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The present study adapted the HotSHOT method, a technique which has been successfully applied on different kinds of tissues, to studies of Sarcoptes. Some modifications of this technique were made which allowed the quick preparation of PCR-quality Sarcoptes genomic DNA (gDNA), namely applying sodium hydroxide as a substrate for three cycles of thermal shock, followed by a short incubation and pH adjustment with a Tris solution (HotSHOT Plus ThermalSHOCK). The performance of this technique was tested by amplifying a approximately 450-bp rDNA fragment of the second internal transcribed spacer (ITS-2) and by multi-locus genotyping using ten microsatellites on 520 individual Sarcoptes samples. No difference in performance was observed between gDNA samples prepared using the HotSHOT Plus ThermalSHOCK technique and those prepared using a commercial kit utilizing proteinase K digestion. The results demonstrated that the HotSHOT Plus ThermalSHOCK technique is time-saving, economic, and easily automatable for the preparation of PCR-quality mite gDNA, which has implications for studying the molecular biology of mites with human and animal health significance. Although tested in the present study using Sarcoptes mites as a model, this technique may find broad applicability in extraction of gDNA from other parasites with small sizes and hard bodies.

Abstract   Sarcoptes mite from collection to DNA extraction forms the cornerstone for studies on Sarcoptes scabiei. Whilst the new science era took a shy leap into the different facets of mite studies, the cornerstone was almost entirely neglected. Mite collection, cleaning, storage and DNA extraction were, basically, humble attempts to extrapolate, adapt, modify or ‘pirate’ those existing methods to the peculiarities of Sarcoptes research. These aspects usually constituted few lines, bashfully mentioned, in the materials and methods section of some papers, which arose in unique problems concerning cost-effectiveness, time profitability, safety and even worse, the credibility of the results, creating contradictory conclusions in some cases. This ‘noisy’ situation encouraged us to collect, classify and review, for the first time to our knowledge, some aspects relating to studies on Sarcoptes mite from collection to DNA extraction, which will be useful for further studies on Sarcoptes, and have implications for the effective control of the diseases Sarcoptes mite causes. Further studies are needed, especially to compare the profitability, safety, sensibility and specificity of the different methods of this neglected realm of the ubiquitous ectoparasite. [ABSTRACT FROM AUTHOR]

Abstract  The objective of the present study was to examine the extent of genetic diversity among Sarcoptes scabiei individuals belonging to different skin subunits of the body from individual mangy hosts. Ten microsatellite primers were applied on 44 individual S. scabiei mites from three mangy Iberian ibexes from Sierra Nevada Mountain in Spain. Dendrograms of the mites from the individual Iberian ibexes, showing the proportion of shared alleles between pairs of individual mites representing three skin subpopulations (head, back, and abdomen subunits), allowed the clustering of some mite samples up to their skin subunits. This genetic diversity of S. scabiei at skin-scale did not have the same pattern in all considered hosts: for the first Iberian ibex (Cp1), only mites from the head subunit were grouped together; in the second individual (Cp2), the clustering was detected only for mites from the abdomen subunit; and for the third one (Cp3), only mites from the back subunit were clustered together. Our results suggest that the local colonization dynamics of S. scabiei would have influenced the nonrandom distribution of this ectoparasite, after a single infestation. Another presumable explanation to this skin-scale genetic structure could be the repeated infestations. To our knowledge, this is the first documentation of genetic structuring among S. scabiei at individual host skin-scale. Further studies are warranted to highlight determining factors of such trend, but the pattern underlined in the present study should be taken into account in diagnosis and monitoring protocols for studying the population genetic structure and life cycle of this neglected but important ectoparasite. [ABSTRACT FROM AUTHOR]