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

Rabbit Dermatology

The majority of rabbit skin disease presentations can be divided into pruritus, alopecia, scaling, and nodules. Some disease will have more than one of these clinical signs. Ectoparasites, bacterial and fungal infections, and neoplasia account for most of the causes seen. Diagnostic tests include skin scraping and cytology, microbial culture, and biopsy. Therapy is dependent on cause. In addition to discussing the various causes and their treatments, important clinical care points are noted.

Mange in Rabbits: An Ectoparasitic Disease with a Zoonotic Potential

Mange in rabbits is a very important parasitic disease causing high losses. The disease is caused mainly by Sarcoptes scabiei, Psoroptes cuniculi, Cheyletiella parasitovorax, and Notoedres cati. Body mange and ear mange are the most common forms of this disease in rabbits. Animals can get mite infestation through direct contact with infected animals or contaminated fomites. This infestation is characterized by zoonotic nature and public health burden. The skin affection is characterized by pruritus, alopecia, severe cachexia, and sometimes death. Infestation is diagnosed mainly by skin scraping and microscopic examination. Control measures mainly depend on the use of different types of systemic and topical acaricides and the use of natural products and supportive elements. Vaccine is not commercially available and is still under investigation. Accordingly, this review article was designed to shed the light on the mange disease in rabbits in terms of mite's infestation and susceptibility, clinical manifestations, zoonosis, diagnosis, and control strategies.

Efficacy of Ivermectin, Liquid Paraffin, and Carbaryl against Mange of Farmed Rabbits in Central Kenya

Mange is a common disease of rabbits globally, and knowledge of efficacy of drugs used in its treatment is critical for effective disease control. The current study evaluated the efficacy of three commonly used therapeutic agents in Kenya against mange. In a controlled laboratory trial, 20 adult rabbits were recruited for the study (16 of which were infested with mange, while 4 were mange-free). The 16 mange-infested rabbits were randomly allocated into 4 treatment groups each consisting of 4 rabbits, while 4 mange-free rabbits formed the negative control group. Treatments were administered as follows: group 1 (G1) received two ivermectin injections at an interval of 14 days, group 2 (G2) was treated with a combination of carbaryl and liquid paraffin applied every other day up to the end of the experiment, group 3 (G3) was treated with liquid paraffin droplets applied daily until the lesion cleared, while group 4 (G4, infected-untreated) received distilled water applied topically on their ears and group 5 (G5, uninfected-untreated negative control) was not treated with any preparation. The lesions were scored and sampled daily to check the viability of the mites. A field efficacy trial of the test compounds was performed using 105 mange-infested rabbits. The results revealed that all the test agents: ivermectin, liquid paraffin, carbaryl-water, and carbaryl-liquid paraffin combination were effective against mange, recording the lesion score of zero for psoroptic mange by day 21 in the laboratory and field trials. Lesion scores in the treated groups were significantly reduced (p < 0.05) at the termination of study compared with those of the positive control group in the laboratory trial. A point-biserial correlation revealed a strong association (r_pb = 0.79, p < 0.05) between the presence of viable mites and degree of psoroptic lesions in the field trial.

Haematological response in the treatment of naturally acquired ectoparasite infestations in rabbits

The objective of this study was to determine changes in haematological values of topical administration of selamectin in rabbits with at least one species of naturally acquired ectoparasite infestation (<em>Sarcoptes scabiei</em> var. <em>cuniculi</em>, <em>Psoroptes cuniculi</em>, or <em>Cheyletiella</em> spp). Thirty-five rabbits were enrolled. They underwent physical examination and assessment of ectoparasite infestations on days 0, 14, 28, 56 and 86. Blood for haematology and serum biochemistry was collected on days 0, 14, 28 and 56. Selamectin was topically applied at a dose of 15 mg/kg onto the skin on days 0, 14 and 28, respectively. No ectoparasites or eggs were found in these rabbits from day 28 onwards by skin scraping and/or tape cytology. Haematology and serum biochemistry values were within normal limit throughout the study. However, the neutrophil to lymphocyte ratio significantly decreased post-treatment from 2.89 (0.90-5.47) on day 0 to 1.38 (0.56-3.09), and 1.44 (0.42-4.47) on days 14 and 56, respectively. There were no adverse drug reactions or treatment-related mortalities during the study. This study indicated that selamectin was effective and safe in the treatment and prevent re-infestation for at least 58 d post-treatment. Moreover, the neutrophil to lymphocyte ratio could be used for monitoring of inflammatory response in rabbits.

Efficacy of oral doramectin as treatment for Psoroptes ovis and Leporacarus gibbus in naturally infested rabbits

ABSTRACT: The present study evaluated the efficacy of a single oral dose of doramectin in the control of Psoroptes ovis and Leporacarus gibbus in naturally infested rabbits. Sixteen adult rabbits were selected and distributed in two experimental groups. The treated group received 200 μg/Kg of oral doramectin and the control group received the same volume of saline solution. The diagnosis of the mites was made with a stereoscopic microscope. Hairs from the dorsal part of the neck, lumbar right, lumbar left, ventral side of the tail and ventral abdomen were evaluated for L. gibbus, and ear wax evaluated for P. ovis. The evaluation of the efficiency and the clinical assessment of the lesions was made in days 0, +3, +7, +14, +21, +28, and +35 after treatment. An efficacy of 75% and 87,5% was observed for L. gibbus in days +3 and +7 after treatment, an efficacy of 100% was observed in days +14, + 21, +28 e +35. An efficacy of 100% for the control of P. ovis was observed following day +7. The clinical lesion score of the control group remained unaltered, except for one animal which conditions worsened during experimentation. In the treated group animals, regression of the lesions was observed following day +3, and on day +21 no signal of infestation by P. ovis was present. None of the animals from the treated group presented secondary collateral effects caused by the doramectin, which proved itself as an optimal alternative for mite control in naturally infested rabbits.

Advances in exotic mammal clinical therapeutics

It is important that veterinarians treating exotic companion mammals stay abreast of the latest developments relating to medications and drug delivery approaches for safety, efficacy and welfare issues. Sustained release formulations of commonly used drugs as well as newer routes for administration of therapeutic agents allow the veterinarian treating exotic companion mammals to reduce the stress associated with drug administration. Interactions can occur between vehicle and drugs when formulations are compounded, therefore research studies are warranted regarding potential problems associated with these formulations.

Eficácia da ivermectina oral no controle de Psoroptes ovis e Leporacarus gibbus em coelhos naturalmente infestados

O objetivo do trabalho foi avaliar a eficácia da ivermectina administrada por via oral no controle de Psoroptes ovis e Leporacarus gibbus em coelhos naturalmente infestados. Foram selecionados 20 coelhos adultos, distribuídos na mesma proporção de ambos os sexos, em dois grupos experimentais, compondo dez animais por grupo. No grupo controle foi administrado o mesmo volume do tratamento de solução salina, enquanto o grupo tratado recebeu dose única de ivermectina oral (400 µg/Kg). O diagnóstico dos ácaros foi realizado com auxílio de microscópio estereoscópico após a devida coleta de material. Para P. ovis foi realizada através de coleta do cerúmen com auxílio de zaragatoas efetuadas nas orelhas e para por L. gibbus foi realizada coleta de pelos nas regiões do pescoço dorsal, lombar direita, lombar esquerda, cauda ventral e abdômen ventral. A avaliação da eficácia e a avaliação clínica das lesões, mensuradas em escores (grau 0 a 4) foi realizada nos dias 0, +3, +7, +14, +21, +28 e + 35, após o tratamento. Foi observada a eficácia de 100% no controle de P. ovis a partir do dia +7 e para L. gibbus a partir do dia +14, mantendo-se negativos até o final do período experimental. O escore da lesão das orelhas do grupo tratado regrediu a partir do dia +14 e no dia +21 todos os animais atingiram grau 0. No grupo controle, dois animais apresentaram aumento no escore da lesão das orelhas, um coelho apresentou aumento do escore de grau 1 para 2 e outro coelho de grau 3 para 4. Não foram observadas quaisquer reações adversas nos animais tratados. A ivermectina administrada por via oral em dose única foi eficaz no controle de P. ovis e L. gibbus em coelhos naturalmente infestados.

Ectoparasites in small exotic mammals

Ectoparasites inhabiting the skin are responsible for significant problems in small mammals, owing to ingestion of blood, lymph, sebaceous secretions, and scavenging skin debris, as well as a hypersensitivity reaction to parasite antigen resulting in severe pruritus and subsequent self-trauma-induced lesions. In general practice, the most common diagnosis in exotic pets is an unspecified mite infestation, but other ectoparasites such as lice, fleas, insects, or even helminths may cause dermatologic diseases. If treatment with topical insecticides is planned, the small mammal should be isolated for a few hours to enable drying and spreading of the product.

Efficacy of the d-phenothrin/pyriproxyfen association against mites in naturally co-infested rabbits

The aim of the present study was to evaluate the efficacy of the d-phenothrin/pyriproxyfen association against Psoroptes ovis, Cheyletiella parasitivorax, and Leporacarus gibbus infestations in naturally co-infested rabbits. Twenty crossbreed (New Zealand White x California) rabbits concurrently infested by the three mite species were randomly divided in two groups. All rabbits presented with hyperemia, erythema and formation of crusts in the ear canals caused by P. ovis. Infestations by both C. parasitivorax and L. gibbus were considered asymptomatic in all animals.Ten animals were treated with a 4.4% d-phenothrin and 0.148% pyriproxyfen spray formulation until have their body surface uniformly sprayed, including external ear canals. The other ten rabbits remained untreated, serving as control group. Observations were done on days +7, +14, +21, +28, and +35 post-treatment. The d-phenothrin/pyriproxyfen association showed 100% efficacy against the three mite species and was responsible for the remission of psoroptic mange lesions on treated animals. No signs of intoxication were observed. The results indicate that d-phenothrin/pyriproxyfen spray formulation in a single application is an effective and clinically safe option for the control of different mite infestations in rabbits.

Bacterial and parasitic diseases of rabbits

Bacterial disease is common in pet rabbits; parasitic disease occurs as well but at a much lower frequency. Of these, bacterial diseases of the respiratory tract and dental structures are seen most commonly in practice. Successful treatment depends on positive diagnosis of the disease process and causative agent. This article focuses on the more common bacterial and parasitic diseases encountered in clinical practice.

RABBITS

This chapter provides an overview of the biology and medical care of rabbits. There are about 50 different breeds of domestic rabbits. Rabbits have very thin and delicate skin that is covered with fine fur comprised of both a soft undercoat and stiff guard hairs. Care must be taken when clipping fur because the skin is prone to tearing. A rabbit enclosure should be large enough to provide a sleeping space, eating space, and latrine. Animals housed for long periods of time should also have ample room to exercise. The enclosure should be tall enough to allow the rabbit to sit up and not have its ears touch the top of the cage. Because rabbits are prone to heatstroke, they should be housed in temperatures ranging from 60°F to 75°F. If rabbits are housed outdoors, they must have access to shade and clean water, and the shelter should protect them from the elements as well as from predators. The ideal substrate for rabbits is grass hay; however, for indoor, caged rabbits, a foam rubber pad or a towel covered with newspaper and a thick layer of timothy hay can also be used.

Clinical toxicoses of domestic rabbits

Toxicoses are an uncommon presentation to rabbit practitioners; however, veterinarians who accept rabbits as patients should be familiar with the basic concepts of toxicosis management and the specific syndromes associated with clinical toxicoses. The objective of this article is to present clinically relevant information for veterinarians presented with rabbits exhibiting characteristic signs of toxicosis. In addition, specific mention is made to the most common clinical toxicoses, including lead, chemicals, rodenticides, aflatoxins, and poisonous plants.

Efficacy of selamectin in the treatment of cheyletiellosis in pet rabbits

Cheyletiellosis is a very common parasitic skin disorder of pet rabbits typically associated with pruritus and scaling. In this study, a total 23 rabbits with cheyletiellosis were treated with a single topical application of selamectin at a dose of 12 mg kg(-1). All rabbits were examined at 3 and 5 weeks after treatment. Five weeks after selamectin application, the scaling and pruritus had resolved in all 23 rabbits, and microscopic examination of epidermal debris collected by acetate tape and flea combing was all negative for mites and eggs. No side-effects were observed in any of the rabbits. This indicates that selamectin is an effective treatment for cheyletiellosis in rabbits.

Treatment of rabbit cheyletiellosis with selamectin or ivermectin: a retrospective case study

BACKGROUND

A retrospective study of rabbits treated against cheyletiellosis was performed to evaluate the efficacy and safety of selamectin or ivermectin in clinical practice.

METHODS

Medical records from 53 rabbits with microscopically confirmed Cheyletiella infestation were collected from two small animal clinics. The rabbits were divided into three groups, based on treatment protocols. Group 1 included 11 rabbits treated with ivermectin injections at 200-476 microg kg-1 subcutaneously 2-3 times, with a mean interval of 11 days. In Group 2, 27 rabbits were treated with a combination of subcutaneous ivermectin injections (range 618-2185 microgkg-1) and oral ivermectin (range 616-2732 microgkg-1) administered by the owners, 3-6 times at 10 days interval. The last group (Group 3) included 15 rabbits treated with selamectin spot-on applications of 6.2-20,0 mgkg-1, 1-3 times with an interval of 2-4 weeks. Follow-up time was 4 months-4.5 years.

RESULTS

Rabbits in remission were 9/11 (81,8%), 14/27 (51,9%) and 12/15 (80,8%) in groups 1, 2 and 3, respectively.

CONCLUSION

All treatment protocols seemed to be sufficiently effective and safe for practice use. Though very high doses were used in Group 2 (ivermectin injections followed by oral administration), the protocol seemed less efficacious compared to ivermectin injections (Group 1) and selamectin spot on (Group 3), respectively, although not statistically significant. Controlled prospective studies including larger groups are needed to further evaluate efficacy of the treatment protocols.

Plasma pharmacokinetics of selamectin after a single topical administration in the American bullfrog (Rana catesbeiana)

Parasitism is common in wild and captive amphibians; however, pharmacologic data are lacking for anthelmintic drugs. This study was developed to determine the plasma pharmacokinetics of selamectin after topical administration in bullfrogs. Thirty-two adult American bullfrogs (Rana catesbeiana) were randomly assigned into eight groups of four with each group representing a different collection time point. Seven groups received selamectin (6 mg/ kg) topically and the remaining group served as the untreated control group. One group of frogs was euthanized and blood samples immediately collected on days 0 (control), 1, 5, 10, 15, 20, 25, and 30. Plasma was analyzed for selamectin using high performance liquid chromatography with fluorescence detection. Individual samples were analyzed, then data were reported as the mean of the four frogs at each time point. A histologic evaluation of the lung, liver, kidney, and skin tissues was performed and none of the frogs showed histologic evidence of toxicity due to selamectin administration. The mean peak plasma concentration was 162.5 +/- 42.3 ng/ml, area under the curve was 2,856 ng day/ml, mean residence time was 12.2 days, and disappearance half-life was 1.87 days. Based on the plasma pharmacokinetics, bullfrogs appear to absorb selamectin very efficiently, concentrations reach high levels in the plasma, and there were no apparent histologic effects from single dose administration.

Use of selamectin for the treatment of psoroptic and sarcoptic mite infestation in rabbits

Selamectin, a novel avermectin compound, was evaluated for its efficacy against naturally occurring infestations of Psoroptes cuniculi and Sarcoptes scabiei. A total of 42 New Zealand rabbits with psoroptic mange and 37 Angora rabbits with sarcoptic mange were used in the present study. On day 0, infested rabbits were treated topically with either selamectin at minimum dose of 6 mg kg(-1) (6-18 mg kg(-1) for New Zealand rabbits, n = 31 and 10-12 mg kg(-1) for Angora rabbits, n = 23) or vehicle only (control groups, n = 11 for New Zealand rabbits, n = 14 for Angora rabbits). The efficacy of selamectin was assessed both clinically and parasitologically by the presence or absence of viable mites. Rabbits were scraped for sarcoptic mites on days 7, 14, 28, 42 and 56 and had otoscopeic and/or microscopic examination for the detection of Psoroptes mites on days 7, 14, 42 and 56. Fisher's exact test was used to assess differences between the vehicle and selamectin treatment in the number of rabbits without mites (cure rates) on each assessment date. It was found that significantly fewer selamectin-treated rabbits had mites detected on skin scrapings (for S. scabiei) or otoscopeic and/or microscopic examination (for P. cuniculi) (P < 0.01) than the vehicle group. Results of the present study suggest that selamectin is effective against naturally infestations of P. cuniculi and S. scabiei in rabbits.

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.

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.