Conference Agenda

Parasitic worms continue to exert major health and economic burdens on humans and livestock, while escalating resistance to existing anthelmintics highlights the urgent need for novel chemotypes with distinct modes of action to support integrated control strategies. We screened 139,916 compounds from the Medicines for Malaria Venture Hit Generation Library 1 against exsheathed third-stage larvae of Haemonchus contortus, with cross-species assessment in Caenorhabditis elegans. High-throughput infrared-based motility and developmental assays in 384-well format showed robust performance (mean Z′ = 0.799 ± 0.012; signal-to-background = 65.6 ± 9.8). From this screen, 272 primary hits (0.194%) were identified, of which 110 reproducibly inhibited larval motility and development. Among these, 39 compounds exhibited IC₅₀ values <10 µM, and 33 induced complete developmental arrest at ≤12.5 µM, often with distinct morphological phenotypes. Four of the 39 compounds showed no detectable toxicity in HepG2 cells (CC₅₀ and MC₅₀ ≥20 µM), with ADME profiling available for a prioritsed subset. Integrating potency, selectivity and ADME properties enabled prioritisation of 16 compounds for advancement through medicinal chemistry. Collectively, these findings demonstrate that antimalarial-focused libraries can yield potent and selective nematocidal scaffolds, and highlight a scalable strategy for repurposing discovery libraries across various parasitic systems.

Gastrointestinal nematodes (GINs) are a major constraint to goat health, welfare and productivity worldwide and represent the highest-priority pathogens affecting goats in Australia. However, contemporary national-scale epidemiological data for Australian dairy goats are limited. This study quantified the prevalence, infection intensity, species diversity and determinants for GIN infections in Australian dairy goats. Faecal samples (n = 1,028) collected from 68 herds across Australia were analysed using a modified McMaster technique. Strongylid-positive samples (n = 500) underwent deep amplicon sequencing of the ITS-2 rDNA region for species identification. Prevalence estimates were adjusted for herd-level clustering, and predictors for strongylid faecal egg counts (FECs) were evaluated using linear mixed-effects models. Strongylids were detected in 91% of goats and in all herds, substantially exceeding the prevalence of Trichuris spp. (13%) and Nematodirus spp. (5%). Strongylid FECs were markedly overdispersed, with 30% of animals contributing 80% of total egg output. Age, climatic zone, anthelmintic treatment and coinfection with Eimeria were statistically significant (P < 0.05) determinants of strongylid FECs. Metabarcoding identified 11 species, dominated by Haemonchus contortus, Teladorsagia circumcincta and Trichostrongylus colubriformis, with distinct regional patterns. These findings demonstrate substantial infection pressure and species diversity, informing evidence-based parasite control for the Australian goat industry.

Fasciola hepatica larval development, infection, and presence of intermediate lymnaeid snail hosts require average daily temperatures >10°C. Livestock producers leverage the seasonal pause between the first and last frosts to guide treatment schedules. Whilst conducting a drug resistance trial in July 2024, numerous lymnaeid snails were discovered when average daily temperatures were <7°C, challenging the foundations underpinning these schedules. We set out to update knowledge on the seasonality of lymnaeid snail populations in the region to refine current F. hepatica risk periods and inform new integrated parasite management strategies.

Twelve sites across six farms endemic for F. hepatica were sampled bi-monthly during 2025. Collected snails were counted and morphologically speciated to determine the average abundance and diversity of susceptible hosts. Snails were visually inspected for F. hepatica larval infection, then confirmed with qPCR. One site significantly deviated from the historical seasonal pattern, recording the study’s highest abundance of lymnaeid snails (N = 240) during winter. The invasive Pseudosuccinea columella was most abundant in July at three sites. This study provides the first seasonal monitoring of the invasive P. columella and their increased abundance in winter suggests that the infective risk period for F. hepatica extends beyond the historical dormancy window.