Monthly application of 10 per cent moxidectin and 2{middle dot}5 per cent imidacloprid spot-on to prevent relapses in generalised demodicosis: a pilot study

Canine generalised demodicosis (GD) can be difficult to cure, with some dogs requiring life-long treatment. The aim of this pilot study was to evaluate the effectiveness of monthly 10 per cent moxidectin/2·5 per cent imidacloprid spot-on in maintaining long-term (12 months) clinical and parasitological remission in dogs with relapsing GD. Fourteen dogs were included: 10 with juvenile-onset GD (JOGD) and four with adult-onset GD (AOGD). All?dogs had been treated previously and relapsed (1-4 times). Each dog was treated again with either milbemycin oxime 2 mg/kg or ivermectin 400 μg/kg orally once daily, until two consecutive negative skin scrapings at one-month intervals (total 4-7 months of treatment). After treatment discontinuation, 10 per cent moxidectin/2·5 per cent imidacloprid spot-on was applied monthly for 12 months. Dogs were rechecked after 1, 2, 3, 6 and 12 months, and multiple skin scrapings were taken. Twelve dogs completed the study and were clinically normal and parasitologically negative at each recheck (four dogs with AOGD and eight with JOGD). One dog died suddenly for unrelated reasons, and one dog relapsed. Results of this pilot study suggest that monthly application of 10 per cent moxidectin/2·5 per cent imidacloprid spot-on may be effective as maintenance therapy in relapsing cases of GD.     

New approaches to the treatment of canine demodicosis.

Topical amitraz is the only approved treatment for CGD; however, it is not always effective or well tolerated. Extra-label use of amitraz, milbemycin oxime, ivermectin, and moxidectin may be effective therapeutical alternatives for dogs with resistant CGD or dogs that have an intolerance to the licensed amitraz protocol. It appears that oral administration of milbemycin oxime (1-2 mg/kg), ivermectin (400-600 micrograms/kg), and moxidectin (400 micrograms/kg) daily is a practical therapeutical alternative and would provide similar cure rates. Nevertheless, milbemycin oxime is expensive, ivermectin is potentially more toxic, and only limited information is available on moxidectin. The average treatment duration with these new regimens is 4 months, with an expected range of 3 to 10 months. Treatment should be administered daily for a minimum of 3 months and for at least 1 month after a series of negative skin scrapings. For chronic cases or cases that take a relatively long time to respond to therapy, 2 to 3 months of treatment beyond negative scrapings may be more appropriate. Dogs with CGD always approach clinical normalcy weeks to months before negative skin scrapings are obtained. All dogs respond at their own rate; as long as the skin scrapings at each visit show fewer mites, the current therapy should be continued for an additional month. If the mite count starts to increase, this may suggest that the treatment protocol is not being followed or it may be that the therapy chosen was suboptimally effective. Although CGD is still a disease that is not easily treated, the prognosis for dogs with this disorder has dramatically improved in the past few years. It must be remembered, however, that the treatment alternatives for CGD described above are not approved and should not be used unless the approved therapeutical regimen has failed.     

Clinicopathologic findings, sensitivity to house dust mites and efficacy of milbemycin oxime treatment of dogs with Cheyletiella sp. infestation

Twenty-three dogs with positive skin scrapings for Cheyletiella sp. were treated with milbemycin oxime using a protocol approximating 2 mg kg⁻¹ orally once weekly for three weeks. Nineteen of these dogs belonged to a household of 41 dogs and two dogs were in households with one other dog. All in-contact dogs were treated. Pre-treatment intradermal skin tests showed positive reactions to D. farinae in 13 dogs and to D. pteronyssinus in 12 dogs; these became negative post-treatment in four and seven dogs, respectively. All dogs showed a dramatic reduction in clinical signs one week after the third treatment. Eighteen dogs no longer had mites on skin scrapings, three had dead mites and two had deformed eggs. Recurrence of clinical signs necessitated two additional courses of the protocol in the multiple dog household and for a dog receiving immunosuppressive treatment for pemphigus foliaceus. Possible adverse reactions to the milbemycin (vomiting, lethargy) were noted once in two dogs.     

米尔贝肟对自然感染疥螨病犬的治疗效果

为了评价米尔贝肟对临床自然感染疥螨犬的治疗效果,选用自然感染疥螨犬65例,随机选择5条服用伊维菌素,另外60条随机分为3组,分别服用高剂量(2g/kg体重)、中剂量(1g/kg体重)、低剂量(0.5g/kg体重)的米尔贝肟。给药后2、14、28、42d和56d,刮取皮屑,检查螨虫和虫卵,同时观察临床症状。试验结束时米尔贝肟高剂量组、伊维菌素组的无螨虫犬的比例和螨虫的下降率均为100%,临床症状如红疹、结痂、过度角化等现象均消失,所有动物毛发都开始大范围重生;米尔贝肟中、低剂量组结果稍差。米尔贝肟按2g/kg体重剂量,每周1次,连续用药3周,给药对自然感染疥螨病犬有很好的治疗效果。     

A comparison between ethanol-induced chemical ablation and ivermectin plus prednizolone in the treatment of symptomatic esophageal spirocercosis in the dog: a prospective study on 14 natural cases

This study included a total of 14 dogs with spontaneous esophageal spirocercosis. Historical and clinical evidence of esophageal dysphagia, detection of parasitic ova in fecal samples and endoscopic documentation of esophageal nodules were the inclusion criteria. The animals were randomly assigned into two groups: group A (n = 6 ) dogs received two intranodular injections of absolute ethanol (96%) via a through-the-endoscope injector, at weekly intervals; group B (n = 8) dogs were put on ivermectin (600 microg/kg BW, subcutaneously, twice, 14 days apart) and oral prednisolone (0.5mg/kg BW, every 12h, for a total of 3 weeks, tapering the dose accordingly). Clinical and fecal examination as well as endoscopy, were performed on admission and at 20, 60 and 180 days from the beginning of the treatment. One group A dog responded poorly and died of pyothorax during the trial and another developed esophagitis due to accidental intraluminal ethanol infusion, only to experience an uneventful recovery. At different times during the 6-month follow-up period, there was a complete disappearance of the clinical signs in 4/6 group A dogs. However, full nodular regression was achieved only in one dog, and parasitic ova were still found in the feces of 4/6 dogs. At the same period of time in five group B dogs still available for evaluation, resolution of the clinical signs and complete nodular regression were seen in four and five animals, respectively, while negative fecal results were obtained in all dogs (8/8) of the same group 2 months from the beginning of the treatment. No significant difference was found between the groups, regarding the resolution of clinical signs, though group B dogs demonstrated a significantly higher rate of regression of esophageal nodules as well as negative fecal results, compared to group A dogs. The combination of ivermectin and prednizolone may be considered an effective treatment in the symptomatic and evidently asymptomatic esophageal spirocercosis of the dog.     

Efficacy of a novel formulation of metaflumizone plus amitraz for the treatment of demodectic mange in dogs

A novel spot-on formulation containing metaflumizone plus amitraz (ProMeris/ProMeris Duo for Dogs, Fort Dodge Animal Health, Overland Park, KS) was evaluated for efficacy against demodectic mange mites in naturally infested dogs. Sixteen dogs were allocated to two equal groups and individually housed. Eight of the dogs were treated topically with metaflumizone plus amitraz at the proposed minimum dose rate (20mg/kg of each of metaflumizone and amitraz, 0.133ml/kg) on Days 0, 28, and 56. The other eight were treated with metaflumizone plus amitraz at the proposed minimum dose rate on Days 0, 14, 28, 42, 56, and 70. Mite numbers were estimated from skin scrapings taken on Days -3 to -1, 28, 56, and 84. Clinical signs of mange and the extent of demodectic lesions on each dog were evaluated when skin scrapings were conducted. Efficacy of the treatment was based on a reduction in mite numbers and an assessment of the clinical signs associated with canine demodectic mange. Treatment at monthly or two-weekly intervals for 3 months resulted in a rapid reduction in mite numbers (>94 and >99% for the monthly and two-weekly treatments, respectively) and an improvement in clinical signs. Success rates, based on zero mite counts in skin scrapings at Day 84 were 42.9 and 62.5% of dogs for the monthly and two-weekly regimens, respectively.     

Long-term delivery of ivermectin by use of poly(D,L-lactic-co-glycolic)acid microparticles in dogs

OBJECTIVE: To evaluate the potential utility of poly(D,L-lactic-co-glycolic)acid (PLGA) as a long-acting biodegradable drug delivery matrix for ivermectin used in the prevention of heartworm disease in dogs. ANIMALS: 30 adult female dogs. PROCEDURE: Microparticle formulations containing 25 weight percent (wt%), 35 wt%, and 50 wt% ivermectin were prepared by an oil-in-water emulsion technique with solvent extraction into excess water. A fourth formulation, consisting of a mixture of 15 wt% and 50 wt% ivermectin microparticles, was blended in a 1:1 ratio to result in a 32.5 wt% ivermectin formulation. Formulations were administered once on Day 0 to groups of 6 dogs at a dose of 0.5 mg of ivermectin/kg, s.c. Half of the dogs in each treatment group and 3 untreated control dogs were infected with Dirofilaria immitis larvae 121 and 170 days after treatment. Six months after infection, dogs were euthanatized and necropsies were performed. Pharmacokinetics and efficacy were investigated. RESULTS: Analysis of pharmacokinetic data revealed sustained release of ivermectin during at least 287 days in 3 distinct phases: a small initial peak, followed by release of drug through diffusion, and polymer degradation. Untreated control dogs were all infected with heartworms. Heartworms were not found in any of the dogs in the ivermectin-PLGA treated groups. Adverse clinical signs were not observed. CONCLUSIONS AND CLINICAL RELEVANCE: All formulations were 100% effective in preventing development of adult heartworms. Results indicate that PLGA microparticles are a promising drug delivery matrix for use with ivermectin for the prevention of heartworm disease for at least 6 months after treatment.     

中药犬螨灵对犬蠕形螨的疗效试验

为筛选具有显著治疗犬蠕形螨的中药制剂,试验将中药小茴香、蛇床子、羊蹄根采用水煮醇沉及蒸馏等提取方法制备成中药制剂犬螨灵,并观察其对犬蠕形螨的疗效。将犬螨灵设为高、中、低3个浓度,其生药含量分别为2.0、1.0和0.5 g/mL,采用点滴法进行体外抑杀蠕形螨试验,在此基础上对12只接种蠕形螨的试验犬进行治疗试验,为验证治疗效果,对临床上已确诊的45只患有蠕形螨的病犬分3组进行临床治疗试验。结果显示,中药犬螨灵3种剂量均有较强的体外抑杀螨虫作用,高剂量组作用后4 h即可完全抑杀蠕形螨,1%伊维菌素对照组则为作用后8 h;高剂量组在治疗3周后,患处有大量新毛生长,红疹结节和皮屑消失,患处皮肤已痊愈,1%伊维菌素治疗组患犬皮肤好转,仅有少量新毛生长,不能达到痊愈标准;高、中剂量组皮肤刮取物螨虫数量平均比例及停药1个月后复发率均为0,1%伊维菌素治疗组皮肤刮取物螨虫数量平均比例及停药1月后的复发率分别为10.63%和9.17%。高剂量中药犬螨灵与1%伊维菌素两种药物联合治疗组,对临床上患病犬进行3周治疗,其虫卵平均转阴率、治愈率与平均治愈天数分别为100.00%、93.33%和19.56 d,其效果均优于中药犬螨灵与1%伊维菌素单独治疗组。结果表明,高剂量自制中药制剂犬螨灵对犬蠕形螨体外抑杀作用、接种蠕形螨试验犬与临床自然感染病例均有显著的治疗效果,优于1%伊维菌素对照组,犬螨灵作为中药杀螨虫制剂具有较好的市场开发前景。     

Efficacy of Chinese Herbal Medicine Canine Acariasis Spirit on Demodex canis

In order to screen the Chinese herbal medicine for the treatment of Demodex canis, canine acariasis spirit was prepared by Foeniculum vulgare, Fructus cnidii and Bauhinia by water alcohol precipitation and distillation extraction methods. To observe the effect on Demodex canis, canine acariasis spirit was set to high, medium and low concentrations, the content of crude drug were 2.0, 1.0 and 0.5 g/mL, respectively. The experiment of killing Demodex canis was carried out by drop method. On this basis, 12 dogs inoculated with Demodex canis were treated. In order to verify the therapeutic effect, 45 clinically diagnosed dogs with Demodex canis were divided into three groups. The results showed that 3 doses of the traditional Chinese medicine canine acariasis spirit all had strong inhibition effect to kill mites, the high dose group could completely kill Demodex canis only 4 h after treatment, the action of 1% ivermectin control group was 8 h after treatment; 3 weeks later, a large number of new hair grew, rash and skin nodules disappeared, the skin lesion had healed in the affected area of high dose group, in 1% ivermectin treatment group, the dog skin improved, only a small amount of new hair grew, it couldn't cure standard; In the high and middle dose group, the average number of the ratio of skin scraping mites and the recurrence rate after drug withdrawal was 0 in one month later; The average number of mites proportion and recurrence rates of skin scrapings in 1% ivermectin treatment group were 10.63% and 9.17% in one month later; After 3 weeks of treatment, the total average eggs negative rate, cure rate and average cure days were 100.00%, 93.33% and 19.56 d in high dose traditional Chinese medicine canine acariasis spirit and 1% ivermectin combined treatment group, the results were better than the traditional Chinese medicine canine acariasis spirit and 1% ivermectin alone treatment group. The results showed that the effect of the high dose group self-made Chinese medicine canine acariasis spirit on killing Demodex canis in vitro, inoculation of Demodex canis and clinical therapeutic effect of natural infection cases were significantly better than 1% ivermectin control group, canine acariasis spirit as a traditional Chinese medicine preparation would have a good market development prospects.     

Comparison of subcutaneous ivermectin and oral moxidectin for the treatment of notoedric acariasis in hamsters

Thirty hamsters diagnosed with a Notoedres infestation on the basis of their clinical signs and skin scrapings were allocated to three matched groups. The hamsters in group 1 received ivermectin at 400 microg/kg subcutaneously once a week for eight weeks, those in group 2 were treated with moxidectin at 400 microg/kg orally once a week, and those in group 3 were treated with moxidectin at the same dosage, but twice a week. The hamsters' skin lesions were scored weekly on the basis of the severity of crusting, erythema, scaling and excoriations at various sites. In all three groups the lesion scores were significantly lower after four and eight weeks, and there was no significant difference between the efficacy of the treatments. However, at the end of the treatment, skin scrapings were negative in only 60 to 70 per cent of the animals in each group.     

The efficacy of an imidacloprid/moxidectin combination against naturally acquired Sarcoptes scabiei infestations on dogs

The study was undertaken to evaluate and compare the efficacy of an imidacloprid (10% w/v)/moxidectin (2.5% w/v) combination (Advocate Bayer HealthCare, Animal Health) with that of selamectin for the treatment of Sarcoptes scabiei on dogs. Thirty naturally infested dogs, of which one was later withdrawn because of distemper, were allocated to two equal groups and individually housed. The dogs in each group were treated twice, four weeks apart, with either the combination product (0.1 mL/kg body weight) or with selamectin (0.05 mL/kg body weight) administered topically. Skin scrapings were made every 14 days over a period of 50 to 64 days after the first treatment to quantify mite numbers. Clinical signs and the extent of sarcoptic lesions were assessed on each dog when skin scrapings were made. Efficacy was based on the presence or absence of mites, supported by clinical signs associated with canine sarcoptic mange. From Day 22 and onwards no Sarcoptes mites were found in the skin scrapings of any of the treated dogs. Treatment with the imidacloprid/moxidectin formulation or with selamectin was highly effective against Sarcoptes scabiei and resulted in an almost complete resolution of clinical signs within 50 to 64 days after the initial treatment.     

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.     

An evaluation of ivermectin in the treatment of sarcoptic mange in dogs

A colony of mixed-breed dogs (n = 298) naturally infested with Sarcoptes scabiei was treated, twice, with 200 micrograms of ivermectin/kg of body weight subcutaneously at 14-day intervals. After the initial injection, positive skin scrapings from 20 treated dogs decreased from 7 to 1 and the degree of pruritus decreased. In contrast, positive skin scrapings from 22 nontreated dogs increased from 10 to 14, and there was an additional deterioration in the condition of the skin and an increase in the degree of pruritus. Complete control was noticed in all treated dogs by posttreatment day 28 (14 days after a 2nd injection) based on negative skin scrapings.     

Evaluation of a covered-rod silicone implant containing ivermectin for long-term prevention of heartworm infection in dogs

OBJECTIVE: To evaluate use of covered-rod (CR) silicone implants containing ivermectin for long-term prevention of infection with Dirofilaria immitisin dogs. ANIMALS: 145 adult male and female dogs. PROCEDURES: Dogs received implants of different sizes, and ivermectin concentrations and serum ivermectin concentrations were monitored for 16, 57, and 56 weeks, respectively, in 3 preclinical dose selection studies. Ability of implants to prevent infection with D immitis was evaluated in 2 further studies; dogs were challenged with 50 infective third-stage larvae 52 weeks after implant administration and necropsied 145 days after challenge, and the total number of adult heartworms was counted. A field study was then undertaken in which client-owned dogs received an implant and plasma samples were collected at intervals until week 52 for ivermectin analysis and heartworm antigen determination. RESULTS: Use of the implants resulted in maintenance of an ivermectin concentration > or = 0.2 ng/mL for 12 months. In challenge studies, no treated dogs had adult heartworms, in contrast to untreated dogs, which all had adult heartworms at necropsy. In the field study, dogs treated with an implant had negative results of heartworm antigen testing for 12 months. CONCLUSIONS AND CLINICAL RELEVANCE: The CR silicone implant containing 7.3 mg of ivermectin was 100% effective in preventing experimental infection with D immitislarvae and resulted in negative results for heartworm antigen in a field trial. This product has the potential to alleviate poor owner compliance with monthly prevention regimens.     

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.     

Long-term outcomes in dogs with sinonasal aspergillosis treated with intranasal infusions of enilconazole

Long-term outcomes (mean 38+/-17 months) were evaluated in 27 dogs with sinonasal aspergillosis after successful medical treatment using intranasal infusions of 1% or 2% enilconazole (1%, n=15; 2%, n=12). Long-term outcomes with both treatment protocols were good, with half of the dogs being asymptomatic throughout the follow-up period. The remaining dogs showed mild clinical signs compatible with chronic rhinitis/sinusitis. These clinical signs were interpreted as chronic lymphoplasmacytic rhinitis/sinusitis and episodes of bacterial rather than fungal infection. Three dogs had confirmed reinfection or relapse 2 to 36 months after clinical resolution.     

Assessment of toxicosis induced by high-dose administration of milbemycin oxime in collies

Fifteen Collies, previously having mild reactions to ivermectin challenge (120 micrograms/kg of body weight; 20 times the recommended dosage level), were studied to evaluate the effects of milbemycin oxime administration at 5 and 10 mg/kg (10 and 20 times the manufacturer's recommended dosage). Five replicates, comprising 3 dogs each, were formed on the basis of body weight. Within replicates, each dog was randomly allocated to treatment with 5 or 10 mg of milbemycin/kg or served as a untreated control. Dogs were examined repeatedly for signs of toxicosis for 4 days after treatment and daily thereafter. Two of 5 dogs treated at 5 mg/kg (10x) developed signs of mild depression on the day of treatment, but were normal 24 hours after treatment. All 5 dogs treated at 10 mg/kg (20x) developed signs of mild depression and ataxia by 6 hours. Signs persisted for 24 hours in 3 dogs. Two of these dogs also had mydriasis, whereas 3 salivated excessively. All dogs recovered completely by day 2 after treatment. The results of this study demonstrated that Collies sensitive to the effects of 120 micrograms of ivermectin (20x)/kg show similar sensitivity to the effects of milbemycin oxine administered at 10 mg/kg (20x). We conclude that ivermectin and milbemycin commercial formulations have similar margins of safety and that milbemycin toxicosis appears to be dose-dependent in Collies with a demonstrated sensitivity to ivermectin.     

Dermal safety study with imidacloprid/moxidectin topical solution in the ivermectin-sensitive collie

A study was conducted to determine the safety of the dermal application of 10% imidacloprid/2.5% moxidectin topical solution in ivermectin-sensitive collies. Each milliliter of this solution contains 100mg of imidacloprid and 25mg of moxidectin. A total of 21 collies were prescreened for ivermectin-sensitivity and heartworm negative status prior to selection for the study. Animals were assigned based on the maximum ivermectin-sensitivity score demonstrated during the prestudy screening. Treatment groups included a 3x and 5x test article group, and a 3x and 5x mineral oil control group. The 3x and 5x doses were administered at three and five times, respectively, the 1x dose based on the animal's body weight. On day 0, 3 of the 21 dogs were treated with dermal applications of a preliminary dose of 3x test article to screen for unexpected signs of toxicity with the remaining 18 dogs being treated with 3x mineral oil to blind for the volume of liquid applied. After no signs of toxicity were observed, these same three dogs were treated with 3x of test article and 2x mineral oil on days 28 and 56. The remaining 18 animals were equally allocated to either a 5x test article group or a 5x control group and were each treated on days 28, 56, and 84. Personnel performing observations were blinded to treatment. Observations were made for clinical signs of ivermectin sensitivity twice daily during non-dosing days. On treatment days, dogs were observed hourly for the first 4h post-treatment and at 6, 8, 12, 18 and 24h. Signs of toxicosis were not observed in any of the dogs throughout the observation period. This study demonstrated the safety of imidacloprid/moxidectin, when administered to collies testing positive for ivermectin sensitivity at dosages up to five times the maximum recommended dose.     

Ivermectin and piperazine toxicoses in dogs and cats

Review of all reports involving anthelmintics in dogs and cats to the IAPIC between January 1, 1986 and August 10, 1988, revealed that ivermectin (extra-label use) and piperazine accounted for over 50% of the calls assessed as toxicoses and suspected toxicoses. Both ivermectin and piperazine are gamma-aminobutyric acid (GABA) agonists and their major effects appear to be on the central nervous system. Ivermectin toxicoses at estimated doses of greater than or equal to 100-less than 500 micrograms/kg were reported more than once only in the collies (n = 25) and Australian shepherds (n = 10); these two breeds accounted for 46% (69 of 150) of the toxicoses and suspected toxicoses calls in dogs. Ataxia, behavioral disturbances, tremors, mydriasis, weakness/recumbency, apparent blindness, hypersalivation/drooling (dogs only), and coma were the most commonly reported clinical signs in dogs and cats with suspected ivermectin toxicoses. Shock, dyspnea, vomiting, and ataxia were the most common clinical signs attributed to the microfilaricidal activity of ivermectin. Piperazine was the anthelmintic with the greatest number of reports of toxicoses and suspected toxicoses in cats. Piperazine neurotoxicity in cats and dogs usually was manifested by muscle tremors, ataxia, and/or behavioral disturbances within 24 hours after estimated daily dose(s) between 20 and 110 mg/kg.     

The efficacy of selamectin in the treatment of naturally acquired infestations of sarcoptes scabiei on dogs

Selamectin, a novel avermectin, was evaluated for its effect on naturally occurring infestations of Sarcoptes scabiei in 42 dogs. In two controlled and masked laboratory studies conducted in the USA and Italy, infested dogs received treatment with either selamectin (6mgkg(-1); range: 6-12mgkg(-1)) or the vehicle only (negative control). Treatments were administered topically to the skin on each animal's back at the base of the neck in front of the scapulae. Study day 0 was defined as the first day of treatment administration. Dogs were treated on days 0 and 30, and efficacy was assessed by counting viable mites recovered from skin scrapings performed on each dog on days 14, 29 or 30, 44, and 60, and by categorising the clinical signs of canine scabies on the same days. Percentage reductions in geometric mean mite counts for selamectin, compared with vehicle, on days 14, 29 or 30, 44, and 60 were > or =98.1, > or =93.5, 100, and 100%, respectively. Analysis of variance, confirmed by Savage Scores, showed that ln(mite counts+1) values for selamectin-treated dogs were significantly lower (P< or =0.0391) than those for vehicle-treated dogs on all post-treatment assessment days. Clinical signs of scabies were markedly reduced in selamectin-treated dogs, compared with vehicle-treated dogs. Topical administration to the skin in a single spot of a single unit dose of selamectin, or of two unit doses given 1 month apart, each providing at least the recommended minimum dosage of 6mgkg(-1), was highly effective against naturally acquired infestations of S. scabiei in dogs, reducing mite counts by >93% (single dose) and 100% (two doses).