Morphology of the Mouthparts of the Sheep Scab Mite, Psoroptes ovis1, 2

Blake, Bruce H.; Bay, D. E.; Meola, Shirlee M.; Price, M. A.

doi:10.1093/aesa/71.3.289

Cited by 17 publications

(10 citation statements)

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“…The distal ends of both digits were chelated for abrasion of the host's skin during feeding. The chelicerae have been described comprehensively in previous studies (Blake et al ., 1978; Rafferty & Gray, 1987) and so were not considered in further detail here.…”

Section: Resultsmentioning

confidence: 99%

“…However, in P. ovis the labrum is short and overlies the mouth (Rafferty & Gray, 1987). Blake et al . (1978) did not observe salivary glands or ducts in the gnathosoma of P. ovis .…”

Section: Discussionmentioning

confidence: 99%

“…Mites were dehydrated, fixed in resin, sectioned and stained for transmission electron microscope (TEM) investigation. Live female mites were killed and fixed in Nesbitt's fluid for 1 h, and then dehydrated through an ethanol series of increasing concentration (10 min at each stage): 10%, 20%, 30%, 40%, 50%, 60%, 70%, 90%, absolute I × 2, absolute II × 3 (Blake et al ., 1978). Specimens were transferred into a ‘LINK’ reagent as follows: 100% ethanol : epoxy propane (2 : 1) for 10 min, 100% ethanol : epoxy propane (1 : 2) for 10 min, epoxy propane for 15 min, before being transferred to a mixture of epoxy propane : TABB 812 Resin (1 : 2).…”

Section: Methodsmentioning

confidence: 99%

“…Two previous studies have considered in detail aspects of the morphology of the gnathosoma of P. ovis (Blake et al ., 1978; Rafferty & Gray, 1987). Nevertheless, many questions remain about the precise relationship between the component elements of the feeding apparatus.…”

Section: Introductionmentioning

confidence: 99%

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Structure and function of the gnathosoma  of the mange mite, Psoroptes ovis

Mapstone

Beasley

Wall

2002

Medical Vet Entomology

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Abstract. Mites of the genus Psoroptes (Acari: Psoroptidae) are obligate, nonburrowing, astigmatid ectoparasites of mammals. A detailed understanding of the morphology of the gnathosoma is an important step towards elucidation of the feeding behaviour of this mite and, hence, the pathology of psoroptic mange. Scanning and transmission electron microscopy were used to examine Psoroptes ovis (Hering) (syn. P. cuniculi). The gnathosoma is composed of an infracapitulum (hypostome), which forms the floor of an extended U-shaped pre-oral trough, bounded by laterally compressed palps and enclosing paired chelicerae. Distally, each palp terminates in a flap-like process and four tapered terminal sensillae. The floor of the infracapitulum is interrupted along its length by a dorsally projecting ridge. At the distal end of the infracapitulum are paired, grooved pseudorutellae and, between them, paired, ungrooved lateral lips. Between the lateral lips is a grooved, elongate labium. Medially, a pair of finger-like projections emanates from the paraxial walls of the palps and project anteriorly. Each chelicera is made up of fixed and mobile digits, with a cheliceral membranous fold articulating the two. The distal ends of both digits are chelated. For much of its length, the mobile cheliceral digit appears to lie within a fold formed by the infracapitular ridge, thereby creating a central channel between the chelicerae. It is suggested that this arrangement of elements may facilitate a two-way flow of liquid, where saliva flows down a central salivary canal and spills out onto the host's skin over the labium at the point where the chelated tips of the chelicerae meet and abrade the skin. Liquid food may move along the grooves of the pseudorutellae and then be sucked up a food canal formed by the paraxial walls of the palps and the outer wall of the chelicerae.

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Section: Resultsmentioning

confidence: 99%

“…However, in P. ovis the labrum is short and overlies the mouth (Rafferty & Gray, 1987). Blake et al . (1978) did not observe salivary glands or ducts in the gnathosoma of P. ovis .…”

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Structure and function of the gnathosoma  of the mange mite, Psoroptes ovis

Mapstone

Beasley

Wall

2002

Medical Vet Entomology

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“…Compromised barrier function in atopic dermatitis patients may be attributable to the proteolytic activity of Der p 1 and 3 [15,16]. In sheep, the mouthparts of P. ovis may also impair barrier function by abrading the stratum corneum [56]. However, it is probable that P. ovis homologues of the HDM proteases Der p 1 and 3 , such as Pso o 1 and 3 , also contribute to the increase in TEWL by disruption of tight junctions.…”

Section: Discussionmentioning

confidence: 99%

The effect of Psoroptes ovis infestation on ovine epidermal barrier function

Stoeckli

McNeilly

Frew

et al. 2013

Vet Res

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Sheep scab is an intensively pruritic, exudative and allergic dermatitis of sheep caused by the ectoparasitic mite Psoroptes ovis. The purpose of the present study was to investigate the effect of P. ovis infestation on different components of the ovine epidermal barrier within the first 24 hours post-infestation (hpi). To achieve this, the expression of epidermal differentiation complex (EDC) genes and epidermal barrier proteins, the nature and severity of epidermal pathology and transepidermal water loss (TEWL) were evaluated.By 1 hpi a significant dermal polymorphonuclear infiltrate and a significant increase in TEWL with maximal mean TEWL (598.67 g/m2h) were observed. Epidermal pathology involving intra-epidermal pustulation, loss of epidermal architecture and damage to the basement membrane was seen by 3 hpi. Filaggrin and loricrin protein levels in the stratum corneum declined significantly in the first 24 hpi and qPCR validation confirmed the decrease in expression of the key EDC genes involucrin, filaggrin and loricrin observed by microarray analysis, with 5.8-fold, 4.5-fold and 80-fold decreases, respectively by 24 hpi.The present study has demonstrated that early P. ovis infestation disrupts the ovine epidermal barrier causing significant alterations in the expression of critical barrier components, epidermal pathology, and TEWL. Many of these features have also been documented in human and canine atopic dermatitis suggesting that sheep scab may provide a model for the elucidation of events occurring in the early phases of atopic sensitisation.

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