Prevalence of dust mites in the homes of people with asthma living in eight different geographic areas of the United States.

The density and species prevalence of dust mites were determined at various times over a 5-year-period in 252 homes of dust mite sensitive people with asthma who lived in eight geographic areas of the United States (Cincinnati, Ohio; New Orleans, La.; Memphis, Tenn.; Galveston, Texas; Greenville, N.C.; Delray Beach, Fla.; San Diego and Los Angeles, Calif.). The most common dust mites found in the homes were Dermatophagoides farinae (DF), D. pteronyssinus (DP), Euroglyphus maynei (EM), and Blomia tropicalis. All homes in all locations contained Dermatophagoides spp. mites, but few homes were populated exclusively by either DF or DP alone. Most homes (81.7%) were coinhabitated by both DF and DP. In coinhabited homes one species was predominant and usually made up at least 75% of the total mite population. Prevalence of the dominant or only species present varied between homes within a geographic area. EM occurred in significant numbers in 35.7% of homes in New Orleans, Memphis, Galveston, Delray Beach, and San Diego. Blomia tropicalis occurred in these same cities but in low densities. For all dust samples, only 13 homes of the 252 sampled had 100 or fewer mites/gm dust, which is considered to be the threshold for sensitivity. Most homes had average mite densities of 500 or more mites/gm dust. The results of the present study suggest a significant and widespread occurrence of both DF and DP. Therefore extracts of both mite species should be considered for diagnostic tests and immunotherapy. Significant levels of EM were present in some areas. Thus sensitivity to EM should be considered in these areas.

Treatment and control of sheep scab (Psoroptes ovis) with ivermectin under field conditions in South Africa.

Four trials including 11,266 sheep were conducted in South Africa to evaluate the efficacy of the systemic parasiticide ivermectin against field outbreaks of sheep scab (Psoroptes ovis) when two doses of approximately 200 micrograms/kg were administered subcutaneously seven days apart (days 0 and 7). As sheep scab is a notifiable disease in South Africa, it was not possible to include an untreated control group. The prevalence of clinically affected animals in the four treated flocks varied from 0.4 per cent to 99 per cent before the two treatments. After the treatments, there were no signs of active clinical infection in any of the sheep between days 28 and 30, or at subsequent examinations. P ovis mites were recovered from scrapings from 114 of 127 indicator sheep before the treatment but no mites were recovered from them between days 28 and 30 or 42 and 58 after the treatments.

Dominancia mensual de acaros oribatidos (acarina) en una zona endémica a la cestodiasis ovina / Monthly dominance of oribatid mites (acarina) in endemic zone of sheep cestodiasis

Se realizaron muestreos mensuales de suelos en dos establecimientos agropecuarios dedicados a la cría de ovinos de la raza Lincoln, en el Partido de Puan, provincia de Buenos Aires, Argentina. Se identificaron 17 especies de oribátidos pertenecientes a 9 superfamilias. Zigoribatula lata, Z. elongata y Ceratozetes sp. habían demostrado anteriormente su papel como hospedadores intermediarios de Moniezia expansa y Helictometra giardi (Cestoda Anoplocephalidae). En base a los datos aportados por los muestreos realizados se discute el posible papel de las especies de oribátidos halladas en la región como hospedadores intermediarios de anoplocefálidos de rumiantes domésticos

Rosacea: a study of clinical patterns, blood flow, and the role of Demodex folliculorum.

BACKGROUND: Rosacea is a common facial eruption that has various clinical presentations. OBJECTIVE: We studied blood flow in lesional skin and explored the role of Demodex folliculorum in patients with rosacea. METHODS: A survey of clinical presentations was made in 108 patients with rosacea. Facial blood flow was studied by laser-Doppler flowmetry. The presence of Demodex was determined by microscopy of skin samples. RESULTS: The sex incidence was equal. The incidence peaked in the fourth and seventh decades of life. Lymphedema was common and was seen in 26 patients. Rhinophyma was present in 15 patients, mostly men. Eleven patients were black, an unexpectedly high number. Laser-Doppler flowmetry showed that lesional blood flow was three to four times that of control subjects. Demodex folliculorum was found in 20 of 25 rosacea patients examined but in only 2 of 20 control subjects. CONCLUSION: The findings indicate that the papillary dermal vasculature is dilated in rosacea. Demodex may be present. These findings give no definitive clue as to the origin of the disease.

Subclinical psoroptic otocariasis in Brazilian sheep with comments on a technique for mite collection.

Subclinical psoroptic otocariasis associated with Psoroptes cuniculi (Delafond) was diagnosed in four out of ten herds of sheep. Transmission of mites between sheep and goats and vice versa was detected in herds kept on the same pastures for over 2 years. Flushing the ear canals of sheep and goats with approximately 50 ml of water appeared to be more efficient than swabbing or otoscopic examination for diagnosis and/or mite collection.

Survey for meningeal worm (Parelaphostrongylus tenuis) and ear mites in white-tailed deer from northern Idaho.

During the fall hunting season of 1990, 95 white-tailed deer (Odocoileus virginianus) heads were collected from hunters in Boundary and Bonner Counties in northern Idaho (USA), an area currently occupied by woodland caribou (Rangifer tarandus caribou). The heads were examined for adult and larval meningeal worms (Parelaphostrongylus tenuis) by physical examination of the brain surfaces, and the Baermann technique, respectively, and for ear mites by examination of ear scrapings. Meningeal worms or mites were not detected.

Notoedric acariasis in the porcupine (Erethizon dorsatum).

Six of 16 porcupines (Erethizon dorsatum) live-trapped in Sullivan County, Pennsylvania were infested with the mite Notoedres douglasi. Alopecia was evident in the ventral inguinal area and the infested skin was thickened, wrinkled and had multifocal areas of extensive hyperkeratosis. Microscopically the skin lesions consisted of extensive acanthosis and hyperkeratosis with variable cellular infiltrate in the dermis. Mites were seen in tunnels in the hyperkeratotic skin sections. This is the first report of notoedric acariasis in the porcupine.

Control of Psoroptes cuniculi in captive white-tailed deer with ivermectin-treated corn.

Psoroptes cuniculi, the ear mite of domestic rabbits, was collected from captive white-tailed deer (Odocoileus virginianus). This is the first report of rabbit ear mite infestations in white-tailed deer in Oklahoma or Texas (USA). In addition to moderate infestations in their ears, two 4-yr-old bucks, two 3-yr-old does, and seven 4-yr-old does showed patchy areas of alopecia along the sides and brisket. Both bucks also had patchy areas of alopecia around the base of antlers. Ear mites were eradicated from all deer except from one doe by providing ivermectin-treated corn to the deer at a rate of 1,000 g (equivalent to 200 mcg/kg of ivermectin)/day/deer for several days. The ear mite infestation in the one doe was eradicated by intramuscularly injection with ivermectin at 400 mcg/kg. After treatment with the ivermectin and eradication of the mites, the alopecia improved and eventually was eliminated. The ivermectin-treated corn also controlled all internal nematode parasites in the deer.

Parasitic and phoretic arthropods of the elephant-eared and the Santa Cruz kangaroo rats.

The parasitic and phoretic arthropods of the elephant-eared kangaroo rat (Dipodomys elephantinus) and Santa Cruz kangaroo rat (D. venustus) are reported; most of these represent new host records. Thirteen of 14 (93%) of D. elephantinus and 11 of 12 (92%) of D. venustus had 11 and nine arthropod species, respectively. Larval and nymphal stages of the tick Dermacentor occidentalis were the most prevalent parasite (77%) on D. elephantinus whereas the mesostigmatid mite Androlaelaps fahrenholzi was the most prevalent (56%) on D. venustus. The arthropod fauna of these two closely related rodents were similar with seven of the 14 arthropod species occurring on both host species. Two species of the host specific listrophorid mite of the genus Geomylichus were found on both hosts.

House dust acarofauna and Der p I equivalent in Australia: the relative importance of Dermatophagoides pteronyssinus and Euroglyphus maynei.

The acarofauna and Der p I allergen concentrations in dust samples from mattresses and lounge room carpets obtained from 20 homes from two coastal cities. Perth and Bunbury, were determined. All samples were shown to contain mites and the geometric mean numbers of total mites/g of mattress and carpet dust for Perth and Bunbury were 480 and 263, and 585 and 992, respectively. Carpets from both centres had a significantly (P less than 0.02) greater mean number of mite species (Perth 9.1, Bunbury 9.0) than mattresses (Perth 5.2, Bunbury 5.7). The predominant mite species were D. pteronyssinus, E. maynei and Tarsonemus spp. D. farinae was found to be absent from all dust samples examined. E. maynei was present in the 10 Bunbury homes and in 50% of the Perth homes, ranging from 0 to 81% of mites identified. The arithmetic mean Der p I concentrations in the mattresses and carpets in Perth and Bunbury were 4.2 and 4.1, and 3.8 and 9.2 micrograms/per gram of fine dust, respectively, and Der p I concentration correlated with mite counts (r = 0.75; P less than 0.001). The concentration of Der p I equivalent per 100 mites was 1.5 micrograms. The data are consistent with the view that asthmatic patients in Western Australia have significant exposure to a variety of house dust mites and that E. maynei may be clinically significant.

Haematological and pathological responses to experimental Trixacarus caviae infection in guinea pigs.

Outbred guinea pigs became infected with the mite Trixacarus caviae (Acarina, Sarcoptidae) when introduced into an infected colony. Mite numbers were highest after one month, then fell progressively. Infected guinea pigs developed a neutrophilia, monocytosis, eosinophilia and basophilia. Despite pronounced reactive changes in the superficial lymph nodes, infected guinea pigs developed only a mild dermatitis. In contrast, home bred animals, susceptible to T. caviae acquired many mites and developed a severe chronic dermatitis. Trixacaral manage in guinea pigs offers considerable potential for the study of mite infections in man and animals.

[Infestation of a cattle herd with the ear mite Raillieta auris (Acarina, Mesostigmata)]. / Befall eines Rinderbestandes mit der Ohrmilbe Raillietia auris (Acarina, Mesostigmata).

An infestation with Raillietia auris in a 4 years old cow is reported. For a period of 3 weeks the animal showed an increasing unrest, extreme efforts while trying to feed, and continuous shaking of the head which slanted to the left. After slaughter numerous specimens of the ear-mite R. auris were found in the basic part of the left auditory canal, located in the vicinity of a purulent paste-like plug. Histological examinations of the brain revealed a severe non-purulent meningoencephalitis with necroses of the vascular walls, focal malacia and gliosis. An etiological correlation of these lesions with the mite-infestation, however, is considered to be most unlikely. To the best of our knowledge the occurrence of R. auris in Switzerland was up to now unknown.

Prevalence and geographical distribution of the ear canker mite (Otodectes cynotis) among arctic foxes (Alopex lagopus) in Iceland.

Three hundred forty five adult arctic foxes (Alopex lagopus) from all counties in Iceland were examined for excess cerumen and ear canker mites (Otodectes cynotis). Only 13 foxes (4%) from a single county in northwestern Iceland were infested, where the prevalence of otodectiasis was 38%. Whether or not this parasite is new to the arctic fox in Iceland is unknown. If it is recently introduced, possible sources of infestation are farmed silver foxes (Vulpes vulpes), domestic dogs, domestic or feral cats, and arctic foxes from Greenland. It appears that the rate of transmission between adult foxes is low; a more common route of transmission is probably from the mother to her offspring or between vixens breeding in the same dens in subsequent years by contamination of the dens. No correlation was found between the prevalence of mites in foxes and Samson character.

New data on the distribution and hosts of larvae of Erythraeidae (Acari, Actinedida) in Poland.

The new data on distribution in Poland and hosts of Charletonia singularis (Oudemans), Leptus phalangii (De Geer) and L. mariae Haitlinger larvae are given. Ch. singularis was collected from the new localities without hosts, L. phalangii was collected from the new localities on Mitopus morio (Fabr.) and Oligolophus tridens (C. L. Koch) (Opilionida), and L. mariae was collected from the new locality on Phyllobius urticae (De Geer) (Coleoptera). O. tridens and Ph. urticae are recognized as the hosts of Erythraeidae larvae for the first time.

[Arthropods found on European beaver (Castor fiber L.) in Poland]. / Stawonogi wystepujace na bobrze europejskim (Castor fiber L.) w Polsce.

In July 1988, arthropods from 6 Castor fiber were collected at Popielno near Ruciane. Schizocarpus numerosus Dub., S. fedjushini Dub., S. brachyurus Dub. are new to the fauna of Poland. Ixodes hexagonus Leach (larvae, nymphs, females) is especially numerous. Under-development of the coxa and trochanter of the third left leg was noted in one female. Moreover, Acarus farris (Oud.), Cunaxoides kielczewskii Mich. and unidentified female of the Phytoseiidae were obtained. Cunaxid mites have not been collected hitherto from mammals. At the present time in Poland, 8 species (including Platypsyllus castoris Rit.) of arthropods are found on C. fiber.