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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.

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Psoroptes are a non-burrowing, ectoparasitic, mange-causing mite that has been documented in American bighorn sheep populations throughout the 19th and 20th centuries; however, it was not seen on Canadian bighorn sheep until 2006. The aim of this study was to determine the potential source of the Psoroptes outbreak in Canadian bighorn sheep. Morphological and molecular analyses were used to compare mites recovered from outbreak-associated bighorn sheep, pet rabbits in Canada, and on historically infested bighorn sheep in the USA. The results revealed that Psoroptes acquired from the Canadian and outbreak-associated American bighorn sheep were morphologically more similar to those collected from rabbits than mites on historically infested bighorn sheep. Outer opisthosomal setae lengths measured an average of 81.7 µm (±7.7 µm) in outbreak associated bighorn mites, 88.9 µm (±12.0 µm) in rabbit mites and 151.2 µm (±16.6 µm) in historically infested bighorn mites. The opisthosomal lobe morphology of bighorn mites in the outbreak herds was also more similar to that of rabbit mites, previously described as P. cuniculi, than historically infested bighorn mites, which match previous descriptions of P. ovis. This finding was supported by DNA sequence data of the mitochondrial cytochrome B gene. This is the first report of Psoroptes of the rabbit ecotype on bighorn sheep. The morphological and molecular data therefore support the hypothesis that the source of Psoroptes outbreak in Canadian bighorn sheep represented a disease spillover event from rabbits rather than transmission from infested American bighorn sheep populations.

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Essential oils and their components represent an appealing alternative strategy against parasitic mites. The chemical complexity and variability of essential oils limit their use and additional work is required to analyze the efficacy and application rate of essential oils' individual components. In the present study, the activity of five terpenes (terpinen-4-ol, citral, linalool, eugenol, and geraniol) was evaluated against Psoroptes cuniculi motile stages and eggs collected from naturally infected rabbits. Eugenol presented the best acaricidal efficacy with a median lethal concentration (LC50) value of less than 0.1% at 24 h, followed by geraniol (0.33%), linalool (0.38%), citral (0.46%), and terpinen-4-ol (0.66%). Geraniol and eugenol were able to kill all mites within 5 min at 1% concentration. The effective concentration to inhibit 50% (EC50) of egg hatching was 0.65%, 0.66%, 0.85%, 1.47%, and 2.87% for eugenol, geraniol, citral, terpinen-4-ol, and linalool, respectively. In conclusion, eugenol, geraniol, citral, terpinen-4-ol, and linalool should be considered as promising agents for the development of botanical acaricides against Psoroptes cuniculi.

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Plant essential oils and its chemical compositions are commonly applied in medicinal and other industries due to their broad advanced pharmacological activities. In the present study, we systematically evaluated the acaricidal activities of twelve compounds of essential oils against Psoroptes cuniculi in vitro and in vivo. In addition, to support the clinic uses, their toxicities against immortalized human keratinocytes (HaCaT) and human liver cells (HL-7702) and skin irritation were studied for evaluating the liver and skin safety. The possible mechanism of action of certain chemical were investigated by determining the inhibitory activities against cytochrome P450 (P450) acetylcholinesterase (AChE) and glutathione-S-transferase (GST). Among all tested compounds, eugenol exhibited the best acaricidal activity with LC50 value of 56.61 µg/ml in vitro. Meanwhile, after the treatment of eugenol for five times within 10 days, the P. cuniculi were eliminated in the naturally infested rabbits, no skin irritation was found in rabbits treated by eugenol. Moreover, eugenol presented no or weak cytotoxicity against HaCaT cells and HL-7702 cells with IC50 values of greater than 100 µg/ml. Furthermore, the moderate inhibitory activities of eugenol against mites P450 and AChE were demonstrated. Above results indicated that eugenol presented the promising acaricidal activity against P. cuniculi in vitro and in vivo, is safe for both humans and animals at the given doses. This work lays the foundation for the development of eugenol as an environmentally friendly acaricide agent.

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In this study, the acaricidal effect of eugenol was measured and its mechanism of action investigated. The results showed that eugenol possessed the effect of killing Psoroptes cuniculi, and could regulate the mRNA expression of glutathione S-transferase (GST), catechinic acid (Ca) and thioredoxin (Trx). PPAR, NF-kappa B, TNF, Rap 1 and Ras signaling pathways might be the main pathways that involved into the process of killing mites. These findings suggested that eugenol could be developed into a new kind of acaricide, and further expand current knowledge on the mechanisms of eugenol for killing Psoroptes cuniculi of eugenol.

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BACKGROUND: Psoroptes cuniculi mites are the most common ear parasites infesting breeding female rabbits. The suffering rabbits show cutaneous signs of the infestation in the ears and are prone to secondary infections. OBJECTIVES: This trial was conducted to eliminate P. cuniculi in farm rabbits with a sustained-release ivermectin-loaded solid dispersion suspension (IVM-SD) suspension, and studied the stability of the formulation. ANIMALS: There were 986 breeding female Hyplus rabbits naturally infected with P. cuniculi. METHODS: All rabbits infected with P. cuniculi were subcutaneously administered with a single dose of IVM-SD suspension at 2 mg/kg body weight. Twenty-seven rabbits with severe infections were observed daily and examined on days 0 and 14 to score the lesions and count mites in crusts. RESULTS: Fourteen days after the treatment no live mites were detected, demonstrating 100% therapeutic efficacy. The mean lesion scores decreased from 4.33 to 0.11 in the left ears and from 4.22 to 0.22 in the right ears. No reinfection occurred within 60 days of treatment. CONCLUSIONS: A single subcutaneous administration of the IVM-SD suspension at 2 mg/kg was effective in eliminating P. cuniculi infection in the rabbit farm.

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A series of cinnamic acid derivatives and its heteroaromatic ring analogues were synthesized and evaluated for acaricidal activity in vitro against Psoroptes cuniculi, a mange mite. Among them, eight compounds showed the higher activity with median lethal concentrations (LC50) of 0.36-1.07mM (60.4-192.1µg/mL) and great potential for the development of novel acaricidal agent. Compound 40 showed both the lowest LC50 value of 0.36mM (60.4µg/mL) and the smallest median lethal time (LT50) of 2.6h at 4.5mM, comparable with ivermectin [LC50=0.28mM (247.4µg/mL), LT50=8.9h], an acaricidal drug standard. SAR analysis showed that the carbonyl group is crucial for the activity. The type and chain length of the alkoxy in the ester moiety and the steric hindrance near the ester group significantly influence the activity. The esters were more active than the corresponding thiol esters, amides, ketones or acids. Replacement of the phenyl group of cinnamic esters with α-pyridyl or α-furanyl significantly increase the activity. Thus, a series of cinnamic esters and its heteroaromatic ring analogues with excellent acaricidal activity emerged.

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The ear mite "Psoroptes cuniculi" is the main cause of ear mange, a highly contagious parasitic skin disease in rabbits all over the world. In the current work, a preliminary therapeutic trial to study the effect of the broad use acaricides doramectin and ivermectin on P. cuniculi was performed on artificially infested rabbits. Twenty five adult New Zealand white rabbits were used in this study. The rabbits were assigned randomly into five groups/ 5 rabbits in each group. Each rabbit was experimentally infested with 100 mites/ ear. The first group was designated the positive control group and was not treated. The second and third groups were treated with doramectin 200 and 400 µg/kg bw, respectively. Groups 4 and 5 were treated by dressing with ivermectin in one dose and 2 doses with a 1 week interval. After the therapy, all rabbits were examined microscopically on the 7th, 14th, and 28th day post treatment and the number of live mites (larvae, nymphs, and adults) on each rabbit was counted at the end of the experiment (28th day). The results showed that the rabbits treated subcutaneously with doramectin at a single dose of 200 µg /kg bw showed a very low effect, although there was significant improvement when the dose was doubled to 400 µg /kg bw, with the number of mites counted decreasing significantly. Rabbits treated topically with ivermectin spot-on, a single dose or 2 doses, showed great improvement of the lesion: the number of mites was reduced to zero. In conclusion, this work showed that ivermectin spot-on applied locally on infested ears proves to be more effective against P. cuniculi than doramectin injected subcutaneously. Further trials on ear mange therapeutics in rabbits are to be encouraged.

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SCOPE: Adonis coerulea Maxim. is a perennial herbaceous plant that grows in scrub, grassy slope areas, and as traditional medicine it has been used to treat animal acariasis for thousands of years. In this paper, we aimed to study the acute toxicity and cytotoxicity of the methanol extract of A. coerulea (MEAC) in vivo and in vitro for supporting the clinic uses. The acaricidal activity and the mechanism of action against Psoroptes cuniculi were investigated. RESULTS: The results showed that isoorientin, luteolin and apigenin were the primary compounds in MEAC. The toxicity test showed that median lethal dose (LD50) and the 50% inhibitory concentration (IC50) of MEAC were estimated to be more than 5000mg/kg in mice in vivo and more than 50mg/ml against RAW 264.7 and GM00637 cells in the 3-(4, 5-dimethylthiazol-2- yl)-2,5-diphenyltetrazolium bromide (MTT) test. After culturing with MEAC, the activities of superoxide dismutase (SOD), catalase (CAT), malonyldialdehyde (MDA), glutathione-S-transferase (GST), acetylcholinesterase (AChE) and Na+-K+-ATPase of mites were evaluated. Compared with the control group, SOD activity of MEAC-treated group of mites was inhibited, and CAT activity was activated at the preliminary phase but was gradually inhibited over the period of incubation. MDA content reached a peak at 6h and then gradually decreased. However, GST activity in the mites was activated in a dose- and time-dependent manner. AChE and Na+-K+-ATPase activities related to neural conduction, vital functions and the transmembrane ion gradient of the mites were inhibited. CONCLUSION: MEAC is safe in the given doses in both the in vitro and the in vivo tests, can be applied in the clinic and it had good acaricidal activity. The extension of the incubation time in the mites led to dynamic disequilibrium between the production and clearing of superoxide anions, a disruption of the energy metabolism and the transmembrane ion gradient, and the inhibition of motor function. These factors may have resulted in mite death.

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In this paper, the acaricidal activities of Rhododendron nivale Hook. f. and its main compound, δ-cadinene were investigated, and the chemical composition of the essential oil was analyzed. The results showed that among aqueous, 70% ethanols, acetic ether, chloroform, petroleum ether and essential oil extracts from the shoots and leaves, the essential oil showed the best in vitro acaricidal activity against adult P. cuniculi, which occurred in a concentration- and time-dependent manner. The median lethal time (LT50) values of four concentrations (33.33-4.17mg/ml) of the essential oil ranged from 1.476 to 25.900h, respectively. After the treatment of P. cuniculi with the essential oil and ivermectin, infected rabbits were free of scabs or secretions in the ear canal by day 20. Then, the percent yield of essential oil from the leaves and shoots was 2.45% (w/w), which includes 50 compounds. The primary component identified was terpenes, and among of compounds identified from the essential oil of R. nivale the highest relative content was δ-cadinene, which also presented the marked acaricidal activity against Psoroptes cuniculi in vitro. These findings provide evidence for the use of acaricides as a traditional medicine and indicate that the essential oil and δ-cadinene could be used to control mites in livestock.

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Bacillus thuringiensis is a bacteria known for its bioinsecticidal toxins and it has been proposed as an alternative in the treatment of several parasites that infect domestic animals (helminths, ticks, mites). In this work, we evaluated the clinical efficiency of the Bacillus thuringiensis GP532 strain in the treatment of six rabbits naturally infested with the P. cuniculi mite. GP532 extract (10mg/ml) was applied by aspersion in both pinna, with a second application after seven days, and the therapeutic effect was measured in both qualitative and quantitative manner. GP532 application resulted in a decreased infestation rate, which was observed as early as 3days post-treatment. At day 14, a decrease from 4.66±0.61 to 0.50±0.10 in the left pinna and from 1.66±0.21 to 0.66±0.16 (P<0.05) in the right pinna was observed. This response was comparable to the commercial drug Ivermectin, which induced a decreased infestation rate from 4.00±0.51 to 0.16±0.10 in the left pinna and from 4.66±0.80 to 0.25±0.11 in the right pinna (P<0.05). At day 30 post-treatment, GP532 decreased the total infested area by 76.80±16.06%, whereas Ivermectin resulted in a 97.41±0.99% decrease. Neither treatment produced irritation or macroscopic lesions. Our results show that the B. thuringiensis GP532 strain has a therapeutic potential in the treatment of psoroptic mange in rabbits.

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Oregano oil possesses marked antioxidant and antimicrobial activity and is widely applied in animal husbandry. In the present study, we aimed to investigate the acaricidal activities of oregano oil and its major component, carvacrol, thymol and p-cymene against Psoroptes cuniculi in vitro and in vivo. The results revealed that oregano oil exhibited significant acaricidal effects against P. cuniculi that were dose- and time-dependent response. In in vitro test, concentrations of 0.05% and 0.02% (v/v) killed all of the mites within 1h and 6h, respectively. Moreover, 0.1mg/ml (w/v) carvacrol, 0.2mg/ml (w/v) thymol and 1% p-cymene (v/v) also possessed marked acaricidal activities, and compared with the control group, elicited mean mortalities of 84.00%, 96.00% and 66% at 24h, respectively. The median lethal times (LT50) against P. cuniculi of the concentrations of 0.02%, 0.01% and 0.005% (v/v) of oregano oil, thymol, carvacrol and p-cymene were 2.171h, 11.396h, 26.102h, and 4.424h, 8.957h and 15.201h, respectively. Meanwhile, twenty naturaly infested rabbits were used to four homogeneity groups: negative control (without treatment), positive control (treated with ivermectin), group treated with 1% of oregano oil and other group with 5% of oregano oil. All the treatments were topically. After the treatment of 1% and 5% oregano oil, the P. cuniculi were completely eliminated in the rabbits, and at the end of the test (day 20), the rabbits of all treatment groups exhibited favorable mental and physical statuses. These results indicated that oregano oil could be widely applied as a potential acaricidal agent in the treatment of animal acariasis in the future.

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The objective of the present study was to investigate the clinico-pathological changes and therapeutic evaluation of gamma-benzene hexachloride and cetrimide along with vit A, D3, E and H in Black Bengal goat infested Psoroptes cuniculi mange. The study was conducted on 14 Black Bengal goats; 6 clinically infested with Psoroptes mange (group I) and 8 healthy goats (group II). Haemato-biochemical profile viz., haemoglobulin concentration, packed cell volume, total leukocyte count, albumin and albumin globulin ratio revealed significantly (P < 0.05) decreased level; whereas, globulin, alanine aminotransaminase, aspartate aminotransaminase, serum creatinine and blood urea nitrogen level were significantly (P < 0.05) increased in goats of group I animals as compared to healthy control (group II) on day 0. Gamma-benzene hexachloride and cetrimide along with adjunct therapy (group I) showed parasitological recovery on day 21 while complete elimination of clinical signs observed on day 28 of post-therapy in all clinical cases.

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Esta pesquisa teve como objetivos avaliar a eficiência da técnica do jato de água, com 50 e 100ml de água, para determinar a prevalência da infecção por Psoroptes cuniculi e estimar o grau de infestação para estudos da dinâmica populacional. O estudo foi realizado no matadouro municipal da cidade de Patos, Paraíba, com 30 caprinos de ambos os sexos e idades variadas. O conduto auditivo esquerdo de cada caprino foi lavado com 100ml de água e o direito, com 50ml. Os ácaros coletados na lavagem e os ácaros obtidos após a abertura dos condutos auditivos foram contados e identificados de acordo com o estádio do ciclo biológico do parasito. Mediante a técnica da lavagem com 100mL, foi identificado o parasita em 22 (91%) dos 24 condutos infectados e, na lavagem com 50mL, foi identificado em 18 (78,3%) de 23 condutos infectados (P>0,05). Após a abertura e contagem do total de ácaros, verificou-se que, na lavagem, haviam sido recuperados de 19% a 35% dos ácaros de todos os estádios de desenvolvimento, exceto para o estádio de ovo, que foi de 11% a 15%, não havendo diferença estatística significativa (P>0,05) entre as taxas de recuperação com 50 e 100mL de água. Conclui-se que a técnica da lavagem do conduto auditivo é eficiente para estudos da prevalência da otocariase, porém, para estudos de dinâmica populacional, recomenda-se a abertura dos condutos auditivos e a contagem de todos os ácaros presentes.

The aim of this study was to evaluate the technique of washing the auditory canal (ear flushing technique) either with 50 or 100mL of water to determine the prevalence of the infection by Psoroptes cuniculi and to estimate the degree of infestation for population dynamics studies. The experiment was conducted in a slaughterhouse in the city of Patos, state of Paraiba, northeastern Brazil, with 30 goats of different ages and both sexes. Left auditory canal of each goat was washed with 100mL of water, and the right with 50mL. Later, the auditory canals were opened to count the remaining parasites. The mites recovered by washing and those recovered after opening the auditory canals were counted and identified in accordance with the stage of development. No significant differences (P=5.81) were found in the prevalence of the infection between the auditory canals washed with 50mL (78.3%), and those washed with 100mL (91%). After opening the auditory canals it was determined that the parasites recovered by washing represented 19% to 35% of the total parasites of the auditory canal for all stages of development, except for the eggs, which varied from 11% to 15% of recovering, with no significant differences (P>0,05) between the auditory canals washed with 50 or 100mL. It is concluded that the technique of washing the auditory canals with 50 or 100mL of water in goats is efficient to study the prevalence of infection by P. cuniculi, however the intensity of the infection and the population dynamics should be studied in slaughtered goats by opening the auditory canals to count the different stages of the parasite.

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The acaricidal activity of the 9-oxo-10,11-dehydroageraphorone (euptox A), a cadenine sesquiterpene from Eupatorium adenophorum (E. adenophorum) against Sarcoptes scabiei and Psoroptes cuniculi was tested in vitro. A complementary log-log (CLL) model was used to analyze the data of the toxicity tests in vitro. The results showed euptox A had strong toxicity against mites, killing all S. scabiei at 3 and 4 mg/ml (m/v) concentration, while 4 mg/ml euptox A was also found to kill all P. cuniculi within a 4 h period. Similarly, 2, 3 and 4 mg/ml concentration of euptox A had strong toxicity against S. scabiei, with median lethal time (LT50) values at 0.687, 0.526, 0.326 h, respectively. 3 mg/ml and 4 mg/ml showed strong acaricidal action against P. cuniculi; the LT50 values were 0.693 and 0.493 h, respectively. The median lethal concentration (LC50) values were 1.068 mg/ml for Scabies mite and 0.902 mg/ml for P. cuniculi in 2 h. The results indicate that euptox A has strong acaricidal activity and may exploit as novel drugs for the effective control of animal acariasis.

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The mite Psoroptes cuniculi is globally widespread and has a serious impact on commercial rabbit breeding. In China, diagnosis of P. cuniculi is currently based on conventional clinical methods that entail numerous disadvantages, including their failure to diagnose subclinical infections. Hence, alternative measures are required, and dot-ELISA is one of the most promising strategies. We cloned and expressed the recombinant P. cuniculi troponin C gene for use as a basis for novel dot-ELISA assay to detect P. cuniculi infections in rabbits. This amplified sequence encoded a 153 amino acid protein of 17·6 kDa and theoretical pI 4·18 without signal peptide. The recombinant troponin C of P. cuniculi is an outer membrane protein and may also be a new P. cuniculi allergen. Results of dot-ELISA test showed that this novel assay had more than 90% sensitivity but low specificity in distinguishing infections with P. cuniculi or Sarcoptic scabiei, despite very high agreement between observers (97-99%; κ values ranged from 0·95 to 0·98 for inter- and intra-observer variability test). This study showed that this novel method, at present, lacks diagnostic utility. Therefore, although simple serological assays such as dot-ELISA show great promise as diagnostic tools, we suggest that troponin C is not a suitable diagnostic antigen candidate.

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