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

Antiparasitic activity of ivermectin: Four decades of research into a "wonder drug"

Parasitic diseases still pose a serious threat to human and animal health, particularly for millions of people and their livelihoods in low-income countries. Therefore, research into the development of effective antiparasitic drugs remains a priority. Ivermectin, a sixteen-membered macrocyclic lactone, exhibits a broad spectrum of antiparasitic activities, which, combined with its low toxicity, has allowed the drug to be widely used in the treatment of parasitic diseases affecting humans and animals. In addition to its licensed use against river blindness and strongyloidiasis in humans, and against roundworm and arthropod infestations in animals, ivermectin is also used "off-label" to treat many other worm-related parasitic diseases, particularly in domestic animals. In addition, several experimental studies indicate that ivermectin displays also potent activity against viruses, bacteria, protozoans, trematodes, and insects. This review article summarizes the last 40 years of research on the antiparasitic effects of ivermectin, and the use of the drug in the treatment of parasitic diseases in humans and animals.

Zoonotic Dermatoses of Exotic Companion Mammals

Integumentary disorders caused by zoonotic agents are very common in exotic companion mammals. This article provides an understanding of the main zoonotic dermatoses including parasitic, fungal, bacterial, and viral diseases to provide the most updated information on their epidemiology, diagnosis, reported clinical signs, and therapies.

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.

Differences among domestic chicken breeds in tonic immobility responses as a measure of fearfulness

Background

One priority for animal welfare is for animals to experience less fear, especially during human contact. For domestic animals, breeds that are less fearful may provide genetic resources to develop strains with improved welfare due to lower susceptibility to fear. Genetic predispositions inherited in these breeds might reflect the large diversity of chicken breeds. The goal of the present study was to systematically test a diverse group of chicken breeds to search for breeds that experience less fear.

Methods

Nineteen chicken breeds from commercial hybrid lines, native layer-type, meat-type and dual-purpose breeds, ornamental breeds as well as bantam breeds were tested in a standardized tonic immobility (TI) test. Chickens were manually restrained on their back, and the time to first head movement and first leg movement, the duration of TI, as well as the number of attempts needed to induce TI were measured.

Results

The TI response differed among chicken breeds (p ≤ 0.001) for naïve, mature hens. The median number of attempts required to induce TI ranged from 1 to 2 and did not differ significantly among breeds. Median durations were much more variable, with Lohmann Brown showing shortest durations (6 s, 12 s, 58 s for time to first head movement, first leg movement and total duration of TI, respectively). In contrast, medians reached the maximum of 600 s for all three measures in German Creepers. Repeated tests on the same individuals did not affect attempts needed to induce TI nor TI durations. Breeds clustered into two main groups, with layer-type native breeds and ornamental breeds having longer TI durations, and bantam, dual-purpose and meat-type native breeds having shorter TI durations.

Conclusions

Our findings provide evidence for substantial variation of fearfulness among breeds. This variation could be linked to the intended use during the breed's specific history. Knowledge and quantitative measurement of these behavioural responses provide the opportunity to improve welfare through selection and future breeding.

Play and welfare in domestic cats: Current knowledge and future directions

Play and welfare have long been linked within animal research literature, with play considered as both a potential indicator and promoter of welfare. An indicator due to observations that play is exhibited most frequently in times when an animal's fitness is not under threat and when immediate needs such as food, water and adequate space are met. And a promoter, because of observations that animals who play more also have better welfare outcomes. However, limited research has been undertaken to investigate this link, especially in companion animals. The domestic cat ( Felis catus) is one of the most popular companion animals in the world, yet little is known about the impact of play behaviour on cat welfare. We review the current literature on play and welfare in cats. This includes examining the role of cat play in mitigating negative welfare outcomes, such as reducing problem behaviours, one of the leading reasons for guardian dissatisfaction and cat relinquishment to shelters. Play is also discussed as a potential tool to provide environmental enrichment and to improve cat-human relationships. Future areas for research are suggested. We find that further research is needed that uses a multifaceted approach to assess how quantity, type and quality of play impact subsequent cat behaviour and welfare. Future research could also assess cat play needs and preferences as well as investigate the role of play in mitigating threats to cat welfare such as reducing problem behaviour and improving human-cat relationships. If play is an indicator and promoter of welfare, studies into the impact of play may offer an accessible approach for monitoring and improving domestic cat welfare.

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.

A Q study: exploring the purpose of transdisciplinary dairy advisory services in Denmark

Background

Structural changes in dairy farming increase farm complexity, thereby inducing a need to combine herd health management, technological solutions, legislation, and human relations among farmers, farm workers, and advisors. This complex situation may require ‘transdisciplinary advisory service’, i.e., a highly integrated network of both non-academic and different academic disciplines. While working in these networks, advisors need to offer specialized knowledge from their own field, interact in a dynamic relationship between different types of professions and facilitate complex processes. The objectives of this study were: (1) to identify and describe different advisor and farmer styles based on their reasons to engage in transdisciplinary advisory services at farm-level, (2) to identify any possible conflicting perspectives between advisors and farmers’ demand, and (3) to discuss these styles and conflicts in the context and future of advisory services for dairy herd health and production management.

Results

Using Q methodology, we explored the purpose of transdisciplinary advisory service on dairy farms. The results were derived from correlations between 40 statements for 25 advisors and 33 statements for nine farmers. We identified three similar styles among advisors and farmers, characterized as: (1) the teamwork and knowledge-focused style, (2) the production and economy-focused style, and (3) the economy and strategy-focused style. These styles included reflections on financial aspects, production, knowledge-exchange and the teamwork process itself. In addition, different emphasis on animal welfare, farm strategy and follow-up procedures between the styles became evident.

Conclusions

This Q-study suggests three comparable styles between advisors and farmers. The main differences between the styles related to the teamwork process and purpose, follow-up process, financial aspects, farm strategy, and operational production objectives. Therefore, styles and expectations should be explored and discussed to create a mutual understanding within a farmer-advisor(s)-team, and to clarify the farmer’s needs and demands, and how the advisors can best meet these expectations. This study illustrates the importance of exploring different advisor and farmer styles to get a mutual understanding of the purpose of the transdisciplinary collaboration.

Evaluation of the effect of afoxalaner with milbemycin 1 oxime in the treatment of rabbits naturally infected with Psoroptes cuniculi

Rabbits (Oryctolagus cuniculi) are very popular as pets. However, problems of otitits caused by Psoroptes cuniculi are one of the main reasons to visit the veterinarian. Isoxazolines are an alternative treatment to treat this mite, and therefore, an evaluation of the effectiveness of oral afoxalaner with milbemycin oxime in rabbits infected with P. cuniculi was carried out. Nineteen rabbits, of New Zealand breed, with otitis due to an infection with P. cuniculi, were treated, whereas six rabbits were left untreated and formed the control group. The ear canals of each individual were examined, through the collection of otic exudate samples with cotton swabs. These were visualized under the microscope to identify the ectoparasite. Each animal was treated with a single oral dose of 2.50 mg / kg of afoxolaner, and 0.50 mg / kg of milbemycin oxime. Clinical signs and lesions associated with the infection, such as the presence of detritus, cerumen and / or scabs, and erythema, were evaluated. After receiving the treatment, all the lesions were classified as: mild, moderate and intense, with a visual analog scale. A week after providing medication, there was a decrease in the lesions of the group treated with Nexgard Spectra®, without further topical or systemic treatment. The decrease was gradual in the treated group and no recurrence was detected of P. cuniculi infection in both ears. Thus, the administration of a single oral dose of afoxolaner with milbemycin oxime was effective for the treatment of P. cuniculi infection in rabbits.

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.

A single subcutaneous administration of a sustained-release ivermectin suspension eliminates Psoroptes cuniculi infection in a rabbit farm

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.

Prevalence and zoonotic risks of Trichophyton mentagrophytes and Cheyletiella spp. in guinea pigs and rabbits in Dutch pet shops

Young rabbits and guinea pigs are often purchased as pets for children and may be infected with zoonotic skin infections. To assess the risk of acquiring such an infection from rabbits or guinea pigs, this study investigated the prevalence of the fungus Trichophyton mentagrophytes and the fur mite Cheyletiella parasitovorax in asymptomatic rabbits and guinea pigs in Dutch pet shops. In 91 pet shops a total of 213 rabbits and 179 guinea pigs were sampled using the Mackenzie technique and cultured. Clean cultures were examined microscopically and a PCR was performed on at least one sample from each pet shop. All animals were investigated for fur mite using a flea comb, a magnifying glass and white paper. From the fur of 3.8% (8/213) of the rabbits and 16.8% (30/179) of the guinea pigs, T. mentagrophytes was isolated. From 1 guinea pig (0,6%) Chrysosporium keratinophilum was isolated. Dermatophyte-positive rabbits and guinea pigs originated from 5.6% (5/90) and 27.3% (24/88) of the investigated pet shops, respectively. Fur mites were not found. Pet shops can play an important role in preventing transmission of zoonotic ringworm infections (dermatophytosis) and educating their customers. Specific preventive measures such as routine screening examinations and (prophylactic) treatment of rabbits and guinea pigs are recommended next to regular hygiene when handling animals.

Sustained release ivermectin-loaded solid lipid dispersion for subcutaneous delivery: in vitro and in vivo evaluation

This work aimed to develop a sustained release solid dispersion of ivermectin (IVM-SD) in a lipid matrix (hydrogenated castor oil, HCO) for subcutaneous delivery. Solvent-melting technology was employed to prepare IVM-SDs using HCO. The physicochemical properties of the IVM-SDs were evaluated by scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), and Fourier transform infrared spectroscopy (FTIR). The release of IVM from IVM-SDs was evaluated with HPLC in vitro. Pharmacokinetics of IVM was studied in rabbits following a single subcutaneous administration of IVM-SD formulations. The efficacy of IVM-SD against the ear mange mite was evaluated in rabbits. IVM was completely dispersed in HCO in an amorphous state at a drug:carrier ratio lower than 1:3. No chemical interactions between drug and carrier were found besides hydrogen bonding for the amorphous IVM-SDs. The amorphous IVM-SDs formulations exhibited a sustained release of IVM versus physical mixtures (PMs) of IVM and HCO. The drug release decreased as the drug:carrier ratios decreased, and the release kinetics of IVM were controlled via diffusion. Cytotoxicity of IVM-SD to MDCK cells was lower than native IVM. The IVM plasma concentration of SD1:3 remained above 1 ng/mL for 49 d. Higher AUC, MRT, and T_max values were obtained at a SD1:3 relative to the IVM group. The IVM-SD improved almost 1.1-fold bioavailability of drug compared with IVM in rabbits. IVM-SD could provide longer persistence against rabbit’s ear mites than a commercial IVM injection. This study shows that these solid lipid dispersions are a promising approach for the development of subcutaneous IVM formulations.

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.

The acaricidal efficacy of aqueous neem extract and ivermectin against Sarcoptes scabiei var. cuniculi in experimentally infested rabbits

Sarcoptes scabiei var. cuniculi is one of the most important veterinary ectoparasites in rabbits and results in considerable loss of weight, productivity, and wool quality. The acaricidal activity of aqueous leaf extract of neem (CAN) and ivermectin (IVR) were evaluated in vitro and in vivo against S. scabiei var. cuniculi. Rabbits were classified into four groups (ten rabbits each). The first group (group 1) was designated as the negative control group. Each rabbit of the other groups was experimentally infested with 50 mites. One month post-infestation, the second group (group 2) was not treated and taken into account as the positive control group. The third group (group 3) was subcutaneously injected with 1 % IVR (200 μg/kg body weight, three times within a week interval). The fourth group (group 4) was treated topically with CAN (25 %) every 3 days for three consecutive weeks. Index scoring of lesions was described weekly. The number of live mites (larvae, nymphs, and adults) on each rabbit was counted on the 14th, 28th, and 42th day post-treatment (PT). Blood samples were taken 28 and 42 days PT for estimation of some chemical parameters. The body weight and cumulative body weight gain were recoded 14, 28, and 42 days PT. CAN (40 %) was highly efficacious against larvae of S. scabiei var. cuniculi as 100 % mortality was reached 24 h PT. On the other hand, all treated mites with CAN (20 %) and IVR died 48 h PT. The lethal values of CAN (LC50, LC90, LC95, and LC99) were 7.496, 14.67, 17.75, and 25.37 %, respectively, 48 h PT. Lesion scoring in groups 3 and 4 were significantly decreased (P ≤ 0.05), reaching 0.20 and 0.40, respectively, when compared with that of group 2 (4.00), 42 days PT. Twenty-eight days PT, the reduction percentages of mites infesting rabbits were 93.38 and 93.09 % for IVR and CAN, respectively. However, complete mite reduction was reached 42 days PT. Rabbits treated with CAN did not show signs of restlessness or irritation, respiratory signs, or inflammation on the eye and/or skin at the time of application or afterwards. Regarding biochemical analysis, the levels of aspartate aminotransferase, alanine aminotransferase, creatinine, and total cholesterol in rabbits treated with CAN were decreased significantly (P ≤ 0.05) than those of rabbits of the positive control group and those treated with IVR. On the other hand, the levels of total protein, albumin, and globulin of rabbits in group 4 were significantly (P ≤ 0.05) increased when compared with the corresponding values of groups 2 and 3. The body weight and cumulative body weight gain of rabbits treated with CAN were significantly increased (P ≤ 0.05) when compared with such values of groups 2 and 3, 28 and 42 days PT. The present data indicated that CAN had in vitro and in vivo acaricidal efficiency similar to that of IVR and improved the performance of rabbits without inducing adverse effects on treated rabbits; consequently, CAN could be suitable as a promising alternative acaricide for veterinary use.

Plasma dispositions of ivermectin, doramectin and moxidectin following subcutaneous administration in rabbits

This study evaluated the comparative plasma dispositions of ivermectin (IVM), doramectin (DRM) and moxidectin (MXD) following subcutaneous administration in rabbits. Fifteen New Zealand white rabbits were allocated into three groups of five animals each. The animals in each group received IVM, DRM or MXD by subcutaneous injection at a single dose of 0.3 mg/kg. Blood samples were collected at various times between 1 h and 40 days after treatment and the plasma samples were analysed by high-performance liquid chromatography using fluorescence detection. Moxidectin was absorbed faster from the injection site and reached the peak plasma concentration ( Cmax) significantly earlier than IVM and DRM. There was no significant difference in Cmax values among the three molecules, whereas the area under the concentration–time curves of DRM (258.40 ng.d/mL) and IVM (191.62 ng.d/mL) was significantly higher than that of MXD (83.17 ng.d/mL). The mean plasma residence time and terminal half-life ( t1/2λ z) were longer for DRM (7.52 and 4.48 days, respectively) and MXD (8.97 and 8.16 days, respectively) compared with IVM (4.73 and 2.75 days, respectively). Considering the pharmacokinetic parameters for the parent molecules, the persistence of DRM and MXD are significantly longer than IVM and this may have a positive effect on their efficacy in rabbits following subcutaneous administration or utility relating to interdosing interval.

Genetic determinants of antibiotic resistance in Staphylococcus aureus isolates from milk of mastitic crossbred cattle

Staphylococcus aureus is one of the major causes of mastitis in dairy animals and its resistance against multiple antimicrobials always remains crucial concern. Present investigation was carried out to detect the distribution of antibiotic-resistant genes of S. aureus isolates. Isolates (128) of S. aureus from mastitic milk were collected, tested for antibiotics with disc-diffusion method, and resistant genes mecA, linA, msrA msrB, vatA, vatB, vatC ermA, ermC tetK, tetM and aacA-D were detected by PCR. The phenotypic antibiotics resistance percent in S. aureus isolates was classified as tetracycline (36.7), gentamycin (30.5), streptomycin (26.6), kanamycin (25.8) and penicillin G (22.7). All the isolates were susceptible to vancomycin. Among isolates, 10.2% were observed as methicillin-resistant. The distribution of antibiotic-resistant genes was linA (51.6) followed by msrB (46.1), tetK + M (34.4), msrA and aacA-D (26.6%). Different antibiotic-resistant genes combinations (mecA/linA-2; mecA/aacA-D/tetK/linA/msrB-3; mecA/linA/msrA/msrB-3; aacA-D/linA/msrA/msrB-4; aacA-D/linA/msrB-7; linA/msrA/msrB-10; tetK/linA/msrA/msrB-11; aacA/tetK/linA/msrB-12 isolates) were observed. All the isolates lacked amplification of vatA, vatB, ermA and ermC genes. Molecular typing resulted genetic variation in protein A (6-12 repeats) and coagulase genes (A-E patterns) were observed. Coagulase A and D genotypes were more prevalent in antibiotic-resistant isolates, while E, B and C in susceptible ones. The significant observation was the prevalence of methicillin-resistant S. aureus, which were resistant to multiple antibiotics. Findings revealed the status of resistant isolates in herd that might be helpful in treatment, controlling of resistant strains and culling of cows for mastitis reduction.