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At least 631 records · Page 35Linked to original sources
PubMed1998

Elimination of an Infestation of Rat Fur Mites (Radfordia ensifera) from a Colony of Long Evans Rats, Using the Micro-dot Technique for Topical Administration of 1% Ivermectin.

Micro-dot delivery of 1% ivermectin was used in an effort to eliminate an infestation of rat fur mites (Radfordia ensifera) from a conventionally housed colony of Long Evans rats. The colony was used for breeding as well as for behavioral testing. A micropipette was used to apply a 1% solution of ivermectin (2 mg/kg of body weight) to the skin on the dorsal aspect of the shoulder. Three treatments were applied at approximately 2-week intervals. All rats in the colony were treated. However, to avoid toxicity to neonates, nursing females and their pups (control group) received mineral oil in lieu of ivermectin until after weaning, at which time they also were treated with ivermectin. During the treatment phase, skin scrapings were used to detect mites. Control rats remained positive for fur mites when treated with mineral oil. After 3 applications of ivermectin, all rats were found to be free of mites. During the posttreatment phase, skin scrapings, dorsal tape tests, and a washing method were performed on euthanatized rats to detect mites. Rats tested up to 129 days (18 weeks) after ivermectin treatment were still free of mites. In a breeding colony composed of rats of various sizes and ages, micropipette delivery of ivermectin allowed for accurate dosing to eliminate fur mites, while preventing inadvertent toxicosis. We did not detect obvious adverse effects on the breeding program or on the behavioral studies in which these rats were subsequently used, nor did we detect morbidity or mortality associated with ivermectin administration.

Journal Article↗
PubMed2002

Allergy to house dust mites in primary health care subjects with chronic or recurrent inflammatory states of respiratory system.

Chronic and recurrent respiratory tract disorders are a frequent problem in general practice. The purpose of the study was to investigate the role of hypersensitivity to house dust mites in respiratory tract diseases in general practice patients. We tried to assess the influence of determined risk factors exposure on development of respiratory tract allergy. Patients from family practitioners surgeries with chronic or recurrent respiratory tract symptoms who had no diagnosis of allergy were recruited to the study (n = 89). All patients responded to a questionnaire focused on history of symptoms, atopic conditions in family and exposure to determined environmental factors like dwelling conditions, obstetrician history, diet in the first year of life. All patients underwent skin prick test with common inhalant allergens. Families of the patients were asked to participate in the study. Families who agreed to take part also responded to the questionnaire and underwent skin tests. In patients and their families blood samples were taken to determine total IgE and specific IgE antibodies to mites allergens. Dust samples were collected by vacuuming of patients' bedroom carpets and mattresses to determine house dust mites allergens concentration. Data on 30 complete patients family sets of their brotherhood, mother and father were collected. Total and specific serum IgE antibodies were determined by disc enzyme-immunoassay (Analco). Mites allergens concentration in dust was measured by simple Acarex strip test (Nexter). The results of the assays (positive skin tests and/or elevated levels of specific IgE) showed allergy to house dust mites in 24 of 89 study patients from general practitioners surgeries (27%). The prevalence of chronic rhinitis, recurrent bronchitis, chronic or recurrent cough, wheezing, dyspnoea was higher in allergic than in nonallergic subjects. Patients with the diagnosis of allergy to house dust mites had usually worse dwelling conditions. Especially the influence of dampness in flats on several respiratory symptoms was observed. Subjects who had been found to be allergic were more frequently exposed to higher concentrations of house dust mites allergens in bedroom carpets and in mattresses. In allergic children early introducing of sensitizing components into the diet in infancy related to shorter breast feeding was observed.

Adolescent↗
PubMedDate not supplied

[The origin of parasitism in trombiculid mites (Acariformes: Trombiculidae)].

On the basis of literary data and original investigations some phylogenetic, ecological and morphological aspects of the origin of parasitism in trombiculid mites are carefully considered for the first time. It is shown that parasitism in this group of trombidiform mites is a relatively young historical phenomenon and was formed after their ontogenesis had differentiated into active and quiescent stages. Therefore, in the life pattern of trombiculid mites the character of individual development, that defines their biotopical restriction, is much more important than the phase parasitism. Primitive organization of the digestive system and extraintestinal digestion, so characteristic of this group, are one of the main reasons of the origin of their parasitism. Under pasture conditions trombiculid mites, that initially were predators-entomophages with bite-sucking mouth parts, pass easily to parasitism on vertebrate animals and become primary lymphophages. They use the vertebrate host's organism exclusively as a source of food and by the extent of polyphagia are very close to free-living blood-sucking insects. Stylostome, that develops during feeding of trombiculid larvae and some other closely related groups of trombidiform mites, is a universal structure for achieving a large amount of food on a wide range of animals during a relatively short period of time and reflects wide host-parasite specificity of these parasitic mites. From the historical view the larvae of trombiculid mites did not pass from one group of hosts to the others, but owing to morphological preadaptation to parasitism passed in a definite historical period, not earlier than Paleogene, to parasitism on all classes of terrestrial vertebrates, especially on mammals, their primary hosts.

Animals↗
PubMed2004

Mite allergen levels and acarologic analysis in house dust samples in Uberaba, Brazil.

Mite allergen exposure has been widely related to sensitization and development of allergic diseases. This study intended to evaluate the degree of allergen exposure in Uberaba, Brazil, through the measurements of Der f 1 and Der p 1 allergen levels associated with the acarologic analysis in house dust samples. A total of 240 dust samples were collected from 60 houses through vacuuming sofas and bedding, during the months of March and July 2000. Indoor temperature and relative humidity were also measured. Mites were counted and identified under light microscopy and allergen levels were measured by two-site monoclonal antibody ELISAs. The major mite family was Pyroglyphidae (39.4%), having D. pteronyssinus as the most frequent species (15.6%), followed by D. farinae (12.3%) and E. maynei (7.9%). The family Glycyphagidae was less commonly found (4.8%), with Blomia tropicalis (4.4%) as its majoritary member. The highest levels of Der f 1 and Der p 1 allergens were found in bedding samples in March (31.7 and 0.9 microg/g of dust, respectively), with Der f 1 levels significantly higher than Der p 1 (p < 0.0001). There was a significant positive correlation between the mite number and allergen levels. These results indicate that Dermatophagoides sp are the most frequent mites in our region followed by E. maynei. Therefore, the knowledge of the local mite fauna would improve the means of investigating the association between allergen exposure and sensitization, allowing the addition of new mite extracts in diagnostic tests.

Air Pollution, Indoor↗
PubMed1990

Transmission of Rickettsia tsutsugamushi from Apodemus speciosus, a wild rodent, to larval trombiculid mites during the feeding process.

Transmission of Rickettsia tsutsugamushi (Rt) from a rodent to trombiculid mites was studied. Wild rodents, Apodemus speciosus, were subcutaneously inoculated with Karp strain of Rt, and larval trombiculid mites were released on the ear lobes for feeding, 10 and 20 days after infection. Isolation of Rt was performed from individual mites or pools of 2 to 7 mites by the mouse passage method. From Apodemus 10 days after Rt infection, possibly at the time of high rickettsiaemia, the infection rates among mites were 4/44 (9.1%) or higher in Leptotrombidium fuji, 1/20 (5%) in L. pallidum and 0/41 in L. deliense. From Apodemus 20 days after infection, no mite was infected in 50 L. fuji or 7 L. pallidum possibly due to reduced rickettsiaemia. Transmission of Rt from rodent to mite was proven to occur at low probability on appropriate conditions but not by the incidental chance.

Animals↗
PubMed2002

Randomized trial to prevent sensitization to mite allergens in toddlers and preschoolers by allergen reduction and education: one-year results.

OBJECTIVE: To evaluate the effectiveness of prevention measures against dust mite sensitization. DESIGN: European (England, Germany, Greece, Lithuania) multicenter prospective single-blind randomized control trial with a follow-up of 12 months. PARTICIPANTS: Toddlers and preschoolers, with at least 1 parent with atopic symptoms and sensitization, who initially were not sensitized to mite allergens. INTERVENTIONS: A combination of education and a simple preventive measure (mattress encasement) to reduce mite allergen exposure. SETTING: Community-based study. MAIN OUTCOME MEASURES: Sensitization to mite allergens (skin-prick test or specific immunoglobulin E). RESULTS: Of 636 children (mean age, 3.1 years) included in the study, 566 (89%) participated in the first-year follow-up. The incidence of sensitization to mite allergens was 10 (3%) of 330 in the intervention vs 20 (6.5%) of 306 in the control arm, including loss of follow-up (intention-to-treat principle). Allergic symptoms were more common in sensitized than in nonsensitized children and so was the prevalence of physician-diagnosed asthma, eczema, and food allergy. CONCLUSIONS: This simple, harmless, and inexpensive measure can be used in toddlers and preschoolers of parents with atopic disorders to reduce sensitization to mite allergens. With regard to clinical manifestations of atopy, follow-up studies are needed to determine the effectiveness of the intervention.

Allergens↗
PubMed1991

Trap perches to assess the activity of pyrethrins against the poultry red mite Dermanyssus gallinae in cage birds.

Trap perches were utilised to quantify mite recoveries during efficacy tests of pyrethrin formulations against experimental infestations of Dermanyssus gallinae (De Geer, 1778) in budgerigars and pigeons, and to monitor mite recoveries from untreated canaries. Pyrethrins applied topically before infestation significantly reduced the mean numbers of poultry red mites found in both budgerigar and pigeon trap perches, over those in untreated controls (P = less than 0.01). In untreated control budgerigars and pigeons, and in untreated canaries, the percentage recoveries after 48 h were 12.6 +/- 1.6, 4.1 +/- 1.9, and 32.6 +/- 1.6%, respectively (geometric mean +/- SD), and the blood engorgements rates were 71.5 +/- 1.7, 11.9 +/- 5.1, and 90.1 +/- 1.0% respectively. The recovery in trap perches of mites from canaries declined exponentially; 85% of the cumulative total recovered was collected 24 h after infestation, but small numbers were recovered daily up to 96 h (limit of observation). The use of the trap perches is discussed as a way of assessing the efficacy of acaricides, and as a laboratory tool in studies on mite aggregation behaviour or immune responses to mite infestation.

Administration, Topical↗
PubMed1994

Survival and retention of infectivity of the mite Psoroptes ovis off the host.

Psoroptes ovis mites were removed from infected sheep and placed in positions where wool and mites normally accumulate during sheep scab outbreaks. The ambient temperature and humidity were monitored over a 3-week period and the survival and infectivity times were examined. The procedure was carried out during each of the seasons. The hatchability of mite eggs was also examined. It was found that little variation occurred between seasons, with mites regularly retaining viability and infectivity for 15 days during all seasons. Mites that survived for more than 16 days failed to infect sheep. Mite eggs retained hatchability for up to 7 days.

Animals↗
PubMed2005

Beauveria bassiana pathogenicity to the citrus rust mite Phyllocoptruta oleivora.

The pathogenicity of Beauveria bassiana to one of the major pests of citrus crops, Phyllocoptruta oleivora, was assessed by inoculating mites with different concentrations of conidia (1 x 10(6), 5 x 10(6), 1 x 10(7), 5 x 10(7) and 1 x 10(8)). Treated mites were kept at controlled conditions (25 +/- 0.5 degrees C, 12 h photoperiod and 98% relative humidity) and mite survivorship was evaluated daily. Mortality was found to increase in time and was dependent on the conidia concentration, with values ranging from 24 to 91% for the lowest and highest conidia concentration, respectively. The calculated LC50 on the fifth day was 4.23 x 10(6) conidia/ml. Mean lethal time was 3.98, 9.79, 3.09 and 2.74 days for 5 x 10(6), 1 x 10(7), 5 x 10(7) and 1 x 10(8) conidia/ml, respectively. Conidia were found to adhere all over the mite body surface, especially at the anal region, where vegetative mycelium was found entering the mite body. We noticed the formation of small crystals inside the mite's body that were produced during colonization of the body cavity by the fungus. This is the first report of B. bassiana pathogenicity for this species.

Animals↗
PubMed1998

Experimental infection of dogs with the nasal mite Pneumonyssoides caninum.

A successful experimental transmission of the canine nasal mite, Pneumonyssoides caninum, is described. Some 11 weeks after repeated systemic ivermectin treatment, four Beagles were inoculated via the right nostril with 20 P. caninum mites of different sexes and life stages, obtained at the necropsy of an infected dog. The inoculated dogs and a matching uninoculated control were observed for clinical signs for 14 weeks and then euthanised. Vague upper respiratory signs and a transient minor increase in the number of eosinophils in peripheral blood were recorded in the inoculated dogs. At necropsy 4-12 P. caninum mites were found in the nasal cavities and sinuses of the inoculated dogs, but none in the control. In three out of the four infected dogs mites were found in both the right and left nasal cavities and sinuses of the skull. Since in no case more mites than the number used for inoculation were detected it is not clear if the mites managed to reproduce in the dogs. Inflammatory lesions were seen most consistently in the olfactory mucosa, respiratory mucosa and tonsils, and growth of opportunistic bacteria was observed in the tonsils of the infected dogs. The inflammatory lesions seen in the olfactory mucosa may explain why dogs infected with P. caninum sometimes appear to suffer from impaired scenting ability.

Animals↗
PubMed1999

Simulation analysis of the population dynamics of the mite, Psoroptes ovis, infesting sheep.

The pattern of population growth of the ectoparasitic mite, Psoroptes ovis (Acari: Psoroptidae), on its ovine host is considered through the development of a Leslie matrix-based, simulation model. The model is parameterised using experimental data in conjunction with reanalysis of published data. The model shows that on sheep P. ovis populations grow at a rate of approximately 11% per day and the population doubles every 6.3 days. Additional rates of adult mortality, in excess of 50% per day, need to be imposed to prevent population growth. The predictions of the model are tested by comparison of the expected numbers of mites with the numbers recorded in lesions either on naturally infested sheep where the date of infestation can be estimated or on one artificially infested animal, where the initial number of mites and date of infestation are known precisely. In both cases the observed number of mites in lesions relate closely to the numbers expected from the simulations. The model simulations do not support the concept of a 'lag' phase as distinct from the 'growth' phase in the changing pattern of mite abundance on an infested sheep and suggests that the observed pattern of growth is a natural function of an exponential increase in numbers. The development of such models and their use in explaining the demographic processes which drive mite population dynamics are discussed.

Animals↗
PubMed2004

Specificity of attachment sites of larval water mites (Hydrachnidia, Acari) on their insect hosts (Chironomidae, Diptera)--evidence from some stream-living species.

This study concerns the parasite-host associations of water mite larvae and their chironomid hosts in a small stream on the North German Plain. The different feeding sites on the host were tested as to whether they represented a strategy of the parasites regarding host partitioning. The attachment sites of nine ectoparasitic water mite species were observed in detail: Aturus fontinalis, Atractides nodipalpis, Feltria rouxi, Hygrobates nigromaculatus, Protzia eximia, Sperchonopsis verrucosa, Sperchon clupeifer, S. setiger and Lebertia inaequalis. Aturus fontinalis, A. nodipalpis, F. rouxi and H. nigromaculatus distinctly preferred sites on the abdomen of the host, whereas the other species preferred feeding sites on the thorax. The four species that preferentially attached to the abdomen of the host showed a distinct specificity for selected segmental and/or intersegmental regions. All species differed in their sites along the length of the abdomen. The order of attachment on the abdominal segments was, from anterior to posterior: H. nigromaculatus, F. rouxi, A. fontinalis and A. nodipalpis. The sites were analysed with regard to segmental and intersegmental attachment, the proportion of dorsal and ventral sites and the differences between attachment to different host species. Larvae attached to their hosts as single individuals showed only slight differences from the sites of mites on hosts that carried many mite larvae. The finding that less than 10% of the chironomids were parasitized by more than one water mite species suggested that, at least in the zoocoenosis of the studied collecting site, the interspecific competition for attachment sites was not strong. However, the specificity of attachment sites clearly had the potential of diminishing competition between water mite species by host partitioning. Intra- and interspecific competition for preferred sites and preparasitic constraints are discussed.

Animals↗
PubMed1993

Laboratory transmission of eastern equine encephalomyelitis virus to chickens by chicken mites (Acari: Dermanyssidae).

Pools of adult female chicken mites, Dermanyssus gallinae (De Geer), were allowed to feed on chicks that had been inoculated with eastern equine encephalomyelitis (EEE) virus and that had a viremia level of 10(6.2)-10(6.6) plaque-forming units per milliliter of blood. Virus remained detectable by plaque assay in samples of these mites for 30 d after the infectious blood meal. Virus was not recovered from any of 151 progeny of virus-exposed female mites. Mites that had fed on viremic chicks were allowed to feed on naive chicks 3, 7, 11, 15, or 30 d later. EEE virus was transmitted to chicks by these mites on days 3 (one transmission in four trials) and 7 (one transmission in four trials). Both transmissions were confirmed by the presence of virus in chick blood 24-72 h after mites had fed, and by plaque-reduction neutralization assays of 21-d convalescent chick sera against the original viral strain.

Animals↗
PubMed1997

Observations on the mite fauna associated with adult Stomoxys calcitrans in the U.K.

Adult females of the blood-sucking muscid Stomoxys calcitrans sampled between June and September 1993 from a cattle farm (n = 839) and from a pig farm (n = 542) in North-West England were examined for mites. Twelve species of mites from ten families and three orders were identified as follows. In the Prostigmata, Eryenetes sp., Family Ereynetidae and Pediculaster mesembrinae, Family Pygmephoridae. In the Astigmata, Procalvolia zacheri Family Saproglyphidae, Acarus farris, Family Acaridae, Bonomoia sphaerocerae and Myianoetus sp., Family Anoetidae. In the Mesostigmata, Macrocheles muscaedomesticae and Macrocheles subbadius Family Macrochelidae, Digamasellus sp., Family Digamasellidae, Halolaelaps sp., Family Halolaelapidae. Prodinychus sp., Family Uropodoidea and Thinoseius sp., Family Eviphididae. Mean infestation rates at the two sites (all mite species) for the entire sampling period were 31.6 +/- 13.9% and 19.8 +/- 3.6% respectively. 51% of synbovine flies sampled in July were infested with mites. Mean numbers of flies infested in August at both farms were significantly lower compared to other months. The presence of tritonymphs of Ereynetes sp. on S. calcitrans demonstrates for the first time that this life cycle stage is naturally associated with insects in the field. All mites were recovered from the ventral thorax and abdomen, and two or more species commonly infested individual flies. Associations of mites with their dipteran hosts are described and discussed.

Animals↗
PubMed1998

Demodex mites in acne rosacea.

The hair follicle mites Demodex folliculorum and Demodex brevis and their role in the pathogenesis of rosacea have been the subject of much debate in the past. We studied the prevalence of Demodex mites in facial skin biopsies obtained from 80 patients with rosacea, 40 with facial eczematous eruption and 40 with lupus erythematosus discoides. The mite prevalence in the rosacea group (51%) was significantly higher than in the rest of the study population (eczema 28% and lupus discoides 31%). Demodex mites were found on all facial sites. The most infested areas in the whole study group were the forehead (49%) and the cheeks (44%). Males were more frequently infested (59%) than females (30%). We did not find any significant difference in mite counts of infested follicles between rosacea and the control group. A lympho-histiocytic cell infiltration was seen around the infested hair follicles. Our results suggest that Demodex mites may play a role in the inflammatory reaction in acne rosacea.

Adolescent↗
PubMed1990

The epidermal location and possible feeding site of Psorergates ovis, the sheep itch mite.

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.

Animals↗
PubMed1999

Mites infesting two migratory birds, Coturnix c. coturnix (quail or Simmaan) and Sturnus v. vulgaris (starling or zarzuur) with reference to avian zoonosis.

Birds are a marvelous group of creatures. Their beautiful coloration, singing, dancing and their attractive ways of life offer great pleasure to birdwatcher. Egypt is one of the most important countries of migratory birds. Not less than 300 species of birds visit Egypt annually from allover the world. The mite fauna of two migratory birds was studied in North Sinai Governorate and Suez Canal Zone. Thirty-one species of mites were recovered from quail and 39 from starling. Both types of birds serve hosts for 26 species of mites. Besides, five species were only recovered from quail and 13 species from starling. These totaled 44 species belonging to 30 families of three suborders (Mesostigmata, Trombidiformes and Sarcoptidiformes). The mite index on quail ranged between 1.0 to 5.0 in North Sinai G. and 1.0 to 17.0 in Suez Canal Z. The mite index on starling ranged between 1.0 to 4.75 in North Sinai G. and 1.0 to 4.5 in Suez Canal Z. Sixteen of the recovered species of mites were not recorded before on the Egyptian resident birds (house sparrow and laughing dove). The medical and veterinary importance of avian zoonosis was discussed. It is hoped to stimulate the awareness to migratory birds as reservoir hosts for microorganisms and parasites from allover the world. Besides, there is an urgent need to protect the resident and the visiting birds.

Animals↗
PubMed2002

Decreased flight performance and sperm production in drones of the honey bee (Apis mellifera) slightly infested by Varroa destructor mites during pupal development.

We developed a bioassay to measure the flying power of drone, in order to determine which drones could reach a drone congregation area. A wind tunnel was used to test unparasitized drones and drones slightly parasitized by one or two mites during pupal development, and counts were made of the number of spermatozoa that they produced. Drones parasitized with one mite flew as long as control drones (x= 6'55" and 6'48", respectively, P = 0.512); however, those that had been infested by two mites flew significantly less (x= 2'16", P<0.001). There was a significant positive correlation (P<0.01) between flight duration and the number of spermatozoa per drone in control group (r = 0.53), and in both the one mite (r = 0.43) and two mite (r = 0.54) groups. Drones infested during development with one or two mites produced 24 and 45% fewer sperm, respectively.

Animals↗