Genetic evidence suggests that Psoroptes isolates of different phenotypes, hosts and geographic origins are conspecific.

The second internal transcribed spacer of the rRNA gene was characterised in 15 Psoroptes isolates collected from the ears or bodies of rabbits, goats, sheep and cattle originating from four continents. Morphologically, the isolates were differentiated as Psoroptes cuniculi, Psoroptes ovis and Psoroptes cervinus. Genotypically, the isolates were highly homogeneous, except for the existence of different rDNA classes. In view of previous phenotypic data, a possible conspecificity of these species is proposed.