28 Jan 2026
Findings can help vets “respond more effectively to disease and drug resistance”, says author.
Chris Simpson
Job Title
A pair of dingoes. Scientists think heartworm may have arrived in Australia with the migration of dingoes from Asia around 4,000 years ago. Image: FiledIMAGE / Adobe Stock
A genomic study of heartworms has offered new insight that could help combat the development of anthelmintic resistance, according to its authors.
A team of international scholars discovered the parasites have a deeper and more complex evolutionary history than previously believed, challenging long-held assumptions that heartworms primarily spread via recent, human-mediated movement of domestic dogs.
The findings, published in Communications Biology, suggested ancestral canid hosts such as wolves and dingoes played a pivotal role in the evolution and dissemination of heartworms around the world.
Lead author Rosemonde Power, a postdoctoral researcher at Stockholm University’s Centre for Palaeogenetics, said: “For decades, we assumed heartworms were spread mainly through recent human activity.
“What we’re seeing instead is evidence of deep co-evolution between heartworms and their canine hosts, even before humans were part of the picture.”
The researchers analysed the whole genomes of 127 adult heartworm specimens collected from mammalian carnivore hosts – 115 of which were domestic dogs – across nine countries in five regions including Australia, the US, Central America, Europe and Asia.
By comparing heartworms around the world, the scholars reconstructed population histories and tracked how the parasites had diverged over time, identifying distinct regional heartworm populations, shaped by the movements and isolation of ancient canids during ice ages and interglacial periods.
The paper concluded: “Our data indicate that surveillance and control strategies should account for geographical variation between parasite populations and consider transmission within and between populations to maximise sustainable parasite control.”
Examining their absolute nucleotide divergence, heartworms in Australia and Asia were found to be the least divergent, suggesting a shared ancestry and that the parasites may have arrived in Australia with the migration of dingoes from Asia, believed to have occurred around 4,000 years ago.
Senior author Jan Slapeta, professor of veterinary and molecular parasitology and associate head of research at The University of Sydney, noted the significance of the findings.
Prof Slapeta said: “Understanding where heartworms come from and how different populations are related helps us respond more effectively to disease and drug resistance. Heartworms are not the same everywhere, and local history matters.”
However, the authors cautioned that further sampling will be needed and said their evidence does not conclusively rule out the alternative explanation that the heartworm was introduced to Australia more recently following European colonisation.
Prof Slapeta added: “While our data suggest an ancient link between Australian and Asian heartworms, the sample size means we need to be careful about drawing firm conclusions.
“What we can say with confidence is that heartworm evolution is far older and more complex than a simple story of parasites hitchhiking with modern dogs.”
