Surgical creation of multiple drainage holes versus local injection of corticosteroids for treatment of aural hematomas in dogs: 51 dogs with 71 aural hematomas (2000-2017)

OBJECTIVE

To investigate the outcome of surgical creation of multiple drainage holes (MDHs) versus local corticosteroid injection (LCI) for treatment of aural hematomas (AHs) in dogs and identify risk factors for recurrence and development of new AHs.

ANIMALS

51 dogs with 71 AHs.

PROCEDURES

Medical records were reviewed, and information on signalment, clinical findings, and outcome was recorded. Recurrence was defined as development of an AH at the primary site after the first month of treatment. Development of a new AH was defined as an AH occurring at a site different from the treated site.

RESULTS

The recurrence rate after the first month of treatment was significantly higher following the LCI procedure (17/48 AHs [33%]) than after the MDH procedure (1/24 AHs [4%]). The odds of recurrence increased as the numbers of LCI in the first month increased (OR, 2.414). Recurrent AHs after LCI resolved with additional LCIs; only 1 AH (2%) required a change to MDHs. No recurrence was observed after the eighth month, and the cosmetic results were good. Sixteen of 51 (31%) dogs had multiple or new AHs. The risk of new AHs was higher in Golden Retrievers and Labrador Retrievers and in dogs with allergic dermatitis.

CONCLUSIONS AND CLINICAL RELEVANCE

Long-term outcomes suggested that both creation of MDHs and LCI can be therapeutic options for dogs with AHs. However, the risk of new AH development should be considered, especially in retriever breeds and dogs with allergic dermatitis.

Clinical features, treatment, and outcome of aural hematomas in horses: 7 cases (2008-2019)

OBJECTIVE

To characterize the clinical features, treatment, and outcome of aural hematomas in horses.

ANIMALS

7 horses with 1 or 2 aural hematomas (8 ears in total) treated at a veterinary teaching hospital in 2008 through 2019.

PROCEDURES

Data retrieved from medical records included signalment, pertinent historical information, clinical signs, diagnostic procedures (including dermatologic assessment), and treatments. Case outcome was determined from documentation in the medical record or via telephone communication with owners or referring veterinarians.

RESULTS

3 horses were presented after recurrence of aural hematoma following treatment by the referring veterinarian. Four horses had a history of allergic skin disease prior to aural hematoma development. Most (6/7) horses were unilaterally affected. Diagnostic assessments included otoscopic evaluation (3 horses), ultrasonography (3 horses), cytologic examination of ear canal swab samples (3 horses), and histologic examination of a pinnal biopsy specimen (1 horse). Of the 8 pinnae, 2 were treated by nonsurgical needle drainage (1 with concurrent corticosteroid injection) and the remaining 6 underwent surgical incision and placement of compressive sutures. Follow-up information was available for 6 horses, and all affected pinnae were fibrotic with 4 horses having permanent drooping of the pinna. One horse developed a hematoma in the contralateral pinna 1 year after hospital discharge.

CONCLUSIONS AND CLINICAL RELEVANCE

Equine aural hematoma is a rare condition. The main principle of treatment is drainage, and treatment options commonly used in small animal practice can be successfully applied in horses. Permanent changes in the cosmetic appearance of the pinna are likely to develop owing to secondary fibrosis.

Comparison of complications and outcome following unilateral, staged bilateral, and single-stage bilateral ventral bulla osteotomy in cats

OBJECTIVE

To compare complications and outcome following unilateral, staged bilateral, and single-stage bilateral ventral bulla osteotomy (VBO) in cats.

ANIMALS

282 client-owned cats treated by VBO at 25 veterinary referral and academic hospitals from 2005 through 2016.

PROCEDURES

Medical records of cats were reviewed to collect information on signalment, clinical signs, diagnostic test results, surgical and postoperative management details, complications (anesthetic, surgical, and postoperative), and outcome. Associations were evaluated among selected variables.

RESULTS

Unilateral, staged bilateral, and single-stage bilateral VBO was performed in 211, 7, and 64 cats, respectively, representing 289 separate procedures. Eighteen (9%), 2 (29%), and 30 (47%) of these cats, respectively, had postoperative respiratory complications. Cats treated with single-stage bilateral VBO were significantly more likely to have severe respiratory complications and surgery-related death than cats treated with other VBO procedures. Overall, 68.2% (n = 197) of the 289 procedures were associated with Horner syndrome (19.4% permanently), 30.1% (87) with head tilt (22.1% permanently), 13.5% (39) with facial nerve paralysis (8.0% permanently), and 6.2% (18) with local disease recurrence. Cats with (vs without) Horner syndrome, head tilt, and facial nerve paralysis before VBO had 2.6, 3.3, and 5.6 times the odds, respectively, of having these conditions permanently.

CONCLUSIONS AND CLINICAL RELEVANCE

Findings suggested that staged bilateral VBO should be recommended over single-stage bilateral VBO for cats with bilateral middle ear disease. Cats with Horner syndrome, head tilt, and facial nerve paralysis before surgery were more likely to have these conditions permanently following surgery than were cats without these conditions.

EAR MITES, OTODECTES CYNOTIS, ON WILD FOXES (PSEUDALOPEX SPP.) IN CHILE

We found the ear mite parasite (Otodectes cynotis; Acari: Psoroptidae) in two distant insular endangered fox populations in Chile. We identified O. cynotis in both the Darwin's fox (Pseudalopex fulvipes) from Chiloé and the Fuegian culpeo (Pseudalopex culpaeus lycoides) in Tierra del Fuego. These populations are approximately 2,000 km apart. Infestation rates were high for both endemic foxes: 76% (19/25) of Darwin's foxes were affected, and 73% (11/15) of Fuegian culpeos had ear mites. Two Darwin's foxes had abundant ear discharge, and one of these also exhibited secondary infections of Morganella morganii and Geotrichum sp. fungi. Mites were characterized molecularly as Otodectes spp. for the Fuegian culpeo samples. Genetic analyses of two mites found the O. cynotis genotype I, as well as what appeared to be a new allele sequence for O. cynotis. These results confirmed the hypothesis of a worldwide distribution species of ear mite. Introduced chilla foxes (Pseudalopex griseus; n=11) on Tierra del Fuego Island and domestic dogs (Canis lupus familiaris; n=379) from both islands were also sampled, but they showed no signs of infection. Our findings provided insight into the genetic diversity, the origins, and the possible impact of this globally distributed mite on endemic free-ranging populations of foxes.

Quantifying parasite presence in relation to biological parameters of harbour porpoises Phocoena phocoena stranded on the Dutch coast

Harbour porpoises are often found to be infected by endoparasites in several organs including the lungs and stomach as well as the heart, liver and ears. Nevertheless there is still little knowledge about the impact, ecology, transmission, and virulence of these parasitic infections. Here, we profile the presence of parasites in 4 frequently infected organs (lungs, stomach, liver and ears) in relation to biological parameters of harbour porpoises stranded along the Dutch coastline between December 2008 and December 2013. We found that parasites were common, with prevalence of 68% in lungs, 74.4% in ears, 26% in stomach and 23.5% in liver. We used generalised linear models to further quantify parasite presence in relation to biological data gathered during necropsy (sex, body length and nutritive condition). Body length (used as a proxy for age) was significant in explaining parasite presence for all organs with increasing probability of having the parasite with increasing body length. For the parasitic infections in the ears and stomach the nutritive condition was an additional significant factor, with a higher probability of parasite presence in porpoises in a poorer nutritive condition. The results of this study can be used as a baseline for assessing parasite presence in harbour porpoises and are a first step towards linking parasite infections to basic biological data gathered during necropsy.

Shope Fibroma in the External Ear Canal of a Domestic Rabbit

A 5-y-old, intact, 2.5-kg female domestic rabbit was presented because of blood spatter on the wall of its cage and the toenails of its right hind limb. Physical examination revealed a red, gelatinous mass that spanned the width of the right vertical ear canal. Radiographic images revealed a soft-tissue opacity at the base of the right ear, which was superimposed over the tympanic bulla and extended to the pinna. A CT scan revealed that the soft-tissue mass was within the vertical and horizontal portions of the right external ear canal and extended to the level of the tympanic membrane, with no bony involvement. An incisional biopsy of the mass and subsequent histopathology revealed heterophilic inflammation with bacteria, necrosis, and no evidence of neoplasia. The patient died during anesthesia for removal of the mass at 1 mo after the initial presentation. Necropsy with histopathology of the mass was consistent with Shope fibroma virus in light of the presence of typical intracytoplasmic eosinophilic inclusions. Electron microscopy of paraffin-embedded tissue revealed electron-dense intracytoplasmic structures within neoplastic cells consistent with the diagnosis of Leporipoxvirus. To our knowledge, this report is the first description of Shope fibroma virus invading the external ear canal of a domestic rabbit. Given the results of this case, Shope fibroma should be considered in rabbits presenting with abnormal tissue in the ear canal.

Atypical manifestations of feline inflammatory polyps in three cats

Inflammatory polyps of the feline middle ear and nasopharynx are non-neoplastic masses that are presumed to originate from the epithelial lining of the tympanic bulla or Eustachian tube. The exact origin and cause are unknown, however, it is thought that inflammatory polyps arise as a result of a prolonged inflammatory process. It is unclear whether this inflammation initiates or potentiates the development and growth of inflammatory polyps. Cats with inflammatory polyps typically present with either signs of otitis externa and otitis media or with signs consistent with upper airway obstruction. Traditional diagnostics involve imaging of the tympanic bulla either with skull radiographs or computed topography (CT). Treatment consists of traction and avulsion of the polyp with or without ventral bulla osteotomy (VBO) to remove the epithelial lining of the tympanic bulla. The three cases described here are unusual manifestations or presentations of feline inflammatory polyps that address the following issues: (1) concurrent otic and nasopharyngeal polyps, (2) potential association with chronic viral infection, (3) polyp development in the contralateral middle ear, (4) CT appearance of the skull following VBO, and (5) development of secondary pulmonary hypertension.

Auricular Chondritis Caused by Metal Ear Tagging in C57BL/6 Mice

Although it has been shown that auricular chondritis in rats is caused by the use of metal identification ear tags, the pathogenesis remains unclear. Based on the hypothesis that the auricular chondritis is caused by metal ions released from metal identification ear tags, we investigated the pathogenesis in male C57BL/6 mice tagged with metal identification ear tags. Twenty-six weeks after the attachment of the ear tags, visible increases in the thickness of the auricle were observed, and the concentrations of copper and iron in the tagged ears were significantly increased ( P <.05) in the tagged ears compared with the untagged ears. There was up-regulation of metallothionein (MT)-I and MT-II mRNA in the tagged ears, and this was confirmed by immunohistologic staining of the destroyed cartilage. Histopathologically, there were observed severe chondritis with extensive granulomatous inflammation, newly formed cartilage nodules, and osseous metaplasia accompanied by cellular infiltrates, such as CD4 T lymphocyte, macrophages, neutrophils, and mast cells, and expression of Th1 cytokines, such as interferon-gamma, tumor necrosis factor-alpha, and interleukin-2 in the tagged ear. Based on these results, we concluded that the release of copper and iron ions from the metal ear tags played a major role in the onset of auricular chondritis. Subsequent cellular interactions, such as CD4 T cells, macrophages, fibroblasts, and mast cells, mediated by cytokines, such as tumor necrosis factor-alpha and interferon-gamma, caused an autoimmune response that may have led to the progression of auricular chondritis as an autoimmune disease.

Immunoglobulin Crystals in Reactive Plasma Cells in a Dog

Intracellular crystalline deposits of immunoglobulin are occasionally seen in human B-cell lymphoproliferative disorders such as multiple myeloma, chronic lymphocytic leukemia, and various forms of lymphoma. Even more uncommon is the occurrence of immunoglobulin crystals in benign plasma cells or reactive lymphocytes. Here we describe the histologic, immunohistochemical, and ultrastructural features of intracellular immunoglobulin crystals in nonneoplastic plasma cells in a chronic inflammatory lesion in a dog. Microscopically, the intracellular, nonbirefringent eosinophilic crystals were square to rectangular, 2–20 μgm long, and caused nuclear displacement to the periphery. The crystal-containing cells, as well as some of the crystals themselves, were positive for lambda light chain. Ultrastructural findings were consistent with a lattice network of protein-molecule alignment. The cause and significance of the crystals is unknown.

Surgical Management of Ear Diseases in Rabbits

Otitis externa and media are frequently diagnosed disorders in rabbits and are particularly common in lop-eared breeds because of the specific anatomy of the ear canal. Medical management for otitis externa and media often provides only a temporary improvement in clinical signs. Surgery by means of partial or total ear canal ablation (PECA or TECA) combined with lateral bulla osteotomy (LBO) represents a feasible approach that is well tolerated and provides a good clinical outcome. Short-term complications associated with PECA/TECA-LBO include facial nerve paralysis and vestibular disease.

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.

[Investigation of potential causes for the development of porcine ear necrosis: different study designs--comparable results?]

During the last years two studies for the investigation of the etiology of porcine ear necrosis were carried out at the Clinic for Swine of the University of Veterinary Medicine Vienna. In study 1, parameters, which are discussed in this context, were collected by veterinary practitioners by completing specially designed questionnaires in farms with symptoms of the porcine ear necrosis syndrome. In study 2, samples of piglets and feed were collected for laboratory analysis of the most important infectious agents as well as mycotoxins. In the present manuscript, the results of both projects were compared. Even if the selection criteria of both studies differed, the affected age class was comparable (5.5 to ten weeks of life in study 1 and six to ten weeks of life in study 2). The herd-specific prevalence of the porcine ear necrosis syndrome varied considerably with percentages between 2 and 10, respectively, to 100%. The evaluation of questionnaires in study 1 showed that 51% of the farms had problems with cannibalism. Particles of plant material, which were frequently seen on the histologic slides of study 2, could have got into the tissue by chewing the ears of the pen mates or cannibalism. Whereas in study 1 the negative effect of parameters as high pig density, suboptimal climate, missing enrichment material and bad quality of feed and water were considered, in study 2 all these factors were checked at sample collection and ruled out as precursor for cannibalism. In both studies bacterial agents proved to be a crucial co-factor for the expansion of the necroses to deeper tissue layers, whereas viral pathogens were classified less important. In both projects it was not possible to estimate the direct impact of infectious agents and mycotoxins as direct trigger of the necroses as well as their participation as co-factors or precursor in the sense of an immunosuppression or previous damage of blood vessels or tissue.

Ultrasound evaluation of tympanic bulla in calves

An ultrasonographic approach for the tympanic bulla in calves is described. Ultrasound evaluation was performed through a lateral approach on 7 fetuses, 2 newborn calves, and 4 living calves of various ages. The probe was positioned caudal to the vertical mandibular ramus, ventral to the base of the ear. Three different positions of the probe were used. The tympanic bulla and adjacent structures were successfully identified and their ultrasonographic appearance described. Fluid within the tympanic bulla was visualized in 12 bullae in the cadavers and in 6 bullae in live calves. Ultrasound imaging has been shown to be useful but its diagnostic value remains to be studied in clinical cases of otitis media in calves.

Comparison of culture and PCR to detect Mycoplasma agalactiae and Mycoplasma mycoides subsp. capri in ear swabs taken from goats

This study was designed to evaluate the validity of PCR for the direct detection of Mycoplasma (M.) agalactiae and Mycoplasma mycoides subsp. capri (Mmc), as the two species most frequently causing contagious agalactia (CA) in goats. The PCR method was compared with the traditional culture technique to determine which method was most efficient at identifying all auricular carriers present in herds. The samples analyzed were 307 ear swabs taken from goats reared in a CA endemic area. We assessed the validity of each technique to detect each species and agreement between both methods. For each species, the result was taken as true-positive when at least one of the two tests was positive. Of the swabs tested, 246 were scored positive by PCR (235 and 11 for Mmc and M. agalactiae, respectively) and 117 showed a positive culture result (113 for Mmc and 4 for M. agalactiae). 133 of the PCR-positive samples (124 and 9 for Mmc and M. agalactiae, respectively) yielded negative culture results and 4 culture-positive samples tested negative using PCR (2 for each species). Sensitivity and negative predictive values for PCR were 84.62 and 99.32 (for M. agalactiae) and 99.16 and 97.22% (for Mmc) respectively, and for culture were 30.77 and 97.03 (for M. agalactiae) and 47.08 and 36.08% (for Mmc), respectively. PCR proved to be a rapid and sensitive method for the detection of mycoplasmas in the external ear of asymptomatic carriers. Tools such as this are needed to adopt efficient control measures against CA.

A practical approach to diagnosing and managing ear disease in dogs

Entire books have been written on the subject of canine ear disease. Rather than attempt to present all the available information here, I am providing an overview of how I diagnose and manage ear disease in dogs. It is critical to appreciate that ear disease is only a clinical problem (no more specific than pruritus) and that steps must be taken to prevent otitis externa from progressing to proliferative otitis. BOX 1 summarizes step-by-step approaches to specific clinical scenarios.

Assessment of middle ear disease in the dog: a comparison of diagnostic imaging modalities

OBJECTIVES

To compare radiography and ultrasound for the assessment of the tympanic bulla against computed tomography results.

METHODS

Thirty-one dogs had dorsoventral, left and right lateral oblique and rostrocaudal open mouth radiographs compared with ultrasound images and computed tomography scans of the tympanic bullae.

RESULTS

Radiography was superior to ultrasonography for the evaluation of the middle ear. However, computed tomography assessment was best predicted by a combination of radiographic and ultrasonographic findings.

CLINICAL SIGNIFICANCE

A combination of radiography and ultrasound can provide a more accurate assessment of the bulla than either of them alone. Ultrasound may have a role in the evaluation of middle ear disease in the dog. Results are operator dependent and not reproducible with current recording techniques.

Subtotal ear canal ablation in 18 dogs and one cat with minimal distal ear canal pathology

A modified technique for performing total ear canal ablations is described. This technique requires less dissection than the standard technique and maintains a portion of the distal vertical ear canal. Subtotal ear canal ablations were performed in 18 dogs and one cat for the treatment of otitis externa or masses of the horizontal ear canal. Animals with otitis externa had minimal involvement of the distal ear canal. Dermatological problems associated with the remaining ear canal and pinnae occurred in eight animals and resolved with medical management. Normal ear carriage was maintained in all animals with erect ears. Further investigation is required before the procedure can be recommended as a treatment for otitis externa not caused by masses or anatomical abnormalities of the horizontal ear canal in dogs with pendulous ears.

Gerbilline cholesteatoma development Part III. Increased proliferation index of basal keratinocytes of the tympanic membrane and external ear canal

OBJECTIVE

To quantify the rate of basal cell division for keratinizing epithelium (KE) of the tympanic membrane (TM) and external ear canal (EAC) in spontaneous and induced gerbilline cholesteatomas.

STUDY DESIGN AND SETTING

Cholesteatomas (3 spontaneous and 5 by induction) were labeled with tritiated thymidine for autoradiography and a KE proliferation index (PI) was determined. The PI was defined as the average number of labeled cells/mm overall and per anatomic region.

RESULTS

For all regions combined, the PI was 27.3 in ears with cholesteatoma and 4.1 in normal ears (P < 0.0001). Additionally, there were significant regional differences in the PI in both normal ears and ears with cholesteatoma.

CONCLUSION

The KE of cholesteatomas in gerbils proliferates at approximately 7 times the rate measured in control ears.

SIGNIFICANCE

Hyperproliferation of keratinocytes is a causative factor in the development and progression of spontaneous and experimental cholesteatomas in gerbils.

Inflammatory aural polyp in a horse

An inflammatory aural polyp was identified in a 1-year-old standardbred filly, which presented with otorrhea and head rubbing. The polyp was removed by traction-avulsion, and the filly showed no subsequent signs of otorrhea. Aural polyps have not been reported in horses, but they are commonly seen in companion animals and humans.

Guttural pouch mycosis in a 6-month-old filly

A 6-month-old filly was presented with unilateral epistaxis. Based on clinical signs, endoscopic examination, and postmortem examination, guttural pouch mycosis was diagnosed. The young age of the filly and the fact that this was the 2nd diagnosis of guttural pouch mycosis on this farm was unusual.

Occurrence of the ear-mite Raillietia auris in cattle in Austria

We describe here the first documented case in Austria of the cattle ear mite Raillietia auris in a four-year-old dairy cow. The cow was mildly depressed, and keratoconjunctivitis was diagnosed in both eyes with Horner's syndrome in the left eye. The animal showed a mild head tilt to the left and a generalized ataxia with a tendency to move to the right side, which became exacerbated if the animal was blind-folded. Head pressing to the right side, dysphagia and a dropped jaw were also observed. Numerous rather mobile ear mites were observed at necropsy in the basal part of the left ear canal. The clinical significance of the cattle ear mite is uncertain and the clinical signs could have been caused by listerial encephalitis, which was also confirmed histologically in this case.

In vitro antimicrobial inhibition profiles of Mycoplasma bovis isolates recovered from various regions of the United States from 2002 to 2003

Antimicrobial therapy continues to be important in reducing losses due to pneumonic forms of Mycoplasma bovis disease in beef and dairy calves. Although M. bovis diseases have been documented as frequent and economically important in the United States, there are no published reports on the antimicrobial activity of approved compounds against US strains. In this study, the authors report on the activity of 9 different antimicrobials against 223 recently recovered isolates of M. bovis. These isolates represent accessions from 5 geographic regions of the United States and were grouped by 4 tissues of origin (milk, respiratory, joint, or ear and eye). A broth microdilution test was used to determine minimum inhibitory concentration (MIC) values by reading redox changes detected in broth with alamarBlue (resazurin) indicator. For each antimicrobial, the median, MIC50, MIC90, mode, and range were calculated, and the values used for comparisons. In the absence of accepted breakpoint values, published MIC cutoff values for animal mycoplasmas as well as Clinical Laboratory Standards Institute interpretive criteria were used as a reference to define in vitro activity. The MIC values from active antimicrobials were found to distribute independently of region of origin of the isolates or of tissue of origin. Enrofloxacin, florfenicol, and spectinomycin were found to be active compounds in vitro. Oxytetracycline and chlortetracycline were active against more than half of the isolates. Very few isolates were inhibited by tilmicosin and none by erythromycin, ampicillin, or ceftiofur. The antimicrobial profiles determined for these US strains were remarkably similar to those reported for European isolates. However, unlike in Europe, there appears to be no diversity of profiles when US isolates are grouped by region or tissue of origin.

Efficacy and safety of imidacloprid 10% plus moxidectin 2.5% spot-on in the treatment of sarcoptic mange and otoacariosis in dogs: results af a European field study

Efficacy and safety of treatment with imidacloprid 10%+moxidectin 2.5% spot-on (Advocate, Advantage multi; Bayer AG, Leverkusen, Germany) were tested in dogs naturally infested with Sarcoptes scabiei or Otodectes cynotis in a multi-centre, controlled, randomized, blinded field study conducted in France, Germany, Albania and the UK. The study was performed according to a non-inferiority design to demonstrate that the efficacy of imidacloprid/moxidectin spot-on was not inferior to that of a control product containing selamectin (Stronghold spot-on; Pfizer). All Sarcoptes-infested dogs were topically treated twice (days 0 and 28) with the dosage recommended by the respective manufacturer (27 dogs with imidacloprid/moxidectin, 26 with selamectin). All Otodectes-infested dogs were treated on day 0 (35 dogs with imidacloprid/moxidectin, 34 with selamectin), and only those still positive on day 28 received a second treatment. Parasitological cure rate in Sarcoptes-infested dogs was 100% for both treatments, while parasitological cures rates in the Otodectes-infested dogs at day 28 and day 56 were 68.6 and 85.7% with imidacloprid/moxidectin, and 64.7 and 88.2% with Stronghold. Non-inferiority of Advocate was confirmed statistically. Clinical assessment of skin lesion scores at day 56 showed that with either product >96% of the dogs treated against sarcoptic mange were improved or cured, the difference between the groups being non-significant. On the basis of a final clinical assessment of lesion scores, 80% of the dogs treated with imidacloprid/moxidectin against otoacariosis and 85.3% of those treated with selamectin were rated cured or improved. Only three mild, possibly drug-related adverse reactions were observed among alI treated animals (two in the imidacloprid/moxidectin group, one in the selamectin group). It is concluded that imidacloprid/moxidectin spot-on is an effective and safe treatment for sarcoptic mange and otoacariosis in the dog.

Fine-needle biopsy of external ear canal masses in the cat: cytologic results and histologic correlations in 27 cases

BACKGROUND

The cytologic diagnosis of ear canal tumors is difficult or impossible by swab alone because cell exfoliation may be poor and neoplastic cells may be masked by associated inflammation. Fine-needle biopsy (FNB) can be used to obtain a higher yield of cells for diagnosis.

OBJECTIVE

The purpose of this study was to assess the efficacy and diagnostic value of FNB and cytologic examination in providing an accurate diagnosis of masses growing in the external ear canal of cats.

METHODS

Cytologic specimens from masses in the external ear canal, taken under inhaled, general anesthesia, were classified into 4 groups: 1) ceruminous gland hyperplasia or adenoma, 2) ceruminous gland adenocarcinoma, 3) inflammatory polyps, and 4) other neoplastic and non-neoplastic masses. Cytopathologic diagnoses were compared with the final histopathologic diagnoses, and indices of diagnostic test accuracy (sensitivity, specificity, likelihood ratios, diagnostic-odds ratios) were calculated.

RESULTS

Twenty-seven masses (from 25 cats, including 2 cats affected bilaterally) were included in the study. The results showed good correspondence between cytologic and histologic diagnoses with an overall agreement index (kappa) of .74, a diagnostic odds ratio of 22, and 100% (27/27) agreement in the diagnosis of inflammatory polyps versus neoplasia (both benign and malignant).

CONCLUSIONS

FNB cytopathology of external ear masses in the cat was sufficiently accurate for distinguishing inflammatory polyps from neoplasia. For differentiation of benign proliferation and malignant neoplasia, however, histopathologic confirmation is recommended.

The mystery of fungal infection in the guttural pouches

Advances in the understanding of guttural pouch physiology and novel therapeutic approaches to mycotic infections in the horse are reviewed. It is suggested that the guttural pouches may contribute to the regulation of arterial blood temperature, cooling the circulation to the brain to below body temperature. Aspergillus spp. is the major organism found in a guttural pouch affected with mycosis but it is unclear why this agent becomes aggressive. Conventional therapy aims to prevent fatal haemorrhage and to treat any neurological lesions but it is desirable to try to prevent the disease. A technique consisting of inserting a transarterial coil into the internal carotid, external carotid and maxillary arteries in normal and affected horses has been reported to be rapid, safe and effective in occluding the arteries and in inducing regression of the mycotic lesions without adjunctive medical treatment. When faced with acute and uncontrollable epistaxis in the field, the most effective means to reduce haemorrhage is probably the occlusion of both common carotid arteries. However, how such arterial occlusions can result in the successful management of guttural pouch mycosis without antifungal medication remains a mystery.

Epidemiologic determinants of aural abscessation in free-living eastern box turtles (Terrapene carolina) in Virginia

Epidemiologic determinants of 46 cases of aural abscessation in free-living eastern box turtles (Terrapene carolina) admitted to the Wildlife Center of Virginia (Virginia, USA) from 1991 to 2000 were evaluated. County human population density, year and season of admission, weight, and sex did not affect the risk for box turtles to develop aural abscessation. Counties with cases of aural abscessation were not randomly distributed, but rather were clustered into two multi-county regions. Geographic location was the only risk factor associated with aural abscessation in box turtles found in this study. Possible etiologies could include chronic infectious disease, malnutrition, or chronic exposure to environmental contamination with organochlorine compounds.

Inheritance of Guttural Pouch Tympany in the Arabian Horse

The objective of the present study was to analyze the mode of inheritance of guttural pouch tympany (GPT) using pedigrees of Arabian horses. Complex segregation analyses were employed to test for the significance of nongenetic transmission and for monogenic, polygenic, and mixed monogenic-polygenic modes of inheritance. Horses affected by GPT comprised 27 Arabian purebred foals. Of these 27 animals, 22 were patients at the Clinic for Horses, School of Veterinary Medicine Hannover, Hannover, Germany, between 1994 and 2001 and 5 Arabian foals were from stud farms. Information on the pedigrees of these patients allowed us to classify the affected foals into four families with a total of 276 animals. The regressive logistic model analysis took into account the nonrandomness of the pedigrees through multiple single ascertainment correction. The complex segregation analysis showed that, among all other models employed, a polygenic and a mixed monogenic-polygenic model best explained the segregation of Arabian foals with GPT. Models including only nongenetic distributions and monogenic inheritance could be significantly rejected. This is the first report in which a genetic component could be shown to be responsible for GPT in horses.

Surgery of the ear and pinna

There are several disease processes of the ear and pinna that warrant surgical intervention. This article reviews surgical anatomy and common surgical procedures of the ear and pinna, including aural hematomas, lateral wall resection, vertical ear canal resection, total ear canal ablation and lateral bulla osteotomy, partial pinna resection, and feline inflammatory polyps. The clinical signs, diagnosis, and surgical treatment along with potential complications for each disease process are discussed.

Diagnostic imaging of the canine and feline ear

Radiographic evaluation of the tympanic bulla is limited. Improper obliquity or angulation of the skull for radiographs or malpositioning of the tongue can result in an inadequate study [4]. Additionally, because of the complex anatomy of the canine and feline skull, with superimposition of multiple osseous structures, radiography can result in false-negative examinations or understimation of the disease present [2]. When compared with surgical findings of 19 clinical cases of presumptive middle ear disease, false-negative radiographic findings were found in 25% of the surgically confirmed cases of otitis media [4]. Therefore, radiographs are not considered to be a highly sensitive mode of diagnosing otitis media. Radiographs may be helpful in determining lysis associated with neoplasia; however, the extent of involvement is still underestimated. In a study comparing CT and radiographic evaluation of otitis media, CT was determined to be more sensitive but less specific than radiography [11]. CT is the preferred modality for the evaluation of the tympanic bulla at our institution. This opinion may be biased by the fact that most cases are presented for recurrent or chronic otitis. Although radiography is more accessible, the availability of CT in local referral settings is increasing as opposed to being limited to university settings. After the cost (i.e., anesthesia, radiographs) and amount of time necessary to make optimum radiographic studies are taken into account, a CT study may actually be faster and more informative. Given our preference for the CT examination, the cost of the examination has been adjusted to make it more appealing to the owner and clinician. For example, a bulla CT study is only 1.3 times the cost of a radiographic bulla study. In conclusion, imaging of the ear canal can provide important information about ear disease, including unilateral or bilateral ear disease, the degree of middle or inner ear involvement, peripheral versus central vestibular disease, an infectious or inflammatory versus neoplastic process, the chronicity of the disease process, involvement of adjacent structures, and postsurgical complications.

Otic flushing

Otic flushing has the potential to help a number of patients with ear disease. Because the diagnostic and therapeutic benefits of this procedure exceed its risks, veterinarians should offer otic flushing for patients with poorly responsive or chronic otitis externa.

Material in the middle ear of dogs having magnetic resonance imaging for investigation of neurologic signs

The aim of this study was to determine the prevalence and potential significance of finding material in the middle ear of dogs having magnetic resonance (MR) imaging. Of 466 MR studies reviewed, an increased signal was identified in the tympanic bulla in 32 (7%) dogs. Cavalier King Charles spaniels, Cocker spaniels, Bulldogs, and Boxers were over-represented compared to the population of dogs having MR imaging. Five (16%) dogs had definite otitis media and one (3%) had a meningioma invading the middle ear. Of the remaining dogs, 13 (41%) had possible otitis media and 13 (41%) had neurologic conditions apparently unrelated to otitis media. The most common appearance of material in the middle ear was isointense in T1-weighted images and hyperintense in T2-weighted images. There was no apparent correlation between the signal characteristics of the material and the diagnosis. Enhanced signal after gadolinium administration was observed affecting the lining of the bulla in dogs with otitis media and in dogs with unrelated neurologic conditions. In dogs without clinical signs of otitis media, finding an increased signal in the middle ear during MR imaging may reflect subclinical otitis media or fluid accumulation unrelated to inflammation. Brachycephalic dogs may be predisposed to this condition.

Diseases of the ear pinna

In conclusion, there are a wide variety of dermatologic diseases that can affect the ear pinnae. Most of these disorders are manifestations of a generalized dermatosis. Therefore, when pinnal lesions are present, a thorough diagnostic workup is indicated.

Neurologic evaluation of the ear

Diseases of the ear often cause signs of neurologic dysfunction because of damage of peripheral nervous system structures associated with the middle and inner ear. Vestibular dysfunction, facial paralysis, Horner's syndrome, and hearing deficits are the most common neurologic deficits that accompany middle and inner ear disease. Differentiating these signs from disease of the central nervous system is crucial for an accurate diagnosis and prognosis but can be difficult. Understanding the normal anatomy of the ear and its association with the brain is crucial to interpretation of the neurologic examination. This article reviews neurologic dysfunction commonly associated with diseases of the ear and differentiating these signs from central disease.

Ultrasound imaging of the canine tympanic bulla

A procedure for imaging the canine tympanic bulla, external ear canal and adjacent structures using currently available ultrasound equipment was established. Lateral and ventral transducer positions were identified for this purpose and a 6.5 MHz curvilinear transducer was considered to be optimal. The sonographic appearance of these structures in cadavers and live dogs unaffected by ear disease is documented. Fluid was introduced into the tympanic bullae of the cadavers and its presence could be identified through the bony wall of the bulla. The ability of ultrasound to differentiate between gas and fluid within the bulla has important clinical implications as this is a common occurrence in dogs with middle ear disease. Ultrasound has several advantages over other imaging modalities and the examination procedure was well tolerated by unsedated dogs.

Auricular chondritis in young ear-tagged Crj:CD(SD)IGS rats

Gross and histopathological features of auricular chondritis in young Crj:CD(SD)IGS rats were examined. Although the rats were identified with metallic ear tags on the right pinnae, auricular chondritis was also observed on the contralateral (left) ear in some animals. Histopathologically, the lesions were characterized by granulomatous inflammation with destruction of the normal cartilaginous plate, formation of new cartilaginous nodules and osseous metaplasia. Proliferative cell nuclear antigen (PCNA) positive cells were present predominantly in chondrocytes found in the centre of the newly-formed cartilaginous nodules. The results suggest that the newly-formed cartilaginous nodules were due to interstitial proliferation of chondrocytes.

Efficacy of selamectin administered topically in the treatment of feline otoacariosis

The efficacy of a novel avermectin, selamectin (Stronghold, Pfizer), was evaluated against naturally acquired aural infestations of Otodectes cynotis. Selamectin was administered topically in a single spot to the skin of each animal's back at the base of the neck in front of the scapulae at a minimum dosage of 6mgkg(-1). Thirty cats of a cattery of 120 animals with an endemic infestation were treated on days 0 and 30. Including untreated control cats was therefore not possible because of animal welfare consideration. Clinical examination and visualization of mites by otoscopic examination of the external ear canal and microscopic examination of aural debris/exudate were performed twice weekly from days 0 to 30. On day 0 (and day 28 if the ears canals were erythematous), a swab was taken from each canal and sent to bacteriology and mycology units for detection and identification of bacteria (Staphylococcus mainly) and yeast (Malassezia pachydermatis only). Selamectin was safe, parasites were killed before day 3 and eliminated before day 17. Selamectin was 100% effective against natural aural infestations, even if erythema (26-33% of cats) and scratch reflex (23-40% of cats) persisted for 2 weeks after the cats tested negative for mites.

Review of diagnostic imaging of ear diseases in the dog and cat

Diagnostic imaging techniques (conventional radiography, computed tomography and magnetic resonance imaging) are an essential tool in the diagnostic work-up of ear diseases. Conventional radiography is commonly used, but often lacks sensitivity. Computed tomography (CT) and magnetic resonance (MR) are complementary imaging studies of the middle ear, labyrinth, internal auditory canal and their contents. CT provides excellent images of bony structures and is indicated where osseous changes are of greatest diagnostic importance. MR is superior in imaging soft tissue components including intralabyrinthine fluid. Therefore, more than one of these imaging techniques may be required in order to make a diagnosis.

Evaluation of the pathology, pathogenesis and aetiology of auricular elephantiasis in slaughter pigs

Ears from slaughter pigs with auricular elephantiasis (n = 24) and the corresponding lymph nodes (lnn.) (n = 26) were grossly, histopathologically and microbiologically examined. Immunostaining for IgM, IgG, Cd3epsilon and bacterial antigens of Arcanobacterium pyogenes and Staphylococcus aureus was performed by indirect enzyme-based techniques. Ears were variably thickened depending on the sampled area (basis, centre and apex). However, at all locations the thickness, the length from basis to apex and the weigh of whole ears with elephantiasis were significantly increased (P < 0.01). The corresponding lnn., that is, ln. parotideus superficialis and profundus, had also increased significantly (P < 0.01) in volume. Histopathologically, lesions of the ears and the corresponding lnn. revealed changes characterized by diffuse fibrosis intermingled with multiple pyogranulomatous foci containing asteroid bodies. In the majority of lesions, four distinct zones due to different cellular infiltrates encircled the central core of the asteroid bodies. In several lesions, the pyogranulomatous foci were contained within the lymph vessels. Immunohistochemically, only the bacterial antigen of S. aureus was detected within the cytoplasm of the macrophages and/or in the asteroid bodies of the ears (41.5%) and in the regional lnn. (30.8%). An abundant number of IgM, IgG and CD3epsilon-positive cells were present in all the pyogranulomatous lesions, whereas a positive IgG-staining was observed only in a single asteroid body. Thus, porcine auricular elephantiasis is a chronic pyogranulomatous inflammation that is frequently positive for S. aureus and is lymphogenically spread. Therefore, the lesions of the ears with auricular elephantiasis and the corresponding lnn. should be termed auricular botryomycosis and botryomycotic lymphadenitis, respectively. Moreover, as the disease is observed frequently in slaughter pigs it must also be considered according to the welfare of the animals and in relation to post-mortem meat inspection.

Morbidity and mortality of reptiles admitted to the Wildlife Center of Virginia, 1991 to 2000

Medical records from 694 reptiles admitted to the Wildlife Center of Virginia (WCV; Waynesboro, Virginia, USA) from 1991 to 2000 were reviewed to determine causes of morbidity and mortality. Eighteen species were represented but the majority of cases were four species; eastern box turtle (Terrapene carolina) (66%), eastern painted turtle (Chrysemys picta) (11%), common snapping turtle (Chelydra serpentina) (10%), and rat snake (Elaphe sp.) (6%). There was a significant increase in reptile cases during the study period both in absolute number and in proportion to the total caseload. Trauma (74%) was the most frequent cause of morbidity and mortality followed by unknown or undetermined (13%), aural abscessation (7%), infectious diseases (2%), and one nutritional disorder (0.1%). In addition, 3% of the cases were healthy animals that had been removed from the wild and consequently brought to the WCV. Causes of morbidity and mortality differed between the four most numerous species. Impact with a motor vehicle was the most frequent cause of trauma for eastern box turtles, eastern painted turtles, and common snapping turtles; however, garden-equipment-related trauma was the most frequent cause for rat snakes. Aural abscessation was only seen in eastern box turtles. Eighty percent of cases occurred between May and September and 65% occurred within the five counties closest to the WCV. The majority of morbidity and mortality was the result of human activities. The expanding human population in Virginia likely will continue to have an impact on the health of wild reptiles.

Validity of species status of the parasitic mite Otodectes cynotis

A combined molecular and phenotypic approach was used to determine whether ear mites of the genus Otodectes (Acari: Psoroptidae) belong to a single species. The second internal transcribed spacer (ITS 2) of the rDNA of 16 isolates from 11 cats, two dogs, one arctic fox and two ferrets originating from four different continents was characterized. In addition, mites from dog, cat and arctic fox were investigated morphologically. Sequence comparisons revealed five different, but closely related genotypes which did not segregate according to host species or geographical origin. Morphologically, mites of the three host species did not differ significantly in their body or leg sizes. These investigations support the view that ear mites of the genus Otodectes from different hosts and geographical origins belong to a single species, Otodectes cynotis (Hering).