Involvement of two genetic lineages of Sarcoptes scabiei mites in a local mange epizootic of wild mammals in Japan.

Similar to wild mammals on the continents, mange caused by the mange mite, Sarcoptes scabiei (Acari: Sarcoptidae) is spreading in wild mammals in most of Japan. We collected crusted or alopetic skin from 120 raccoon dogs (Nyctereutes procyonoides viverrinus), three raccoons (Procyon lotor), six Japanese badgers (Meles anakuma), one Japanese marten (Martes melampus), one stray dog (Canis lupus familiaris), four wild boars (Sus scrofa leucomystax), and one Japanese serow (Capricornis crispus), mainly in an area where mangy wild animals have been increasingly noted in the past 4 yr. The second internal transcribed spacer (ITS2) region of the ribosomal RNA gene and the partial 16S and cytochrome c oxidase subunit I (cox-1) genes of mitochondrial DNA (mtDNA) were characterized in these skin samples. The ITS2 sequencing (404 base pairs [bp]) identified the causative mite for mangy skin lesions of 128 animals as S. scabiei, regardless of host origin. The cat mite (Notoedres cati) was the cause in one raccoon dog and one raccoon. Most mites had almost identical ITS2 nucleotide sequences to those recorded in a variety of mammals worldwide. Partial 16S and cox-1 fragments of mtDNA amplified and sequenced successfully (331 bp and 410 bp, respectively) showed an identical nucleotide sequence except for one site (C vs. T) for the former and four sites (G, C, C, C vs. A, T, T, T, respectively) for the latter fragment. These substitutions were always synchronized, with the two mitochondrial DNA haplotypes (i.e., C/GCCC and T/ATTT) appearing to separately colonize in geographic units. The T/ATTT haplotype fell into a clade where animal-derived mites worldwide dominated, whereas the C/GCCC haplotype formed a geographic branch unique to Japanese isolates. These results suggest that heterologous populations of monospecific S. scabiei are expanding their populations and distributions regardless of host species in an apparently local mange epizootic of wild mammals in Japan.