Are humans the initial source of canine mange?

Area of Science:

• Veterinary Dermatology
• Parasitology
• Molecular Epidemiology

Background:

• Scabies, caused by the mite Sarcoptes scabiei, is a significant veterinary concern causing widespread animal disease.
• A prevailing hypothesis suggests humans initially contaminated animals with S. scabiei, but this lacks empirical evidence.
• This study investigates the origin of S. scabiei mites in canids to test the human-to-animal transmission hypothesis.

Purpose of the Study:

• To determine the origin of Sarcoptes scabiei mites in domestic dogs through phylogenetic analysis.
• To validate or refute the hypothesis that humans are the original source of canine scabies infestations.
• To inform epidemiological control strategies by understanding mite transmission dynamics.

Main Methods:

• Phylogenetic analyses were conducted on Sarcoptes scabiei mite populations from humans and various canids (dogs, foxes, raccoon dogs, jackals).
• A portion of the cytochrome c oxidase subunit 1 (cox1) gene was amplified and sequenced from mite samples.
• Phylogenetic trees were constructed using Maximum Likelihood and Bayesian Inference, with Otodectes cynotis as the outgroup.

Main Results:

• Twenty-one haplotypes of S. scabiei were identified across five host species and nine geographical regions.
• Phylogenetic analyses did not support the hypothesis of a human origin for S. scabiei mites in dogs.
• The data suggested a possible host switch from dogs to humans, rather than the reverse.

Conclusions:

• The findings challenge the long-held hypothesis of human origin for canine scabies.
• Recent studies, including this one, indicate a need to reassess the transmission dynamics between domestic dogs and humans.
• Understanding mite relatedness is crucial for developing effective epidemiological control strategies.