Scabies mite genomes reveal genetic differences linked to host origin

Genome study identifies host-associated groups of scabies mites

The mite that causes scabies in humans also infests companion animals, livestock and wildlife. An international study published in Science in One Health analysed 83 quality-filtered whole-genome datasets and identified seven ancestry clusters broadly associated with host origin. The findings provide a resource for future One Health surveillance of human scabies and animal sarcoptic mange.

The research brought together scientists from Guangxi University, the University of Melbourne and collaborating institutions in China, Italy and France. Corresponding authors were Fang Fang of Guangxi University and Robin B. Gasser of the University of Melbourne, a Fellow of the Australian Academy of Science.

Genome-wide data reveal strong host-associated structure

The team generated whole-genome sequence data for 106 samples and incorporated 19 publicly available datasets. After quality filtering, 83 sample-level datasets were retained, including both individual-mite and pooled-mite sequences. The analysis covered humans, companion animals, livestock and diverse wildlife hosts.

The researchers identified more than 1.56 million nuclear variants, including approximately 698,000 single-nucleotide polymorphisms. Ancestry, principal component and phylogenetic analyses supported host-associated population structure. Across the sampled populations, genetic grouping corresponded more closely to host association than to geographical origin. The seven ancestry clusters did not correspond one-to-one with host species: human- and pig-derived datasets shared one cluster, as did cat- and dog-derived datasets.

Human-derived mites from Australia and Italy clustered together in the phylogenetic analysis, as did pig-derived mites from Australia, China and Italy. Another comparison showed distinct lineages for mites from domesticated and wild rabbits, with a fixation index of approximately 0.90, indicating substantial genetic differentiation. Mites from domesticated pigs and wild boars, by contrast, were more closely related in the phylogenetic analysis. These patterns may reflect host history, husbandry, geography and opportunities for contact, but the study does not establish their respective contributions.

Towards host-stratified One Health surveillance

The findings offer a new perspective on the One Health control of human scabies and animal sarcoptic mange. Strong host-associated genetic structure does not rule out occasional connectivity between mites from different hosts. However, the study does not establish how frequently such events occur, in which direction they occur, or their epidemiological importance.

The findings support coordinated One Health surveillance that accounts for host-associated differences. Combining genomic data with information on host origin, location, sampling time and contact could help future studies investigate transmission within and between host populations.

Uneven representation of host species and geographical regions, relatively few human-derived datasets and the inclusion of pooled-mite samples limit interpretation. Candidate selection regions provide leads for further research rather than experimentally confirmed mechanisms. The genomic resource can support future investigations of transmission, adaptation and acaricide resistance, which was not directly assessed in this study.