Dr Elise Ringwaldt is a Postdoctoral Researcher at the University of Tasmania. She is currently investigating the landscape epidemiology of sarcoptic mange in bare-nosed wombats in New South Wales as part of the Curb Wombat Mange Project, supervised by Prof. Scott Carver, funded by the New South Wales Department of Environment and Planning. Elise completed her PhD at the University of Tasmania last year, where she focused on how visually apparent diseases in wildlife offer opportunities to study landscape epidemiology, especially when combined with remote-surveillance technology, such as camera trapping. Her thesis used Tasmanian wildlife and their visual disease as case studies, including wombats with sarcoptic mange and possums with rumpwear. Her broader research interests include disease ecology, landscape epidemiology, wildlife conservation, parasitology, and animal health. Elise is also a keen fieldworker and finds any excuse to be outside collecting the data. She is also currently a field technician at the Royal Veterinary College, University of London, collecting data for rodent virome research.Talk Title: “The epidemiology of rumpwear in common brushtail possums: insights from visual clinical signs, camera trapping, and machine-learning.”
Ringwaldt, E.M., Buettel, J.C., Carver, S., & Brook, B.W
Abstract: Visually apparent diseases are valuable for investigating and monitoring the occurrence and prevalence of pathogens in wildlife populations, particularly through passive monitoring methods like camera trapping. Rumpwear, characterized by visible clinical signs of hair breakage and damage on the lumbosacral region, affects common brushtail possums (Trichosurus vulpecula) across Australia. However, the etiology of rumpwear remains unclear (hypothesised to be an ectoparasite), and the spatiotemporal factors are understudied. This study investigated the epidemiology of rumpwear in common brushtail possums at Adamsfield, Tasmania (Australia), and predicted rumpwear distribution across the Tasmanian landscape. We visually classified images of rumpwear clinical signs in 6,908 individual possums collected from a three-year camera trapping network. Our results revealed that: (1) adults were twice as likely to show signs of rumpwear compared to young possums; (2) rumpwear occurrence increased with the relative activity of possums at a site; and (3) prevalence of rumpwear was seasonal, being lowest in May (3.2% – late autumn) and highest in December (27.1% – early summer). Collectively, these findings suggest that the occurrence of rumpwear may be density dependent, the putative etiological agent seems to be influenced by seasonal factors or site use. Additionally, a convolution neural network (CNN) was trained to identify rumpwear automatically based on the manually (human-expert) classified camera trap images. Applying the trained classifier to 38,589 brushtail possum images from across Tasmania, the CNN predicted that rumpwear is widespread, with an overall prevalence of 18.6%. This study provides new insights into the epidemiology of rumpwear, identifies factors for further investigation within this host-pathogen system, and demonstrates how passive surveillance, combined with CNN models, can enhance broader wildlife health monitoring and management.
Long Huynh completed an Honours project under the supervision of Prof. Stuart Ralph at the University of Melbourne, investigating the role of the P. falciparum apicoplast in constructing glycophosphatidylinositol (GPI) anchors and their subsequent roles in egress and invasion. He has continued on with a PhD project in Prof. Stuart Ralph’s lab investigating how mutations in the P. falciparum K13 protein confers resistance to artemisinin, a key frontline antimalarial. Long is utilising techniques such as expansion microscopy, super-resolution microscopy and cryo-electron tomography to elucidate phenotypic differences in K13 mutant parasites.
We propose that mutation of K13 reduces its stability and abundance, impacting the formation and maintenance of new cytostomes and thus parasite feeding. By employing immunofluorescence assays alongside ultrastructure expansion microscopy (u‑ExM) combined with super-resolution microscopy techniques, we resolved K13 as ring-shaped structures approximately 160 nm in diameter, which localise to the periphery of the parasite surrounding the neck of the cytostome. We performed live cell and u-ExM at various stages throughout the asexual life cycle and the morphology and number of K13 rings were compared between mutant and wild-type (WT) parasites. Our findings suggest that K13 mutant parasites form new K13 rings at a slower rate than WT parasites, and in some cases, the cytostomes in K13 mutants displayed altered morphologies. These findings provide new insights into how K13 mutations could reduce haemoglobin uptake, potentially linking this defect to artemisinin resistance.
Our ASP Online Seminar Series image is created by Thorey Jonsdottir.
