Detection of levamisole and ivermectin in organ samples from a dead collie.]

A collie, known for its breed-dependent adverse reaction to ivermectin, was without any clinical signs. The dog was prophylactically treated with 3 mg/kg KG (s.c.) of levamisole. Within 15 minutes, the dog showed convulsions, vomitus, and dyspnea, and perished 2.5 hours after injection of the drugs. The pathological findings were not informative as to the cause of death, and with regard to the adverse reactions, additional application of ivermectin was not excluded. Therefore, organ samples were submitted for toxicological analysis of both levamisole and ivermectin. For detection of levamisole and ivermectin, modified GC/MS and HPLC procedures were developed. Concentrations up to 535 micrograms levamisole and up to 26 ng ivermectin were found per g tissue. Both analytical methods are sensitive enough to detect these drugs after application of low doses. This study elucidates that combination of low-dosed ivermectin and levamisole is no recommendable means against adverse effects of ivermectin, with respect to collies. Moreover, the synergistic effects of ivermectin and levamisole suggests the same drug incompatibility in other dog breeds and animal species.     

Retinopathy associated with ivermectin toxicosis in two dogs

CASE DESCRIPTION: 2 dogs (dogs 1 and 2) were examined for sudden onset of blindness. Both dogs had mild obtundation and mydriasis in both eyes. It was thought that dog 1 may have ingested ivermectin; dog 2 had been treated with ivermectin for demodectic mange. CLINICAL FINDINGS: On initial examination, both dogs had mydriasis and decreased pupillary light reflexes in both eyes. Dog 1 had an absent menace response bilaterally. Fundic examination of both eyes in both dogs revealed regions of multifocal retinal edema and folds with low-lying retinal separation. The electroretinogram was extinguished in dog 1 and attenuated in dog 2. Ivermectin was detected in serum samples from both dogs. TREATMENT AND OUTCOME: Both dogs made a complete clinical recovery following cessation of exposure to ivermectin; electroretinographic findings improved, and retinal edema resolved with some residual chorioretinal scarring. CLINICAL RELEVANCE: To our knowledge, this is the first report of resolution of retinal edema and electroretinographic changes associated with ivermectin toxicosis in dogs. In dogs that develop blindness suddenly, fundic examination, electroretinography, and assessment of serum ivermectin concentration are diagnostically useful, even if exposure to ivermectin is unknown.     

Safety of moxidectin in avermectin-sensitive collies

OBJECTIVE: To evaluate the safety of moxidectin administration at doses of 30, 60, and 90 microg/kg of body weight (10, 20, and 30 times the manufacturer's recommended dose) in avermectin-sensitive Collies. ANIMALS: 24 Collies. PROCEDURE: Collies with mild to severe reactions to ivermectin challenge (120 mg/kg; 20 times the recommended dose for heartworm prevention) were used. Six replicates of 4 dogs each were formed on the basis of body weight and severity of reaction to ivermectin test dose. Within replicates, each dog was randomly allocated to treatment with oral administration of 30, 60, or 90 microg of moxidectin/kg or was given a comparable volume of placebo tablet formulation. Dogs were observed hourly for the first 8 hours and twice daily thereafter for 1 month for signs of toxicosis. RESULTS: Signs of toxicosis were not observed in any control group dog throughout the treatment observation period. Likewise, signs of toxicosis were not observed in any dog receiving moxidectin at 30, 60, or 90 microg/kg. CONCLUSIONS AND CLINICAL RELEVANCE: The moxidectin formulation used in the study reported here appears to have a wider margin of safety than ivermectin or milbemycin in avermectin-sensitive Collies.     

Evaluation of the safety of ivermectin administered in a beef-based formulation to ivermectin-sensitive Collies

Twenty-four Collies sensitive to the toxic effects of ivermectin, when administered at high dosages, were studied to evaluate the effects of repeated monthly treatment with an ivermectin beef-based formulation at amounts up to 10 times the dosage recommended for heartworm prevention in dogs. Collies were treated 3 times at 30-day intervals at rates of 12, 36, or 60 micrograms of ivermectin/kg of body weight, or with vehicle. Complete physical and neurologic examinations were performed on all dogs prior to the first treatment and after the final treatment. Clinical observations and ivermectin reaction scores were recorded daily for each dog throughout the study. Clinical or neurologic signs characteristic of ivermectin toxicosis were not observed for any dog during the study. Single episodes of vomiting were recorded for 2 vehicle-treated dogs and 2 dogs treated with ivermectin at 12 micrograms/kg from 6 to 21 days after treatment. At the end of the study, all dogs were challenge-exposed with ivermectin at 120 micrograms/kg to reconfirm their sensitivity to this class of compounds. All dogs developed signs typical of ivermectin toxicosis during the subsequent 48- to 72-hour period. Results of this study demonstrated that ivermectin can be administered repeatedly without adverse effects at rates up to 60 micrograms/kg (10 times the recommended use level) to Collies known to be sensitive to this drug.     

Electroretinographic changes after intravenous lipid emulsion therapy in a dog and a foal with ivermectin toxicosis

This case report describes ivermectin‐induced blindness in a dog and a foal with normal ophthalmic fundic examinations and attenuated electroretinography (ERG). Subsequent recovery in ERG was noted following intravenous lipid emulsion (ILE) therapy. A dog and a foal were evaluated for ivermectin‐induced blindness. Clinical signs included dull mentation, absent pupillary light reflexes (PLRs), and absent menace on presentation. The animals had normal fundoscopic examinations; however, in both cases ERG was consistent with neurosensory retinal dysfunction. Following ILE therapy for ivermectin toxicosis, return of menace, PLRs, and normal mentation were noted, as was improvement in ERG and serum ivermectin levels. These are the first documented cases of ivermectin‐induced blindness in a dog and a foal with normal fundic examinations and attenuated ERG. ERG improved in both animals after ILE therapy. ERG may assist in the diagnosis of ivermectin toxicosis in dogs and horses. ILE therapy may hasten recovery in treatment of ivermectin‐induced blindness.     

Proliferative glomerulonephritis and chronic active hepatitis with cirrhosis associated with Corynebacterium parvum immunotherapy in a dog

Ivermectin, a broad-spectrum antiparasitic agent, was believed responsible for signs of CNS dysfunction in a dog. Within 2 hours of oral administration of ivermectin, the dog had hind limb ataxia. Neurologic signs progressed rapidly until the dog was in a semicomatose state at admission 20 hours later. The dog improved gradually under supportive care. The ivermectin had been given for suspected endoparasitism. Clinical signs were similar to those reported in dogs with clinical and experimental exposure to ivermectin.     

Efficacy of ivermectin controlled-release capsules for the control and prevention of nasal bot infestations in sheep

Objective To investigate the therapeutic and prophylactic efficacy of an ivermectin controlled-release capsule against nasal bots (Oestrus ovis) in sheep.
Design Trial 1 – A pen study with controls. Trial 2 – A field study with controls.
Animals Trial 1 – Forty Merino wethers with natural infestations of nasal bot were used. Trial 2 – One hundred nasal bot-free wethers were used.
Procedure Trial 1 – Ten randomly selected animals were slaughtered and the heads split and examined to confirm bot infestation. Fifteen animals were allocated to untreated controls and 15 to treatment with a controlled-release capsule delivering ivermectin at ≥ 20 μg/kg/day for 100 days. Twenty-nine days after treatment the sheep were killed and examined for nasal bots. Trial 2 – Nasal bot-free sheep were allocated to two groups of 45 animals. One group was untreated the other sheep were treated with capsules as above. The sheep were grazed as a single group exposed to natural challenge from O ovis . Ninety days after treatment the animals were slaughtered and examined for nasal bot infestation.
Results Trial 1 – Live O ovis larvae were recovered from 60% of control sheep. No live larvae were collected from treated sheep. Trial 2 – Forty-one percent of untreated sheep harbored nasal bot infestations. No live larvae were collected from any treated animal.
Conclusion Treatment with a single ivermectin controlled-release capsule was 100% effective against existing infestations of O ovis and as a prophylactic treatment for this parasite.     

Efficacy of an ivermectin and pyrantel pamoate combination against adult hookworm, Ancylostoma braziliense, in dogs

A chewable tablet incorporating ivermectin and pyrantel was tested in 12 Beagle dogs for efficacy against the adult hookworm, Ancylostoma braziliense. The dogs were administered infective larvae of A braziliense orally. Twenty-one days after infection the dogs were weighed and allocated randomly to receive either an oral treatment with ivermectin and pyrantel in a beef-based chewable tablet or no treatment. The chewable tablet was a commercially available product, which was made to deliver ivermectin at 6 μg/kg and pyrantel at 5.0 mg/kg to each dog. Seven days after treatment the dogs were euthanased, necropsied, and examined for adult hookworms. At necropsy, no adult A braziliense was observed in any of the 6 treated dogs and all 6 dogs that had been left untreated were infected with adult A braziliense (range, 48 to 161). It was concluded that this combination product is 100% efficacious against adult A braziliense.     

An Epidemiological Survey of Therapy and Diagnostic Procedures Used by Norwegian Small Animal Practitioners in Cases of Nasal Mite (Pneumonyssoides caninum) Infection in Dogs

Forty per cent of the members of the Norwegian Small Animal Veterinary Association (NSAVA) returned a questionnaire regarding the treatment and diagnosis of canine nasal mite infection in their practices in 1996. A total of 2392 dogs were treated for this infection by 156 NSAVA members in clinical practice in that year, averaging 15.3 treated dogs per veterinarian. An estimated minimum of 6000 Norwegian dogs were treated for nasal mite infection in 1996, at an estimated cost of treatment exceeding 3.3 million NOK. Fifty-nine per cent of the practitioners included at least a case history and clinical examination as diagnostic criteria prior to initiating treatment for nasal mite infection. Fewer than 10% routinely performed more thorough diagnostic procedures, and only 1.8% of the diagnoses were verified prior to treatment. A total of 27 different treatment regimens, involving either subcutaneously injected ivermectin or orally administered milbemycin oxime, were routinely used by NSAVA veterinarians to treat these dogs. Seventy-two (53%) of the veterinarians used ivermectin exclusively, 14 (10%) used milbemycin oxime exclusively, while 50 (37%) used both ivermectin and milbemycin oxime. No other drugs were used. Evaluation of treatment was made by assessing resolution of the clinical signs following treatment, and 97% of the veterinarians were satisfied with the effect of the treatment regimen they used. Adverse side-effects following treatment for nasal mite infection in 1996 were seen on 9 occasions; 4 following ivermectin administration and 2 following milbemycin oxime treatment, while in 3 cases no information on the drug used was provided. The risk of adverse reactions to treatment of nasal mite infection in dogs was 0.4%.     

Efficacy of an ivermectin/pyrantel pamoate chewable formulation against the canine hookworms, Uncinaria stenocephala and Ancylostoma caninum.

The effectiveness of the combination of pyrantel pamoate (5 mg kg-1) and ivermectin (6 micrograms kg-1) against the canine hookworms Uncinaria stenocephala and Ancylostoma caninum was determined. This combination is intended for monthly use as a heartworm preventative and for treatment and control of canine hookworms. The formulation was found to be effective (99.6% reduction in worm burdens) against both species of hookworms in experimentally infected dogs. No adverse effects due to the drug combination were observed in any dog during the course of this study.     

伊维菌素注射剂与浇泼剂驱除藏犬肠道线虫的疗效

应用伊维菌素注射剂与浇泼剂,驱除藏犬肠道线虫,并用粪检法检查其疗效。结果表明：伊维菌素注射剂0.2mg/kg剂量对藏犬肠道线虫的虫卵转阴率与减少率均为100.0%;伊维菌素浇泼剂0.5mg/kg剂量转阴率及减少率为100%。     

Canine atopic disease: investigations of eosinophils and the nasal mucosa

Blood eosinophil counts were comparable in dogs with and without canine atopic disease. Eosinophils were not observed in the nasal smears of any of the dogs studied. Of 46 dogs with atopic disease, a significant increase (P less than 0.001) in nasal airway resistance was observed in 2 dogs after nasal provocation with nebulized allergens of grasses and in 1 dog after provocation with summer weed extracts.     

Demodex injai infestation and dorsal greasy skin and hair in eight wirehaired fox terrier dogs

Demodex injai mites were detected on trichoscopic examinations and/or deep skin scrapings in eight wirehaired fox terrier dogs with dorsal greasy skin and hair. Histological examination performed in five dogs revealed marked sebaceous gland hyperplasia with lympho-plasmacytic periadnexal dermatitis in all of them. One mite section was observed in one patient. Seven dogs were parasitologically cured after 2 to 7 months of oral ivermectin treatment. Greasy skin and hair resolved in four dogs, was partially reduced in two dogs and persisted in the remaining dog. Skin biopsies were repeated after parasitological cure in two dogs and revealed the persistence of sebaceous gland hyperplasia with mild lympho-plasmacytic periadnexal dermatitis and no parasites. Based on the findings in this case series, the terrier dog breed might be at increased risk for the development of D. injai mite infestation associated with dorsal greasy skin and hair, and microscopically with sebaceous gland hyperplasia. Persistence of sebaceous gland hyperplasia after parasitological cure in some patients suggested that this histological finding may not always be resulting from Demodex infestation. Moreover, low numbers of adult mites and variable clinical responses to acaricidal therapy suggested a contributory rather than a major role of D. injai in this skin condition. Dermatopathological diagnosis of sebaceous gland hyperplasia, particularly in case of dorsal trunk specimens from terrier dog breeds, warrants the search for D. injai mites on trichoscopic examinations and/or deep skin scrapings.     

Nasal tumor with widespread cutaneous metastases in a Golden Retriever

An intact, 8-year-old, male Golden Retriever dog was presented for evaluation of a nasal mass and approximately 30 firm, raised, variably ulcerated dermal and subcutaneous masses. Histopathology of both nasal and multiple skin masses revealed multiple nonencapsulated, infiltrative masses comprising clusters, anastomosing trabeculae, and packets of neoplastic, round to ovoid, hyperchromatic cells with marked nuclear molding. Surrounding the neoplastic cells was a marked stromal response in which many of the spindle-shaped cells expressed muscle-specific actin and had ultrastructural features consistent with myofibroblasts. A literature search indicates that this is the first report in a peer-reviewed journal of cutaneous metastasis of a nasal neuroendocrine tumor in any domestic animal species.     

Nasal polyps in dogs: five cases (2005 to 2011)

This series describes five dogs with nasal polyps diagnosed between 2000 and 2011. Clinical signs included reverse sneezing, nasal discharge, epistaxsis, and stertor when breathing. Computerised tomographic findings included soft tissue mass, turbinate destruction, extension through the bony nasal septum and partial lysis of bones surrounding the nasal cavity. Three dogs were treated by dorsal rhinotomy, one dog was treated by ventral rhinotomy, and in one dog the polyp tissue was removed during nasal flushing. Three dogs have no clinical signs of nasal disease. One dog had confirmed recurrence of nasal polyps and was successfully treated with megavoltage radiation. One dog had recurrent nasal disease eight months after dorsal rhinotomy. Nasal polyps are a possible cause of nasal disease in dogs with nasal discharge, epistaxsis and stertor, and a differential diagnosis for dogs with extensive soft tissue lesions of the nasal cavities on computerised tomography. Nasal polyps can be treated successfully by rhinotomy in some cases but may reoccur.     

Delayed recurrence of nasal aspergillosis in a dog

A two-year-old, female spayed Australian cattle dog was diagnosed with nasal aspergillosis. The dog was treated topically with clotrimazole. Clinical signs recurred two months later and the clotrimazole treatment was repeated and 5 mg/kg itraconazole twice daily was added to it. The recommended dose of itraconazole for nasal aspergillosis is 5 mg/kg twice daily administered orally. The dog's symptoms completely resolved, but it developed an adverse febrile reaction to the Itraconazole. The Itraconazole was discontinued and the dog remained asymptomatic for four years. The dog then developed mucopurulent discharge from the right nostril and was diagnosed as having recurrent nasal aspergillosis. Itraconazole at 5 mg/kg twice daily was prescribed, which again induced a fever. When the itraconazole was decreased to 5 mg/kg once daily there were no fever episodes, but the nasal discharge was not completely resolved. The dog was then treated with topical clotrimazole Infusion, and maintained on 5 mg/kg itraconazole daily. To the authors' knowledge, this case is unique because of the delayed recurrence of nasal aspergillosis. Additionally, the idiosyncratic febrile reaction to the itraconazole has not previously been reported in the veterinary literature, but is similar to reports of drug-induced fever in humans.     

Failure to identify an association between serologic or molecular evidence of Bartonella infection and idiopathic rhinitis in dogs

OBJECTIVE: To determine whether infection with or exposure to Bartonella spp was associated with idiopathic rhinitis in dogs. DESIGN: Case-control study. ANIMALS: 44 dogs with idiopathic nasal discharge and 63 age- and weight-matched control dogs without nasal discharge and no clinical signs of bartonellosis. Procedures-Serum was tested for antibodies against Bartonella henselae and Bartonella vinsonii subsp berkhoffii with indirect fluorescent antibody assays. Blood was tested for Bartonella DNA with a PCR assay. RESULTS: Results of the antibody and PCR assays were negative for all 44 dogs with idiopathic nasal discharge. One control dog had antibodies against B henselae; a second control dog had positive PCR assay results. We did not detect a significant association between assay results and group designation. CONCLUSIONS AND CLINICAL RELEVANCE: The present study failed to confirm an association between idiopathic rhinitis and exposure to or infection with Bartonella spp in dogs. Findings do not rule out the possibility that Bartonella infection may cause nasal discharge in some dogs, but the failure to find any evidence of exposure to or infection with Bartonella spp in dogs with idiopathic nasal discharge suggested that Bartonella infection was not a common cause of the disease.     

Intranasal hemangiosarcoma in a dog

Magnetic resonance (MR) was conducted for an 8-year-old, intact male Spitz with sneezing, serous discharge and epistaxis from the left nasal cavity. MR imaging showed a nasal cavity-occupied mass of iso-intensity on T1WI , high-intensity on T2WI and markedly enhanced on contrast-enhanced T1WI at parts of rostal to medial ocular angle in the left cavity. After Surgery and intraoperative radiation, the mass was diagnosed intranasal hemangiosarcoma by histopathology. Although the dog showed the finding, which suggested recurrence after the treatment ending, about 30 months later, it maintained good conditions without evidence of metastasis.     

Ivermectin toxicosis in a dog

A 5-year-old male Doberman Pinscher was examined after ingesting an equine paste dewormer containing approximately 115 mg of ivermectin. Clinical signs consisted of profound hypothermia, mild dehydration, dilated unresponsive pupils, localized muscle group fasciculations around the face and hind limbs, and no response to any external stimuli. Twelve days after parenteral administration of isotonic fluids and IV administration of dexamethasone and dimethyl sulfoxide, the dog returned to a clinically normal neurologic state. Ivermectin toxicosis has been reported frequently in Collies; however, other breeds may have idiosyncratic reactions to low doses. Patients with severe toxicosis should eventually recover completely if given appropriate intensive care.     

Cosmetic rostral nasal reconstruction after nasal planum and premaxilla resection: technique and results in two dogs

Objective— To describe a novel reconstructive technique after nasal planum and premaxilla resection.
Study Design— Case report.
Animals— Dogs (n=2) with squamous cell carcinoma (SCC) of the nasal planum.
Methods— A 9-year-old neutered female Labrador retriever (dog 1) and an 11–year-old neutered male Golden retriever (dog 2) had resection of the nasal planum and premaxilla for treatment of locally invasive SCC. Reconstruction of a nasal planum facsimile was based on use of the nonhaired pigmented margins of bilateral labial mucocutaneous rotation-advancement flaps.
Results— Reconstruction of the premaxilla by construction of a nasal planum facsimile resulted in uncomplicated wound healing and improved cosmesis. There was no tumor recurrence at 1290 (dog 1) and 210 (dog 2) days after surgery.
Conclusion— Reconstruction of a nasal planum facsimile was successfully performed without complications in 2 dogs with high owner satisfaction with cosmetic appearance.
Clinical Relevance— This technique represents a significant advancement in surgical cosmetic outcome, may potentially reduce postoperative complications, and should be considered for dogs requiring nasal reconstruction after nasal planum resection with premaxillectomy.