Population identification of Sarcoptes hominis and Sarcoptes canis in China using DNA sequences

Abstract

There has been no consistent conclusion on whether Sarcoptes mites parasitizing in humans and animals are the same species. To identify Sarcoptes (S.) hominis and S. canis in China, gDNA was extracted from individual mites (five from patients with scabies and five from dogs with mange) for amplification of rDNA ITS2, mtDNA 16S, and cox1 fragment sequences. Then, the sequences obtained were aligned with those from different hosts and geographical locations retrieved from GenBank and sequence analyses were conducted. Phylogenetic trees based on 317-bp mtDNA cox1 showed five distinctive branches (species) of Sarcoptes mites, four for S. hominis (S. hominis Chinese, S. nr. hominis Chinese, S. hominis Australian, and S. hominis Panamanian) and one for S. animal (S. animal). S. animal included mites from nine animal species, with S. canis China, S. canis Australia, and S. canis USA clustering as a subbranch. Further sequence divergence analysis revealed no overlap between intraspecific (≤ 2.6 %) and interspecific (2.6-10.5 %) divergences in 317-bp mtDNA cox1. However, overlap was detected between intra- and interspecific divergences in 311-bp rDNA ITS2 or 275-bp mtDNA 16S when the divergences exceeded 1.0 %, which resulted in failure in identification of Sarcoptes. The results showed that the 317-bp mtDNA cox1 could be used as a DNA barcode for molecular identification of Sarcoptes mites. In addition, geographical isolation was observed between S. hominis Chinese, S. hominis Australian, and S. hominis Panamanian, but not between all S. canis. S. canis and the other S. animal belonged to the same species.

A review of Sarcoptes scabiei: past, present and future

“…However, other studies that analyzed mtDNA 16S and mtDNA cox 1 and rDNA ITS2 of scabies mites from different animal hosts found they exhibited differences [73, 74]. A similar analysis by Zhao et al [68] identified scabies mites from humans and scabies mites from dogs in China as distinct Sarcoptes populations but humans could be infected with Sarcoptes from dogs [68]. However, they also concluded that based on the 317-bp mtDNA cox 1 gene, scabies mites from buffalo, rabbits, sheep, wombats, wallabys, pigs, chimpanzees and dogs belong to the same species and that the scabies mites from humans are a separate species from the animal species [68].…”

“…Taken together, these data suggest there are subpopulations of scabies mites within a host species and this raises the possibility of multiple species of scabies mites within humans and other host populations. This concept was more recently supported by research in China suggesting that there are many different strains (species) of scabies mites that parasitize humans [68]. Based on the mitochondrial cytochrome c oxidase subunit 1 (mtDNA cox 1) gene, the Sarcoptes from humans in Australia, Panama, and 2 populations in China were reported to represent 4 different species of Sarcoptes [68].…”

Population identification and divergence threshold in Psoroptidae based on ribosomal ITS2 and mitochondrial COI genes

“…Most studies involve the ITS2 gene (Zahler et al 1998;Essig et al 1999;Ochs et al 1999;Lohse et al 2002;Noge et al 2005;Pegler et al 2005;Hestvik et al 2007;Jia et al 2008), which cannot objectively reflect the evolution between species. The species evolution is imbalance for different genes based on the fact that rDNA ITS2 is not as good as mtDNA COI in the molecular classification and identification of Sarcoptes mites confirmed by our previous studies (Zhao et al 2015); (3) The mtDNA COI is the most common target gene used for identification at species level. As there are only two studies using mtDNA COI for molecular classification and identification of Psoroptidae Andre et al 2014), it is difficult to evaluate the value of the mtDNA COI gene in this regard; (4) The samples used in all reported studies are limited to particular hosts or species in a genus.…”

First detection of Sarcoptes scabiei from domesticated pig (Sus scrofa) and genetic characterization of S. scabiei from pet, farm and wild hosts in Israel

“…In our study, the condition and the number of the individual samples from which DNA was extracted did not allow high resolution morphological examination. Recent studies on S. scabiei genetics used several markers, both nuclear and mitochondrial (Alasaad et al 2009;Amer et al 2014;Makouloutou et al 2015;Zhao et al 2015). It was concluded that while ITS-2 sequence variations are not linked to host or geographic differences, variations in mitochondrial markers may better reflect population differences stemming from host preference or geographic location.…”