Conference Agenda

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.