Novel technologies to investigate the epicentre of tick-borne diseases
Wenna Lee1,2,3, Rym Ben-Othman2, Amy H-Y Lee4, Miles Beaman5, Amanda D Barbosa1,6, Andrew Currie3,7, Nathan T Harvey5,8, Prasad Kumarasinghe3,9,10, Tobias R Kollmann2, Peter J Irwin6, Charlotte Oskam1,3
1Centre for Biosecurity and One Health, Harry Butler Institute, Murdoch University, Murdoch, WA, Australia.; 2Systems Vaccinology, Telethon Kids Institute, Perth, WA, Australia.; 3School of Medical, Molecular, and Forensic Sciences, College of Environmental and Life Sciences, Murdoch University, Murdoch, WA, Australia.; 4Molecular Biology and Biochemistry, Simon Fraser University, British Columbia, Canada.; 5Faculty of Health and Medical Sciences, Pathology & Laboratory Medicine, University of Western Australia, Perth, WA, Australia.; 6School of Veterinary Medicine, College of Environmental and Life Sciences, Murdoch University, Murdoch, WA, Australia.; 7Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA, Australia.; 8Department of Anatomical Pathology, PathWest Laboratory Medicine, QEII Medical Centre, Perth, WA, Australia.; 9School of Medicine, University of Western Australia, Crawley, WA, Australia.; 10Western Dermatology, Hollywood Medical Centre, Nedlands, WA, Australia.
Tick-borne diseases (TBDs) present challenges due to complex interactions among hosts, tick toxins, salivary proteins, and microbes. Limited understanding of these interactions leads to undetected cases despite clinical guidelines. The rise of omics technologies offers a promising solution by shifting from pathogen-centric to host-centric studies, which can elucidate the complexity of TBDs. The skin, the primary site of tick bites, has been largely overlooked. We hypothesise that studying interactions at the skin can provide insights into disease progression. Using the NanoString GeoMx platform, we performed spatial transcriptomics on skin tissues from tick-bitten patients, comparing the tick-bite epicentre within 72 hours post-bite and contralateral ‘healthy’ skin. Our data reveal perturbations in several pathways. Spatial analysis identified tissue signatures distinguishing acute from chronic tick bites, highlighting differentially expressed genes. Our study shows that skin signatures can correlate with biomarkers from other omics data, improving diagnostic outcomes and informing treatment options. This approach enhances understanding of tick-associated pathogenesis, aiding in developing better management strategies for TBDs.
Multi-centre study demonstrates that scabies infestations decrease the microbial diversity and promote the presence of pathogens in scabies lesions
Sara Taylor1, Martha Zakrzewski1, Charlotte Bernigaud2, Nuzhat Surve3, Deepani D Fernando1, Pallavi Surase3, Gourie Hule3, Mohan G. Karmakar2, Francoise Botterel2, Julie Ross4, Helen Hanush5, Vince Connellan6, Natasha Coventry7, Troy Darben8, Olivier Chosidow2, Katja Fischer1
1Infection and Inflammation Program, QIMR Berghofer Medical Research Institute, Brisbane, Australia; 2Dermatology Department, Assistance Publique des Hôpitaux de Paris (AP-HP), Hôpital Henri Mondor, Université Paris-Est, Créteil, France; 3King Edward Memorial Hospital, Seth Gordhandas Sunderdas Medical College, Mumbai, India.; 4Hope Vale Primary Health Care Centre, Hope Vale QLD, Australia; 5Cooktown Multi Purpose Health Service, Cooktown, QLD, Australia; 6Wujal Wujal Primary Health Care Centre, Wujal Wujal, QLD , Australia; 7Cooktown Hospital, Cooktown, QLD, Australia; 8Robina Skin Centre, Robina, QLD, Australia
Scabies is a neglected tropical disease caused by the obligate parasitic mite Sarcoptes scabiei. With an estimated 400 million cases annually, mainly in the tropics, scabies is one of the most common dermatological diseases globally. The burrowing of mites within the epidermis combined with mite excretory proteins interfering with the host immune system causes secondary bacterial infections. Epidemiology has demonstrated a correlation between scabies and disease caused by Staphylococcus aureus and Streptococcus pyogenes, though there is little molecular evidence to underpin this link. We undertook a collaborative multi-national study collecting skin scrapings from scabies patients in three countries. Microbial DNA was extracted and 16s full length rRNA and ITS1-4 sequencing were performed using the PacBio sequel. Using an established bioinformatics pipeline, a total of 22,678 amplicon sequence variants were identified from 751 samples. Community composition and microbial abundance was analysed using the programming language R. Our results demonstrate a significant decrease in microbial diversity and an increase of pathogenic bacteria in scabies infected lesions (P<0.05). This study is the first to identify and quantify the scabies associated microbiome at the molecular level to provide a basis to improve treatment approaches for this disease complex.
Population Genetic Structure of Amblyomma triguttatum in the Swan Coastal Plain of Western Australia
Xavier Barton1, Joe Fontaine2, Shanan Tobe1, Charlotte Oskam1
1School of Medical, Molecular and Forensic Sciences, College of Environmental and Life Sciences, Murdoch University; 2School of Environmental and Conservation Sciences, College of Environmental and Life Sciences, Murdoch University
Arthropod ectoparasites play a crucial role in disease transmission worldwide, with ticks being particularly significant due to their ability to carry and transmit a diverse array of pathogens. Understanding the population structure of ticks is essential for predicting their movement and spread of associated pathogens. This study employs ddRADseq, a cost-effective population genetic tool that provides high-resolution SNP data. This was used to assess the population structure of Amblyomma triguttatum (ornate kangaroo tick) in the Swan Coastal Plain of Western Australia. One hundred ninety-two A. triguttatum specimens were collected and analysed, most of which fell within a 330km range. Results indicate that specimens collected in closer geographic proximity are more genetically related. Urbanisation (e.g., cities and suburbs) and natural barriers (e.g., the Swan River) contribute to genetic segregation. In contrast, within non-disrupted areas, genetic connectivity was more homogeneous, although genetic distance still increased with spatial separation. These findings provide valuable insights into previously unknown genetic structure and movement patterns of A. triguttatum. This information is crucial for future research on tick-borne diseases affecting humans, companion animals, and livestock, as it helps identify potential transmission corridors for current and emerging pathogens.
The chromosome-scale assembly of the Australian Paralysis Tick, Ixodes holocyclus
Amrita Vijay1, Thomas Karbanowicz2, Quentin Gouil1, Alexander Gofton3, Louise Baker1, Balu Balan1, Ala Tabor2, Nathan Lo5, Stefano Gaiarsa4, Steve Barker6, Jan Riemer7, Fabrizia Stavru8, Davide Sassera9, Peter Czabotar1, Tony Papenfuss1, Aaron R Jex1,10
1Walter and Eliza Hall Institute, Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia; 2The University of Queensland, Queensland Alliance for Agriculture & Food Innovation, Brisbane St Lucia, Queensland, Australia; 3Health and Biosecurity, Ecosciences Precinct Dutton Park, Brisbane, Queensland, Australia; 4Microbiology and Virology unit at Policlinico San Matteo, Fondazione IRCCS, Pavia, Province of Pavia, Italy; 5School of Life and Environmental Sciences, The University of Sydney, New South Wales; 6School of Chemistry and Molecular Biosciences, Faculty of science,The University of Queensland, Brisbane St Lucia, Queensland, Australia; 7Department for Chemistry, Institute for Biochemistry, University of Cologne, Cologne, Germany; 8Unité de Biologie Evolutive de la Cellule Microbienne, Institut Pasteur, Paris, France; 9Department of Biology and Biotechnology, University of Pavia, Pavia, Italy.; 10Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, Australia
Ixodes holocyclus, the Australian eastern paralysis tick, is an obligate hematophagous ectoparasite known for causing flaccid paralysis in animals and humans due to its potent neurotoxin, holocyclotoxins. Treatment typically involves administering antiserum once symptoms develop. However, a lack of genomic, transcriptomic, and proteomic resources hampers understanding of I. holocyclus biology, including toxin production, host preference, and survival mechanisms. To address this resource gap, we generated the first high-quality chromosome-scale genome assembly of I. holocyclus. This integrated approach, combining Oxford Nanopore long-read sequencing, Illumina short-read sequencing, Hi-C chromatin interaction maps, and long- and short-read RNA sequencing, facilitated the construction of comprehensive gene models. The resulting chromosomal-scale draft genome spans 1.9GB and includes approximately 35,000 predicted protein-coding genes, alternative splice isoforms, and transposable elements. Given I. holocyclus's limited distribution along Australia's eastern coast, we generated ~100 I. holocyclus genomes from this region and intent to perform comparative analyses. This aimed to understand genetic complexity, link genomic variation with geographic distribution, ecological adaptation, vector capacity, and potential drug resistance emergence. Our study provides the first genetic resource for I. holocyclus, a potential paralysis-inducing hematophagous ectoparasite. These insights can inform future interventions against this tick and tick-transmitted infections.
Innovative RNAi for ectoparasites of livestock (Lucilia cuprina)
Yakun yan
UQ, QAAFI,Australia
RNAi technology has emerged as a potential biocontrol strategy against various pests, including Lucilia cuprina, an ectoparasite that causes significant harm to sheep. Blowfly strike is the second most costly parasitic disease of sheep in New Zealand and costs the New Zealand industry more than $37 million per year. In this study, we explored the effects of dsRNA on the blowfly. Initially, six dsRNA constructs were assessed via microinjection, focusing on their impact on RNA expression, hatching, and mortality. Building on these insights, we evaluated two novel materials systems: Bentonite combined with either Polyethylenimine or Poly (dimethylaminoethyl methacrylate), referred to as BenPol. These systems were assessed for cytotoxicity, stability in midgut juice, and their protective effects on dsRNA. Initial findings showed that the BenPol composites exhibited low cytotoxicity. Further investigations focused on the loading and pH-dependent release of dsRNA from these nanoparticles. The BenPol systems demonstrated effective protection of dsRNA within the harsh gastric environment of L. cuprina for over 24 hours. Subsequent experiments involved loading RNAi targets onto the BenPol systems through oral feeding. Results from these bioassays indicated that both BenPol systems (PEI and pDMAMAE) significantly enhanced RNAi efficacy while safeguarding the integrity of dsRNA.
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