic and co-segregates with specific dimorphs of the nuclear and mitochondrial genomes. These findings, together with other recent studies, support full species status for the two causative agents of ovale malaria in humans, necessitating a revision of the nomenclature used up until now. We propose redefining the original species name Plasmodium ovale Stephens by designating a neotype from Kenya for what was previously referred to as ‘P. ovale curtisi’. A new species, Plasmodium wallikeri sp. n., is also described using a type specimen from West Africa. Morphological descriptions will be provided and sequence information defined for three genetic loci that distinguish these two species at nuclear, mitochondrial and apicoplast genome levels, respectively.

The combination of atovaquone and proguanil (e.g., Malarone^®) has been used for decades for malaria prevention and treatment. Atovaquone inhibits cytochrome bc₁ (complex III), a component of the Plasmodium mitochondrial electron transport chain (mETC). Proguanil is a biguanide prodrug that is metabolized in vivo by liver cytochrome P450 (CYP2C19) enzymes into cycloguanil, a dihydrofolate reductase (DHFR) inhibitor that blocks the synthesis of pyrimidines which are required for nucleic acid synthesis. Proguanil can potentiate the activity of atovaquone in vitro, and we demonstrated that this drug also has slow action in vitro activity against P. falciparum (e.g., Pf3D7 96h IC₅₀ 0.1 µM) that is independent of DHFR inhibition and isoprenoid metabolism and does not appear to be directly linked to pyrimidine synthesis. However, our understanding of the clinical implications of proguanil’s intrinsic activity are complicated by an incomplete understanding of the slow action mechanism of this drug and the lack of information on clinical resistance to proguanil. To address this, we have utilised a range of approaches to investigate resistance mechanisms associated with proguanil, including generation of proguanil-resistant P. falciparum lines and examining differences in sensitivity to proguanil by P. falciparum lab lines, field isolates and the zoonotic P. cynomolgi species. These data will be discussed in the context of clinical use of proguanil in the atovaquone and proguanil combination.

Onchocerciasis (river blindness), caused by Onchocerca volvulus and transmitted by Simulium blackflies, remains a public health challenge in sub-Saharan Africa. Although prevalence has declined following aerial larviciding under the Onchocerciasis Control Programme (OCP) and African Programme for Onchocerciasis Control (APOC) through community-directed treatment, achieving the World Health Organization elimination target of sustained microfilarial (mf) prevalence below 1% requires identifying areas of persistent transmission. Mf prevalence data from 1,353 surveys across 671 villages were obtained from the Expanded Special Project for Elimination of Neglected Tropical Diseases and the Ghana Neglected Tropical Diseases Programme. Environmental predictors were structured around four transmission constructs: climatic suitability, flowing-water probability, vector blood-feeding probability, and bioregional land-use context. A Bayesian spatiotemporal zero-inflated beta-binomial model was fitted using Stan via brms in R, incorporating ecozone-specific temporal smooths, a two-dimensional spatial smooth, and nested random effects. MF prevalence was spatially and temporally heterogeneous. Northern ecozones declined to near-elimination levels by 2015, whereas southern forest and forest-agriculture transition zones showed slower and less consistent declines. The Tano-Ankobra transmission zone emerged as a persistent hotspot. This first comprehensive spatiotemporal analysis of onchocerciasis across Ghana highlights the need for intensified, targeted interventions in southern Ghana to achieve elimination.

Canine leishmaniasis (CanL) has important implications for both human and animal health. Leishmania infantum is the primary causative agent of CanL, with dogs acting as the main reservoir for human visceral leishmaniasis. A qPCR assay originally developed to aid CanL diagnosis has been widely used for the identification of L. infantum over the past two decades. However, evidence of cross-amplification of other Leishmania species raises concerns regarding species misidentification.

Through a systematic review of publications retrieved from major databases from 2006 to 2026, 177 studies were identified that used this CanL qPCR, of which only 51 (28.8%) applied a confirmatory molecular method.

We further evaluated the analytical and diagnostic performance of this assay using DNA from 15 cultured Leishmania species representing four subgenera, as well as vector and clinical samples from dogs and humans across endemic regions in the Old and New Worlds and performed species confirmation by nanopore sequencing targeting the heat shock protein 70 gene. We demonstrated that the assay amplified seven non-L. infantum species in cultured samples, and L. major and L. braziliensis from field samples. These findings demonstrate the potential of the CanL qPCR to obscure global Leishmania diversity, underscoring the need for improved diagnostic strategies.

Soil-transmitted helminth (STH) infections remain prevalent in northeastern Bangladesh despite the national school-based deworming programme implemented since 2008. This study reports STH epidemiology in underprivileged communities of Sylhet and Moulvibazar districts.

A total of 772 stool samples were collected from 16 urban slum and tea garden communities between May and October 2025 and analysed using sodium nitrate flotation, Kato-Katz, and Baermann techniques. Descriptive statistics estimated prevalence, adjusted for clustering, with 95% confidence intervals.

Based on sodium-nitrate-flotation, overall STH prevalence was 35.1% (271/772; 95% CI 26.2-45.2), with Ascaris lumbricoides predominating at 31.1% (240/772; 21.8-42.2), followed by hookworm (38/772; 4.9%, 2.6-9.1) and Trichuris trichiura (34/772; 4.4%, 2.0-9.5). All infections were of light to moderate intensity. STH prevalence ranged from 12.5% to 70.9% across communities, with similar levels in tea garden (57/162; 35.2%) and slum settings (214/610; 35.1%). Using Kato-Katz, overall prevalence was 28.4% (219/772; 20.1-38.4), with A. lumbricoides predominant (193/772; 25.0%, 16.5-36.1) followed by T. trichiura (26/772; 3.4%, 1.3-8.2) and hookworm (19/772; 2.5%, 1.4-4.4). SNF was more sensitive than Kato-Katz, with concordance analysis planned. Strongyloides spp. prevalence by Baermann was lower than expected (0.4%; 3/772; 0.1-1.6).

These findings highlight persistent transmission and community-level variation, supporting community-based control strategies targeted to high-risk areas.

Schistosomiasis caused by Schistosoma japonicum remains highly prevalent in the Philippines despite decades of preventive chemotherapy, partly due to the absence of accurate, field‑deployable diagnostics. We recently developed two semi–point‑of‑care diagnostics (POCs): (1) an equipment‑free cotton‑syringe stool DNA extraction device paired with portable quantitative PCR, and (2) a latex microsphere‑based lateral flow immunoassay detecting anti‑SjSAP4 antibodies in serum. Laboratory validation using infected human samples showed diagnostic performance comparable to established methods—87.7%/92.1% sensitivity/specificity for the cotton‑syringe system relative to Kato‑Katz (KK) and commercial stool qPCR, and 80.6%/98.0% for the anti‑SjSAP4 LFIA compared with KK. To evaluate field applicability, both POCs were deployed in six endemic Philippine villages, where community health workers were trained to perform the tests on residents (n=250 per village). Acceptability was assessed through questionnaires and focus group discussions. Preliminary findings highlight key challenges, including reluctance among health workers to handle stool samples and workflow bottlenecks during stool homogenization in the cotton‑syringe method. Addressing these operational pain points will be essential for improving uptake and ensuring that these POCs can support more accurate, community‑level schistosomiasis surveillance and monitoring.

Combating malaria caused by Plasmodium falciparum requires strategies to mitigate drug resistance. The clinical candidates cipargamin and SJ733 target the Na⁺ pump PfATP4. A G358S mutation in PfATP4, identified in 68% of recrudescent cases in a cipargamin clinical trial, confers high-level resistance to both compounds while simultaneously increasing parasite sensitivity to PfATP4 inhibitors belonging to two distinct chemical classes (‘I’ and ‘II’). To investigate whether collateral sensitivity could be leveraged in preserving cipargamin efficacy, we exposed ‘hypermutator’ parasites to class I and II compounds in combination with a high (20× IC₅₀) concentration of cipargamin. The cipargamin/class I combination led to an L354V mutation in PfATP4, while for cipargamin/class II, no viable parasites emerged across 6 selections. However, exposure of PfATP4^G358S parasites to a class II compound drove the acquisition of an additional PfATP4 mutation (N355Y). The N355Y+G358S mutants exhibited > 2000-fold and 650-fold resistance to cipargamin and SJ733, respectively. The PfATP4-G358A mutation was also associated with treatment failure in the clinical trial. We show that this mutation confers 500-fold resistance to cipargamin, confirming its clinical significance. Together, these findings highlight that while multiple PfATP4 mutations can compromise cipargamin efficacy, combining certain PfATP4 inhibitors increases the barrier for resistance.

Resistance to the frontline antimalarial drug artemisinin is primarily mediated by mutations in the Plasmodium falciparum protein Kelch13 (K13), whose function has remained unclear. Parasites carrying mutant K13 ingest red blood cell haemoglobin more slowly. Because artemisinin is activated by haem released during parasite feeding, reduced haemoglobin uptake likely lowers intracellular levels of toxic artemisinin-derived species. How wild-type or mutant K13 contributes to this feeding process was unknown. Using multiple imaging approaches, we show that K13 localises to the collar that maintains the cytostome, a stable parasite invagination used for uptake of host cytosol. Three-dimensional electron microscopy reveals that mislocalised K13 abolishes formation of the electron-dense collar that stabilises the cytostomal neck and disrupts cytostome formation itself. Consistent with this, haemoglobin degradation products, including haem and haemozoin, are reduced when K13 is inactivated. Using expansion microscopy together with super-resolution and lattice light-sheet microscopy, we further show that new K13 collars form and segregate to daughter cells before division, but that this biogenesis is delayed in mutant parasites. These findings indicate that artemisinin resistance arises through defective cytostome formation, reduced endocytosis, and diminished drug activation in resistant parasites.

Fleas (Siphonaptera) are globally important blood-feeding ectoparasites that infest companion animals, livestock, and humans. They are vectors of bacterial pathogens such as Rickettsia and Bartonella. Yet, many flea species and their associated bacterial communities in Cambodia remain poorly characterised. This project aims to identify flea species parasitising dogs in Cambodia and characterise their bacteriome. Fleas collected from dogs across multiple Cambodian regions were morphologically identified using established dichotomous keys. Genomic DNA was extracted from individual fleas, and full-length 16S rRNA gene nanopore metabarcoding will be performed, following previously developed and validated workflows to characterise flea-borne bacteria (FBB). This flea bacteriome data will be analysed alongside previously generated dog blood bacterial profiles, using paired samples from the same individual hosts. Preliminary morphological work revealed that most fleas parasitising Cambodian dogs belong to the genus Ctenocephalides, with C. orientis predominating. Sequencing will confirm species identity and the diversity of FBB pathogens, potentially detecting well known zoonotic agents and novel taxa that conventional PCR-based approaches may fail to detect. Integrating flea species identification with bacteriome data and host blood infection status provides initial evidence on the potential vector role of canine fleas in Cambodia and identifies gaps for future surveillance in under-resourced settings.

Exposure to Toxoplasma gondii in dogs has been recognised for decades, including an Australian study conducted at the University Veterinary Teaching Hospital in Sydney (UVTHS) in 1982, which showed that exposure was common among dogs presented for veterinary care. Since then, major changes in canine lifestyle, urbanisation and veterinary practice have occurred, raising questions about whether exposure patterns have shifted and what factors now best explain risk. Using diagnostic serology data from approximately 500 dogs, we examined a contemporary cohort of client‑owned dogs presented to a veterinary teaching hospital. Serological evidence of prior exposure remains common, consistent with historical findings. Age was the dominant predictor of seropositivity, with dogs aged four years or older showing substantially higher odds of exposure, reflecting cumulative lifetime contact with the parasite. Breed‑associated exposure ecology further clarified risk: Toy breeds consistently showed the lowest likelihood of seropositivity, while other purebred dogs had markedly higher odds, suggesting lifestyle and environmental exposure, rather than fine breed distinctions, drive risk. From a veterinary perspective, canine T. gondii seropositivity reflects prior exposure rather than disease, and positive serology (particularly in older, non‑Toy dogs) represents an expected background finding rather than evidence of toxoplasmosis.

Strongyloides stercoralis is an intestinal nematode infecting humans and dogs, but its occurrence in dogs from temperate, traditionally non-endemic regions is poorly characterised, partly due to limited veterinary diagnostics. Recent reports from metropolitan areas raise concern that infections may be under-recognised. This study screened archived canine faecal DNA (n = 448) collected between 2014 and 2024 from two university veterinary teaching hospitals in Sydney, New South Wales, Australia, using a highly sensitive 18S rRNA real-time qPCR (limit of detection: two DNA copies). One sample (0.02%) was positive, containing approximately 6.8 × 10³ 18S rDNA copies, equivalent to 3.2 Strongyloides ratti third-stage larvae per 250 mg of faeces. Deep amplicon sequencing of partial cox1 and 18S rDNA (HVR‑I and HVR‑IV) confirmed S. stercoralis potentially circulating between dogs and humans. The positive sample originated from a Border Collie puppy with gastrointestinal signs. Although rare, detection confirms the parasite’s presence in companion dogs in a temperate urban setting. These findings support the utility of 18S rDNA-based qPCR for retrospective surveillance and its inclusion in molecular diagnostic panels for canine gastrointestinal disease and highlight the need for expanded surveillance in non-endemic regions.

Schistosoma japonicum, the Asian schistosome, is a zoonotic parasite that infects humans and more than 40 species of domestic animals. It is a principal causative agent of schistosomiasis, a neglected tropical disease affecting 240 million people globally. In endemic regions, bovines are major reservoirs responsible for up to 75-90% of environmental egg contamination that perpetuate transmission. Current control efforts rely heavily on chemotherapy with Praziquantel, though effective at reducing worm burdens, does not prevent reinfection with risk of developing drug resistance if used solely. These limitations highlight the urgent need for integrated strategies to achieve sustainable control. Mathematical modelling has indicated that coupling chemotherapy with an effective transmission-blocking vaccine (TBV) could achieve elimination of S. japonicum within a decade. In this context, my PhD project seeks to develop an mRNA TBV by evaluating parasite-derived proteins with demonstrated immunogenicity and protective potential. Preliminary murine trials demonstrated significant reductions in worm and egg burdens, as well as alleviation of liver pathology. The integration of such promising antigens in a multivalent mRNA vaccine represents a rational strategy to maximize protection and durability of response and combined with control measures offers a promising pathway toward sustainable schistosomiasis control and improved global public health outcomes.

The prevalence and diversity of intestinal parasites in Papua New Guinea (PNG) and their potential impact as co-morbidities on endemic infectious diseases, such as tuberculosis (TB), remain poorly understood. This cross-sectional study provides an updated assessment of intestinal parasites (helminths and protozoa) in a TB-endemic rural PNG community. Participants were recruited from Balimo District Hospital, with stool and blood samples collected in June 2019 and January 2020. Faecal specimens (n=164) were examined by microscopy and qPCR, and plasma samples (n=121) were tested for Strongyloides-specific IgG antibodies using a commercial ELISA

Overall, 95.1% of participants had at least one type of intestinal parasite. Intestinal protozoa were detected in 85.4% of participants, most commonly detected were Blastocystis spp. (77.4%), Entamoeba hartmanni (29.3%), E. coli (23.3%), Dientamoeba fragilis (16.5%) and E. polecki (12.8%). Helminths were detected in 65.9%, predominantly Necator americanus (44.5%), Ascaris lumbricoides (37.8%) and Strongyloides spp. (17.7%). Polyparasitism was common, with 44.5% harbouring multiple protozoan and 31.1% infected with two or more helminths. These findings demonstrate a high burden and diversity of intestinal parasites in rural PNG. Whether co-infection with these parasites impacts the clinical outcome TB remains to be determined.

Insecticide treated nets (ITNs) are the most widely used mosquito control tool. To ensure efficacy and quality, ITN products undergo a prequalification process, with any changes to prequalified products to be reported to the World Health Organization. As a result, recipients can expect to receive products exhibiting consistent physical and insecticidal properties. A durability study showed that Yahe ITNs distributed in Papua New Guinea (PNG) in 2021 did not retain insecticidal efficacy for longer than several months. ITNs are frequently exposed to elevated temperatures during transport and storage and throughout their lifespan in the tropics. To better understand the potential impact of elevated temperature on insecticidal efficacy of Yahe, and to investigate why ITNs failed insecticidal efficacy tests after 6 months in PNG, Yahe ITNs were stored at elevated temperatures and evaluated using cone bioassays. Results revealed diverging physical and insecticidal properties of ITNs sampled from a single batch with ITNs exhibiting differences in colour, mesh size, weave, and insecticidal efficacy. Furthermore, ITNs exposed to 35- 50°C exhibited significantly decreased insecticidal efficacy. This study highlights inconsistencies in basic product properties of Yahe LN ITNs that are apparently not controlled or reported, and the importance of assessing current products for temperature-stability.

Strongyloidiasis, “the most neglected tropical disease”, caused by the helminth Strongyloides stercoralis, is a major global concern. It can persist life-long following infection, unless treated, due to the auto-infective lifecycle. Infection can be fatal, particularly among patients with immunosuppression. Despite health risks, knowledge surrounding strongyloidiasis burden and diagnostics remains limited.

The World Health Organization (WHO) advocates for strongyloidiasis’ inclusion in parasite control programs; however, with no population-based diagnostic tests and no large-scale surveys, large-scale treatments are not being provided. Global strongyloidiasis targets are off-track, and millions of people suffer from preventable debility.

Microscopy is a mainstay of population-based helminth surveys. Artificial intelligence (AI) improvements have led to AI-guided microscopy. A novel automated AI-based platform that images and digitises samples on standard microscopy slides to detect and quantify parasitic infections recently showed increased sensitivity and rapidity over human slide readers.

We are developing the first AI model for detecting S. stercoralis using larvae from lab and clinical samples, supporting AI training. We are trialling different preparations for Strongyloides spp. detection, and will undertake field validation in North East Arnhem Land. Our expected outcome is the first field-validated, AI-based S. stercoralis population-level diagnostic test, to allow population treatment programs to commence.

Artemisinin resistance in Plasmodium parasites, driven by mutations in the parasite's Kelch 13 (K13) protein, threatens global malaria control. K13 is important for regulating the cytostome, a double-membraned invagination used to ingest host-cell haemoglobin. This process is important because haemoglobin digestion releases haem-iron as a toxic byproduct, which is required to activate artemisinin. Mutations in K13 cause slowed-feeding and lower haem levels, allowing parasites to survive drug exposure. However, the precise mechanisms by which K13 mutations impairs parasite feeding remains unclear.
We performed a variety of high-resolution and spatial-temporal microscopy techniques to investigate cellular changes when K13 is mutated. By expansion microscopy, we confirmed K13 to localise to distinctive ring-shaped structures (~160 nm) surrounding cytostomal necks. Using a machine-learning segmentation and automated quantification pipeline, we found K13 mutant parasites produced new cytostomes at significantly slower rates than the wild-type. K13 mutants had a 4h egress delay, producing fewer total K13 rings compared to wild-type, despite maintaining normal progeny counts. Furthermore, these mutants occasionally exhibited aberrant cytostome morphologies where K13 was absent from the cytostomal neck, correlating with decreased haemoglobin uptake efficiency.

These findings fundamentally advance understanding of artemisinin resistance by providing a mechanistic explanation for K13-mediated feeding defects.

Malaria is a disease of significant and ongoing global burden, caused by parasites of the Plasmodium genus, with Plasmodium falciparum responsible for 90% of global malaria mortality. Effective drug treatment is instrumental to control of this disease, and the World Health Organisation (WHO) recommends artemisinin (ART) combinations for treatment of uncomplicated P. falciparum malaria. In this process of treatment, intentionally or otherwise, ART derivatives may be coadministered with apicoplast-targeting antibiotics such as doxycycline or clindamycin. However, previous work from our laboratory indicated an antagonistic relationship between these drugs. Antagonism between ART derivatives and apicoplast-targeting drugs may reduce efficacy and lengthen duration of treatment, as well as potentially increasing susceptibility to resistance mutations. In order to shed light on the mechanism of this antagonism, we are optimising a novel mass spectrometry assay that directly measures the degradation of ART under different conditions. Despite the discrete cellular targets of the drugs of interest, we posit that the downstream effects of these antibiotics on haemoglobin uptake are critical to ART activation and may be responsible for the antagonistic effect. Clarification of these drug class interactions may hold clinical significance for coadministration of antimalarial therapeutics.

Acanthocolpids are a family of digenean trematodes mired with taxonomic instability and complexity. The life cycle is generally typified by trophic transmission via fish second-intermediate hosts and fish definitive hosts, with some exceptions. We described a new species of Acanthocolpidae from the Great Barrier Reef, which is the first known parasite for its definitive host, the sailfin snapper, Symphorichthys spilurus (Lutjanidae). Morphologically, this new species is consistent with the genus Pseudolepidapedon. However, phylogenetic analyses with our novel sequence data, the first for an Indo-Pacific species of the genus, also implicates some species of Stephanostomum, an infamously problematic and likely polyphyletic genus with over 90 species. These findings complicate the relationship and blur the boundaries between Pseudolepidapedon and Stephanostomum. Additionally, although the sailfin snapper is a large predatory fish, it feeds mostly on benthic invertebrates, and our new species bears some similarity to one of the exceptional species of acantholpids known to use molluscs, rather than fishes, as second-intermediate hosts. We discuss the potential taxonomic and life cycle revelations suggested by the discovery of this new species.

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease affecting ~1% of the global population, with current therapies largely limited to symptom control and are associated with adverse effects. There is an urgent need for novel treatments targeting underlying disease mechanisms. Hookworms secrete immunomodulatory proteins that have evolved to regulate host immunity.

Here, we investigate a recombinant fatty acid- and retinol-binding protein, Ac-FAR-2, derived from the secretome of Ancylostoma caninum, as a hookworm-inspired therapeutic candidate for RA. Ac-FAR-2 significantly attenuated disease severity in a murine model of RA, with histological and confocal analyses revealing reduced macrophage infiltration in joint tissues. In vitro, Ac-FAR-2 suppressed inflammatory cytokine production in human peripheral blood mononuclear cells and THP-1-derived macrophages. This effect was associated with reduced co-stimulatory marker expression and impaired T-cell proliferation in co-culture systems.

Mechanistically, Ac-FAR-2 interacted with macrophage surface molecules and disrupted the arachidonic acid–prostaglandin E2 pathway. Transcriptomic profiling further demonstrated downregulation of NF-κB signaling, inflammasome-related genes, and other pro-inflammatory pathways in LPS-stimulated human macrophages.

These findings identify Ac-FAR-2 as a promising immunomodulatory candidate for RA and other macrophage-driven autoimmune diseases.

Malaria remains a major global health burden, with an estimated 282 million cases and 610,000 deaths across 80 countries in 2024. However, the mechanisms underlying protective immunity and inter-individual immune heterogeneity are still poorly understood, contributing to variation in susceptibility, disease severity, and vaccine efficacy.

This study applies a systems immunology and multi-omics approach to investigate the molecular basis of immune heterogeneity during Controlled Human Malaria Infection (CHMI). We aim to define an integrated framework of genes, proteins, and immune cell states that underpin Plasmodium parasite control and immune heterogeneity.

Using bulk RNA sequencing and single-cell data from peripheral blood mononuclear cells (PBMCs), we identified highly expressed and strongly correlated transcript pairs across mRNA, miRNA, and long non-coding RNAs (lncRNAs). These were incorporated into co-expression and regulatory networks to map transcriptional interactions. Correlation analyses revealed putative regulatory relationships, with lncRNA–mRNA pairs showing predominantly positive associations, suggesting coordinated expression across patient samples and over time.

Building on these findings, we are applying a probabilistic unsupervised machine learning framework to link transcriptional programs with proteomic signatures of immune activation. This integrative approach provides new insights into immune mechanisms driving parasite control while advancing multi-omics capabilities to the field of parasitology.

Background and Aims

The earliest stages of helminth infection, during which parasites migrate through host tissues to their final niche, determine whether infection is successfully established and pathology ensues. Yet this critical window has remained largely inaccessible in vivo. Here, we present the first intravital microscopy (IVM) workflow to visualise any helminth parasite in real time within a living mammalian host. Using Fasciola hepatica as a model, we captured newly excysted juveniles (NEJ) during the earliest stages of infection in experimentally infected C57BL/6 mice.

Methods

Mice were infected with 175 F. hepatica metacercariae and serially imaged from 6 hours to 8 days post-infection (PI), with matched tissue and parasite sampling at 6, 12, 48, 120, 144, 168, 180 and 192 hours PI.

Results

Multiphoton IVM enabled real-time visualisation of parasite invasion, migration and host–parasite interactions within intestinal and hepatic tissues. These data provide the first direct view of early helminth pathogenesis as it unfolds in vivo, overcoming a major technical barrier that has constrained the field for decades.

Conclusion

This work establishes a new experimental framework for studying tissue-migrating helminths and provides a critical in vivo benchmark for refining emerging 3D co-culture models.

Blood flukes of the genus Cardicola (Digenea: Aporocotylidae) are a significant health concern in farmed and ranched bluefin tuna (Thunnus spp., BFT), contributing to substantial economic losses. Although recombinase polymerase assays (RPA) have been developed for two species of Cardicola, the high degree of sequence conservation across all three species infecting BFT limits reliable species-level discrimination. This study aimed to design, optimise and validate loop-mediated isothermal amplification (LAMP) for the detection of the three Cardicola species infecting BFT and apply these assays to Pacific bluefin tuna (Thunnus orientalis, PBT) cultured in Japan. Species-specific LAMP assays were successfully developed for Cardicola forsteri, C. opisthorchis and C. orientalis targeting ITS-2 ribosomal DNA. In addition, these assays were applied to DNA from three sample types targeting sites of significant pathology, the heart, gill necropsy and gill biopsy of 15 PBT. Results were compared to outputs of quantitative polymerase chain reactions (qPCR), the gold standard method for blood fluke detection in Australia, with LAMP demonstrating greater sensitivity. This research constitutes the first development and application of LAMP diagnostics for all three Cardicola species infecting BFT, providing a rapid, cost-effective and user-friendly alternative to conventional molecular diagnostics to support improved monitoring and management.

Plagioporus and Podocotyle are historically the largest, most problematic and among the oldest genera in the Opecoelidae, the richest family of the Trematoda. Both genera were defined by combinations of generalised characters prone to homoplasy. Nevertheless, the two concepts have always been considered mutually exclusive. Through an integrated approach, we present a close phylogenetic relationship, clearly congeneric, between a nominal species of each genus. We recollected the two nominal species from known hosts near to their type-localities, Podocotyle parupenei from goatfishes (Mullidae) on the Great Barrier Reef, Australia (type locality: Fiji) and Plagioporus jagannathi from threadfinbream (Nemipteridae) in Sri Lanka (type locality: India). Podocotyle is currently recognised in the subfamily Podocotylinae, but Podocotyle parupenei has since been recombined as Podocotyloides parupenei in the Hamacreadiinae. Likewise, Plagioporus currently belongs to the Sphaerostomatinae, but Plagioporus jagannathi was recombined as Macvicaria jagannathi in the Opistholebetinae. Our analysis revealed that two species are distinct, but closely related, andbelong to none of Plagioporus, Podocotyle, Macvicaria, or Podocotyloides, but instead resolve within a fifth subfamily, the Decemtestinae. We have proposed and delineated a new genus to accommodate these taxa, exemplifying how homoplasy has long obscured true relationships and how intergrated taxonomy can cut through.

Haemocystidium spp. are apicomplexan parasites infecting reptiles, particularly freshwater turtles, yet their diversity and epidemiology remain poorly understood. This study aimed to detect and characterise Haemocystidium spp. in freshwater turtles from diverse populations in Australia. In total, 114 blood samples were collected from 8 turtle species. Blood smears were prepared from each turtle and examined by light microscopy, and genomic DNAs were isolated from matching blood samples using the DNeasy Blood & Tissue Kit (Qiagen). Molecular detection was performed using a nested PCR, targeting the small subunit (SSU) rRNA gene, employing primers HaemNF1/HaemNR2 in the first reaction and HaemF/HaemR2 in the second, generating an amplicon of ~480 bp. Haemocystidium DNA was detected in 36/114 (31.6%) samples by PCR, while intraerythrocytic stages observed in 25 samples by microscopy (21.9%) were consistent with Haemocystidium spp. Morphologically, parasites appeared as elongated or irregular forms within erythrocytes, occasionally causing host cell distortion. The higher detection rate achieved using PCR indicates an increased sensitivity compared with microscopy, although DNA sequencing is required to confirm amplicon specificity. These findings show that Haemocystidium infections are relatively common in freshwater turtles and emphasise the importance of combining molecular and morphological approaches for parasite detection.

The state of Florida, USA is a global invasion hotspot where more than 150 species of non-native reptiles and amphibians have been introduced. One of the most detrimental, the Burmese python (Python bivittatus), is less well-known for having co-introduced an invasive parasite, Raillietiella orientalis. This pentastome has since spilled over into both native and invasive herpetofauna and is a suspected contributor to the decline of several native snake populations, including the banded water snake (Nerodia fasciata). To investigate the influence of invasive R. orientalis infection on the physiology and native parasite communities of N. fasciata, we conducted metabolic rate testing prior to euthanasia and necropsies. We examined snakes externally then screened the mouth, respiratory tract, gastrointestinal tract and body cavity for parasites. Invasive pentastomes were found in 74% (23/31) of snakes with an infection intensity of 1-45, while no native pentastomes were found. Hosts with invasive pentastomes had a higher prevalence of nematodes, trematodes, cestodes, acanthocephalans, and respiratory mites relative to snakes without pentastomes. Results are discussed in regard to the potential impacts of invasive species on native parasite communities and resulting influence on hosts.

Plasmodium parasites, the causative agents of malaria, must cycle between mosquito vectors and vertebrate hosts, encountering population bottlenecks at each transition. Parasite numbers can drop from billions in the bloodstream to only a few in the mosquito midgut after feeding, and again during transmission back to a host, where only a small fraction of sporozoites establish a liver infection. These bottlenecks shape parasite population structure and key selective pressures, influencing drug resistance and vaccine escape. However, the magnitude of these bottlenecks has not been precisely quantified.

Here, we use cellular barcoding to track parasite populations at high resolution across the lifecycle. We generated a library of P. berghei parasites containing over 1,000 unique DNA barcodes integrated into a neutral genomic locus. This diverse population was transmitted between mice and mosquitoes via natural bites or intravenous sporozoite injection, with samples collected across the lifecycle stages for barcode sequencing.

Our initial analyses quantify changes in barcode diversity throughout the lifecycle, identifying where parasite diversity is lost or maintained. These results define key transmission bottlenecks and highlight stages most susceptible to intervention. This framework can be extended to assess how drugs and vaccines impact parasite population dynamics, informing more precise malaria control strategies.

The LSHTM Human Malaria Transmission Facility provides access to human malaria parasite transmission both for research groups within the London School of Hygiene & Tropical Medicine and external collaborators worldwide. Our specialist team works with these collaborators to design and execute studies relating to the transmission of Plasmodium parasites using gametocytes grown in vitro in the laboratory or collected directly from clinical samples received by the UK HSA Malaria Reference Laboratory and fed to insectary-reared Anopheles mosquitoes. As a case study illustrating the support offered by the HMTF, we present new data indicating an important role for pyridoxal 5’-phosphate biosynthesis (vitamin B6; PLP) in mosquito stage development of P. falciparum. Enzymes in this pathway were found to be highly enriched in an analysis of the stage V gametocyte “translatome”, the subset of the total gametocyte proteome actively incorporating a pulse of labelled methionine in late-stage gametocytes. Disruption of PDX2, one of two subunits of pyridoxal 5’-phosphate synthase, reduced gametocyte infectivity to Anopheles coluzzi mosquitoes. This reduction was manifest in three measures: oocyst numbers per mosquito midgut, oocyst diameter and, most profoundly, number of salivary gland sporozoites per mosquito. All three negative outcomes were rescued by vitamin B6 supplementation.

Transmission-blocking vaccines aim to induce antibody responses that prevent human-to-mosquito malaria transmission by targeting the parasite inside the mosquito midgut. The furthest advanced transmission-blocking vaccine candidates are based on the Pfs230:Pfs48/45 complex. During the preparation of a cryo-EM structure of the endogenous Pfs230:Pfs48/45 complex, we found a previously unidentified protein that interacts with Pfs230. This protein is without described function and is conserved throughout all Plasmodium spp.. Based on structural homology modelling, we have tentatively dubbed this protein PfHAP2-novel (PfHAP2n). We generated a PfHAP2n^KO parasite line that is able to undergo gametocytogenesis and gametogenesis. However, just like Pfs230^KO parasites, male microgametes are no longer able to attach to erythrocytes and no longer form “exflagellation centres”. PfHAP2n^KO parasites have a strong, male-dependent reduction in mosquito infectivity. We have recombinantly produced PfHAP2n, and we are testing whether these constructs can elicit malaria transmission-blocking antibodies in immunization studies. Our results have uncovered a novel protein that is essential for malaria transmission, which might be a suitable target for future transmission-blocking vaccine development.

Plasmodium falciparum sporozoites must successfully invade Anopheles mosquito salivary glands and human liver hepatocytes to establish infection. While CERLI1 and CERLI2 are known critical mediators of blood-stage invasion, their potential roles during these sporozoite-specific events remain unexplored.

This study investigates CERLI1 and CERLI2 function during sporozoite transmission. Using CRISPR/Cas9, we generated transgenic parasite lines with inducible knockouts for CERLI1 and CERLI2. Phenotypic analyses revealed that inducing these knockouts significantly reduces the sporozoite load within the salivary glands of Anopheles mosquitoes. Furthermore, utilizing ultrastructure expansion microscopy (U-ExM), we demonstrated that this impaired salivary gland colonization correlates with structural defects in the rhoptry organelles.

Collectively, our findings establish CERLI1 and CERLI2 as essential, multi-stage mediators of the Plasmodium invasion machinery. Elucidating their function in the mosquito vector, alongside pending investigations into hepatocyte entry, provides vital insights into the fundamental biology of parasite transmission.

Light microscopy is the most widely used tool in the study of cell biology but many of the subcellular structures of parasites are too small to see even with the best light microscopes. Recently, a technique called expansion microscopy that physically enlarges parasites has revolutionised parasite cell biology. To date, expansion microscopy has only been applied on either parasites grown in vitro or from isolated host tissues. We wanted to perform expansion microscopy on whole mosquitoes, to simultaneously visualise the ultrastructure of both malaria parasites and their mosquito hosts, but the presence of the Chitin-rich mosquito cuticle prevents expansion. Here, we develop expansion microscopy for whole mosquitoes by first digesting the cuticle with enzymes. We validate that the mosquitoes expand as expected, show preservation of mosquito anatomy, and visualise it at exquisite detail. The application of this methodology allows for the co-visualisation of parasite and mosquito ultrastructure including microvilli, salivary glands, gut-microbiome and ovaries. Additionally, we have validated this technique for other arthropods: Ixodes holocyclus and Drosophila melanogaster, highlighting its versatility across arthropods. While developed to investigate cell biology, application of this technique could greatly improve the resolution of spatial omics techniques in the study of vector-parasite interactions.

Human infection with malaria begins with the injection of sporozoites by a feeding mosquito. The sporozoite surface has a dense layer of one, immunodominant protein, called circumsporozoite protein (CSP). This protein contains 38 NANP amino acid tandem repeats which are highly immunogenic. The current licensed malaria vaccines being rolled out in Africa (RTS,S and R21) both target CSP, however they require multiple boosters to maintain high antibody titre, with vaccine efficacy waning overtime. Given CSP’s immunodominance and prevalence, could it be acting as an immunological decoy, evolved to evade an immune response from other critical cell surface proteins on the parasite? Here, we have used a CSP-tolerant mouse model, immunising mice with human infective Plasmodium falciparum sporozoites to induce an immune response towards non-CSP antigens on the surface of the sporozoite. We then performed 10x single-cell sequencing of the expanded B cell clones from immunized mice and generated a panel of monoclonal antibodies. Using these monoclonals alongside, polyclonal sera we have identified non-CSP sporozoite surface antigens as potential targets for next generation malaria vaccines.

Plasmodium vivax is the most widespread Plasmodium species causing human malaria, remains a major global health risk. Effective interventions against P. vivax remain challenging due to its distinct biology. Although vaccines exist for Plasmodium falciparum, P. vivax lacks a licensed vaccine and has few candidates in clinical trials. Naturally acquired clinical immunity to malaria, driven by antibody responses that develop through repeated exposure in endemic areas, provides promising insights for vaccine development. This study evaluated whether IgG and IgM responses to P. vivax antigens are associated with protection against clinical malaria across transmission settings. Antibody responses to 61 antigens were simultaneously measured using the Luminex INTELLIFLEX platform in longitudinal cohorts from low transmission settings (Brazil, n = 258; Thailand n = 70) and a high transmission setting (Papua New Guinea, n = 184), where participants were followed over time for clinical malaria episodes used in the data analysis. The study shows that high IgG levels against RBP2b, EBPII, MSP3a, MSP5, RBP2a, CyRPA, RIPR, Pv-fam-a (PVX_090265), MSP7, RAMA, RBP2c-non-binding region and stAR related lipid transfer protein are strongly associated with protection from clinical malaria across all three cohorts. Overall, this study has identified both well-studied vaccine candidates and underexplored candidates.

Plasmodium falciparum malaria remains a major global health burden. Co-infection with HIV, common among adults in malaria endemic regions, increases susceptibility to malaria and disease severity. However, the impact of HIV on vaccine induced and naturally acquired malaria immunity remains poorly understood. We evaluated a cohort of Kenyan adults naturally exposed to malaria who were vaccinated with the RTS,S malaria vaccine as part of a phase-IIb clinical trial. Individuals were either HIV-negative (n=204) or HIV-positive (n=45) at baseline. Using a multi-antigen multi-functional assay platform, we quantified antibody responses (IgG, Fc-receptor binding and complement fixation) to 35 malaria antigens, including the RTS,S vaccine antigen CSP, in plasma samples collected 28 days after vaccination. There was no difference in CSP IgG responses, including functional activities between HIV-negative and HIV-positive individuals. However, IgG and functional antibody responses to a majority of the non-vaccine malaria antigens were significantly higher in HIV-negative compared to HIV-positive individuals. HIV infection was associated with widespread impairment in the acquisition of naturally acquired malaria immunity, but did not substantially impact RTS,S vaccine induced immunity. Our findings suggest that malaria vaccines could provide benefit to HIV-positive people who have impaired acquired immunity and are at a higher risk of malaria.

Bali, an Indonesian island located at the centre of the Coral triangle, is considered a marine biodiversity hotspot; however, the diversity and taxonomy of many parasitic groups in fishes remain poorly understood. Myxosporeans a taxonomically diverse group, are obligate, spore-forming parasitic cnidarians. Their true diversity is likely much higher than currently described, due to cryptic species and limited number of studies in region. To date, no myxosporean species have been formally described from Bali. This study aims to identify myxozoan infections in marine fishes from Bali. Gall bladder and muscle samples from 18 host families, including commercially significant families Carangidae, Siganidae, Lutjanidae and Scombridae, were obtained from the Queensland Museum research collection. Morphological traits of myxospores were described using light microscopy following the guidelines of Lom & Arthur (1989). DNA was extracted from spore preparations, and ribosomal DNA regions (18S-28S) were amplified using universal and myxosporean-specific primers. PCR amplicons were prepared for long-read sequencing (Oxford Nanopore PromethION), and the resulting sequences were analysed using Geneious Prime. Based on morphological and molecular approaches, these samples are provisionally assigned to the genera Kudoa spp. and Ceratomyxa spp., pending formal description. This dataset will provide the first comprehensive baseline for myxosporean in Bali.

Myxosporean parasites are obligate spore-forming, microscopic, parasitic cnidarians. The genera Unicapsula and Kudoa are increasingly recognised as contributors to post-harvest myoliquefaction (“jellymeat”) in commercially important marine fishes. Despite the economic and social impact, these parasites remain understudied, particularly in Australian waters. Molecular data remains limited, with most studies relying on partial 18S and 28S ribosomal DNA (rDNA) sequences. This study focuses on the genetic characterisation of myxosporean parasites infecting wild-caught Yellowtail Kingfish (Seriola lalandi) and Mahi Mahi (Coryphaena hippurus), and the identification of infections in previously unreported species, including Australasian Snapper (Pagrus auratus) and Australian Bonito (Sarda australis). Long-range amplification of the complete rDNA operon (18S-ITS1-5.8S-ITS2-28S) was performed using LongAMP Taq DNA polymerase followed by Oxford Nanopore long-read sequencing. This resulted in the generation of high-coverage, near-complete rDNA operons without the need for multiple overlapping PCRs, addressing a key limitation in current myxosporean molecular studies. These findings expand the known host range of myxosporean parasites in Australian fisheries and provide genomic resources for future diagnostics and ecological studies. This work also highlights the need for improved molecular surveillance of myxosporean parasites in Australian waters using long-read sequencing approaches.

The Opecoelidae is the richest family of the Trematoda, with sexual adults in a broad range of marine and freshwater fishes. Opecoelids are usually recognisable for a combination of generalised characters and the lack of specialised features; the most conspicuously absent feature is tegument spines. We present a new opecoelid, representing a new genus, with tegument spines, justified as belonging to the family on the basis of morphological and phylogenetic study. The new species was found in the northern pearl perch Glaucosoma buergeri (Glaucosomatidae) from Ningaloo Reef, Western Australia. It is the first trematode known from any pearl perch, which is a small but commercially important family comprising four species, three of which are endemic to Australian waters. The most intriguing question raised by this discovery is determining whether the spines in this opecoelid can be considered homologous with those found in many other trematode families – we will present a case that the spines are indeed homologous.

Knowledge of the parasitic infections of freshwater fish in Australia is sporadic but is concentrated on reports of infection in larger specimens. The dynamics of infection with parasites in larval and juvenile freshwater fish is unknown. Thus, this study utilised fish specimens previously collected for a river health monitoring program to determine levels of parasitic infection: the native Macullochella peelii, Retropinna semoni, Hypseleotris spp., Phylipnodon grandiceps, Macquaria ambigua, and the introduced Cyprinus carpio. Dissections of fish found six different morphotypes: the monogenean Dactylogyrus extensus, the adult nematode Procamallanus (Spirocamallanus) sp., the mite Hydrozetes sp., and the unidentified larval cysts, larval nematodes and adult nematodes. Histological examination determined infections with the protozoans Trichodina sp. and Chilodonella sp. The smallest fish found to be infected with a parasite was a 6mm C. carpio.

Despite major progress over the past 25 years, malaria remains a significant global health burden, and protection from current vaccines is limited. Pre-erythrocytic vaccines targeting the liver stage of infection are therefore promising. Immunisation with genetically attenuated Plasmodium parasites, such as P. falciparum GA2, can induce strong, even sterile, protection in humans. Liver-resident memory CD8⁺ T cells play a key role in this protection, yet their antigenic targets remain poorly defined.

To address this, we isolated reactive T cells following immunisation with a protective dose of P. berghei GA2. Antigen-responsive clones were identified using the “Timer of Cell Kinetics and Activity” (Tocky) mouse model, which detects recently activated T cells via Nr4a3-driven fluorescent protein expression and enables analysis of signalling dynamics. These cells underwent single-cell RNA and TCR sequencing to define transcriptional profiles and clonal expansion as compared to mock-immunised controls.

A subset of expanded TCRs was expressed in murine CD8⁺ Jurkat cells and used to screen ~200,000 predicted epitopes via a chimeric SABR platform. This system presents pMHC complexes linked to signalling domains, enabling antigen discovery. This pipeline will identify targets for validation and inform next-generation malaria vaccine design.

Malaria vaccine development is heavily challenged by the extensive genetic diversity of Plasmodium falciparum antigens. The full-length merozoite surface protein 1 (MSP1) is a promising blood-stage vaccine candidate, but its global diversity remains a critical hurdle for broad efficacy. To inform rational vaccine design, we evaluated the population genetic diversity and patterns of selection across MSP1 domains, followed by serological analysis of one highly polymorphic region.

Using 10,974 P. falciparum genomes from 26 countries globally, our population genomic analyses identified Block 4 as a putative target of immune selection, with high levels of polymorphism and strong signatures of balancing selection. We synthesised a peptide representing the most common variant of the MSP1 Block 4 domain and measured IgG antibody reactivity against it using Enzyme-Linked Immunosorbent Assays (ELISAs), utilising sera from Papua New Guinean children exposed to natural infection.

Despite the extensive polymorphism and balancing selection, we found antibody reactivity to the MSP1 Block 4 peptide in children developing immunity. Further work will include testing additional circulating variants individually and in combination using competition ELISAs to identify antigenically distinct variants, defining their relevance for multivalent vaccine design.

While platelets are known for their clotting function, they have immune functions as well. A recent discovery that platelets preferentially bind to senescent erythrocytes and aid in their clearance suggests that platelets are involved in erythrophagocytosis. This preferential binding is also observed in blood diseases including malaria. This project aims to explore the immune protective role of platelets in the clearance of infected erythrocytes during blood stage malarial infection.

We first determine whether platelets aid in the clearance of infected erythrocytes by infecting platelet-depleted mice with Plasmodium berghei. We observed a decrease in phagocytosed infected erythrocytes in the spleens of platelet-depleted mice compared to controls.

Next, we investigate whether it is platelets directly affect splenic macrophage function or is binding to erythrocyte an essential first step. We co-incubate murine splenic macrophages with erythrocytes in the presence of platelets. We observed increased erythrophagocytosis in the presence of platelets ex vivo. We will compare the expression level of functional markers of splenic macrophages in platelet-depleted mice to controls.

Finally, we will look at a cohort of spleen-intact and splenectomised malaria patients to determine whether our findings can also be observed in humans.

Resistance of Plasmodium falciparum to artemisinin, the current frontline anti-malarial, greatly threatens global malaria control. Mutations in the parasites' Kelch13 (K13) protein is the major driver behind this resistance. In asexual stages, K13 forms ring at neck of parasites' cytostome, the membrane invagination responsible for haemoglobin uptake from RBC. Activation of artemisinin requires reaction with haem released from digested haemoglobin. K13 mutation is thought to cause resistance through decreasing haemoglobin uptake, causing reduced activation of artemisinin. How K13 modulates this process is undetermined. Despite continued spread of resistance in endemic regions, the role of K13 and K13 mutations on parasite transmission remain unresolved. Using an endogenously tagged version of K13, we imaged K13 throughout gametocyte development, using standard fixes as well as expansion microscopy. Similar to its asexual counterpart, K13 was found to form ring structures throughout gametocyte development, though the amount and the location of these rings varies across stages. In late-stage gametocytes, K13 also forms a hollow tubular structure, likely serving a distinct function compared to the rings. To test if K13 modulates gametocyte sensitivity to artemisinin, we have employed the Knock sideway (KS) system and KS of K13 potentially increases gametocyte survival under artemisinin treatment.

Malaria, caused by single-cell parasites of the genus Plasmodium, currently has a widespread

impact on global public health security. As a sexually reproducing species, understanding the

sexual biology of Plasmodium is fundamental to developing approaches to control malaria

transmission. It is widely accepted that Plasmodium exhibits a female-biased sex ratio (male to

female is <1) during gametocyte development and actively adjusts this ratio to promote

outcrossing.

However, due to the lack of straightforward research models, how Plasmodium controls and

changes its sex ratio is still unclear. By genetically manipulating sexual differentiation in

Plasmodium berghei, we could artificially bias sex ratio. Using this system, we found that,

contrary to existing evidence, when the growth of the parasite stabilizes, the sex ratio of the

gametocytes (male to female) is close to 1:1. Furthermore, isogenic parasite lines do not modify

sex ratio in response to an overabundance of one sex.

Marine mammals are long-lived apex predators that integrate ecological signals across their ocean habitat. Their diverse and often still cryptic parasite fauna reflects their evolutionary history, adaptations and trophic links in marine ecosystems. Gastro-intestinal helminths, respiratory nematodes and arthropod parasites are frequently found in harbour and grey seals as well as harbour porpoises of the North and Baltic Sea. As opportunistic hunters, they consume diverse fish species and are exposed to trophically transmitted gastro-intestinal helminths with complex life cycles involving invertebrate and fish hosts. Variation in parasite infection patterns reflect differences in diet, host immune traits, and environmental conditions that influence parasite life cycles. Given the zoonotic potential of some helminths, species identification and monitoring their epidemiology in marine food webs is critical within a One Health framework. The respiratory tract of marine mammals is crucial to enable efficient oxygen exchange in diving animals. Lung nematodes belonging to the Metastrongyloidea are among the most pathogenic parasites in odontocetes and seals and can cause severe pathology and mortality. Little is known about parasite fauna of orcas. The first record of lungworms occurred in neonate killer whales and indicated a direct transmission and a new pseudaliid species in orcas. Arthropod parasites in marine mammals have developed unique traits to adapt to the marine environment and their vagile marine mammal hosts over long evolutionary time scales. Seal lice and nasal mites are directly transmitted between their hosts and reflect social interactions and population dynamics of their hosts. Marine mammal parasites can serve as valuable bio indicators for wildlife health and host ecology. Understanding host parasite interactions in marine wildlife is essential for assessing epidemiology of infectious pathogens, biodiversity conservation, and ecosystem resilience under ongoing environmental change.

The drug praziquantel (PZQ) has been used for over 40 years to treat many parasitic worm infections, and serves as the key clinical therapy for schistosomiasis. Our laboratory has proposed that the target of PZQ is a parasite ion channel belonging to the transient receptor potential melastatin (TRPM) subfamily, named TRPM_PZQ. Structural insight across orthologs of TRPM_PZQ in different parasites provides opportunity to expand our toolbox of ligands at these targets, which in turn provides new approaches to modulating parasitic flatworm biology and understanding the endogenous role played these fascinating channel throughout the parasitic lifecycle.

In this presentation, I will discuss our emerging understanding of the workings of TRPM_PZQ, highlight new opportunities for targeting TRPM_PZQ and other members of the TRPM family for the purpose of developing new anthelmintics, and speculate on how identification of TRPM_PZQ informs the likelihood and possible trajectories toward clinical resistance to PZQ.