Genomic insights into the origins and genetic diversity of the canine heartworm (Dirofilaria immitis)
Rosemonde Power1, Stephen Doyle2, Jan Šlapeta1,3
1Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, New South Wales 2006, Australia; 2Wellcome Sanger Institute, Hinxton, Cambridgeshire CB10 1SA, UK; 3The University of Sydney Institute for Infectious Diseases, New South Wales 2006, Australia
Canine heartworm (Dirofilaria immitis) is a filarial parasitic nematode that causes severe cardiopulmonary disease in domestic and wild canids. D. immitis is present in tropical, subtropical, and temperate regions of the world, with infections reported on almost every continent. Despite its global prevalence, the origins and global dispersal history of D. immitis remain unknown. In addition, the recent discovery of drug-resistant D. immitis in the USA underscores the urgent need to further understand the genomic landscape of this parasite. We conducted whole-genome sequencing on 130 adult D. immitis from nine countries (Australia, Thailand, Malaysia, USA, Panama, Costa Rica, Greece, Italy, and Romania), with D. repens and D. ursi as outgroups. This dataset represents the world’s largest collection of D. immitis genomes. Preliminary analyses revealed distinct partitioning between broad geographical regions, aligning with an ancient origin and dispersal scenario. Genetic similarity between some D. immitis from Central America and those from Europe was consistent with modern transatlantic transportation of dogs. This presentation will reveal the final outcomes of this population genomics study.
A nationwide cross-sectional study on canine vector-borne pathogens in pet dogs and associated awareness and preventative practices of veterinarians and dog owners in Australia
Ushani Atapattu1, Anke Wiethoelter1, Luca Massetti1, Rebecca Traub1,3, Louise Rae2, Phillip McDonagh2, Vito Colella1
1University of Melbourne, Australia; 2Boehringer Ingelheim Animal Health Australia, North Ryde, New South Wales 2113, Australia; 3Department of Infectious Diseases and Public Health, City University of Hong Kong, Hong Kong
Canine vector-borne pathogens (CVBP), such as Anaplasma platys, Babesia vogeli, and Dirofilaria immitis, are known to be endemic in Indigenous communities in Australia, while information on pet dogs is limited. Recent outbreaks of Ehrlichia canis, a pathogen previously exotic to Australia, highlighted the urgent need to assess the status of CVBP in pet dogs in the country. To address this knowledge gap, we screened 729 canine blood samples from temperate and non-temperate regions of Australia. In addition, we administered two independent questionnaires to veterinarians and dog owners to assess their awareness and preventative practices around CVBP. Our findings revealed an overall apparent prevalence of 3% for CVBP, with haemotropic Mycoplasma being the most common pathogen (2.1%, 95% CI 1.2-3.4%), followed by canine filarial worms (0.8%, 95% CI 0.3-1.8%). Additionally, one dog from Woree, Queensland, tested molecularly positive for Hepatozoon canis. Despite veterinarians considering CVBP less important in their practices and dog owners having low awareness, satisfactory prophylaxis recommendations and administration practices were identified. However, to maintain low CVBP prevalence and mitigate the associated biosecurity risk in Australia, we recommend educating dog owners, ensuring adequate surveillance, and implementing risk-based control measures for CVBP.
Persistence of gastrointestinal protozoan in two populations of companion dogs in Perth, Western Australia
Breanna Knight1, Alan Lymbery2, Sam Abraham1, Amanda Ash1,3
1Centre for Biosecurity and One Health, Murdoch University, Harry Butler Institute Murdoch, WA, Australia; 2Centre for Sustainable Aquatic Ecosystems, Harry Butler Institute, Murdoch University, Western Australia; 33 School of Medical, Molecular and Forensic Sciences, Murdoch University, Western Australia
Companion dogs are a popular pet, providing physiological and psychological benefits to owners, with Australia retaining one of the highest pet ownership rates in the world with over six million dogs. Gastrointestinal (GI) parasites are a common health concern in dogs, often causing chronic or recurrent infections, with some parasites possessing zoonotic potential.
To determine the prevalence of GI parasites in pet dogs, faecal samples were collected from healthy six-week-old puppies in kennel environments, and healthy juvenile/adult dogs in public dog areas to analyse via coproscopy. Protozoans, Cystoisospora spp. and Giardia sp. were the dominant parasite genera detected in both kennels and juvenile/adult dogs, and persisted throughout almost all age groups.
This persistence of protozoans is likely linked to the common use of monthly ‘all-wormers’ which have active ingredients not effective against protozoan parasites. As both helminths and protozoa inhabit the same environmental niche, the reduction of helminths through the use of anthelmintics may allow protozoans to proliferate. Upon genotyping of microscopy-positive Giardia samples, two puppies and one juvenile/adult were detected to be carrying zoonotic Giardiaassemblages, highlighting the potential public health implications associated with Giardia, and the need for suitable anti-protozoan drugs to reduce parasite transmission to the community.
Survey of feline and canine helminths in New Zealand and part of Australia with an assessment of diagnostic tools
Madisson Nam1, Patsy Zendejas Heredia1, Christina Murray1, Ushani Attapattu1, Carl Eden3, Maureen Forsyth3, Louise Rae2, Phillip McDonagh2, Rebecca Traub1, Neil Young1, Robin Gasser1, Vito Colella1
1Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Victoria 3010, Australia; 2Boehringer Ingelheim Animal Health Australia, North Ryde, New South Wales 2113, Australia; 3Boehringer Ingelheim Animal Health New Zealand, Mount Wellington, Auckland 1060, New Zealand
Dogs and cats are now considered integral members of families, present in nearly 50% of
households in Australia and New Zealand. However, their health can be impacted by
numerous pathogens, including helminths, some of which are transmissible to humans. In
spite of the importance of these parasites, surprisingly, there are limited data on the
epidemiology of parasitic diseases in dogs and cats in these countries. Clinical diagnosis is
sometimes challenging and diagnostic methods can be unreliable. In this study, we are
investigating the prevalence, distribution, and risk factors associated with helminths in
dogs and cats in parts of Australia and in New Zealand, and will critically assess the
sensitivity and specificity of conventional and molecular methods. We aim to achieve a
comprehensive investigation of parasitic helminths affecting dogs and cats in parts of
Australasia and of the performance of diagnostic methods.
Is raw meat and seafood a source of gastrointestinal disease in Australian cats? A meta-analysis, survey of cat owners and microscopic examinations of cat faeces
Natalie Jefferson1, Shokoofeh Shamsi1, Richard Malik2, Agasthya Thotagamuwa1
1Charles Sturt University, Wagga Wagga NSW 2678, Australia; 2The University of Sydney, Sydney NSW 2050, Australia
The main aim of this project is to determine if (raw) food-borne parasites can infect cats in Australia. This project aims to answer this question by analysing the VetCompass database to identify cats fed raw food. This will be done to identify links between signs of gastrointestinal disease and parasitic infection.
This project will also involve surveying Australian cat owners. Faecal samples of cats will be requested and examined for the possible presence of food-borne parasites. It is hypothesised that cats fed raw diets will have parasites of different species and lifecycles/hosts.
Surveying of Australian cat owners will also be used to identify households that use parasite prevention products. It is hypothesised that households that (regularly) use parasite prevention products will have cats with no or very low parasite burdens. On the other hand, households that do not use parasite prevention products for their cats will likely correlate with higher parasite burdens.
Shining a light on heartworm disease: first report of a non-invasive in vivo method for the diagnosis of dirofilariasis in dogs
Silvia Ciocchetta1, Constantin Constantinoiu2, Brendon Goh1, Tessa Mackie2, Iris Cheadle3, Glen Coleman4, Tharanga Niroshini Kariyawasam1, Jennifer Elliman2, Ricardo Soares Magalhães1, John Stenos5, Swaid Abdullah1, Ian Marsh6, Malcolm Jones1, Paul Visendi1, Maggy Sikulu-Lord1
1The University of Queensland, Brisbane, Australia; 2James Cook University, Townsville, Australia; 3Animal Care and Adoption Centre, Townsville, Australia; 4University of Southern Queensland, Toowoomba, Australia; 5Australian Rickettsial Reference Laboratory, Geelong, Australia; 6New South Wales Department of Primary Industries, Australia
Background: Heartworm (Dirofilaria immitis) disease poses a significant risk to domestic and wild canines and felines. Traditional diagnostic methods for dogs face limitations in accuracy, cost and accessibility, leading to underdiagnosis. Near-infrared spectroscopy (NIRS) combined with Artificial Intelligence (AI) presents a promising solution to overcome these limitations. NIRS utilises infrared radiation to analyse biological samples cost-effectively, while AI interprets the resultant data to predict samples' infection status.
Methods: Utilising a handheld NIRS device, we scanned the ears and blood smears of 183 dogs. Each dog was tested for D. immitis by antigen detection, microfilariae presence in blood and PCR. We developed machine learning algorithms to detect the presence/absence of infection using artificial neural networks, and we used the models obtained to predict the infection status of independent samples.
Results: We attained optimal accuracies by scanning specific regions of the ears (90.9%, n=22) and blood smears (88.9%, n=18). Both models exhibited 100% sensitivity (n=8) and 85.7% specificity (n=14) for the ears and 80% specificity (n=10) for blood smears. Additionally, we identified distinctive D. immitis NIRS spectra peaks.
Conclusion: This study demonstrates that NIRS /AI has the potential to be a rapid and effective surveillance and diagnostic tool for heartworm infection.
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