Efficacy and safety of selamectin against Sarcoptes scabiei on dogs and Otodectes cynotis on dogs and cats presented as veterinary patients

A series of randomized, controlled and masked field studies was conducted in veterinary patients to evaluate the efficacy of selamectin, a novel avermectin, in the treatment of naturally occurring Sarcoptes scabiei infestations on dogs and Otodectes cynotis infestations on dogs and cats. A total of 342 dogs and 237 cats participated in these studies, which were conducted at 40 veterinary practices in the USA and Europe. Animals were randomly assigned to treatment with selamectin or a positive-control product (existing approved products). Selamectin was administered as a unit dose providing a minimum of 6mgkg(-1) (range: 6-12mgkg(-1)) in a topical preparation applied to the skin in a single spot on day 0 (O. cynotis in cats, n=144), or on days 0 and 30 (O. cynotis and S. scabiei in dogs, n=83 and n=122, respectively). The presence of parasites was assessed before treatment and at 30 days (for all studies) and 60 days (for O. cynotis and S. scabiei dog studies) after first treatment. The animals were also evaluated clinically at each assessment period. Based on skin scrapings, the efficacy of selamectin against S. scabiei infestations on dogs was >95% by day 30, and 100% by day 60. Against O. cynotis, selamectin eliminated mites in 94-100% of cats by day 30, and in 90% of dogs by day 60. The positive-control products achieved similar results. Thus, selamectin was safe and effective against ear mites in dogs and cats and sarcoptic mange in dogs when used in field (veterinary patient) studies in dogs and cats of a wide variety of ages and breeds.     

Use of doramectin for treatment of sarcoptic mange in five Angora rabbits

The efficacy of administering doramectin after moxidectin treatment, which has previously proved only partially effective, was evaluated in five Angora rabbits naturally infested with Sarcoptes scabiei mange. Evaluations included physical examination for clinical signs of sarcoptic mange and collection of skin scrapings for determination of mites. The rabbits first received two subcutaneous injections, 10 days apart, of moxidectin 1% injectable solution at a dosage of 0.2 mg kg(-1) of bodyweight. Although moxidectin treatment resulted in clinical improvement within 10 days post initial injection, on days 10 and 35 post initial treatment live mites were present in skin scrapings. Administration of doramectin 1% injectable solution using the same route and dosage and at similar intervals to moxidectin led to complete disappearance of signs of scabies and parasitological cure in all rabbits.     

Efficacy and safety of topical administration of selamectin for treatment of ear mite infestation in rabbits

OBJECTIVE: To evaluate the efficacy and safety of topical administration of selamectin in rabbits naturally infested with Psoroptes cuniculi. DESIGN: Randomized controlled trial. ANIMALS: 48 mixed-breed domestic rabbits with active P. cuniculi mite populations and clinical ear lesions. PROCEDURES: Rabbits were randomly allocated to 1 of 6 treatment groups. On day 0, rabbits in groups 1 and 2 were given vehicle, rabbits in groups 3 and 4 were given selamectin at a dose of 6 mg/kg (2.7 mg/lb), and rabbits in groups 5 and 6 were given selamectin at a dose of 18 mg/kg (8.2 mg/lb). On day 28, rabbits in groups 2, 4, and 6 were given a second dose of vehicle or selamectin. Otoscopic examinations were performed and ear lesion size was measured weekly for 8 weeks. Quantitative viable mite counts were performed on day 56. RESULTS: On days 7 through 56, lesion sizes for all selamectin-treated groups were significantly lower than sizes for control groups; there were no significant differences in lesion sizes among selamectin-treated groups. All rabbits in the 2 control groups had viable adult P. cuniculi mites for the duration of the study, as determined by otoscopic examination, whereas all rabbits in the 4 selamectin-treated groups were free from P. cuniculi mites on days 7 through 56. No adverse reactions associated with selamectin treatment were observed. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that topical application of selamectin at a dose of 6 or 18 mg/kg can completely eliminate mites from rabbits naturally infested with P. cuniculi.     

P-23 Clinical and epidemiological characteristics of 153 cases of Sarcoptic acariosis in dogs

A randomized and controlled field study was performed in canine patients to evaluate the efficacy of selamectin in the treatment of naturally occurring Sarcoptes scabiei and Otodectes cynotis infestations in dogs. A total of 227 dogs from six veterinary practices in South Korea were included. Dogs were randomly assigned to treatment with selamectin or a positive-control product. Selamectin was administered as a unit dose providing a minimum of 6 mg/kg in a topical preparation applied to the skin in a single spot on days 0 and 30 [ S. scabiei ( n =  113) and O. cynotis ( n =  114)]. The presence of parasites was assessed before treatment and at 14, 30 and 60 days after the initiation of treatment. The animals were evaluated clinically at each assessment period. Based on skin scrapings, the efficacy of selamectin against S. scabiei infestations on dogs was >95% by day 30, and 100% by day 60. Against O. cynotis , selamectin eliminated mites in 100% of dogs by day 60. However, clinical signs of pruritus, erythema, scale, and crusted papules did not diminish concomittantly with resolution of S. scabiei in skin scrapings. The positive-control products achieved similar results. Therefore, selamectin was safe and effective against sarcoptic mange and ear mites in dogs.
Funding: Pfizer Animal Health.     

Efficacy of an injectable formulation of eprinomectin against Psoroptes cuniculi, the ear mange mite in rabbits

Thirty rabbits naturally infected with ear mange mite, Psoroptes cuniculi, were subcutaneously administrated with a single dose of eprinomectin at 100, 200 and 300 microg/kg body weight or vehicle on day 0. The extent of lesions was scored on day -6 (prior to treatment), day 0 (treated), days 7, 14, 21, 28 and 35, the ear scabs were collected simultaneously; mites in scabs were examined and counted. The results showed that a single dose of eprinomectin at 200 or 300 microg/kg body weight following subcutaneous administration was able to eliminate P. cuniculi infection in rabbits, and a dose of eprinomectin at 100 microg/kg could significantly reduce mites but was unable to eliminate P. cuniculi.     

Control of cattle mange in southern africa using ivermectin

Seven trials including 768 cattle were conducted in South Africa and Namibia to evaluate the efficacy of the systemic parasiticide ivermectin when administered subcutaneously at a dose rate of 200 micrograms/kg against sarcoptic (Sarcoptes scabiei var. bovis), chorioptic (Chorioptes bovis) and psoroptic (Psoroptes ovis var. bovis) mange mites. The efficacy of a single treatment against Psoroptes and Sarcoptes was greater than against Chorioptes. There was marked clinical cure in all treated cases with loss of crusts and hair regrowth. The number of cases of psoroptic mange in two large herds, of which 42.4% of 724 animals were clinically affected prior to mass treatment, was reduced by 99.3% following a single subcutaneous treatment with ivermectin; a single animal from which mites were recovered may not have been treated. The apparent prevalence and prospects for control and eradication of cattle mange in South Africa and Namibia are discussed.     

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.     

Clinical development and serological antibody responses in sheep and rabbits experimentally infested with Psoroptes ovis and Psoroptes cuniculi

Psoroptes ovis of sheep origin, and Psoroptes cuniculi of rabbit origin were used in experimental infestations. In experiment I, groups of four rabbits and four sheep were infested with 50-100 mites of each isolate on the skin of the back (skin infestation, SI) or in the external auditory canal (aural infestation, AI). In rabbits, SI and AI with P. cuniculi and AI with P. ovis induced in all animals typical ear lesions and pronounced antibody reactions to P. cuniculi antigens in ELISA. After SI of rabbits with P. ovis no clinical signs were detected, no mites could be reisolated and no specific antibodies were detected. In sheep, P. ovis SI induced mange whereas AI did not induce typical clinical signs and mites could not be reisolated. In both these animal groups, ELISA revealed pronounced and comparable specific antibody reactions. After SI and AI with P. cuniculi no clinical symptoms were observed and no mites could be reisolated. Nevertheless, low levels of specific antibody were detected. In experiment II, clinical progression and antibody reactions to P. ovis SI in naive sheep were compared with sheep previously exposed to P. ovis or P. cuniculi. In both pre-exposed groups of animals, clinical signs appeared within 2 days after challenge infestation and three days earlier than in primarily infested sheep. Subsequently, no obvious difference in the clinical progression was observed between the three groups of animals. The results of this study document antigenetic crossreactivity of the two morphologically and genetically distinguishable Psoroptes species but differences in their biological behaviour and virulence which both are of epidemiological and taxonomic relevance.     

P‐24 Efficacy of selamectin in canine scabies and ear mite infestation in Korea

A randomized and controlled field study was performed in canine patients to evaluate the efficacy of selamectin in the treatment of naturally occurring Sarcoptes scabiei and Otodectes cynotis infestations in dogs. A total of 227 dogs from six veterinary practices in South Korea were included. Dogs were randomly assigned to treatment with selamectin or a positive‐control product. Selamectin was administered as a unit dose providing a minimum of 6 mg/kg in a topical preparation applied to the skin in a single spot on days 0 and 30 [S. scabiei (n = 113) and O. cynotis (n = 114)]. The presence of parasites was assessed before treatment and at 14, 30 and 60 days after the initiation of treatment. The animals were evaluated clinically at each assessment period. Based on skin scrapings, the efficacy of selamectin against S. scabiei infestations on dogs was >95% by day 30, and 100% by day 60. Against O. cynotis, selamectin eliminated mites in 100% of dogs by day 60. However, clinical signs of pruritus, erythema, scale, and crusted papules did not diminish concomittantly with resolution of S. scabiei in skin scrapings. The positive‐control products achieved similar results. Therefore, selamectin was safe and effective against sarcoptic mange and ear mites in dogs. Funding: Pfizer Animal Health.     

Comparative efficacy of injection routes and doses of ivermectin against Psoroptes in rabbits

Rabbits infested with Psoroptes ovis (Hering) or with P cuniculi (Delafond) were injected IM or subcutaneously with ivermectin or with vehicle. A single injection of ivermectin (200 micrograms/kg) either IM or subcutaneously was inadequate to eliminate all mites in the ears of the rabbits. However, a single injection of ivermectin at 400 micrograms/kg, regardless of the route of injection, eliminated all P cuniculi mites, but eliminated P ovis mites in only 50% of the rabbits. Ivermectin was more effective against P cuniculi than against P ovis at both doses tested, regardless of the route of injection.     

Efficacy of a novel formulation of metaflumizone plus amitraz for the treatment of sarcoptic 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 sarcoptic mange mites in naturally infested dogs. Sixteen dogs were allocated to two equal groups and were housed individually. 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, at a dose volume of 0.133ml/kg) on Days 0 and 28. The other eight were treated with metaflumizone plus amitraz at the proposed minimum dose rate on Days 0, 14, 28 and 42. To enumerate Sarcoptes scabiei mites, skin scrapings were taken on each of Days 2, 14, 28, 42 and 56. Clinical signs of mange and the extent of sarcoptic lesions were evaluated on each dog when scrapings were made. Evaluation of the efficacy of the treatment was based on the absence of mites supported by the absence of clinical signs associated with canine sarcoptic mange. Treatment with metaflumizone plus amitraz at the minimum proposed dose rate at monthly (two treatments) or two-weekly (four treatments) intervals resulted in a rapid reduction of mites and improved clinical signs. The overall cure rates at Day 56, based on zero mite counts and/or resolution of clinical signs were 75% and 83% of dogs for the monthly and two-weekly regimens, respectively.     

Efficacy of topical administration of eprinomectin for treatment of ear mite infestation in six rabbits

Six rabbits naturally infested with Psoroptes cuniculi were treated topically on the skin at the base of the neck with 0.5 mg kg(-1) of 0.5% pour-on eprinomectin for cattle, twice at 14-day intervals. Efficacy of the drug was based on the disappearance of clinical signs and the absence of live mites for a period of 6 weeks. Clinical improvement was seen within 3 days of the first application; however, complete recovery of clinical signs and elimination of mites in 5/6 rabbits did not occur until the end of the study. No adverse reactions attributable to eprinomectin treatment were observed during the observation period. Results of this trial indicated that eprinomectin was partially effective in the treatment of psoroptic mange in rabbits.     

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。     

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).     

Treatment with ivermectin of sarcoptic mange in pigs

Ivermectin injectable solution (1% w/v) was highly effective against Sarcoptes scabiei var suis when administered subcutaneously once to swine at 300 mcg/kg body weight. There were significantly (P < 0.05) fewer Sarcoptes mange mites counted on pigs treated with ivermectin than on untreated pigs at each count up to day 56 after treatment. The results indicate ivermectin should provide an efficient, practical means of control of sarcoptic mange in intensive piggeries.     

Effect of ivermectin on the ear mange mite, Psoroptes cuniculi, of rabbits

Rabbits, naturally infected with ear mange mite, Psoroptes cuniculi, were injected subcutaneously with a single dose of ivermectin at 200 micrograms or 400 micrograms/kg of body weight. The effect of the drug was evaluated clinically and parasitologically over 4 weeks. The animals in both groups became negative for mites 6 days after treatment and remained so until the end of trial. The ear lesions disappeared in both groups. However, the regression of lesions was faster in rabbits administered 400 micrograms/kg of ivermectin.     

FC-44 The therapeutic effect of selamectin and ivermectin regimens in canine sarcoptic mange

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

The effect of UV rays on parasitic arthropods. 3. In vitro and in vivo studies of the effect of a fractionated UV irradiation on the development stages of Psoroptes cuniculi (Acaridida: Psoroptidae)

In vitro studies were conducted into Psoroptes (Ps.) cuniculi larvae and nymphs of undefined age and gender. 30 males and females were involved in each of the experiments. Evidence was found the life expectancy of mites exposed to daily UV irradiation for 1, 2, 3, 4 or 5 minutes was reduced with significance, as compared to non-irradiated mites or to those with only one irradiation of the same length. Developmental stages of Ps. cuniculi responded in differentiated ways to the same dose rate, when applied by one single extended or fractionated shorter irradiation. Fractionated irradiation was more often survived by females than one single extended irradiation, whereas earlier death occurred to larvae following exposure to fractionated irradiation. Mange mites were not eliminated from rabbits with moderate ear mange by fractionated locally delimited in vivo irradiation, up to 16 applications of 10 minutes each or 6 or 9 applications of 10, 20 or 40 minutes each, with one-week intervals in between. Ear mange was clinically re-manifested, after irradiations had been discontinued.     

Efficacy of moxidectin against sarcoptic mange and effects on milk yield of ewes and growth of lambs

Forty-eight dairy ewes and 45 lambs naturally infested with sarcoptic mange, were divided into three equal groups and treated with moxidectin 1% inj. sol. at a dose rate of 0.2 mg moxidectin kg(-1) bodyweight once or twice ten days apart. During the study, the skin lesions were scored and the number of mites recovered in facial skin scrapings from the animals were recorded. Moxidectin was found to be effective against ovine sarcoptic mange, when given twice; the percentage reduction of mites was 100% (p < 0.0001) and the skin lesions disappeared completely (p = 0.0001). In sheep treated once only, the percentage reduction of mites varied from 75% to 92%. Treated ewes produced up to 22.4% more milk than the infested ones (p = 0.0001). Treated lambs had up to 15% greater final weight and up to 23.7% more growth than infested controls (p = 0.0001). It is concluded that two injections of moxidectin 1% inj. sol. at a dose rate of 0.2 mg kg(-1) bodyweight, given ten days apart, were effective against ovine sarcoptic mange. Furthermore, it is considered that sarcoptic mange adversely affects the production of the infested animals.     

Observations on the potential for natural transfer of Psoroptes cuniculi and Chorioptes bovis (Acari: Psoroptidae) between goats and sheep

Goats and sheep were pastured together and held in close contact in yards twice a month for 21 months. The goats had a high prevalence of both the rabbit ear canker mite, Psoroptes cuniculi and the chorioptic mange mite, Chorioptes bovis. The sheep were not infested with P. cuniculi at the beginning of the study and viable C. bovis could not be detected. At no time during the study did P. cuniculi establish in the ears of sheep, despite a maximum prevalence of >95% P. cuniculi in goats. This may have been related to the viscous nature of sheep cerumen. Levels of cerumen in goats' ears increased with increasing prevalence of the mite in the flock. The prevalence of C. bovis in the sheep flock did not exceed 10%, despite a maximum prevalence of >90% infested goats. The difficulty of detecting light infestations of mites means that it was not clear whether the C. bovis infestation of sheep was derived from goats or was present when the study began. Whatever the source, close contact with goats with an active and extensive C. bovis infestation seems unlikely to seriously influence populations of the ectoparasite in sheep. Psoroptes cuniculi was found to he established in goats as young as five days and post-mortem examination of goats' ears was more successful at revealing P. cuniculi than was use of an otoscope during life.