Trombiculosis in a cat.

Trombiculosis (dermatitis caused by trombiculid mites) in a Domestic Shorthair cat was characterized by diffuse thickening and crusting of the skin of the abdomen and limbs and by multiple papules on the face, ears, and sides of the trunk. Skin biopsy revealed acanthosis and hyperkeratosis involving the epidermis and hair follicles, mites in epidermal tunnels, and edema of the dermis, with infiltration of eosinophils and mast cells. Mites from skin scrapings were identified as Walchia americana. The cat was treated systemically with a broad-spectrum antibiotic and topically with a carbaryl and pyrethrin powder preparation. The lesions were resolved within 2 months.     

Patch test reactions to house dust mites in dogs with atopic dermatitis

The purpose of this study was to determine the percentage of dogs with spontaneous atopic dermatitis that show a positive patch test reaction to a commercially available 20% house dust mites mixture containing equal parts of Dermatophagoides farinae and Dermatophagoides pteronyssinus in white petrolatum. In addition, we evaluated whether skin reactions induced after the epicutaneous application of house dust mites were clinically and histologically similar to naturally developed skin lesions of dogs with atopic dermatitis. Furthermore, we investigated if the reactions induced by house dust mites were true allergic reactions by comparing them to atopic lesional skin and to patch test reactions induced by an irritant substance (sodium lauryl sulphate). White petrolatum alone and nonlesional skin sites were used as negative controls. Macroscopic and microscopic evaluations of the patch test and control sites were performed in a blinded fashion at 48 and 72 h after patch test application. Microscopic results were evaluated in a qualitative and quantitative manner. A chi‐square test for homogenicity was used for the quantitative analysis to compare the proportion of each dermal inflammatory cell type among positive histopathological tested sites. P values ≤ 0.05 were considered significant. The study included 12 healthy nonatopic dogs and 13 dogs with nonseasonal atopic dermatitis. None of the nonatopic dogs reacted to house dust mites and white petrolatum. Ten (77%) of the 13 atopic dogs reacted macroscopically and histopathologically to house dust mites. Macroscopic reactions induced by house dust mites were characterized by erythema, oedema and papules. The macroscopic reactions induced by house dust mites were identical to lesional skin in 20% of the dogs and identical to reactions induced by sodium lauryl sulphate in 40% of the dogs. Qualitative histopathological findings showed that the reactions induced by house dust mites were similar to atopic lesional skin in 80% of the dogs and were similar to sodium lauryl sulphate in 20% of the dogs. Quantitative analyses showed that the proportion of neutrophils in reactions induced by sodium lauryl sulphate was significantly higher (P < 0.05) compared to house dust mites reactions, which could be a differentiator factor between an allergic and an irritant reaction. These results showed that the epicutaneous application of house dust mites in dogs with atopic dermatitis induced histopathological lesions similar to spontaneous atopic lesions in dogs. Therefore, this study demonstrated that house dust mites penetrated the skin of dogs with atopic dermatitis and induced an inflammatory response that resembled a true allergic reaction. Funding: Small Companion Animal Grant, University of Minnesota.     

IN THIS ISSUE – August

Seroconversion to avian influenza virus in chickens in Victoria · Feeding of prohibited swill to pigs in Australia · Long distance dispersal of vectors for bovine ephemeral fever · Risk of poisoning from sorghum infected with ergot · Effects on bovine embryos of oxidative stress in sperm · Muscle strain injuries of the hindlimb in eight horses · T-shaped malformation of the ventral colon in foal · Zolpidem poisoning in a cat · Cutaneous trombidiosis in a Lesueur's tree frog     

Trombiculid mites (Hannemania sp.) in canyon tree frogs (Hyla arenicolor).

Six wild-caught, captive canyon tree frogs (Hyla arenicolor) purchased as a group and housed at the North Carolina Zoological Park were diagnosed with intradermal Hannemania mites, the first described infestation of this frog species by this mite. Typical gross lesions were orange-colored skin vesicles approximately 1 mm in diameter, predominantly located on the ventrum and ventral hind limbs. The larval mites had ovoid bodies approximately 44 microm in length and 240 microm in width. Three of the frogs died, and three became free of mites and pathologic changes after approximately 28 wk of treatment with transcutaneous ivermectin and manual mite removal. The frogs remained free of mites at a 1-yr recheck.     

Ectoparasites are the major causes of various types of skin lesions in small ruminants in Ethiopia

Ectoparasites are the major causes of skin lesions in animals. Clinical, skin scraping examination, and histopathological studies were conducted to identify and characterize skin lesions in small ruminants caused by ectoparasites. Mange mites, lice, sheep keds, and ticks were collected from the skin of affected animals for species identification. Skin biopsies were collected from affected part of the skin and fixed in 10% neutral buffered formalin for histopathology. Of 1,000 sheep and 600 goats examined, 815 (81.50%) sheep and 327 (54.5%) goats were infested with one or more types of ectoparasites. Sarcoptes scabiei var ovis, Demodex ovis, Psoroptes ovis, Bovicola ovis, Melophagus ovinus, and Amblyomma variegatum and other tick species were identified from sheep. S. scabiei var caprae, Demodex caprae, Linognathus stenopsis, and A. variegatum and other tick species were identified from goats. Gross skin lesions or defects observed on the skin include stained and ragged wool, loss of wool/hair, nodules, crusts, lichenification, and fissuring. Microscopic evaluation of H and E stained skin sections revealed lesions in the epidermal layer such as hyperkeratosis, acanthosis, and melanin inconsistency on the basal cells of the epidermis. Follicular keratosis, perifolliculitis, frunculosis, perivasculitis, and aggregates of inflammatory cells (of acute and chronic type) with fibrosis were experiential in the dermal layer of the skin. Most of the skin lesions caused by ectoparasites are overlapping. Thus, ectoparasites control program should be executed to reduce skin lesions as skins are the major export commodity of the country.     

HELMINTH PARASITES AND ARTHROPODS OF FERAL CATS

SUMMARY The prevalence (%) of helminth parasites in 327 mainly adult feral cats from 3 habitat groupings in Victoria and New South Wales was determined. The cestodes Taenia taeniaeformis (33%) and Spirometra erinacei (33%) were common; Dipylidium caninum was rare (2%). The nematodes Toxocara cati (28%), Cyathospirura dasyuridis and Cylicospirura felineus combined (27%) and Aelurostrongylus abstrusus (14%) were common but their prevalence differed markedly between habitats. Ollulanus tricuspis (5%), Gnathostoma spinigerum (<1%) and an Acanthocephala, Onicola sp (19%), also occurred. Arthropod parasites were collected from 204 of these cats, Ctenocephalides felis (16%) and Echidnophaga spp. (28%) were common. Spilopsyllus cuniculi (3%) and Ctenocephalides canis and Nosopsyllus fasciatus (<1% each) were rare. Other rare ectoparasites were the louse, Felicola subrostrata (4%), the mites, Otodectes cynotis, Cheyletiella sp and a trombiculid (<1% each); and the tick Ixodes tasmani (<1%). There was no correlation between degree of parasitism and general condition of the cats.     

FC‐42 Sarcoptic mange epidemic in a cat population

Worldwide, sarcoptic mange in cats is seldom reported, and then only in sporadic individual cases. We describe an epidemic in a household with a dog and 25 cats. From September 2002, the dog was repeatedly treated with ivermectin for sarcoptic mange. The diagnosis was confirmed by skin scrapings. Fifteen months later, cats from the same household were diagnosed with severe sarcoptic mange. Twenty‐one of the cats were euthanized and necropsies were performed. Skin samples were taken from all cats from different body sites for histology, and skin scrapings were examined for ectoparasites. Samples for bacterial and dermatophyte culture were taken from six cats. Smears for cytology were made from lesions on four cats with severe mange. Sera from 21 cats and the dog were analysed for specific antibodies to Sarcoptesscabiei. Molecular characterizations of six individual mites were done. Large numbers of S.scabiei were isolated from the infected skin of most of the cats. Two‐thirds of the cats showed skin lesions compatible with chronic sarcoptic mange. Macroscopically, internal organs exhibited no obvious pathology. Yeast organisms and coccoid bacteria were found in the smears; penicillinase‐negative Staphylococcus aureus was isolated from all samples and Malassezia pachydermatis was identified from four cats. Sarcoptes scabiei was seen histologically in all cats showing chronic skin lesions. No other ectoparasites were found. All analysed cats had specific antibodies against S. scabiei. Twenty‐one cats tested negatively for FeLV and FIV. The mites had DNA sequences identical to S. scabiei from naturally infected dogs and Swedish wildlife. Funding: Self‐funded.     

Risk factors of infestation by Psoroptes spp. mites in buffalo (Bubalus bubalis) at smallholder farms in the Nile Delta region, Egypt

The aim of the present study was to explore the prevalence and potential risk factors associated with infestation by Psoroptes spp. mites in buffalo at smallholder farms in the Nile Delta region, Egypt. A total of 318 out of 1234 buffalo in 77 small scale herds were examined. The age of buffalo varied from three months to seven years. In all, 53 (16.66%) buffalo were recorded to be infested; 51 (16.35%) with Psoroptes spp. mites and two cases (0.31%) with Chorioptes spp. mites. Multivariate logistic regression was performed for significant risk factors at univariate analysis on both animal and herd level. The results of multivariate analysis showed that, on the animal level, the prevalence was affected by animal age (P?<?0.01; OR: 0.71; CI 95%: 0.441–1.11), season (P?<?0.01; OR: 1.20; CI 95%:0.541–1.15), indoor management (P?<?0.001; OR: 6.625; CI 95%:2.489 –17.631) and rearing with other animals (P?<?0.01; OR: 2.22; CI 95%:1.340 –7.132). However, on the herd level, the prevalence was affected by indoor rearing (P?<?0.05; OR: 22.4; CI 95%:2.75–16.431), mixed rearing with other animal species (P?<?0.05; OR: 4.5; CI 95%:1.66–7.941), and season (P?<?0.01; OR: 2.3; CI 95%:0.575–2.426). Clinically, mild skin lesions with mild pruritis were significantly prevalent in buffalo with the infestation by Psoroptes spp. mites (P?<?0.001), where 33/51 cases showed mild lesions. Also, psoroptic mites had significant association with inappitence (P?<?0.001). The result of the present study indicates that Psoroptes spp. mites are the most prevalent in buffalo in the Nile Delta Region, Egypt. Moreover, recognition of risk factors associated with mange mites in buffalo may enable the practitioner to establish the most appropriate control measures.     

The incidence of Chorioptes bovis (Acarina: Psoroptidae) on the feet of horses,sheep, and goats in the Netherlands

Summary

The feel of horses, sheep, and goats of different breeds and from many different localities were examined for Chorioptes bovis. In horses, mites were mainly found in the Belgian and Frisian breeds (40% and 62% infected, respectively). In sheep and goats, respectively 63% and 86% were infected. In horses as well as in sheep and goats, mange‐lesions were rarely seen. A number of sheep and goats were examined for mites and lesions quantitatively. In sheep all mites were restricted to the region close to the accessory digits and the claws. In goats the average number of mites was higher than in sheep, and mites could be found on all locations of the feet at least as far as the carpal and tarsal joint. Both in sheep and goats the biggest density of mites was found just below the accessory digits. When crusts were present, they were generally small and hidden under the coat. In sheep, which were housed for a long period, crusts were seen more often and were more distinct than in pastured animals. A negative correlation between the number of mites and the presence and extensiveness of crusts was observed A possible explanation for this phenomenon is suggested. From the results of this study it is clear that there is no necessity to list chorioptic mange in sheep and goats as a notifiable disease.     

Sarcoptic mange infestation in pigs in a hilly region of Meghalaya

Skin lesions were collected from 15 adult crossbred pigs maintained at the pig farm of ICAR Research Complex for the North-Eastern Hill Region, Umiam, a hilly region of the state of Meghalaya, India. Skin scrapings of these 15 animals were examined by KOH digestion method. Presence of mites were detected in five animals which were indistinguishable from Sarcoptes scabiei var. suis. Infected pigs were treated with a single dose of Ivermectin at 200 ug/kg body weight, subcutaneously. No mites were recovered from treated pigs after a period of 10 days of post-treatment. The presence of S. scabiei var. suis in pigs from this part of the country has never been reported. This infestation has great significance because it affects the growth rate and feed conversion significantly, specially to the grower and weaned pigs. It can be concluded that S. scabiei var. suis infestation is prevalent in hilly region of Meghalaya. The pig producers are generally unaware about the severity of the problem of mite infestation, so precaution should be taken to prevent their valuable pigs from S. scabiei var. suis infestation.     

Small Demodex populations colonize most parts of the skin of healthy dogs

Background – It is unproven that all dogs harbour Demodex mites in their skin. In fact, several microscopic studies have failed to demonstrate mites in healthy dogs. Hypothesis/Objectives – Demodex canis is a normal inhabitant of the skin of most, if not all, dogs. This hypothesis was tested using a sensitive real‐time PCR to detect Demodex DNA in the skin of dogs. Animals – One hundred dogs living in a humane society shelter, 20 privately owned and healthy dogs and eight dogs receiving immunosuppressive or antineoplastic therapy. Methods – Hair samples (250–300 hairs with their hair bulbs) were taken from five or 20 skin locations. A real‐time PCR that amplifies a 166 bp sequence of the D. canis chitin synthase gene was used. Results – The percentage of positive dogs increased with the number of sampling points. When a large canine population was sampled at five cutaneous locations, 18% of dogs were positive for Demodex DNA. When 20 skin locations were sampled, all dogs tested positive for mite DNA. Our study indicates that Demodex colonization of the skin is present in all dogs, independent of age, sex, breed or coat. Nevertheless, the population of mites in a healthy dog appears to be small. Demodex DNA was amplified from all 20 cutaneous points investigated, without statistically significant differences. Conclusions and clinical importance – Using a real‐time PCR technique, Demodex mites, albeit in very low numbers, were found to be normal inhabitants of haired areas of the skin of healthy dogs.     

Immunodeficiency in canine demodectic mange. I. Experimental production of lesions using antilymphocyte serum

Two experiments were conducted to further clarify the importance of cell-mediated immunity in cases of canine demodectic mange. Pups obtained from pregnant pedigreed beagle bitches were exposed to mites (Demodex canis Leydig, 1859) and then injected with rabbit anticanine lymphocyte serum (ALS). Littermates received either mites alone, ALS alone, or were retained as negative controls. Squamous lesions of demodicosis developed in all pups receiving both ALS and mites as well as in two pups receiving only mites. No lesions were observed in any of the remaining pups. A marked decline in the number of peripheral lymphocytes developed in pups receiving ALS. These cells returned to normal numbers 3 weeks after treatment was discontinued. The squamous lesions on affected pups continued to coalesce until generalized demodicosis became established. Spontaneous resolution of mite-infested areas was never observed and pustular lesions did not develop.It was concluded that the cellular immune system of the dog, functioning as a defense mechanism against the establishment and proliferation of D. canis, is of paramount importance in preventing the development of demodectic mange.     

The prevalence and microbiology of pneumonia in a flock of lambs

A flock of New Zealand Romney lambs on a property in Hawkes Bay was examined from August 1978 to June 1979. In November, the lambs in the flock were allocated to groups as follows: 600 lambs from which groups were selected for slaughter by commercial criteria each month (selected groups); 700 lambs which were subdivided into 8 groups (random groups), one of which was sent for slaughter each month; and 25 lambs to monitor serological responses to viral infections (surveillance group). At slaughter, lesions in the anterior lobes of the lungs were classified into small, large or mottled lesions while those in the posterior regions of the diaphragmatic lobes comprised a separate group. The prevalence of the pneumonic and pleural lesions was recorded in all groups of lambs. Pneumonic lesions in lambs from the random groups were further classified after microscopic examination. The prevalence of infections with parainfluenza virus type 3, adenoviruses, Mycoplasma spp., and Pasteurella haemolytica was also recorded in the random groups. Average carcase weights of all groups of lambs were also recorded.

The prevalence of large lesions in the anterior lobes, pleural lesions and devaluation of carcases due to pleural lesions was significantly lower in the selected than in the random groups.

In the random groups, the prevalence of small lesions in the anterior lobes of the lungs was high and was not always associated with infections with the viruses, P. haemolytica or Mycoplasma spp. Microscopically, these lesions could he divided into four types as previously described. The prevalence of large lesions in the anterior lobes was low in November but increased to peak levels in February and March and then declined to intermediate levels. The prevalence of large lesions was associated with that of infections with the micro-organisms and significantly more large lesions contained P. haemolytica and Mycoplasma spp. than did small lesions or normal lungs. The prevalence of large lesions also appeared to be inversely related to the average carcase weights of the lambs. Most large lesions were similar on microscopy to those of “enzootic” or “atypical” pneumonia but were divided into four types on the basis of exudative and proliferative features. The prevalence of mottled lesions in the anterior lobes was low throughout the period of observation but peaks were observed in January and May. The peaks were associated with adenovirus infection and elevated prevalence of infection with P. haemolytica and Mycoplasma spp. Significantly more mottled lesions contained P. haemolytica than did small lesions or normal lungs. Microscopically, most mottled lesions were similar to exudative large lesions.

Lesions in the posterior diaphragmatic lobes were most numerous in November and from April to June. Their prevalence appeared to be related to anthelminthic treatment and environmental conditions. Microscopically, these lesions were typical of those following infection with Dictyocaulus filaria.     

First isolation and identification of Elizabethkingia meningoseptica from cultured tiger frog, Rana tigerina rugulosa

Elizabethkingia meningoseptica has been recognised as an occasional but serious opportunistic bacterial pathogen to human beings. Recently, it was frequently isolated from tiger frog, Rana tigerina rugulosa, with cataract disease, which is the most common disease of unknown aetiology of frogs in Hainan, China. The purpose of this study was to identify and characterise the bacterial strains isolated from the recent outbreaks of cataract disease in farmed tiger frog in Hainan, China, and to evaluate their pathogenicity to the frog and their sensitivity to 20 chemotherapeutic agents.The 16S rRNA gene sequences of strains W0701 (1478 bp), W0702 (1477 bp) and W0703 (1478 bp) showed 98.6–98.7% similarity with the sequence of E. meningoseptica type strain (ATCC 13253) and 99.9–100% similarity with that of E. meningoseptica NTU 870424-IL. Six strains (W0701–W0706) were selected to represent 24 isolates retrieved from six moribund frogs. The morphological, physiological and biochemical characteristics of the six representative isolates were consistent with those of E. meningoseptica strains. The organisms were only susceptible to vancomycin and moderately susceptible to cefoperazone among the 20 investigated chemotherapeutic agents. Virulence test with strain W0702 was conducted and pathogenicity (by intramuscular injection) was demonstrated in the tiger frog. In conclusion, 24 isolates obtained from frogs with cataract disease were the E. meningoseptica strains highly pathogenic to tiger frog, and this is the first report of E. meningoseptica as a pathogen for tiger frog.     

Prevalence of Demodex canis‐positive healthy dogs at trichoscopic examination

Demodex canis is thought to be present in small numbers in the skin of most healthy dogs; however, available data on the prevalence of normal dogs harbouring D. canis are scarce. The purpose of this study was to investigate, using microscopic examination of plucked hairs, the prevalence of healthy dogs harbouring D. canis. Seventy‐eight clinically healthy dogs with no history of dermatological problems and clinically normal skin and hair coat were included in the study. Five areas (perioral skin 2–3mm from both labial commissures, periungual skin of the third digit of both anterior paws and chin) were examined in each dog. Fifty to sixty hairs were plucked from each skin site and microscopically examined. No D. canis mites were observed and only one adult form of Demodex injai was found in the labial commissure of one dog. Based on these results, the estimated prevalence of healthy dogs harbouring D. canis in clinically normal skin should not exceed the threshold of 5.4%, with 95% confidence level. Considering our and previous findings, we propose that, although small numbers of D. canis might inhabit the skin of normal dogs, the probability of finding these mites in normal dogs is low. Consequently, in most cases, the presence of a D. canis mite in the skin should not be considered as indicative of normality.     

P‐87 Alopecia in two guinea pigs due to hypopodes of Acarus farris

Mites are frequent agents of skin diseases in veterinary dermatology, particularly in rodents. The authors report an original case of infestation in two guinea pigs of the same household. Two adult guinea pigs were presented with a 3‐month history of alopecia, matted hair, erythema, scales and mild pruritus. The first guinea pig showed almost complete truncal alopecia with mild scaling, whereas the other one had only recently developed mild alopecia of the abdomen and mild pruritus. Numerous live, long‐legged mites were present both in adhesive tape and skin scrapings. Mycology (Wood's lamp and DTM agar culture) was negative. Histopathological examination of a skin biopsy did not reveal any significant inflammatory disease and morphological changes were limited to hair follicles in the telogen phase. Mites were identified as hypopodes of Acarus farris (Acaridae), but no adult stages were present. Hypopodes were also found in the hay. Control was obtained with acaricidal treatment with Phoxim 0.05% once weekly for 4 weeks, and the elimination of contaminated hay. The lesions and the alopecia resolved rapidly. Hypopodes are additional nymphal stages of some mites of the suborder Astigmata. They develop for dispersing or dormancy under disadvantageous conditions. They can be active or inert, and some can be phoretic on the skin surface or intrafollicular. Although nonparasitic, they may cause dermatitis. Acarus farris have been rarely mentioned in the literature as a cause of dermatitis. This condition could be underdiagnosed or misdiagnosed in veterinary dermatology. Funding: Self‐funded.     

P‐30 Use of fipronil for treatment of Lynxacarus radovskyi in outdoor cats in Rio de Janeiro (Brazil)

The aim of this study was to report 20 cases of Lynxacarus radovskyi infestationin 20 cats. Lynxacarus radovskyi was diagnosed by physical examination and microscopic examination of plucked hair where countless adult mites and immature stages were identified. Microscopic examination was repeated every 7 days. The animals were observed daily for the first 7 days, and again on day 15 and day 30 for mites, pruritus and clinical signs. Clinical signs included salt‐and‐pepper appearance to a dull and opaque hair coat, alopecia of the dorsal and lateral areas of the hind limbs, and evidence of self‐mutilation. One case had papules and crusts of the hind limbs. The pruritus was mild in animals with low infestation, but very intense in those with a heavy infestation. Most mites occurred in the lateral area of the hind limbs and sacral area. Twenty of 100 animals had confirmed L. radovskyi infestation. Therefore, we suggest that the transmission occurs through fomites. Treatment consisted of 0.5 mL application of Fipronil^® (Frontline TopSpot) per cat, with resolution in 100% of cases by day 15. Funding: Merial.     

P‐59 Three cases of opportunistic dermatoses associated with internal diseases in cats

Opportunistic dermatoses can occur in case of immunosuppressive diseases. The first case was a 12‐year‐old domestic short‐haired cat suffering from diabetes with a phaeohyphomycosis due to Scytalidium spp.associated with cutaneous hemangiosarcoma. A painless and ulcerated nodule was observed on a digit with fistulous tracts over the metatarsal joint. Histopathological examination of the nodule revealed a hemangiosarcoma in which brownish fungal colonies were found. Itraconazole (5 mg/kg twice daily), then amputation, allowed 12 months of survival (pulmonary metastases). The second case concerned a 13‐year‐old Siamese cat with cheyletiellosisassociated with spontaneous Cushing's disease and diabetes mellitus. This cat exhibited scales and miliary dermatitis on the trunk associated with polyuria, polydipsia and a pot‐belly. Acetate tape impression showed Cheyletiella blakei mites and eggs. Blood analysis revealed diabetes mellitus and spontaneous hyperadrenocorticism. The owner refused treatment. The third case was a 14‐year‐old domestic short‐haired cat with generalized demodicosis associated with iatrogenic Cushing's disease and diabetes mellitus. Long‐acting glucocorticoids had been used for treatment of plasma cell stomatitis for 5 years. This cat exhibited erythema, scales, self‐induced alopecia, thin skin and moderate pruritus associated with polyuria and polydipsia. Cutaneous lesions principally developed on the abdomen and flanks. Skin scrapings and trichogram showed numerous Demodex cati mites. Routine blood work demonstrated diabetes mellitus and iatrogenic Cushing's disease. Treatment was based on insulin therapy, milbemycin oxime (1 mg/kg once daily) and chlorambucil (0.2 mg/kg once daily). The demodicosis was cured after 4 months, but the cat died of cutaneous and ocular herpesvirus infection 10 months later. Funding: Self‐funded.     

Stimulation of the <Emphasis Type="Italic">In Vitro</Emphasis> Migration of Ovine Eosinophils by Factors Derived from the Sheep Scab Mite, <Emphasis Type="Italic">Psoroptes ovis</Emphasis>

The ectoparasitic astigmatid mite Psoroptes ovis causes sheep scab, a highly contagious, severe allergic dermatitis associated with damage to the fleece and hide, loss of condition and occasional mortality. The scab lesion is characterized by a massive infiltration of eosinophils that begins very rapidly after infection. This paper reports the finding that mite-derived factors directly enhance the migration of ovine eosinophils in vitro. Significant (p < 0.01) and dose-dependent (r = 0.972 ± 0.018 (SD)) activity was initially identified in whole mite extracts, by comparison with medium controls in an assay based on modified Boyden chambers and ovine bone marrow target cells. Similar pro-migratory activity (p < 0.005; r = 0.928 ± 0.069 (SD)) was detected in washes containing mite excretory/secretory material. By direct comparison with migration ratios (n = 3) for defined chemotactic (rmeotaxin = 3.430 ± 0.360 (SD)) and chemokinetic (rminterleukin-5 = 0.982 ± 0.112 (SD)) stimuli it was determined that the activity in both mite extracts (0.992 ± 0.038 (SD)) and mite washes (0.969 ± 0.071 (SD)) was chemokinetic. Subsequent experiments (n = 3) in which live mites were incorporated directly into the in vitro assay system indicated that they produced factors that significantly (p < 0.001) enhanced eosinophil migration to a degree directly related to mite numbers (r = 0.993 ± 0.005 (SD)). The identity of the factor(s) responsible is uncertain, but their presence suggests that mites may be capable of directly activating eosinophils in vivo, and raises the possibility that mites could directly influence, perhaps even initiate, the rapid early tissue eosinophilic response observed in experimental sheep scab infections.     

Mycoplasmas and mites in the ears of clinically normal goats

SUMMARY Mycoplasmas were detected in the external ear canal of goats by swabbing and culture. Up to 10⁸ colony forming units were recovered from single swabs. The resulting cultures were usually mixtures of mycoplasmas containing up to 5 species. The species present in sequential swabs varied. Pathogenic species (M.agalactiae, M.capricolum, M.mycoides subsp. capri, M.mycoides subsp. mycoides of the large colony (LC) type, M.putrefaciens) were isolated from the ears and in addition 3 untyped mycoplasmas G, U and V were often present. The same mycoplasmas were found in large numbers in the mites Psoroptes cuniculi and Raillietla caprae which were sometimes present in the external ear canal. The role of the mycoplasmas in the external ear canal as a source of infection and disease and of the mites in the spread of infection requires further elucidation.