title: The epidermal location and possible feeding site of Psorergates ovis, the sheep itch mite.
abstract: Skin biopsies from two Merino sheep heavily infested with Psorergates ovis were immersed in liquid nitrogen and cut into vertical frozen sections stained with lipophilic Sudan IV or Oil Red O and haematoxylin. A survey of the lateral distribution of mite sections showed a majority (ca 80%) were in or within 0.2 mm of the follicle mouth. A survey of vertical distribution showed no mite penetration deeper than inner stratum corneum where 57% of mite sections were seen; 30% were within outer stratum corneum or scurf; 13% were on the outer surface and less than 1% were detached. Lipid was the only material seen within stained mites at a location considered to be gut. This was supported by dosing sheep with quinacrine, taking biopsies at Day 6 and Day 14 and examining frozen sections under blue light. Fluorescent lipid was seen at a location considered to be mite gut. From these results it was recommended that acaricide treatments against P. ovis be lipophilic and administered transepidermally because less than 15% of mites were at a superficial location likely to be reached by topical application.
authors.affiliation: Department of Wool and Animal Science, University of New South Wales, Kensington.
authors.forename: A
authors.initials: A
authors.lastname: Sinclair
mesh_terms: D000818:Animals; D001706:Biopsy / Q000662:veterinary; D004817:Epidermis / Q000469:parasitology* / Q000648:ultrastructure; D005247:Feeding Behavior; D005260:Female; D005629:Frozen Sections; D008855:Microscopy, Electron, Scanning; D008924:Mite Infestations / Q000469:parasitology / Q000662:veterinary*; D008925:Mites / Q000033:anatomy & histology / Q000502:physiology*; D012756:Sheep; D012757:Sheep Diseases / Q000469:parasitology*