First description of sarcoptic mange in wild European rabbit (Oryctolagus cuniculus)

Epidemiological survey and risk factors associated with Sarcoptes scabiei in wild lagomorphs in Spanish Mediterranean ecosystems

Although mortality caused by Sarcoptes scabiei has been reported in European wild rabbit (Oryctolagus cuniculus) and Iberian hare (Lepus granatensis), there is a lack of detailed information regarding the exposure of wild lagomorph species to this parasite. Here, we aimed to determine the seroprevalence and potential risk factors associated with S. scabiei exposure in European wild rabbits and Iberian hares in Mediterranean ecosystems of southern Spain. Between 2018/2019 and 2021/2022 hunting seasons, serum samples from 464 wild rabbits and 132 Iberian hares were collected from 100 hunting grounds in Andalusia (southern Spain). Sera were tested using an in-house indirect ELISA to detect specific anti-S. scabiei antibodies based on the immunodominant protein Ssλ20ΔB3. The overall apparent individual seroprevalence was 15.9% (95/596; 95%CI: 13.0-18.9). Antibodies against S. scabiei were detected in 11.6% (54/464; 95%CI: 8.7-14.5) of the European wild rabbits and 31.1% (41/132; 95%CI: 23.2-39.0) of the Iberian hares. Species (Iberian hare), age (adults) and geographical area (western Andalusia) were identified as risk factors potentially associated with S. scabiei exposure using generalized estimating equation analysis. By applying spatial analysis, two significant cluster of high seropositivity were detected in western and central Andalusia, respectively. The seroprevalence values obtained provide evidence of endemic, widespread and heterogeneous exposure to S. scabiei among wild lagomorph populations in Spanish Mediterranean ecosystems. Our findings underscore the importance of implementing integrated surveillance programs for sarcoptic mange in wild lagomorphs as well as in other sympatric species.

Camera traps reveal a high prevalence of sarcoptic mange in red foxes from northern Spain

The mite Sarcoptes scabiei affects numerous mammal species causing the sarcoptic mange, a widespread disease with relevance for wildlife conservation, welfare, and management. The red fox (Vulpes vulpes) could become infested by direct and indirect routes leading to external skin lesions potentially recognizable by devices such as camera traps (CTs). In the present study, 86 randomly placed CTs were used to investigate the apparent prevalence and severity of S. scabiei in a red fox population from northern Spain. Their potential environmental and population-related drivers were also assessed. A total of 341 independent encounters were examined to visually identify mange-compatible lesions. The apparent prevalence was 19.16% (confidence interval (CI) 95%: 15.08-23.80) of which 82.81% (CI95%: 71.33-91.10) were severe. Our results revealed that habitat attributes such as lower altitudes, higher coverage of water-linked habitats and woodland predominance, were significant predictors of the apparent risk of mange. The models also suggested that the apparent prevalence of mange was associated with poor body condition and elevated frequencies of spatial coincidence among fox encounters, which facilitates indirect transmission. Interestingly, we did not observe mange-compatible lesions in other sympatric wild species (>15,000 encounters examined). This could be explained by the mite's host specificity and the low probability that these other potential hosts use sites where transmission among foxes usually occurs, such as dens. This study illustrates how camera trapping can be used as an interesting tool for the surveillance of wildlife diseases, thus overcoming the logistic constraints derived from direct sampling and allowing the early detection and better management of pathogens in the riskiest areas.

The local skin cellular immune response determines the clinical outcome of sarcoptic mange in Iberian ibex (Capra pyrenaica)

Introduction

Sarcoptic mange, caused by Sarcoptes scabiei, is a disease with implications for wildlife conservation and management. Its severity depends on the host's local skin immune response, which is largely unknown in Iberian ibex (Capra pyrenaica), a mountain ungulate dramatically affected by mange. In this species, the clinical outcome of sarcoptic mange varies among individuals, and the local immune response could be key to controlling the infestation. This study aims to characterize the local cellular immune response and its relationship with the clinical outcome.

Methods

Fourteen Iberian ibexes were experimentally infested with S. scabiei and six more served as controls. Clinical signs were monitored, and skin biopsies were collected from the withers at 26, 46, and 103 days post-infection (dpi). The presence and distribution of macrophages (including M1 and M2 phenotypes), T lymphocytes, B lymphocytes, plasma cells, and interleukine 10 were quantitatively evaluated using immunohistochemical techniques.

Results

An inflammatory infiltrate that decreased significantly from 26 to 103 dpi was observed in all the infested ibexes. The predominant inflammatory cell population in the skin of the mangy ibexes was formed by macrophages (mainly the M2 phenotype) followed by T lymphocytes, with lower numbers of B lymphocytes and plasma cells. Three clinical courses were identified: total recovery, partial recovery, and terminal stage. The inflammatory infiltrates were less pronounced in the fully recovered ibexes than in those that progressed to the terminal stage throughout the study.

Discussion

The results suggest an exacerbated but effective Th1-type cellular immune response controlling mange in Iberian ibex. Furthermore, the local immune response appears to determine the variability of the clinical responses to S. scabiei infestation in this species. This first report on the progression of local skin immune cells is relevant not only for individuals but also for population management and conservation.

Notoedric mange (Notoedres centrifera) in two species of free-ranging rabbits from Florida, USA

Mange is a contagious skin disease caused by different mite species affecting numerous domestic and wild animals, worldwide. This report details notoedric mange in an eastern cottontail (Sylvilagus floridanus) and in a marsh rabbit (Sylvilagus palustris) from Florida, USA. Clinical examination revealed similar gross lesions including poor nutritional condition, multifocal alopecia and hyperkeratosis. Skin scrapings from both rabbits revealed numerous subcutaneous mites identified as Notoedres centrifera, a species previously only associated with rodents, primarily squirrels. Mites from both rabbits were identified based on morphology and confirmed by sequencing the internal transcribed spacer-2 (ITS-2) region. These cases emphasize the need for continued surveillance and accurate diagnostic evaluation to determine the cause and characterization of the skin disease, while distinguishing it from other potential pathogens that may manifest similarly in rabbits, such as Notoedres cati, Sarcoptes scabiei or Psoroptes cuniculi.

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.

First Description of Sarcoptic Mange in a Free-Ranging European Wildcat (Felis silvestris silvestris) from Spain

Simple Summary

Sarcoptic mange caused by the mite Sarcoptes scabiei is a worldwide-distributed skin infestation with a wide range of hosts, among them several species within the Felidae family. Sarcoptes scabiei was diagnosed in a dead adult female European wildcat (Felis silvestris silvestris) from Spain. This is the first description of Sarcoptes scabiei in a European wildcat. Since this is a species of conservation concern due to its critical demography in the southernmost population of the Iberian Peninsula, the impacts of infectious diseases, including sarcoptic mange, should be considered during disease surveillance programs of the species’ populations.

Abstract

Sarcoptic mange caused by the mite Sarcoptes scabiei is a worldwide-distributed skin infestation with a wide range of hosts, among them several species within the Felidae family. Sarcoptes scabiei was diagnosed in a dead adult female European wildcat (Felis silvestris silvestris) from Spain, based on histological evaluation of skin biopsies and identification of the arthropod from skin scrapings and molecular methods. This is the first description of Sarcoptes scabiei in a European wildcat. Due to its critical demography in the southernmost population of the Iberian Peninsula, the impacts of infectious diseases, including sarcoptic mange, as a new potential threat should be considered during disease surveillance programs of the species’ populations.

First description of sarcoptic mange in an Iberian hare (Lepus granatensis)

The Iberian hare (Lepus granatensis) is a popular small game species in the Iberian Peninsula, and it has never been reported to be affected by sarcoptic mange. An adult female Iberian hare with overt skin lesions on forelimbs and ventral thorax, suggestive of sarcoptic mange, was culled in Quart de les Valls municipality in the Valencian Community, Spain, in 2019. Skin scrapings were digested in 10% KOH solutions to confirm the presence of mites. Ten Sarcoptes microsatellite markers were used to characterize the genetic structure of mites obtained from the hare, and from sympatric and allopatric wild rabbits (Oryctolagus cuniculus) and red foxes (Vulpes vulpes). A total of 56 alleles were counted across the 10 microsatellite loci. Six private alleles were found at four loci (Sarms 33, 38, 41, 45). The multivariate analysis characterized three main clusters, corresponding to mites collected on foxes originating from Catalonia, foxes from Valencia and the hare plus wild rabbits. To our knowledge, this is the first reported case of sarcoptic mange in the Iberian hare. The origin was molecularly traced back to contacts with endemically infected wild rabbits. We encourage further investigations on cross-transmissibility of S. scabiei between wild rabbits and the diverse representatives of Lepus spp.

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Crusted scabies in an Iberian hare was detected for the first time in Valencia, Spain in 2019.

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Wild rabbits might be a natural source of infection of S. scabiei for the Iberian hare, rather than sympatric predators.

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Microsatellite markers are efficient epidemiological tools for tracing the source of Sarcoptes scabiei infection.

First Infestation Case of Sarcoptic Mange from a Pet Rabbit Oryctolagus Cuniculus in Republic of Korea

In November 2019 a 5-month-old mixed-breed rabbit presented to Chungbuk National University Veterinary Teaching Hospital, Cheongju-si, Chungbuk, Republic of Korea (Korea) with symptoms comprising pruritus, crusts on skin, poor appetite and reduced defecation. The rabbit was purchased 2 months prior from a pet shop located in a big market, and that the symptoms were first observed about 2 weeks prior to the hospital visit. Physical examination revealed that the patient had crust formation and alopecia on the nose together with lesions on the digits. A skin scraping test was performed using mineral oil and a high density of mites was observed by microscopy. Each mite showed a round, tortoise-like body with 4 comparatively short pairs of legs. The anus was located at the terminal unlike with suspected pathogen, Notoedres cati. Based on morphological characteristics, we identified the mite as Sarcoptes sp. Ivermectin was administered weekly by subcutaneous injection at a dosage of 0.4 mg/kg, and 4 weeks of follow-up study revealed the patient was fully recovered. And no more mites were detected from the case. This is the first case report of sarcoptic mange in a pet rabbit in Korea.

First description of sarcoptic mange in the endangered Iberian lynx (Lynx pardinus): clinical and epidemiological features

A 6-month-old female Iberian lynx (Lynx pardinus) cub that was severely affected by mange died in September 2016 in the Montes de Toledo (Spain) with crusts and fissures on its face, outer ears, nipples and footpads. The body condition of the cub was very poor, and it also had a mandibular abscess and a severely ankylosed luxation on its left knee. After confirming that the origin of the deceased cub’s dermal lesions was Sarcoptes scabiei, the subsequent search for ectoparasites and a comparison of histopathological and immunohistochemical findings in all sympatric lynxes handled (n = 30) and submitted for necropsy (n = 4) during 2016 and 2017 revealed the presence of S. scabiei mites and/or milder mange compatible lesions in five members of her family group, which was treated against mange together with two exposed contiguous family groups. An ELISA developed by the authors showed the presence of antibodies against S. scabiei in the deceased female cub and one brother. The presence of concomitant immunosuppressive factors in the dead female cub and the results obtained for the other sympatric lynxes studied since 2016 suggest that S. scabiei had a limited effect on immune-competent Iberian lynxes in the local population of the Montes de Toledo. However, a different evolution and relevance of sarcoptic mange in different populations—or even in the same one in the presence of immunosuppressive factors—cannot be ruled out, thus confirming the need for further research in order to attain a complete comprehension of the epidemiology and the real threat that this ectoparasitic disease may imply for L. pardinus.

The range of the mange: Spatiotemporal patterns of sarcoptic mange in red foxes (Vulpes vulpes) as revealed by camera trapping

Sarcoptic mange is a widely distributed disease that affects numerous mammalian species. We used camera traps to investigate the apparent prevalence and spatiotemporal dynamics of sarcoptic mange in a red fox population in southeastern Norway. We monitored red foxes for five years using 305 camera traps distributed across an 18000 km² area. A total of 6581 fox events were examined to visually identify mange compatible lesions. We investigated factors associated with the occurrence of mange by using logistic models within a Bayesian framework, whereas the spatiotemporal dynamics of the disease were analysed with space-time scan statistics. The apparent prevalence of the disease fluctuated over the study period with a mean of 3.15% and credible interval [1.25, 6.37], and our best logistic model explaining the presence of red foxes with mange-compatible lesions included time since the beginning of the study and the interaction between distance to settlement and season as explanatory variables. The scan analyses detected several potential clusters of the disease that varied in persistence and size, and the locations in the cluster with the highest probability were closer to human settlements than the other survey locations. Our results indicate that red foxes in an advanced stage of the disease are most likely found closer to human settlements during periods of low wild prey availability (winter). We discuss different potential causes. Furthermore, the disease appears to follow a pattern of small localized outbreaks rather than sporadic isolated events.

Vaccination of rabbits with immunodominant antigens from Sarcoptes scabiei induced high levels of humoral responses and pro-inflammatory cytokines but confers limited protection

BACKGROUND

Vaccination is an attractive ecological alternative to the use of acaricides for parasite control. However, effective anti-parasite vaccines against sarcoptic mange have not yet been developed. The purpose of this study was first to identify Sarcoptes scabiei immunodominant antigens and second to evaluate them as vaccine candidates in a rabbit/S. scabiei var. cuniculi model.

METHODS

The S. scabiei Ssλ15 immunodominant antigen was selected by immunoscreening of a S. scabiei var. hominis cDNA. The full-length cDNA was sequenced and cloned into the pGEX vector and the recombinant protein expressed in BL21 (DE3) cells and purified. A vaccination trial was performed consisting of a test group (n = 8) immunised with recAgs (a mix of two recombinant antigens, Ssλ15 and the previously described Ssλ20∆B3) and a control group (n = 8) immunised with PBS. All analyses were performed with R Statistical Environment with α set at 0.050.

RESULTS

The full-length open reading frame of the 1,821 nt cloned cDNA encodes a 64 kDa polypeptide, the sequence of which had 96 % identity with a hypothetical protein of S. scabiei. Ssλ15 was localised by immunostaining of skin sections in the tegument surrounding the mouthparts and the coxa in the legs of mites. Rabbit immunisation with recAgs induced high levels of specific IgG (P < 0.010) and increased levels of total IgEs. However, no significant clinical protection against S. scabiei challenge was detected. Unexpectedly, the group immunised with the recAgs mix had significantly higher lesion scores (P = 0.050) although lower mean mite densities than those observed in the control group. These results might indicate that the lesions in the recAgs group were due not only to the mites density but also to an exacerbated immunological response after challenge, which is in agreement with the specific high levels of pro-inflammatory cytokines (IL-1 and TNFα) detected after challenge in this group.

CONCLUSIONS

The selected antigens delivered as recombinant proteins had no clinical protective efficacy against S. scabiei infestation although immunisation reduced mite density. However, these results pave the way for future studies on alternative production systems, adjuvants, delivery methods and combinations of antigens in order to manage stimulation of clinical protective immune responses.

Evaluation of an ELISA using recombinant Ssλ20ΔB3 antigen for the serological diagnosis of Sarcoptes scabiei infestation in domestic and wild rabbits

An ELISA, based on the Sarcoptes scabiei Ssλ20ΔB3 inmunodominant antigen, was evaluated for the detection of antibodies to S. scabiei in experimentally infested (n=10), farm (n=109), and wild (n=78) rabbit sera. The S. scabiei antigen Ssλ20ΔB3, a major structural protein present over the entire mite's body, was produced as a recombinant protein in Escherichia coli and purified for its use in the ELISA. The resulting ELISA showed, in experimentally infested domestic rabbits, detectable specific antibody responses (IgG) above the cut off level from week three post-infestation indicating that the assay is able to detect positive rabbits very early during the course of the infestation. The ELISA was validated on a panel of 109 domestic breeding rabbit sera collected from 26 Spanish farms, of which 41 were obtained from rabbits with skin lesions compatible with sarcoptic mange, 26 with skin lesions compatible with psoroptic mange, and 42 from unexposed individuals from mange-free farms. The ELISA in this group was characterized by 95% sensitivity, 97% specificity, and a high degree of repeatability. In the psoroptic mange compatible lesions group, included in the study as control group for cross-reactivity with the closely related mite Psoroptes cuniculi, cross-reacting antibodies to Ssλ20ΔB3 S. scabiei antigen were detected in 42.30% of the rabbit sera. However, mean% OD values of the sarcoptic-mange group (55.61 ± 39.20%) were significantly higher (p<0.001) than OD values of the psoroptic-mange (3.64% ± 5.4%) and also of the free-mange (0.21% ± 0.67%) groups. In addition, the ELISA was also evaluated in serum samples obtained from both naturally infested and non-infested wild rabbits from Mallorca Island. The sensitivity of the assay for this group was 100% (4 out of the 4 rabbits with sarcoptic mange compatible lesions and presence of S. scabiei mites were seropositive) and the specificity was 90% (67 out of 74 wild rabbits without detectable mange lesions were seronegative). Although, the total number of tested samples from experimentally infested, farm and wild rabbits was limited, our study showed that the ELISA is able to differentiate between infested and non-infested animals in all tested groups with very high sensitivity and specificity indicating that recombinant Ssλ20ΔB3 is a reliable diagnostic antigen. This assay might be a cost-effective tool for detecting the presence of mangy animals and therefore helping prevent spread of mange among domestic rabbits, reducing potential transmission from female breeding rabbits to other farms, and detecting infestation with sarcoptic mange in the wild.

Primary and secondary experimental infestation of rabbits (Oryctolagus cuniculus) with Sarcoptes scabiei from a wild rabbit: factors determining resistance to reinfestation

Studies of sarcoptic mange and immunity are hampered by lack of mite sources and natural infestation models. We have investigated the clinical and pathological signs, specific IgG response and acquired immunity in naïve New Zealand White rabbits (Oryctolagus cuniculus) experimentally infested with Sarcoptes scabiei originally isolated from a clinically affected free-living European wild rabbit. Twenty rabbits were infested using two methods, direct contact for a 24 h period with a seeder rabbit simulating the natural process of infestation and application of a dressing holding approximately 1800 live mites on each hind limb (foot area) for a 24h period. Eight weeks post infestation, rabbits were treated with ivermectin and infestation cleared. Eight weeks later seventeen previously infested and four uninfested naïve controls were then re-exposed to the same S. scabiei variety using the same methods and followed for another 8 weeks. The progress of the disease was markedly more virulent in the animals infested by contact, indicating that the effective dose of mites managing to thrive and infest each rabbit by this method was higher. Nevertheless, infestation by contact resulted in partial protection to reexposure, rabbits developed high non-protective antibody titres upon reinfestation and presented severe clinical signs. However, rabbits reinfested by dressing developed lower IgG titres, and presented high levels of resistance to reinfestation, which might be due to induction of a strong local cellular response in the inoculation point that killed the mites and resulted in a lower mite effective dose, with subsequent reduced lesion development. Statistical analysis showed that sex, method of infestation and previous exposure are key factors determining the ability of rabbits to develop immunity to this disease. The rabbit-mange model developed will allow the further study of immunity and resistance to this neglected pathogen using a natural host system.

Experimental infection of wild-caught European rabbits (Oryctolagus cuniculus) with Sarcoptes scabiei from a naturally infected wild rabbit

Scabies was recently reported for the first time in the European wild rabbit, Oryctolagus cuniculus (Lagomorpha: Leporidae). We experimentally exposed 10 seronegative wild-caught rabbits to skin from a mangy wild rabbit. Serological, physiological, parasitological and histopathological changes were recorded. Three rabbits developed antibodies at 2-5 weeks post-infection (w.p.i.), two of which then developed lesions at 7 w.p.i. One of these had a small area of alopecia on the hind limb that healed naturally within 1 week; the other developed more extensive lesions restricted to the hind limbs (as typically observed in wild rabbits) that lasted until the rabbit died (12.5 w.p.i.). The third rabbit died of trauma 5 w.p.i. before developing any lesions. Antibodies in the healed rabbit disappeared from serum at 8 w.p.i., whereas antibody levels in the sick rabbit increased until its death. Disseminated intravascular coagulation and hepatic necrosis, probably arising from a concomitant infection with rabbit haemorrhagic disease virus, were the likely final cause of death in this rabbit. The mangy rabbit that served as a donor died of a multifocal fibrinosuppurative pneumonia that may have been secondary to the skin bacterial pyoderma.

Characterization and evaluation of a Sarcoptes scabiei allergen as a candidate vaccine

Background

Sarcoptic mange caused by the mite Sarcoptes scabiei is a worldwide disease affecting both humans and animals. Here we report the molecular characterization and evaluation of a recombinant S. scabiei tropomyosin (SsTm) protein in a vaccination trial in rabbits.

Methods

The full-length cDNA was cloned in a bacterial pET vector, and the recombinant protein was expressed in BL21 (DE3) cells and purified. Using specific rabbit antiserum, tropomyosin was localized immunohistochemically in mite tissue sections. Vaccination trials with the recombiant SsTm was carried out in New Zealand rabbits.

Results

The full-length open reading frame (ORF) of the 852 bp cloned gene from S. scabiei encodes a 32.9 kDa protein. The amino acid sequence showed 98.94%, 97.89% and 98.59% homology to Dermatophagoides farina and Dermatophagoides pteronyssinus group 10 allergens and Psoroptes ovis tropomyosin, respectively. Tropomyosin was localized immunohistochemically in mite tissue sections mainly in the mouthparts, legs and integument of the epidermis. The predicted cross-reactivity of SsTm indicated that it is an allergenic protein. While vaccination with the recombiant SsTm resulted in high levels of specific IgG (P < 0.01), a low IgE antibody response and no significant protection against S. scabiei challenge were observed. After challenge, specific IgG levels remained significantly higher than the control (P < 0.01), while changes of total IgE levels were not significant (P > 0.05). However, the lesion areas in the vaccination group decreased at the end of the experiment compared with controls.

Conclusions

Although vaccination with recombinant SsTm did not efficiently control sarcoptic mange in rabbits, the immunogenic properties of tropomyosin suggest it may be developed as a vaccine with alternative adjuvants or delivery methods.

Widespread exposure to Sarcoptes scabiei in wild European rabbits (Oryctolagus cuniculus) in Spain

Sarcoptic mange was recently described in the wild European rabbit (Oryctolagus cuniculus) in north-eastern Mediterranean Spain, the first such infection reported in this species anywhere in the world. This finding has created concern in conservationists and game managers given that an outbreak of mange after a translocation would have catastrophic consequences for naïve rabbit populations in other parts of Spain. A retrospective serosurvey using an 'in house' ELISA test based on the use of a recombinant antigen aimed at determining the rates of contact with Sarcoptes scabiei was carried out on sera from 966 rabbits collected between 1993 and 2010 in Spain. Antibodies were found in 13% of wild rabbits in 60% of the 53 areas surveyed, as well as in 16 of the 17 Spanish provinces and islands studied. Seropositive rabbits were found amongst the oldest samples analyzed and in all studied years. Antibodies were also detected in 36% of rabbits from the protected island of Dragonera, where rabbits have probably not been released since the 1970s. On Mallorca, where 89 rabbits were inspected for both lesions and antibodies, the prevalence of lesions (5.6%) was much lower than the seroprevalence (22.5%), indicating that rabbits often survive infection or that ELISA detects infected rabbits before they develop visible lesions. Seroprevalence was higher in areas with medium levels of rabbit abundance, no restocking and high rainfall. The results show that mange is widespread in rabbits and that the mite is not a recent introduction. Thus, sarcoptic mange could be considered as an enzootic disease in the wild rabbit and so prophylactic measures implemented during rabbit translocations are to be encouraged to avoid local outbreaks in naïve populations.