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At least 19 recordsLinked to original sources
PubMed2006

In vitro entomopathogenic activity of Beauveria bassiana against Psoroptes spp. (Acari: Psoroptidae).

An indigenous strain (IHEM 18747) of Beauveria bassiana (Balsamo) Vuillemin (Deuteromycetes) was evaluated for its in vitro entomopathogenic activity against the parasitic mite Psoroptes ovis Hering (Acari: Psoroptidae) from rabbits. The following aspects were evaluated: (1) effects of conidial concentration on the viability of adult females; (2) influence of the infection on the fertility, and on the hatchability of eggs; (3) and transmission of infection between mites, and from contaminated surface. Adult females immersed into increasing concentrations of conidia (10(4)-10(9)conidia ml(-1)) showed a dose-related susceptibility. At the highest concentration of conidia, LT50 was 1.6 days while LT50 of the controls reached 5.8 days. The fungus was able to sporulate on the body surface and 100% of the mites were covered with mycelium after immersion in solutions containing 10(7)-10(9)conidia ml(-1). One hundred percent of healthy mites exposed to infected cadavers or surfaces acquired the infection (LT50 reached 1.9 and 1.73 days, respectively, versus 6.1 and 5.1 days in controls, respectively). Egg laying was not reduced by the fungal infection but both the hatchability of the eggs and the life span of the emerging larvae were significantly reduced. Eggs directly infected with the fungus did not show reduced hatchability but the life span of the larvae was shortened. It is concluded that B. bassiana has a high entomopathogenic activity against Psoroptes spp. The in vivo use of this biocontrol agent against Psoroptes spp. in rabbit, sheep and cattle deserves further attention.

Animals↗
PubMed2004

Otodectes cynotis (Acari: Psoroptidae): examination of survival off-the-host under natural and laboratory conditions.

The biological and environmental factors affecting survival off-the-host of Otodectes cynotis (Acari: Psoroptidae) ear mites were investigated under natural and laboratory conditions. From November 2000 to November 2002 mites were collected monthly from cats and divided into four groups according to sex and stage. In laboratory conditions, the mites were placed in an incubator with a steady 95% relative humidity (r.h.), a 10 degrees C. All the plates were examined by stereomicroscopy every 24 h until all the mites had died. The data were analysed statistically by multiple linear regression and survival analysis. At 10 degrees C, the maximum survival time of mites was between 15 and 17 days, while at 34 degrees C, it was between 5 and 6 days. The maximum survival time of adult females was significantly longer than that of other stages. No differences were observed in maximum survival times of mites that had been offered food and those that had not, or in the time (in days) to reach 50% mortality (LT50). When exposed to environmental conditions, the maximum survival time (12 days) was observed at temperatures ranging from 12.3 to 14.2 degrees C and r.h.s between 57.6 and 82.9%. Multiple regression analysis showed that temperature alone influenced the maximum survival time and LT50 of mites, and that the rate of survival declined linearly with increasing mean temperature. This basic understanding of off-host survival suggests that, places which have been inhabited by infected animals may need to be disinfected or remain vacated for at least 12 days before occupancy by clean cats or dogs.

Animals↗
PubMed2001

Cebus apella (Primata: Cebidae) as a new host for Fonsecalges johnjadini (Acari: Psoroptidae, Cebalginae) with a description of anatomopathological aspects.

Mites collected from the auditory canal of Cebus apella (capuchin monkey), family Cebidae, were identified as Fonsecalges johnjadini (Psoroptidae, Cebalginae). It is the first record of this parasite from this monkey. This paper emphasizes the importance of clinical and anatomopathological examinations for parasitic diagnosis in wild animals.

Animals↗
PubMed2005

Ultrastructural morphology of the male and female genital tracts of Psoroptes spp. (Acari: Astigmata: Psoroptidae).

The structure of the male and female genital systems of the astigmatid mite Psoroptes ovis (Hering) is described. The male genital system is composed of a paired testis, fused at its proximal part, two vasa deferentia, an ejaculatory duct, into which a single accessory gland opens, and a copulatory organ. The testis is characterized by a peripheric syncytial cell surrounding spermatogonia, spermatocytes, spermatids and spermatozoa which are distributed regularly in the gonad according to the sequence of spermatogenesis. The female genital system consists of a copulatory pore (the bursa copulatrix), a seminal receptacle, paired ovaries and oviducts, a glandular uterus and an ovipositor which leads to the oviporus. Ovaries are composed of somatic cells, germ cells and a central cell, with a multilobular nucleus, connected to oocytes by a stalk. Similarities with other astigmatic mites belonging to Psoroptidia and Acaridia are also discussed.

Animals↗
PubMed2003

A physiological and biochemical model for digestion in the ectoparasitic mite, Psoroptes ovis (Acari: Psoroptidae).

Mites are an important group of arthropod pests affecting crops, animals and humans. Despite this, detailed physiological studies on these organisms remain sparse due largely to their small size. Unifying models are required to draw together the diverse information from studies on different groups and species. This paper describes a model for digestion in the parasitic mite, Psoroptes ovis, the causative agent of psoroptic mange or sheep scab disease. The limited information about this species is supplemented with data from other acarines, especially house dust mites and ticks. We review the range of enzymes and allergens found in mites and consider their possible roles in digestion in mites, generally and in particular, P. ovis. Histological studies, enzyme biochemistry and molecular biology and experimental evidence suggest that P. ovis utilises a digestive system reliant upon acid peptidases functioning in a largely intracellular environment. The actions of the digestive enzymes are supplemented by the involvement of bacteria as potential direct and indirect sources of nutrition. It is possible that some extra-corporeal digestion also takes place. The interaction of bacteria and digestive enzymes on the skin surface of the sheep may be responsible for the excessive pathological reactions evident in clinical sheep scab.

Animals↗
PubMed1982

Effects of Psoroptes ovis (Acarina:Psoroptidae) on certain biochemical constituents of cattle serum.

Sera from Psoroptes ovis-infested calves were examined for 17 selected biochemical constituents to determine if P. ovis caused changes in any of these constituents. In order to recognize a scabies effect, there had to be a statistically significant (P less than or equal to 0.10) scabies exposure X time interaction and the changes in the biochemical constituents should have been correlated with the changes in the mite infestation. Five serum biochemical constituents fulfilled these criteria. Total protein, alpha-, beta-, and gamma-globulin were increased and total cholesterol was decreased at the peak of the scabies infestation. Precipitating antibodies to a P. ovis antigen were detected by immunodiffusion in some of the stored sera of the infested calves just after the peak of the infestation. Total protein, beta-, and gamma-globulin values were probably increased as a result of antibody production; alpha-globulin values were probably increased as a result of inflammation. As the scabies infestation declined, the mean values of all the above constituents from the infested calves, except cholesterol, began declining. Decreases in total cholesterol occurred, but they could not be entirely attributed to scabies. Examination of the serum biochemical constituents from a heavily infested calf that died during the test suggested that, in addition to antibody production and inflammation, kidney and liver damage may have occurred.

Alpha-Globulins↗
PubMed1983

Development of serum antibody activity as determined by enzyme-linked immunosorbent assay to Psoroptes ovis (Acarina:Psoroptidae) antigens in cattle infested with P. ovis.

Calves infested with Psoroptes ovis (Hering, 1838) for the first time (naive) or previously infested calves were examined for serum antibody activity to P. ovis (obtained from rabbits) antigens by enzyme-linked immunosorbent assay (ELISA) to determine the temporal appearance of specific serum antibody activity. The development of the serum antibody activity to P. ovis antigens was then correlated with the development of lesions (% scab) and with changes in the number of P. ovis. The serum antibody activity [ELISA OD414 value (EODV) greater than 0.290] to P. ovis antigens in naive calves, in most cases, is first detected at the same time or slightly after the detection of mites and mite-caused lesions; and the development of specific serum antibody activity paralleled the increase in the P. ovis population and the percentage scab until 7 weeks post-infestation (PI). In previously infested calves, if serum antibody activity to P. ovis antigens was not already present from the previous infestation, specific serum antibody activity was detected at the same time and developed in a similar manner as in the naive calves. The serum antibody activity to P. ovis antigens could be detected after calves were relieved of their P. ovis burdens by pesticide treatment or after the P. ovis population began to decline when the calves were allowed to groom themselves. Serum antibody activity to P. ovis antigens was not detected in any of the control calves during the test period.

Animals↗
PubMed1983

The prevalence and pathogenicity of Chorioptes bovis (Hering, 1845) and Psoroptes cuniculi (Delafond, 1859) (Acari: Psoroptidae) infestations in feral goats in New Zealand.

Between October 1976 and January 1980 a total of 368 feral goats was examined in New Zealand for the presence of Chorioptes bovis and 434 for the presence of Psoroptes cuniculi. The seasonal pattern of C. bovis infestation in feral goats was similar to that seen in sheep and cattle. The prevalence of infestation reached 100% in July and August (winter) and declined to 27% in February and March (summer). Fewer goats were infested with P. cuniculi and prevalence of infestation reached a maximum of 41% in July. No goats were found infested in the December and January samples. Chorioptes bovis infestation was independent of the age and sex of hosts. Infestation with P. cuniculi was independent of the sex of the hosts, but older goats were more frequently infested (16%) than younger goats (8.6%). Unilateral infestation with P. cuniculi was more common (74.5%) than bilateral infestation. No severe lesions were associated with C. bovis, but 21.3% of goats with P. cuniculi had the external auditory meatus blocked by waxy material and 12.8% had scabby encrustations on the ears. The importance of goats as a possible source of infestation to domestic animals is discussed.

Age Factors↗
PubMed1984

In vitro feeding of Psoroptes ovis (Acari:Psoroptidae).

An in vitro feeding test is described for Psoroptes ovis. The criterion for feeding response was established on the basis of coloration of mites by a red dye or by red blood cells. Feeding response was about 85% for female mites held off host cattle for 1 day. Mites preferred water plasma or serum and low-salt diets over whole blood. Feeding response was detected within 5 min of exposure to the diet, and maximum response was observed within 30 min of contact. Mites ingested an average 0.29 microliter of diet/100 mites in a single feeding. At temperatures between 10 degrees and 42 degrees C, feeding response was not significantly different.

Animal Feed↗
PubMed1988

Comparison of cryofixation methods for skin biopsies from sheep infested with Psoroptes ovis (Acari: Psoroptidae).

Two methods of cryofixing skin samples from sheep infested with Psoroptes ovis were compared. In one method the skin biopsy was placed in a capped vial before immersion, while the other allowed direct contact with liquid nitrogen. No statistically significant differences were found between the cryofixation methods with regard to location of P. ovis sections or engaged mouthparts. Direct contact with liquid nitrogen is recommended as the preferred method for cryofixing epidermal feeding ectoparasites on skin samples.

Animals↗
PubMed1989

Lipid ingestion from sheep epidermis by Psoroptes ovis (Acari: Psoroptidae).

Skin biopsies from three groups of sheep infested with Psoroptes ovis were cryofixed in liquid nitrogen to preserve outer epidermis with its lipid. From one group of five sheep (Group A), biopsies were taken from relatively healthy skin near the edge of scab lesions where mites had congregated. Frozen vertical sections from these biopsies were stained with Oil Red O and haematoxylin before mounting. Red lipid globules were plentiful within the body cavity of sectioned mites, but ingested lipid could not be distinguished from endogenous mite body stores by this technique. In a second group of five sheep (Group B), enclosed lumbar skin areas were coloured red with the lipophilic stains Oil Red O or Sudan IV. These enclosed coloured skin areas were inoculated with P. ovis and sampled by skin biopsy 1 or 4 days later. Cryofixed biopsies were cut into vertical frozen sections and mounted without staining for examination. Red-coloured lipid within mites, matching red-coloured lipid on outer epidermis, was evidence for the epidermal origin of P. ovis ingesta in the early stages of an infestation. From two other sheep (Group C), cryofixed biopsies were examined by scanning electron microscope and mites were seen with mouthparts embedded in abraded outer epidermis, but the precise depth of epidermal penetration was not determined. A light microscope survey of 3198 frozen vertical skin sections from the first 10 sheep (Groups A and B) showed that inner stratum corneum of the epidermis was the deepest penetration recorded for gnathosomes of P. ovis cryofixed in situ by liquid nitrogen. No structure of P. ovis was identified in dermal tissues.

Animals↗
PubMed1992

Field efficacy of injectable and pour-on moxidectin in cattle naturally infested with Psoroptes ovis (Acarina: Psoroptidae).

Field efficacy of moxidectin, a macrocyclic lactone endectocide, was evaluated in cattle naturally infested with Psoroptes ovis. Three groups of six animals were used based on parasitological and clinical status. Group 1 animals received one subcutaneous injection of injectable moxidectin at 0.2 mg kg-1 body weight; Group 2 animals received topically one dose of 0.5 mg kg-1 body weight of pour-on moxidectin; Group 3 individuals remained untreated as controls. Efficacy was assessed by (a) taking skin samples from each animal on Days -4, 14, 28, 42 and 56 post-treatment (PT) and observing numbers of viable mite stages and species and (b) clinical examination of animals on Days 14, 28, 42 and 56 with the percentage of affected body surface calculated for each animal on Days -4, 28 and 56. Both formulations gave 100% efficacy as no live mites were found in Groups 1 or 2, 14, 28 and 56 days after treatment. Clinical indices showed a sharp decrease in the affected body surface area from a mean of 5.48% and 6.1% on Day -4 in Groups 1 and 2, respectively, to 0% in both groups on Days 28 and 56 PT. All untreated animals remained positive until Day 28. The clinical condition of the controls worsened rapidly during the experiment (mean clinical index: 2.87% and 13.05% on Days -4 and 28, respectively) and they were given an emergency treatment on Day 28. No side-effects were observed with either formulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Topical↗
PubMed2002

Ultrastructure of the alimentary canal of the sheep scab mite, Psoroptes ovis (Acari: Psoroptidae).

The mite Psoroptes ovis causes sheep scab disease in flocks throughout much of the world. A serious impediment to the development of novel control measures for this mite is our inability to produce in vitro colonies of the mite. Here, we describe the alimentary canal of the mite with the particular aim of determining what it feeds on, as part of a longer term goal, to develop in vitro culture techniques for P. ovis. The alimentary canal of P. ovis consists of a cuticle-lined foregut and hindgut separated by a microvilli-lined midgut. The foregut is divided into a pre-oral cavity and a muscular pharynx and oesophagus. The midgut consists of three ultrastructurally discrete areas: a stomach with bi-lobed ventriculi, a colon and a post-colon. The stomach is composed of two cell types. The most common cells (Type 1) are either cuboidal or squamous depending on the degree of gut distension and possess short microvilli, a single basally located nucleus, extensive rough endoplasmic reticulum and other components suggesting active secretion. The less common cells (Type 2), possess an extensive apical network of tubules and basally food vacuoles suggesting intracellular digestion. These cells extend into the gut lumen, become free-floating and degenerate. The colon and post-colon are composed of cells similar to Type 1 stomach cells but the post-colon epithelium possesses significantly longer microvilli. Cells from these areas have not been observed to leave the surrounding epithelium and enter the gut lumen, but it is suggested that significant absorption occurs in these two areas. Faecal pellets, often containing a significant number of bacteria, leave the digestive system through the cuticle-lined anal atrium.

Animals↗
PubMed1998

Efficacy of ivermectin in a controlled release formulation against Psoroptes ovis (Hering, 1838) gervais, 1841 (Acari: Psoroptidae) on sheep.

Three trials including 42 sheep were conducted in Brazil or Germany to evaluate the therapeutic (two trials) and prophylactic (one trial) efficacy of an ivermectin controlled release capsule (CRC) against Psoroptes ovis infestation. In one therapeutic trial naturally infested sheep were used while in the other trials infestations were experimentally induced. In each trial half of the animals were treated on Day 0 with one ivermectin controlled release capsule that delivers ivermectin at a rate of 1.6 mg/day for approximately 100 days, that is 20 mcg/kg/day to a 80 kg animal, while the other half remained untreated. In both therapeutic trials mites were counted in skin scrapings and their presence was recorded at predilection sites one day before treatment and at weekly intervals from Day 7 to Day 56. In the trial conducted to evaluate the prophylactic efficacy the sheep were experimentally infested with P. ovis 21 and 28 days post-treatment and mites were counted and recorded at predilection sites on Days 42, 49 and 56. The ivermectin controlled release capsule was completely effective in eliminating the P. ovis mites within 28 days of administration and it prevented the establishment of an infestation of P. ovis induced 21 and 28 days after administration.

Animals↗
PubMed1999

Inter- and intra-specific variation within the genus Psoroptes (Acari: Psoroptidae).

In this paper the taxonomy and relative importance of various species within the genus Psoroptes are reviewed with respect to inter- and intra-specific variations in cross infestivity and host specificity, site of infestation and morphological characters. Intra-specific variation within populations of the sheep scab mite, Psoroptes ovis will then be discussed critically with respect to virulence (the relative growth of the scab lesion and mite burdens), epidemiology, susceptibility to the systemic acaricide, ivermectin, and resistance to synthetic pyrethroid and organophosphate acaricides. Finally, it is suggested that the ear mite, P. cuniculi, and the sheep scab mite, P. ovis are variants of the same species. Information was collected from published literature and from the results of unpublished studies carried out at the VLA, Weybridge over the last 10 years.

Animals↗