Reduction In Mite Counts Research Articles

Fluralaner 5.46% (w/w) flavored chewable tablet (Bravecto\xae 1-Month) is effective for treatment of canine generalized demodicosis

BackgroundOrally administered fluralaner (13.64% w/w) is effective for treating canine generalized demodicosis. A study was initiated to assess the efficacy of a novel 5.46% w/w fluralaner chewable tablet formulation for monthly administration in the treatment of this disease.MethodsClient-owned dogs diagnosed with generalized demodicosis were acclimatized to laboratory conditions and randomized to receive either orally administered fluralaner (Bravecto® 1-Month) (10.0 to 14.4 mg/kg body weight) (n = 8) or topical imidacloprid-moxidectin (Advocate® for dogs, Elanco) applied per label on days 0, 28, and 56 (n = 8), or more frequently for ongoing severe demodicosis. On days −2, 28, 56, and 84, deep skin scrapings were taken from five sites on each dog for mite identification and counting, and semiquantitative clinical assessments of generalized demodicosis were recorded. Primary efficacy was based upon arithmetic mean mite count reductions relative to pre-treatment.ResultsBy day 28, mean pre-treatment mite counts, > 600 in both groups, were significantly reduced by 99.7% and 89.5% (both P < 0.001) in the fluralaner and imidacloprid-moxidectin groups, respectively. Parasitological cure (100% reduction in mite counts on days 56 and 84) was achieved in all fluralaner-treated dogs (100%) and in two imidacloprid-moxidectin-treated dogs (25%). In the imidacloprid-moxidectin group, the reduction in mean mite counts was 89.5% (day 28), 94.4% (day 56), and 97.5% (day 84). All study dogs were free of crusts on days 56 and 84. Scales resolved by day 84 in all fluralaner-treated dogs and in three imidacloprid-moxidectin-treated dogs. All fluralaner-treated dogs and five imidacloprid-moxidectin-treated dogs had > 90% hair regrowth on day 84.ConclusionThree consecutive monthly orally administered treatments with fluralaner (5.46% w/w) flavored chewable tablets (minimum dose rate 10 mg/kg body weight) eliminated Demodex canis mites from dogs diagnosed with generalized demodicosis.Graphical

Evaluation of a clinical scoring system for canine demodicosis.

Canine demodicosis is a common disease in small animal practice. Although a number of studies evaluating treatment efficacy for canine demodicosis have used clinical scoring systems, none have been validated. This study evaluated the validity, reliability, reproducibility and sensitivity to change of a clinical scoring system for canine demodicosis. Fifty-eight dogs with generalised demodicosis were evaluated using a clinical scoring system that assessed erythema, comedones/ papules/pustules, follicular casts/scales/crusts and alopecia, rated from none to mild, moderate and severe in 36 body locations. Two evaluators scored lesions at monthly consecutive visits during treatment. Mites were counted to a maximum of 50 in four deep skin scrapings. With >50 mites, the approximate mite number was calculated with the help of a grid drawn onto the slide before placing the scraped material onto it. A Pearson correlation coefficient showed a high interobserver reliability (r=0.97) between two different clinicians evaluating the same dog. The Wilcoxon signed rank test showed good sensitivity to change with a reduction of clinical scores with each of the first six evaluations (P<0.0001). A linear mixed model also showed a clear reduction in mite counts (P<0.001) and clinical scores (P<0.0001) from the first evaluation with time. The clinical scoring system for canine demodicosis evaluated in this study showed a good sensitivity to change and interobserver reliability, and can be used in studies evaluating canine demodicosis.

Successful treatment of otodemodicosis due to Demodex cati with sarolaner/selamectin topical solution in a cat

Case summaryA 10-year-old spayed female Russian Blue cat was presented with a 3-month history of excessive otic discharge and scratching, only involving the right ear. Other than a moderate amount of ceruminous exudate present within the right ear on video-otoscopic examination, there were no other cutaneous abnormalities. The cat was deemed to be otherwise in good health based on physical examination and several laboratory profiles. A diagnosis of otodemodicosis was determined due to the presence of a large number of Demodex cati mites retrieved from cerumen. Treatment consisted only of monthly topical application of sarolaner/selamectin to the nape of the neck with a marked reduction in mite counts and otic pruritus after a single dose. Complete resolution was achieved after a total of four doses.Relevance and novel informationThis is the first report to describe the resolution of mite infestation owing to D cati after treatment with a sarolaner-containing spot-on product. In addition, to the best of the author’s knowledge, this is the first report of any isoxazoline product used in the successful treatment of demodicosis affecting the ear canal. In general, there is a lack of reports describing safe and effective treatments for feline otodemodicosis. Topically applied sarolaner/selamectin resulted in resolution of mites while avoiding any potential ototoxic events from medications applied directly into the ear, and provided a treatment that was easier to apply than oral or injectable macrocyclic lactones.

Assessment of laying-bird welfare following acaricidal treatment of a commercial flock naturally infested with the poultry red mite (Dermanyssus gallinae).

The poultry red mite (PRM), Dermanyssus gallinae, a potential vector of pathogens to animals and humans, causes impaired bird welfare. A study investigated changes in behavioural variables, physiological biomarkers, and health parameters following acaricidal treatment of PRM infestation of laying hens on a commercial farm. Mite traps determined the challenge to 12,700 hens before and after drinking water administration of the acaricide, fluralaner (Exzolt®, 0.5 mg/kg; Weeks 0 and 1). Weekly daytime direct observations and night-time video recordings monitored bird behaviours from Weeks -6 through +6. Blood samples were collected from randomly-selected birds (Weeks -6, -1, and +6). Following treatment, mite count reductions (>99%) were statistically significant (P < 0.0001), as were night-time reductions in the percent of hens showing activity, preening, head scratching (all P < 0.0001), and head shaking (P = 0.0007). Significant daytime reductions were observed in preening and head scratching (both P < 0.0001), head shaking (P = 0.0389), severe feather pecking (P = 0.0002), and aggressive behaviour (P = 0.0165). Post-treatment, comb wounds were significantly reduced (P = 0.0127), and comb colour was significantly improved (P < 0.0001). Heterophil/lymphocyte ratio was significantly reduced at Weeks 1 and 6 (P = 0.0009 and P < 0.0001, respectively). At Week 6, blood corticosterone (P = 0.0041) and total oxidant status (P < 0.0001) were significantly reduced, and haemoglobin and mean corpuscular haemoglobin significantly increased (P < 0.0001). Farm production records indicated that those post-treatment improvements were accompanied by significant reductions in weekly mortality rate (P = 0.0169), and significant recovery in mean weekly egg weights (P < 0.0001) and laying rate (P < 0.0001). The improvements in behavioural variables, physiological biomarkers, and health parameters that were observed following the elimination of PRM on a commercial farm indicate that infestations can be a cause of reduced hen welfare.

New insights into the use of a mite count reduction test for the detection of therapeutic acaricide efficacy in Psoroptes ovis in cattle

When used for the evaluation of drug efficacy against Psoroptes ovis, the diagnostic performance of different sampling strategies for a mite count reduction test (MCRT) remains unclear. In the present study, a novel simulation framework was constructed that accounted for relevant biological features of P. ovis infestations in cattle and that was parameterized with field data from 16 farms (154 animals). Second, this framework was applied to explore the impact of study specific factors (number of animals, number of sampled lesions, and number of scrapings per lesion) and biological factors (mite infestation intensity and size of lesions) on the diagnostic performance of MCRT. Its outcome provided a basis to determine the diagnostic performance of MCRT when it was applied according to the World Association for the Advancement in Veterinary Parasitology (WAAVP) and the European Medicine Agency (EMA) guidelines, and to formulate recommendations to ensure a good diagnostic performance of the MCRT. For both guidelines, the MCRT allowed to correctly detect (power 80%) reduced and normal efficacy when the therapeutic efficacy was <70%, and ≥95%, respectively. The results highlighted a reliable diagnostic performance of the MCRT when performed as recommended by WAAVP and EMA for the detection of normal drug efficacy. When used for the detection of reduced efficacy, therapeutic efficacies between 70% and 90% could not be detected with sufficient reliability. The diagnostic performance can be improved by increasing the total number of skin scrapings (increasing the number of animals, number of sampled lesions and/or number of samples per lesion). In order to help researchers and veterinarians to optimize the design of the MCRT to their field settings, the findings were translated into a simple tool.

Resistance against macrocyclic lactones in Psoroptes ovis in cattle

BackgroundPsoroptic mange is an important disease in Belgian Blue cattle. Treatment failure of macrocyclic lactones against Psoroptes ovis has been reported, but clear evidence of in vivo resistance is lacking. This study assessed the efficacy of macrocyclic lactone products on 16 beef farms in Belgium and the Netherlands in vivo and in vitro.MethodsOn each farm a group of animals (n = 7–14) with psoroptic mange was treated with two subcutaneous injections of a macrocyclic lactone product with 7–10 days interval (15 farms) or a single injection with a long-acting macrocyclic lactone (1 farm). In vivo efficacy was assessed by the reduction in mite counts, clinical index (proportion of the body surface affected by lesions), the proportion of the animals with negative mite counts after the first treatment round and the number of treatment rounds needed to obtain zero mites counts in all animals. A mite population was categorized as sensitive when the mite count reduction after the first treatment round > 95% and the lower limit of the uncertainty interval > 90%. Resistance was detected when both parameters were below their threshold and suspected when one parameter was too low. In vitro knockdown and mortality were evaluated in a contact test.ResultsThe proportion of the animals with negative mite counts after the first treatment round varied from 0 to 80%. All farms needed two or more treatments rounds to obtain zero mite counts on all animals. Clinical index only started to reduce after the second treatment round. Mite populations from three farms were categorized as sensitive, one as suspected resistant and 12 as resistant. No correlation was found between in vitro lethal dose 50 and knockdown dose 50 values and in vivo efficacy parameters.ConclusionsUnambiguous treatment failure was detected on 12 out of 16 farms, confirming the presence of macrocyclic lactone resistance on Belgian Blue beef farms. In vitro parameters could not discriminate the farms based on their in vivo sensitivity. The mean reduction in mite counts and the lower limit of the confidence interval are proposed as parameters to identify acaricide resistance.

Clinical and parasitological evaluation of pour-on fluazuron and ivermectin for treating canine demodicosis

The objective of the study was to evaluate the efficacy of pour-on formulations of fluazuron and ivermectin in different therapeutic protocols for treatment of demodicosis by means of quantifying mites with skin scraping, histological and clinical evaluation in dogs. Eighteen dogs with skin scrapings positive for Demodex canis were evaluated, divided into three groups. All the animals were treated every 14 days, completing 6 treatments for each animal (days 0, 14, 28, 42, 56 and 70). In group 1, pour-on 2.5% fluazuron was used at the dose of 20mg/kg; in the group 2 pour-on 2.5% fluazuron at a dose of 20 mg/kg in association with pour-on 0.5% ivermectin at the dose of 0.6mg/kg; and in group 3, pour-on 0.5% ivermectin alone was used, at the dose of 0.6mg/kg. The treatment was evaluated and monitored through skin scrapings and clinical follow-up of the lesions every 14 days for 84 days, and through histopathological examination at the end of each treatment protocol. The success rate was defined as the percentage of dogs in each group that had negative skin scrapings after the treatment: this was 16.67% for group 1, and 50% for groups 2 and 3. The reduction in mite counts reached effectiveness of 67.66%, 88.99% and 84.29% for groups 1, 2 and 3 respectively. The Wilcoxon test showed that there was a significant difference between the number of mites before and after treatment in groups 2 and 3. The histopathological examination revealed that only group 1 showed no significant difference in the intensity of infestation between days 0 and 84. Clinically, there was no significant difference between the evaluation before and after treatment in the three groups. pour-on 2.5% fluazuron and pour-on 0.5% ivermectin were not effective for treating canine demodicosis, either in association or as single therapy, when applied every 14 days for a period of 70 days. Quantification of mites using skin scrapings and histological evaluation proved to be ineffective, either one as sole therapeutic evaluation parameters, for canine demodicosis.

Efficacy of a topical application of Certifect®(fipronil 6.26% w/v, amitraz 7.48% w/v, (S)-methoprene 5.63% w/v) for the treatment of canine generalized demodicosis

The efficacy of the treatment with Certifect ® (containing fipronil 6.26% w/v, amitraz 7.48% w/v, (S)-methoprene 5.63% w/v) applied topically was assessed in 18 dogs diagnosed with clinical generalized demodicosis. Three treatment regimens were compared over a 3-month period. Starting at Day 0, dogs were treated monthly (group 1) or every two weeks (group 2) with the combination of fipronil, amitraz, and (S)-methoprene or with monthly topical applications of the combination of amitraz and metaflumizone (group 3, reference treatment). Clinical examinations including deep skin scrapings were performed every month in order to evaluate the resolution of clinical signs and the reduction in mite counts. On Day 84, the percentage reduction of mite counts in group 1 was 99.8%, whereas no Demodex canis could be detected in groups 2 and 3 (i.e. 100% parasitological efficacy). As a result of the Demodex mite count reduction, the skin condition of the dogs improved significantly in all groups. This study illustrates, that both monthly and bi-weekly treatments with Certifect were effective in treating dogs with generalized demodicosis over a 3-month period.

Comparative therapeutic effect of moxidectin, doramectin and ivermectin on psoroptes mites infestation in buffalo (Bubalus bubalis)

The aim of the present study was to carry out comparative therapeutic effect of moxidectin pour on, doramectin and ivermectin on psoroptes infestation in buffalo. A total of 318 buffalo in 77 small scale herds suspected to have mange mites were examined clinically and parasitologically. Fifty-three (16.66%) buffalo in 25 herds were recorded to be infested; 51 (16.35%) with psoroptic mites, and two (0.31%) with chorioptic mites. Buffalo with psoroptic mites were randomly allocated into three groups (17 buffalo each). First group was treated with moxidectin pour on at a dose rate of 0.5 mg kg(-1). The second group received doramectin (200 microg kg(-1) twice subcutaneously, 14 days apart). The third group received ivermectin (200 microg kg(-1) twice subcutaneously, 14 days apart). Adjunct to each drug, deltamethrin was applied to the surrounding environment twice at a two week interval. Treatment outcomes of 51 buffalo with psoroptic mites showed that moxidectin pour on and doramectin had a significant higher effect on mite count reduction (MANOVA, P < 0.01; Walks' Lambda, P < 0.01) and clinical sum scores (MANOVA, P < 0.05; Walks' Lambda, P < 0.05) compared with injectible ivermectin. On clinical level, the number of clinically recovered buffalo in moxidectin and doramectin treated groups was significantly (P < 0.05) higher than that of ivermectin treated group. The result of the present study indicated that psoroptic mites are the main cause of mange in buffalo in Lower Egypt. This is the first report that describes the effect of moxidectin in buffalo. Moxidectin is a good alternative and easily applied drug for treatment of psoroptes infestation in buffalo.

Comparative study of the efficacy of eprinomectin versus ivermectin, and field efficacy of eprinomectin only, for the treatment of chorioptic mange in alpacas

The efficacy of eprinomectin versus ivermectin (Study 1: a single-centre, randomised, treatment-controlled, blinded field trial), and the field efficacy of eprinomectin (Study 2: a single-centre, open, un-controlled field trial) for the treatment of chorioptic infestation in naturally infested alpacas were assessed in two studies. Thirty alpacas, all positive for Chorioptes sp. mite, were randomly allocated to two treatment groups in Study 1. Group A received a single topical administration of a 0.5% formulation of eprinomectin at the dose rate of 500 μg/kg. Group B received three subcutaneous administrations at 14 days interval of a 1% formulation of ivermectin at the dose rate of 400 μg/kg. Response to treatment was assessed by periodic mite count, and skin lesions scored. In Study 2, one group of 19 alpacas received four administrations at weekly interval of topical eprinomectin at the dose rate of 500 μg/kg, and response to treatment was monitored by mite counts. No localised or systemic side effects were observed in either trial. There was a statistically significant decrease in mite counts on day 7 ( P < 0.001) within treatment Groups A and B of Study 1, but mite counts increased again on day 14 and remained high for the duration of the trial in both treatment groups. On day 14 of Study 2, there was a statistically significant reduction in mite counts ( P < 0.008) and the mite counts remained very low throughout the remainder of the study. The eprinomectin protocol employed in Study 2, consisting of four weekly topical administrations at the dose rate of 500 μg/kg of body weight, proved highly effective at reducing the Chorioptes mite burden in alpacas.

Controlled field efficacy of injectable moxidectin against naturally acquired psoroptic mange in sheep

Twenty-one ewes naturally infected with Psoroptes ovis were allocated into three groups of 7 animals each. Animals in group A were kept as untreated controls. Animals in groups B and C were treated on day 0 and on day 0 and +10, respectively with 1% injectable moxidectin at a dose of 0.2 mg/kg body weight (b.w.). In group B, efficacy based on mite count reduction, ranged from 22.1% on day +7 to 97.1% obtained on day +56. In group C, this ranged from 19.4% on day +7 to greater than 90% from days +42 to +56. Active lesions produced by P. ovis remained essentially unchanged through the trial in the untreated animals. In group B, the percentage of efficacy based on reduction of lesions was between 60–90% until day +35 and was higher than 90% at the last three sampling dates (+42, +49 and +56). In group C, the reduction of lesions was between 70–90% from days +7 to +21, greater than 97% on days +28 and +35 and was 100% from days +42 to +56. The high reduction of mites and disappearance (group C) or significant decrease (group B) of clinical signs make moxidectin an effective drug in the control of psoroptic mange in sheep.