Otodectic and bacterial etiology of feline otitis externa in Tripoli, Libya.

Background: Feline otitis externa is a dermatological disorder with a multifactorial complex etiology. Aim: This study aimed to investigate the prevalence of different etiological agents, particularly the parasitic and bacterial, responsible for the cases of feline otitis externa in Tripoli, Libya, and to assess the antimicrobial susceptibility of the bacterial isolates from those cases. Methods: Cerumen and otic discharges of the suspected cats were collected for parasite detection and bacterial culture. Kirby-Bauer's disk diffusion method was used for antimicrobial susceptibility testing. Results: The results showed that otodectic mites and bacterial causes were equally the most prevalent in those cases, with a prevalence of 47.1% each. Otodectes cynotis infestation was more frequently bilateral and severe. Staphylococcus spp. were the most prevalent among bacterial causes (75%), followed by Proteus spp. (16.6%) and Pseudomonas spp. (8.4%). Norfloxacin and gentamicin were the most effective antimicrobials against bacterial isolates, as they were effective against 83.3% and 70.8% of isolates, respectively. Conclusion: Otodectes cynotis infestation and staphylococcal infections constituted the most common etiology of feline otitis externa in Tripoli, Libya, and norfloxacin represented a cogent antibacterial for the treatment of otitis externa.

Combined use of ivermectin, dimethyl sulfoxide, mineral oil and nematophagous fungi to control Rhabditis spp.

Rhabditis spp., is a nematode known to cause otitis externa, an infection difficult to control, in cattle reared within tropical regions. The objective of this study was to assess the combined use of ivermectin 1%, dimethyl sulfoxide 1% and mineral oil 100% containing nematophagous fungi of both Duddingtonia flagrans (AC001) and Monacrosporium thaumasium (NF34) species to control in vitro Rhabditis spp. Thus, 12 experimental groups were designed with eight replicates each: G1 (nematodes + AC001); G2 (nematodes + NF34); G3 (nematodes + ivermectin 1%/positive control); G4 (nematodes + dimethyl sulfoxide 1%/positive control); G5 (nematodes + mineral oil 100%/positive control); G6 (nematodes + AC001 + ivermectin 1%); G7 (nematodes + NF34 + ivermectin 1%); G8 (nematodes + AC001 + mineral oil 100%); G9 (nematodes + NF34 + mineral oil 100%); G10 (nematodes + AC001 + dimethyl sulfoxide 1%); G11 (nematode + NF34 + dimethyl sulfoxide 1%); G12 (nematode + distilled water/negative control). The results demonstrated that all experimentally treated groups differed statistically (p < 0.01) from the control group. In the present study, the use of dimethyl sulfoxide 1% and mineral oil 100% in conjunction with conidia fungi portrayed noteworthy outcomes, which represents a future premise for the combined use of nematophagous fungi within these vehicles in both controlling Rhabditis spp.

Efficacy of fluralaner plus moxidectin (Bravecto® Plus spot-on solution for cats) against Otodectes cynotis infestations in cats.

BACKGROUND: The efficacy of the fixed combination of fluralaner plus moxidectin for the treatment of Otodectes cynotis infestations was evaluated in cats after topical application. METHODS: Sixteen cats experimentally infested with O. cynotis were allocated randomly to two groups of 8 cats each. One group was treated topically with the fixed combination of fluralaner plus moxidectin at the minimum dose rate of 40 mg fluralaner and 2 mg moxidectin/kg body weight. The other group was treated with physiological saline solution. Before and 14 and 28 days after treatment the ears of all cats were examined otoscopically for live mites and for the amount of debris and cerumen. Twenty-eight days after treatment, the cats were sedated and had both ears flushed to obtain the total number of live mites per animal. Efficacy was calculated, based on the results of the ear flushing, by comparing mean live mite counts in the fluralaner plus moxidectin treated group versus the saline group. RESULTS: A single topical application of the fixed combination of fluralaner plus moxidectin to cats reduced the mean mite counts by 100% (P < 0.001) by 28 days after treatment. No mites were visible during otoscopic examination at either 14 or 28 days after treatment. All fluralaner plus moxidectin treated cats had less ceruminous exudate 28 days after treatment compared to pre-treatment and 14 days after treatment. No treatment related adverse events were observed in any cats enrolled in the study. CONCLUSIONS: Single topical application of the fixed combination of fluralaner plus moxidectin was highly effective against O. cynotis infestations in cats.

Ear Mite Removal in the Santa Catalina Island Fox (Urocyon littoralis catalinae): Controlling Risk Factors for Cancer Development.

Ear mites (Otodectes cynotis) and ear canal tumors are highly prevalent among federally endangered Island foxes (Urocyon littoralis catalinae) living on Santa Catalina Island off the coast of Southern California. Since studies began in the 1990s, nearly all foxes examined were found to be infected with ear mites, and ceruminous gland tumors (carcinomas and adenomas) were detected in approximately half of all foxes ≥ 4 years of age. We hypothesized that reduction of ear mite infection would reduce otitis externa and ceruminous gland hyperplasia, a risk factor for tumor development. In this study, we conducted a randomized field trial to assess the impact of acaricide treatment on ear mite prevalence and intensity of infection, otitis externa, ceruminous gland hyperplasia, and mite-specific IgG and IgE antibody levels. Treatment was highly effective at eliminating mites and reducing otitis externa and ceruminous gland hyperplasia, and mite-specific IgG antibody levels were significantly lower among uninfected foxes. Ceruminous gland hyperplasia increased in the chronically infected, untreated foxes during the six month study. Our results provide compelling evidence that acaricide treatment is an effective means of reducing ear mites, and that mite removal in turn reduces ear lesions and mite-specific IgG antibody levels in Santa Catalina Island foxes. This study has advanced our understanding of the underlying pathogenesis which results in ceruminous gland tumors, and has helped inform management decisions that impact species conservation.

PCR amplification and DNA sequencing of Demodex injai from otic secretions of a dog.

BACKGROUND: The identification of Demodex mites from dogs is usually based on morphology and location. Mites with uncharacteristic features or from unusual locations, hosts or disease manifestations could represent new species not previously described; however, this is difficult to determine based on morphology alone. HYPOTHESIS/OBJECTIVES: The goal of this study was to identify and confirm Demodex injai in association with otitis externa in a dog using PCR amplification and DNA sequencing. METHODS: Otic samples were obtained from a beagle in which a long-bodied Demodex mite was identified. For comparison, Demodex mite samples were collected from a swab and scraping of the dorsal skin of a wire-haired fox terrier and an otic sample from a dog with generalized and otic demodicosis. To identify the Demodex mite, DNA was extracted, and 16S rRNA was amplified by PCR, sequenced and compared with Demodex sequences available in public databases and from separate samples morphologically diagnosed as D. injai and Demodex canis. RESULTS: PCR amplification of the long-bodied mite rRNA DNA obtained from otic samples was approximately 330 bp and was identical to that from the mite morphologically identified as D. injai obtained from the dorsal skin of a dog. Furthermore, the examined mite did not have any significant homology to any of the reported genes from Demodex spp. CONCLUSIONS: These results confirmed that the demodex mites in this case were D. injai.

Otitis externa and myringitis due to demodicidosis.

We report on an 84-year-old woman with chronic pruritic otitis externa and myringitis. Microbiological and mycological investigations failed to establish the cause, but histology revealed a large amount of Demodex mites. Topical treatment for this ectoparasite resulted in a complete remission. The myringitis was eventually treated successfully with myringoplasty. To the best of our knowledge this is the first case report on Demodex-induced otitis externa and myringitis.

Prevalence and intensity of Otodectes cynotis in kittens from Thessaloniki area, Greece.

From May 2007 to May 2008 we have examined by otoscopy a total number of 214 cats, aged between 0 and 6 months, brought in for their first veterinary examination to a private veterinary clinic. All cats were of urban origin. In all positive cats we performed a washing of the ear using warm paraffin oil in order to determine intensity of infection. Statistical analysis was performed using the Chi-square test. A total number of 30 cats were found to be infected with Otodectes cynotis (prevalence 14.02%). Prevalence of infection was significantly (p<0.05) higher in cats aged between 3 and 6 months (17.58%) than in cats aged below 3 months (11.38). Intensity of infection ranged between 7 and 85 (mean intensity 35.60) mites per infected cat. The same age group of cats between 3 and 6 months had significantly (p<0.05) higher mean intensity (47.19) compared to cats aged under 3 months (22.36). No statistical significance was found between males and females for neither prevalence nor intensity. Differences and similarities with other studies are discussed.

A previously unidentified Chorioptes species infesting outer ear canals of moose (Alces alces): characterization of the mite and the pathology of infestation.

BACKGROUND: During the past decade, Chorioptes mites occupying the outer ear canals have been a common finding at routine necropsies of moose (Alces alces) in Sweden, but neither the taxonomy of the mites nor lesions from the infestation have been investigated. In this study, the mites are characterized by morphological and molecular techniques, and the histopathology of the skin of the outer ear canal is described. METHODS: External auditory meatuses from 53 necropsied moose were examined for the presence of Chorioptes, and samples from outer ear canals were taken for histopathological and microbiological examination. A proportion of the mites from each moose was identified to species. The DNA was extracted from mites from three moose, and their ITS-2 sequences were determined; these sequences were compared phylogenetically to sequences from other Chorioptes taxa. RESULTS: Chorioptes mites were found in 43 (81%) of the 53 moose. The mites had morphological and genetic characteristics distinct from those of C. texanus and C. bovis, the two species generally accepted within the genus. Morphology also did not argue for a diagnosis as C. crewei, C. mydaus or C. panda. On histopathology, lesions were characterized by a hyperplastic perivascular to interstitial dermatitis with epidermal hyperkeratosis and crust formation. Dermal inflammatory infiltrates were composed of mixed T- and B-lymphocytes, plasma cells and macrophages, whereas eosinophils were notably uncommon. Staphylococcus aureus was grown from the infested epidermis of five of 14 examined moose. CONCLUSION: Chorioptes mite infestation was frequently detected in the outer ear canals of moose in Sweden. The mites were evidently pathogenic, being associated with inflammatory lesions of the external auditory meatus. Our studies indicate infestations with a previously undescribed Chorioptes species.

Epidemiological aspects of bovine parasitic otitis caused by Rhabditis spp. and/or Raillietia spp. in the state of Minas Gerais, Brazil.

The occurrence of bovine external otitis in tropical regions is predominantly assigned to parasitic infections by rhabditiform nematodes and infestations by mites of the genus Raillietia. This research had the purpose of investigating the prevalence of parasitic otitis in the dry and rainy seasons of Minas Gerais and correlating it with variables age, breed and the presence of horns. The secretion or cerumen of 981 cattle was collected with sterile swabs, placed in test tubes and exposed to sunlight for the identification of clinical infections caused by rhabditiform nematodes. The ear canals of 109 animals were flushed to study the occurrence of mites of the genus Raillietia. Clinical otitis caused by rhabditiform nematodes was observed only in animals of the Gyr breed, affecting 169 (60.1%) of the total (278) of these cattle. The prevalence of otitis in this breed was significantly higher for mature adult cows (P<0.001) and in cows with horns (P<0.001). In a total of nine animals suspected of raillietiosis, the examinations revealed the presence of Raillietia spp. in two Dutch cows. These results demonstrate that treatment must be focused on adult Gyr cattle with horns. This and future studies with an emphasis on epidemiological aspects may contribute to development of alternative approaches to reduce disease.

Otodectic otoacariasis in free-ranging Eurasian lynx in Sweden.

An infestation with Otodectes cynotis, the ear mite of cats and dogs, was observed in three free-ranging Eurasian lynx (Lynx lynx) killed in Sweden. The ear canals were obstructed by waxy secretions and exfoliated epithelium. Histologically, there were hyperkeratosis and acanthosis, and the epithelial surface was overlained by hyperkeratotic and parakeratotic crusts with mites, mite detritus and cerumen. In the subcutis there was a slight to moderate infiltration of lymphocytes and macrophages. The ceruminous glands were bypertrophic and hyperplastic, and there was also an hyperplasia of the sebaceous glands. The lesions seemed to correlate with the degree of infestation. To our knowledge, this is the first report of otoacariasis in free-ranging lynx.

Factors affecting the frequency of ear canal and face infestation by Otodectes cynotis in the cat.

Otodectes cynotis is responsible for at least 50% of canker cases diagnosed in cats world-wide. The role of Demodex cati in the pathogenesis of otitis and acne is still obscure. The aims of this study were to estimate the prevalence of O. cynoyis and D. cati infestations in clinically normal cats in northern Greece, to determine the factors that are associated with the probability and severity of infestation in the cat, and to examine the importance of these mites in the pathogenesis of feline acne. Samples from 161 cats were examined by flushing the ear canals and by taking skin scrapings of the chin and lip area. The results were combined with various factors (sex, age, living style, hair coat type and presence of pruritus, of ear discharge, of acne-like lesions) in order to carry out a risk analysis. Two separate logistic regression analyses were performed. One, on the infestation/non-infestation potential with O. cynotis and the other, on the degree of such infestation as mild-to-moderate (< or =5 mites/field) or severe (>5 mites/field). D. cati was not detected in any of the 161 cats. The prevalence of O. cynotis was estimated at 25.5% (95% confidence interval (CI) 19-32). The rate of mite infestation was higher with the presence of ear discharge (odds ratio 9, 95% CI 3.3-24.5), periaural pruritus (odds ratio 3.6, 95% CI 1.8-8) and acne-like lesions (odds ratio 3.3, 95% CI 1.2-9). Cats with mild-to-moderate degree of infestation had 18 times higher chance of exhibiting an ear discharge than those with a severe infestation. The log-odds of mild-to-moderate parasitism were linearly related to the age.

Ectopic Psoroptes cuniculi infestation in a pet rabbit.

A case of Psoroptes cuniculi infestation of the ears and body of a pet rabbit, with severe lesions on the skin of the caudoventral abdomen, is reported. Treatment with ivermectin injection followed by fipronil application appeared to be safe and was successful in eliminating infection.