The neglected navigating web of the incomprehensibly emerging and re-emerging Sarcoptes mite

Human scabies and sarcoptic mange in northeast Brazil: Results from a rapid assessment method covering an entire state

Scabies is a neglected tropical disease and has been highlighted as a target for control. Sarcoptic mange affects animals, but mange is also considered a zoonosis. We present rapid assessment data on scabies and sarcoptic mange collected from key informants via a web-based questionnaire in Ceará State (1265 data entries). A total of 181/184 (98.3%) municipalities reported the occurrence of human scabies; 149 (80.9%) current occurrence; 168 (91.3%) severe cases; and 113 (61.4%) severe cases currently. Sarcoptic mange was reported from 149/184 (80.9%) municipalities, and severe mange from 128 (69.9%), most commonly in dogs (117 municipalities), cats (79), pigs (17), cattle (15), horses (15), and goats (2). Respondents from 171 (92.9%) municipalities observed seasonality of occurrence. Scabies and sarcoptic mange are important public health issues in a northeast Brazilian state. The wide distribution of severe cases requires an integrated One Health approach effectively and sustainably to reduce the disease burden.

Epidemiological factors conditioning sarcoptic mange spreading in wild boar (Sus scrofa)

Sarcoptic mange is a widely distributed disease, with numerous potential hosts among domestic and wild animals. Nowadays it is considered a neglected re-emergent infection in humans. As a difference with domestic pigs, and even with several clinical cases reported in some European countries, it seems that Eurasian wild boars (Sus scrofa) have a low susceptibility to clinical mange. However, because of a case of confirmed transmission from Spanish ibex (Capra pyrenaica) to wild boar in the province of Tarragona, we planned a large-scale ELISA survey in the neighboring Valencian Community (SE Spain). We compared 419 wild boar sera from different management systems (fenced vs. open game estates), different ages (piglets, juveniles, and adults), with different behaviour (gregarious females of all ages and male piglets vs. solitary juveniles and adult males), from areas with different wild boar densities, different wild ruminant densities and different sarcoptic mange epidemiologic situations. The whole prevalence of antibodies against sarcoptic mange in the tested wild boars was 10.5%. No significant differences were found when comparing fenced and free ranging wild boars, males and females, gregarious vs. solitary individuals or among different ages. However, wild boar density was a relevant factor. In areas with a hunting bag of <1 wild boar/km2, considered as a low density of suids, the seroprevalence was 2.94%, but rose to 11.52% in high density districts, constituting a significant difference (p = 0.037). Low wild boar populations would act as a protective factor (OR 0.233; p = 0.049) against coming into contact with the mite. The wild ruminant densities or their sarcoptic mange status did not show any effect on wild boars seroprevalence against this disease. These results reinforce the suggested host-taxon Sarcoptes scabiei specificity and the independence of host-species foci.

Scabies: Immunopathogenesis and pathological changes

Scabies is an itchy skin disease caused by the burrowing mite Sarcoptes scabiei. During their lifespan, the female mites invade the stratum corneum and create tunnels, in which they reside, move, feed, deposit fecal pellets, and lay eggs. Recently, scabies was included in the World Health Organization roadmap for neglected tropical diseases 2021-2030. This review attempts to summarize our knowledge about the mite's biology and the disease pathogenesis, pathological changes, and complications. Generally, the host-parasite interaction in scabies is highly complex and involves different mechanisms, some of which are yet largely unknown. Elucidation of the nature of such interaction as well as the underlying mechanisms could allow a better understanding of the mite's biology and the development of novel diagnostic and therapeutic options for scabies control programs. Moreover, identification of the molecular basis of such interaction could unveil novel targets for acaricidal agents and vaccines.

In Silico Exploration and Experimental Validation of Camellia sinensis Extract against Rhipicephalus microplus and Sarcoptes scabiei: An Integrated Approach

Sarcoptes scabiei is an ectoparasite of humans and animals that causes scabies. The Rhipicephalus (Boophilus) microplus is a blood-sucking ectoparasite that transmits various pathogens. These two parasites have caused great losses to a country's dairy and agriculture sectors. The aim of this study was to determine the in vitro and in silico efficacy of Camellia sinensis plant extracts. Different concentrations of C. sinensis ethanolic plant extracts were prepared using the maceration method and were used against mites and ticks (in adult immersion test AIT and larval packet test LPT) to evaluate their in vitro acaricidal activity. Additionally, in silico molecular docking was performed to investigate the inhibitory interactions between the phytochemicals of the plant and S. scabiei and R. microplus glutathione transferase proteins (SsGST and RmGST). This study observed that the plant extract showed high efficacy in vitro against mites and different tick stages in adult immersion and larval packet tests. Additionally, the in silico study revealed a strong binding interaction between ellagic acid and SsGST protein, with a binding energy of -7.3 kcal/mol, with respect to permethrin (-6.7 kcal/mol), whereas quercetin and RmGST resulted in a docking score of -8.6 kcal/mol compared to deltamethrin (-8.2 kcal/mol). Overall, this study explored the potential of C. sinensis as a natural alternative for controlling tick and mite infestations and provided insights into the inhibitory mechanisms of its phytochemicals.

Integrating In Vitro and In Silico Approaches to Assess Monotheca buxifolia Plant Extract against Rhipicephalus (Boophilus) microplus and Sarcoptes scabiei

Tick and mite infestations pose significant challenges to animal health, agriculture, and public health worldwide. The search for effective and environmentally friendly acaricidal agents has led researchers to explore natural alternatives. In this study, we investigated the acaricidal potential of the Monotheca buxifolia plant extract against Rhipicephalus microplus ticks and Sarcoptes scabiei mites. Additionally, we employed a computational approach to identify phytochemicals from the extract that could serve as drug candidates against these ectoparasites. The contact bioassay results demonstrated that the M. buxifolia plant extract exhibited significant efficacy against R. microplus and S. scabiei, with higher concentrations outperforming the positive control acaricide permethrin in terms of mite mortality. Time exposure to the extract also showed a positive correlation with better lethal concentration (LC50 and LC90) values. Similarly, the adult immersion test revealed a notable inhibition of tick oviposition via the plant extract, especially at higher concentrations. The two-protein primary structure, secondary structure and stability were predicted using the Expasy's ProtParam server, SOPMA and SUSUI server, respectively. Using Homology modeling, the 3D structure of the protein was obtained and validated through the ERRAT server, and active sites were determined through the CASTp server. The docking analysis revealed that Alpha-Amyrenyl acetate and alpha-Tocopherol exhibited the highest docking scores for S. scabiei and R. microplus aspartic protease proteins, respectively. These phytochemicals demonstrated strong binding interactions, suggesting their potential as acaricidal drug candidates. In conclusion, the M. buxifolia plant extract displayed significant acaricidal activity against R. microplus and S. scabiei. Moreover, the computational approach identified promising phytochemicals that could serve as potential drug candidates for controlling these ectoparasites.

Snow Metrics as Proxy to Assess Sarcoptic Mange in Wild Boar: Preliminary Results in Aosta Valley (Italy)

The widespread diffusion of the wild boar on the Italian territory and its consistent use for hunting have created the possibility to conduct multiple studies on the pathologies afflicting this ungulate. Nevertheless, in the last two decades, only some pathologies such as classical and African Swine Fever, Tuberculosis, Brucellosis from Brucella suis have benefited from substantial public funding and the consequent great interest from the scientific world, while less attention was addressed to parasitic diseases including sarcoptic mange. Therefore, to fill this gap, the purpose of this study was to contribute to the knowledge of sarcoptic mange in the wild boar population in Aosta Valley in the Northwest of Italy, including sympatric species as foxes. Due to past field surveys, it has been possible to find a possible role of snow metrics in the spread of this pathogen. Even if there are only empirical evidence and the mechanism remain unknown remote sensing analysis considering snow metrics were performed to provide to veterinarians, foresters, biologists, and ecologists new tools to better understand wield board dynamics and join to ordinary tool an instrument to enhance management and planning strategies. The snow metrics (SM) were derived from USGS NASA Landsat 8 L2A retrieved from Theia CNES platform and processed in Orfeo Toolbox LIS extension package. The relationship between SM and the disease spread was tested per each Aosta Valley municipality obtaining LISA maps for each hunting season. The results have showed that this parasite is present in an endemic form even if with rather low prevalence values, equal to 1.2% in the season hunting season 2013/2014, and equal to 7.5% in the hunting season 2014/2015. Moreover, within simultaneous given values of SM, sarcoptic mange seem to find good conditions for spreading.

Vaccination with a cocktail vaccine elicits significant protection against Sarcoptes scabiei in rabbits, whereas the multi-epitope vaccine offers limited protection

Sarcoptes scabiei cause scabies in humans or sarcoptic mange in animals. Currently, information regarding vaccines against S. scabiei is limited and no commercial vaccine is available. In present study, we expressed and mixed recombinant S. scabiei serpin (rSs-serpin), recombinant S. scabiei chitinase-like protein-5 [rSs-CLP5] and -12 [rSs-CLP12] as a cocktail vaccine (three proteins mixed), and also a multi-epitope protein derived from these three S. scabiei genes was expressed as a vaccine candidate to evaluate the effects of two vaccine strategies. Four test groups (n = 12 per group) and a control group (n = 12 per group) were involved in this vaccination trial. The results showed that 91.67% (11/12) and 83.33% (10/12) of rabbits exhibited no detectable skin lesions from S. scabiei infestation in cocktail vaccine groups, whereas two multi-epitope groups produced only a few rabbits (5/12, 6/12) having no detectable skin lesions. Four test groups displayed significant increases in specific IgG antibodies (Abs) and total IgE Abs after immunized with recombinant proteins. Taken together, our data demonstrated a mixture of rSs-serpin, rSs-CLP5 and rSs-CLP12 was a promising vaccine candidate that induced robust immune protection and could significantly decrease mite populations to reduce the direct transmission between rabbits. However, vaccination with the multi-epitope protein showed limited protection in rabbits.

Essential Oils against Sarcoptes scabiei

Herbal remedia are widely employed in folk medicine, and have been more and more often studied and considered in the treatment of several infections. Sarcoptic mange (scabies, when referring to human patients) is a highly contagious skin disease caused by Sarcoptes scabiei (sarcoptiformes, Sarcoptinae), an astigmatid mite which burrows into the epidermis, actively penetrating the stratum corneum. This parasitosis negatively affects livestock productions and represents a constraint on animal and human health. The treatment relies on permethrine and ivermectine but, since these molecules do not have ovicidal action, more than a single dose should be administered. Toxicity, the possible onset of parasite resistance, the presence of residues in meat and other animal products and environmental contamination are the major constraints. These shortcomings could be reduced by the use of plant extracts that have been in vitro or in vivo checked against these mites, sometimes with promising results. The aim of the present study was to review the literature dealing with the treatment of both scabies and sarcoptic mange by plant-derived agents, notably essential oils.

The genetic characteristics of Sarcoptes scabiei from Chinese serow (Capricornis milneedwardsii) and goral (Naemorhedus goral arnouxianus) compared with other mites from different hosts and geographic locations using ITS2 and cox1 sequences

Scabies is a common parasitic disease in many mammalian species, caused by the infestation of Sarcoptes scabiei. There is no consistent conclusion on whether Sarcoptes mites from different hosts or geographic locations have apparent genetic divergence. In this study, we collected and morphologically identified S. scabiei from Chinese serow and goral, and we described the genetic diversity of S. scabiei and other mites based on phylogenetic analyses of the ITS2 and cox1 sequence fragments, including data available in GenBank. The mites isolated from Chinese serow and goral were S. scabiei, and they were morphologically similar. The phylogenetic trees and haplotype networks showed that S. scabiei from other locations worldwide did not cluster according to host divergence or geographical distribution. Additionally, the Fst values were - 0.224 to 0.136 and - 0.045 to 1 between S. scabiei from different hosts, including humans and domestic and wild animals, based on partial ITS and cox1 sequences. Worldwide S. scabiei samples formed three clusters (with H2, H5, and H12 at their centers) in the ITS and one cluster (with C9 at the center) in the cox1 haplotype phylogenetic network. The S. scabiei collected from Chinese serow and goral were morphologically similar and had the same genotype. A study on the genetic characteristics of S. scabiei from Chinese serow and goral together with other mites from different hosts and geographic locations around the world showed no obvious divergence. These findings indicated that scabies likely is a zoonotic disease and that the global prevalence of scabies is probably related to the worldwide trade of domestic animals.

Structure-based in silico design and in vitro acaricidal activity assessment of Acacia nilotica and Psidium guajava extracts against Sarcoptes scabiei var. cuniculi

Infestation by Sarcoptes scabiei var. cuniculi mite causes scabies in humans and mange in animals. Alternative methods for developing environmentally friendly and effective plant-based acaricides are now a priority. The purpose of this research was the in silico design and in vitro evaluation of the efficacy of ethanol extracts of Acacia nilotica and Psidium guajava plant leaves against S. scabiei. Chem-Draw ultra-software (v. 12.0.2.1076.2010) was used to draw 36 distinct compounds from these plants that were employed as ligands in docking tests against S. scabiei Aspartic protease (SsAP). With docking scores of - 6.50993 and - 6.16359, respectively, clionasterol (PubChem CID 457801) and mangiferin (PubChem CID 5281647) from A. nilotica inhibited the targeted protein SsAP, while only beta-sitosterol (PubChem CID 222284) from P. guajava interacted with the SsAP active site with a docking score of - 6.20532. Mortality in contact bioassay at concentrations of 0.25, 0.5, 1.0, and 2.0 g/ml was determined to calculate median lethal time (LT₅₀) and median lethal concentration (LC₅₀) values. Acacia nilotica extract had an LC₅₀ value of 0.218 g/ml compared to P. guajava extract, which had an LC₅₀ value of 0.829 g/ml at 6 h. These results suggest that A. nilotica extract is more effective in killing mites, and these plants may have novel acaricidal properties against S. scabiei. Further research should focus on A. nilotica as a potential substitute for clinically available acaricides against resistant mites.

Sustaining Transmission in Different Host Species: The Emblematic Case of Sarcoptes scabiei

Some pathogens sustain transmission in multiple different host species, but how this epidemiologically important feat is achieved remains enigmatic. Sarcoptes scabiei is among the most host generalist and successful of mammalian parasites. We synthesize pathogen and host traits that mediate sustained transmission and present cases illustrating three transmission mechanisms (direct, indirect, and combined). The pathogen traits that explain the success of S. scabiei include immune response modulation, on-host movement capacity, off-host seeking behaviors, and environmental persistence. Sociality and host density appear to be key for hosts in which direct transmission dominates, whereas in solitary hosts, the use of shared environments is important for indirect transmission. In social den-using species, combined direct and indirect transmission appears likely. Empirical research rarely considers the mechanisms enabling S. scabiei to become endemic in host species—more often focusing on outbreaks. Our review may illuminate parasites’ adaptation strategies to sustain transmission through varied mechanisms across host species.

First report of interspecific transmission of sarcoptic mange from Iberian ibex to wild boar

BACKGROUND

Sarcoptic mange is a globally distributed parasitic disease caused by the burrowing mite Sarcoptes scabiei. This mite has a certain degree of host specificity, although interspecific transmission can occur among phylogenetically related species or through prey-predator mediated exposure. In 2018, a wild boar (Sus scrofa) with lesions compatible with sarcoptic mange was hunted in Ports de Tortosa i Beseit Natural Park (PTB, north-eastern Spain), where an active epizootic outbreak of sarcoptic mange is affecting Iberian ibexes (Capra pyrenaica) since 2014.

METHODS

A complete necropsy, skin scrapings and skin digestions with hydroxide potassium were performed to confirm the diagnosis. Routine histopathological analysis, toluidine blue staining and immunohistochemistry were used to characterize the lesions and the inflammatory infiltrate. Finally, 10 specific S. scabiei microsatellites were molecularly genotyped through polymerase chain reactions in mites obtained from the affected wild boar. For phylogenetic comparison, mites obtained from sympatric Iberian ibexes and allopatric wild boars and Iberian ibexes from southern Spain were analysed.

RESULTS

Sarcoptes scabiei was visually and molecularly identified in the infested wild boar from PTB, causing skin lesions with dermal inflammatory infiltrate rich in T and B cells, which indicate an adaptive immune response. Three S. scabiei genetic clusters were identified: one included mites from southern Iberian ibexes, another included mites from southern wild boars, and a third one distinctively grouped the wild boar from PTB with the sympatric ibexes.

CONCLUSIONS

To the authors' knowledge, this is the first reported case of sarcoptic mange in wild boar in Spain and the first documented case of S. scabiei cross-transmission from a wild ruminant host to a wild boar. The wild boar presented an ordinary scabies type reaction, which is typical of the self-limiting infestations reported in other cases of interspecific transmission.

Environmental suitability of bare-nosed wombat burrows for Sarcoptes scabiei

Some of the most important pathogens affecting wildlife are transmitted indirectly via the environment. Yet the environmental stages of pathogens are often poorly understood, relative to infection in the host, making this an important research frontier. Sarcoptic mange is a globally widespread disease caused by the parasitic mite Sarcoptes scabiei. The bare-nosed wombat (Vombatus ursinus) is particularly susceptible, and their solitary nature and overlapping use of burrows strongly indicate the importance of environmental transmission. However, due to the challenge of accessing and monitoring within wombat burrows, there has been limited research into their suitability for off-host mite survival and environmental transmission (i.e., to serve as a fomite). We created a model using published laboratory data to predict mite survival times based on temperature and humidity. We then implemented innovative technologies (ground-penetrating radar and a tele-operated robotic vehicle) to map and access wombat burrows to record temperature and relative humidity. We found that the stable conditions within burrows were conducive for off-host survival of S. scabiei, particularly in winter (estimated mite survival of 16.41 ± 0.34 days) and less so in warmer and drier months (summer estimated survival of 5.96 ± 0.37 days). We also compared two areas with higher and lower average mange prevalence in wombats (13.35% and 4.65%, respectively), finding estimated mite survival was slightly higher in the low prevalence area (10.10 and 12.12 days, respectively), contrary to our expectations, suggesting other factors are also important for population prevalence. Our study is the first to demonstrate the suitability of the bare-nosed wombat burrow for off-host mite survival and environmental transmission. Our findings have implications for understanding observed patterns of mange, disease dynamics and disease management for not only bare-nosed wombats, but also other burrow or den-obligate species exposed to S. scabiei via environmental transmission.

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Wombat burrows are a source of environmental transmission of Sarcoptes scabiei.

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We used ground-penetrating radar and a robotic vehicle to measure burrow conditions.

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We estimate S. scabiei can survive 5.96–16.41 days within burrows depending on season.

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Seasonal variation in environmental survival may influence disease dynamics in wombats.

Host-Parasite Interaction in Sarcoptes scabiei Infestation in Porcine Model with a Preliminary Note on Its Genetic Lineage from India

Simple Summary

Scabies or mange caused by Sarcoptess cabiei is the latest addition of WHO’s list oftropical neglected diseases. It causes severe itching to the host. It has a wide host range including humans, farm animals, companion animals, and wild animals. It is anemerging/re-emerging disease with high prevalence in underdeveloped and developing countries. The disease has zoonotic importance and is of significant public health concern as cross-transmission or species jumping is very common. To date, fifteen Sarcoptes varieties have been reported as per host origin. Differential diagnosis at variety level is very crucial for epidemiological study and scratching future eradication program of the disease. As morphotaxonomy fails to differentiate varieties, use of molecular markers is crucial. Moreover, it is very important to understand the host-parasite interaction at the systemic level for a better understanding on the pathogenicity of the disease. Here, we report the genetic characterization of S. scabiei from India and host-parasite interaction in a porcine model.

Abstract

The burrowing mite Sarcoptes scabiei causes scabies in humans or mange in animals. It infests a wide range of mammalian species including livestock, companion animals, wild animals, and humans. Differential diagnosis of Sarcoptes varieties is key for epidemiological studies and for formulation of an eradication program. Host-parasite interaction at the systemic level is very important to understand the pathogenicity of the mite. This communication deals with the preliminary report on the genetic characterization of S. scabiei from India. Moreover, the effect of S. scabiei infestation on host physiology with special emphasis on serum biochemical parameters, lipid profile, oxidant/antioxidant balance, stress parameters, and immune responses were evaluated in a porcine model. Cytochrome C oxidase 1 and voltage-sensitive sodium channel based phylogenetic study could distinguish human and animals isolates but could not distinguish host or geographical specific isolates belonging to animal origin. An absence of host-specific cluster among animal isolates argues against the hypothesis of delineating S. scabiei as per host origin. Elevated levels of markers of liver function such as albumin, AST, ALT, ALP, and LDH in infested animals indicated impaired liver function in infested animals. S. scabiei infestation induced atherogenic dyslipidemia indicated by elevated levels of total cholesterol, low-density lipoprotein cholesterol and triglycerides, and a decreased level of high-density lipoprotein cholesterol. Oxidative stress in infested animals was indicated by a high level of nitric oxide and serum MDA as oxidative stress markers and low antioxidant capacity. S. scabiei triggered stress response and elevated levels of serum cortisol and heat shock proteins were recorded in infested animals. S. scabiei infestation increased the serum concentration of immunoglobulins and was associated with up-regulation of IL-2, IFN-γ, IL-1β, and IL-4 indicating both Th1 and Th2 response. The results of the study will be helpful for a better understanding of host-parasite interaction at the systemic level in crusted scabies in pigs.

Sarcoptic Mange in Wild Caprinae of the Alps: Could Pathology Help in Filling the Gaps in Knowledge?

Sarcoptic mange represents the most severe disease for wild Caprinae individuals and populations in Europe, raising concerns for both conservation and management of these ungulates. To date, this disease has been investigated in different wild caprine species and under many different perspectives including diagnostics, epidemiology, impact on the host populations, and genetics of both hosts and parasite, with the aim to disentangle the host-Sarcoptes scabiei relationship. Notwithstanding, uncertainty remains and basic questions still need an answer. Among these are the effect of immune responses on mange severity at an individual level, the main drivers in host-parasite interactions for different clinical outcomes, and the role of the immune response in determining the shift from epidemic to endemic cycle. A deeper approach to the pathology of this disease seems therefore advisable, all the more reason considering that immune response to S. scabiei in wild Caprinae, generally classified as a hypersensitivity, remains poorly understood. In this paper, we reviewed the pathological features associated to sarcoptic mange in wildlife, exploring different kinds of hypersensitivity and outcomes, with the objective of highlighting the major drivers in the different responses to this disease at an individual level and proposing some key topics for future research, with a particular attention to Alps-dwelling wild caprines.

Characterization of mitochondrial COX-1 gene of Sarcoptes scabiei from rabbits in East Java, Indonesia

OBJECTIVE

The purpose of this study was to characterize the mitochondrial COX-1 gene of Sarcoptes scabiei in rabbits from three districts of Malang, Nganjuk, and Kediri, East Java, Indonesia. The gene was aligned with a DNA isolated from S. scabiei of Chong'qing rabbit (accession number: EU256388.1) to construct a molecular analysis of phylogenetic in S. scabiei COX-1 gene.

MATERIALS AND METHODS

This study has been verified by the Committee Ethics (Faculty of Veterinary Medicine, Universitas Airlangga). The mites were collected and identified from rabbits that have an indication of scabies infection. DNA was extracted with QIAamp DNA mini kit and polymerase chain reaction (PCR) analysis was done. The PCR products were purified with the protocol of the BigDye XTerminator™ Purification Kit (Thermo Scientific) and were double-sequenced with the forward and reverse PCR primers of ABI PRISM 310 Genetic Analyzer. The sequence product was confirmed with Clone Manager Professional 9 (Sci-Ed Software) and the Neighbor-Joining method was done with MEGA6 to build a phylogenetic tree.

RESULTS

The target product of DNA amplification in this PCR was around 290-bp. The amplicon was visualized in 2% of agarose gel electrophoresis. The homology analysis of these sequences showed that it had more than 99% similarity.

CONCLUSION

COX-1 gene sequences of S. scabiei from rabbits in Malang, Nganjuk, and Kediri were very similar to COX-1 gene sequences in S. scabiei acquired from several hosts according to NCBI data.

Spatio-temporal patterns of sarcoptic mange in red deer and Iberian ibex in a multi-host natural park

The reliance on multiple hosts to survive is what makes the management and control of multi-host infectious agents challenging. Sarcoptes scabiei causes sarcoptic mange in a wide range of mammal species with ungulates being an important host. Little is known about the role different ungulates play in sustaining endemic transmission of the disease and no study has yet to describe the long-term multi-host sarcoptic infestation dynamics in free-ranging wildlife. Here, we explore 24 years of sarcoptic mange infestation data for two Mediterranean ungulate species, red deer and Iberian ibex, living in the Sierras de Cazorla, Segura y Las Villas Natural Park of southern Spain. The temporal analysis showed a clear seasonal pattern of infestation in both ungulates with a peak in early spring and a decline throughout the summer. The spatial analysis, however, showed that caprinae rather than cervidae is the most competent host for sarcoptic mange spreading and persistence. Considering that few studies have described the spatio-temporal pattern of mange outbreaks for long periods of time, the information reported in this work aims to improve our understanding of sarcoptic mange epizootic in wild ruminant populations.

Sanitary Emergencies at the Wild/Domestic Caprines Interface in Europe

Simple Summary

Even if it is an important achievement from a biodiversity conservation perspective, the documented increase in abundance of the four native European wild Caprinae (Rupicapra rupicapra, R. pyrenaica, Capra ibex, C. pyrenaica) can also be a matter of concern, since tighter and more frequent contact with sympatric livestock implies a greater risk of transmission of emerging and re-emerging pathogens. This article reviews the main transmissible diseases that, in a European scenario, are of greater significance from a conservation perspective. Epidemics causing major demographic downturns in wild Caprinae populations during recent decades were often triggered by pathogens transmitted at the livestock/wildlife interface.

Abstract

Population density and distribution of the four native European wild Caprines (Rupicapra rupicapra, Rupicapra pyrenaica, Capra ibex, Capra pyrenaica) have increased in recent decades. The improved conservation status of this valuable wildlife, while a welcome event in general terms, is at the same time a matter of concern since, intuitively, frequent and tighter contacts with sympatric livestock imply a greater risk of cross-transmission of emerging and re-emerging pathogens, and offer unexpected opportunities for pathogens to spread, persist and evolve. This article recalls the transmissible diseases that are perceived in Europe to be of major significance from a conservation perspective, namely brucellosis (BRC) by Brucella melitensis, infectious kerato-conjunctivitis (IKC) by Mycoplasma conjunctivae, pestivirosis (PV) by the border disease virus strain 4 and mange by Sarcoptes scabiei. Special emphasis has been put on the epidemiological role played by small domestic ruminants, and on key knowledge needed to implement evidence-based prevention and control strategies. Remarkably, scientific evidence demonstrates that major demographic downturns in affected wild Caprinae populations in recent decades have often been triggered by pathogens cross-transmitted at the livestock/wildlife interface.

Possible transmission of Sarcoptes scabiei between herbivorous Japanese serows and omnivorous Caniformia in Japan: a cryptic transmission and persistence?

Background

Two transmission patterns of Sarcoptes scabiei in host mammal communities have been reported based on microsatellite-level genetic studies in the last two decades. While one involves restrictions among different host taxa, the other is associated with predator–prey interactions between different host taxa. In contrast to these observations, the present study reports a possible irregular case of transmission of S. scabiei between herbivorous Japanese serow and omnivorous Caniformia mammals in Japan, though under very weak predator–prey relationships.

Methods

DNA from 93 Sarcoptes mites isolated from omnivorous Caniformia (such as the domestic dog, raccoon dog, raccoon and Japanese marten), omnivorous Cetartiodactyla (wild boar) and herbivorous Cetartiodactyla (Japanese serow) in Japan were analyzed by amplifying nine microsatellite markers. Principal components analyses (PCA), Bayesian clustering analyses using STRUCTURE software, and phylogenetic analyses by constructing a NeighborNet network were applied to determine the genetic relationships among mites associated with host populations.

Results

In all the analyses, the genetic differentiation of Sarcoptes mites from wild boars and Japanese serows was observed. Conversely, considerably close genetic relationships were detected between Caniformia-derived and Japanese serow-derived mites. Because the predator–prey interactions between the omnivorous Caniformia and herbivorous Japanese serow are quite limited and epidemiological history shows at least a 10-year lag between the emergence of sarcoptic mange in Japanese serow and that in Caniformia, the transmission of S. scabiei from Caniformia to Japanese serow is highly suspected.

Conclusions

The close genetic relationships among mites beyond Host–taxon relationships and without obvious predator–prey interactions in Caniformia and Japanese serow deviate from previously reported S. scabiei transmission patterns. This type of cryptic relationship of S. scabiei populations may exist in local mammalian communities worldwide and become a risk factor for the conservation of the remnant and fragmented populations of wild mammals.

Electronic supplementary material

The online version of this article (10.1186/s13071-019-3630-5) contains supplementary material, which is available to authorized users.

Sequence analysis of the cytochrome c oxidase subunit 1 gene of Sarcoptes scabiei isolated from goats and rabbits in East Java, Indonesia

Aim

This study aimed to sequence the Cytochrome c oxidase (COX-1) gene sequence from mitochondrial DNA of Sarcoptes scabiei isolated from Lamongan goats and Mojokerto rabbits, align it with DNA isolated from Zi'gong rabbit (GenBank accession No. EU256389.1), and produce a phylogenetic analysis of S. scabiei COX-1 gene.

Materials and Methods

S. scabiei mites were obtained from goats and rabbits, and DNA was extracted using QIAamp DNA Mini Kit. The forward and reverse primer sequences were designed based on the DNA sequence of an S. scabiei COX-1 gene isolated from the Zi'gong rabbit (5'-TCTTAGGGGCTGGATTTAGTATG-3' and 5'-AGTTCCTCTACCAGTTCCAC-3', respectively). To confirm sequencing output, the sequence resulting from the reverse primer was inverted and aligned to the sequence from the forward primer using Clone Manager Professional Version 9 for Windows (Scientific & Educational Software; http://www.scied.com). This alignment was subsequently used to build a phylogenetic tree, using the Neighbor-Joining method, in the MEGA6 program (https://www.megasoftware.net/).

Results

Polymerase chain reaction (PCR) products from S. scabiei isolates from Lamongan goats and Mojokerto rabbits produced bands of around 290 bp with 2% agarose gel electrophoresis. Comparing the DNA sequences of the S. scabiei COX-1 gene with those isolated from Lamongan goats and Mojokerto rabbits showed 99% homology.

Conclusion

PCR products of the S. scabiei COX-1 gene isolated from Lamongan goats and Mojokerto rabbits were around 290 bp long. The sequences had more than 99% homology. The sequences of the COX-1 gene of S. scabiei from Lamongan goats and Mojokerto rabbits were relatively close to the sequence of the gene in S. scabiei obtained from various hosts according to National Center for Biotechnology Information data.

Treatment of canine sarcoptic mange with afoxolaner (NexGard®) and afoxolaner plus milbemycin oxime (NexGard Spectra®) chewable tablets: efficacy under field conditions in Portugal and Germany

The efficacy of NexGard^® and NexGard Spectra^® against sarcoptic mange in dogs was evaluated in a clinical field study. Skin scrapings from dogs presenting signs suggestive of sarcoptic mange were examined to confirm infestation. A total of 106 dogs were screened at eight sites in Portugal and Germany. In all, 80 dogs that had demonstrated ≥5 live Sarcoptes mites in five skin scrapings were enrolled, scored for specific clinical signs (pruritus; papules and crusts; alopecia), and allocated at random to receive either NexGard^® or NexGard Spectra^® twice, one month apart per label instructions. To determine efficacy, live Sarcoptes mites in five skin scrapings per dog were counted, and clinical signs were scored one month and two months after first treatment and compared to pre-treatment (baseline) values. Based on compliance, 65 dogs were determined to be evaluable cases at the end of the study. The efficacy, in terms of reduction of geometric mean live Sarcoptes mite counts, was 98.9% and 99.7% for NexGard^®-treated (n = 38) and 99.6% and 100% for NexGard Spectra^®-treated dogs (n = 27) at one month and two months after treatment initiation (p < 0.001, both treatments). Both treatments resulted in a significant improvement in pruritus, papules and crusts, and alopecia one month and two months after treatment initiation (p = 0.0001, both treatments). In conclusion, this field study confirms that both NexGard^® and NexGard Spectra^® administered twice one month apart provide an effective and safe treatment against sarcoptic mange in dogs.

A chitinase-like protein from Sarcoptes scabiei as a candidate anti-mite vaccine that contributes to immune protection in rabbits

BACKGROUND

Scabies is caused by Sarcoptes scabiei burrowing into the stratum corneum of the host's skin and is detrimental to the health of humans and animals. Vaccines are an attractive alternative to replace the acaricides currently used in their control.

METHODS

In the present study, the S. scabiei chitinase-like protein 5 (SsCLP5) was characterized and recombinant SsCLP5 (rSsCLP5) was evaluated as a candidate vaccine protein for anti-mite protection in rabbits. The expression, characterization and immunolocalization of SsCLP5 were examined. Vaccination experiments were performed on three test groups (n = 12 per group) immunized with purified rSsCLP5. Control groups (n = 12 per group) were immunized with PBS, QuilA saponin or empty vector protein. After challenge, the inflammatory reaction and skin lesions were graded and rSsCLP5 indirect ELISA was used to detect antibody IgG levels in serum samples at the time of vaccination and post-challenge.

RESULTS

The results showed that rSsCLP5 had high immunoreactivity and immunogenicity. In S. scabiei, SsCLP5 had a wide distribution in the chewing mouthpart, legs and exoskeleton, especially the outer layer of the exoskeleton. Vaccination with rSsCLP5 resulted in 74.3% (26/35) of rabbits showing no detectable lesions after challenge with S. scabiei.

CONCLUSIONS

Our data demonstrate that rSsCLP5 is a promising candidate for a recombinant protein-based vaccine against S. scabiei. This study also provides a method for studying scabies vaccine using rabbit as an animal model and a basis for screening more effective candidate proteins.

International meeting on sarcoptic mange in wildlife, June 2018, Blacksburg, Virginia, USA

Sarcoptic mange is a globally distributed disease caused by the burrowing mite Sarcoptes scabiei, which also causes scabies in humans. A wide and increasing number of wild mammal species are reported to be susceptible to mange; however, the impacts of the disease in wildlife populations, mechanisms involved in its eco-epidemiological dynamics, and risks to public and ecosystem health are still unclear. Major gaps exist concerning S. scabiei host specificity and the mechanisms involved in the different presentations of the disease, which change between individuals and species. Immunological responses to the mite may have a relevant role explaining these different susceptibilities, as these affect the clinical signs, and consequently, the severity of the disease. Recently, some studies have suggested sarcoptic mange as an emerging threat for wildlife, based on several outbreaks with increased severity, geographical expansions, and novel wild hosts affected. Disease ecology experts convened for the “International Meeting on Sarcoptic Mange in Wildlife” on 4–5 June 2018, hosted by the Department of Fish and Wildlife Conservation at Virginia Tech in Blacksburg, Virginia, USA. The meeting had a structure of (i) pre-workshop review; (ii) presentation and discussions; and (iii) identification of priority research questions to understand sarcoptic mange in wildlife. The workgroup concluded that research priorities should be on determining the variation in modes of transmission for S. scabiei in wildlife, factors associated with the variation of disease severity among species, and long-terms effects of the mange in wildlife populations. In this note we summarize the main discussions and research gaps identified by the experts.

Humoral and cellular immune response induced by antigenic protein of Sarcoptes scabiei var. caprae

Aim:

Scabies is one of the most important diseases in goats and caused by a complex hypersensitivity process that involves both humoral and cell-mediated immune responses. This phenomenon shows that the variety of Sarcoptes scabiei has different characteristics of specific antigenic protein or different immune-dominant. This research aims to detect the humoral and cellular immune response of rabbits which were immunized with the protein of S. scabiei var. caprae.

Materials and Methods:

This research was done as follows, identification and collection of Sarcoptes scabiei var caprae from goat infected with scabies, separation of protein antigen from S. scabiei mites with ultrasonic sonicator, measurement of protein content with spectrophotometry, rabbit injection with 500 μg dose of antigen protein which was repeated 5 times (5x booster) every 2 weeks. Measurement of IgG titer using indirect ELISA, whereas to detect the expression of cellular immune response (TLR-9, CD4, and CD8) using Direct Immunofluorescence assay.

Results:

Based on the statistical analysis, it showed that there was a significant enhancement (p<0.05) for optical density value or antibody titer and cellular immune response was shown by TLR-9, CD4, and CD8 expression in rabbit T lymphocytes which appear yellow to green fluorescent color using fluorescence microscope. The amount of fluorescence T lymphocytes showed a significant difference (p<0.05) between the control and various boosters.

Conclusion:

Antigenic protein of S. scabiei var. caprae contains ligands, which are involved in the pathogen-associated molecular pattern that has an ability to induce humoral and cellular immune response in rabbit. Specifically, that TLR-9 is not only involved in innate immunity but also in adaptive immunity and can be used as alternative adjuvant development research.

Identification of a novel PYP-1 gene in Sarcoptes scabiei and its potential as a serodiagnostic candidate by indirect-ELISA

Scabies is a parasitic disease caused by the ectoparasite Sarcoptes scabiei, affecting different mammalian species, including rabbits, worldwide. In the present study, we cloned and expressed a novel inorganic pyrophosphatase, Ssc-PYP-1, from S. scabiei var. cuniculi. Immunofluorescence staining showed that native Ssc-PYP-1 was localized in the tegument around the mouthparts and the entire legs, as well as in the cuticle of the mites. Interestingly, obvious staining was also observed on the fecal pellets of mites and in the integument of the mites. Based on its good immunoreactivity, an indirect enzyme-linked immunosorbent assay (ELISA) using recombinant Ssc-PYP-1 (rSsc-PYP-1) as the capture antigen was developed to diagnose sarcoptic mange in naturally infected rabbits; the assay had a sensitivity of 92·0% and specificity of 93·6%. Finally, using the rSsc-PYP-1-ELISA, the Ssc-PYP-1 antibody from 10 experimentally infected rabbits could be detected from 1 week post-infection. This is the first report of S. scabiei inorganic pyrophosphatase and the protein could serve as a potential serodiagnostic candidate for sarcoptic mange in rabbits.

Expression and characterisation of a Sarcoptes scabiei protein tyrosine kinase as a potential antigen for scabies diagnosis

Scabies is a disease that harms humans and other animals that is caused by the itch mite Sarcoptes scabiei burrowing into the stratum corneum of the skin. In the early stages of scabies, symptoms are often subclinical and there are no effective diagnostic methods. Herein, we cloned, expressed and characterised an S. scabiei protein tyrosine kinase (SsPTK) and evaluated its diagnostic value as a recombinant antigen in rabbit during the early stages of Sarcoptes infestation. The SsPTK protein is ~30 kDa, lacks a signal peptide, and shares high homology with a PTK from the rabbit ear mite Psoroptes ovis cuniculi. The protein was widely distributed at the front end of mites, particularly in the chewing mouthparts and legs. Indirect ELISA using recombinant SsPTK showed good diagnostic value, with 95.2% (40/42) sensitivity and 94.1% (48/51) specificity for detecting anti-PTK antibody in serum samples from naturally-infested rabbits. More importantly, PTK ELISA could diagnose infection in the early stages (infestation for 1 week) with an accuracy of 100% (24/24). SsPTK therefore shows potential as a sensitive antigen for the early diagnosis of parasitic mite infestation.

A review of Sarcoptes scabiei: past, present and future

The disease scabies is one of the earliest diseases of humans for which the cause was known. It is caused by the mite, Sarcoptes scabiei, that burrows in the epidermis of the skin of humans and many other mammals. This mite was previously known as Acarus scabiei DeGeer, 1778 before the genus Sarcoptes was established (Latreille 1802) and it became S. scabiei. Research during the last 40 years has tremendously increased insight into the mite’s biology, parasite-host interactions, and the mechanisms it uses to evade the host’s defenses. This review highlights some of the major advancements of our knowledge of the mite’s biology, genome, proteome, and immunomodulating abilities all of which provide a basis for control of the disease. Advances toward the development of a diagnostic blood test to detect a scabies infection and a vaccine to protect susceptible populations from becoming infected, or at least limiting the transmission of the disease, are also presented.

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.

New techniques to collect live Sarcoptes scabiei and evaluation of methods as alternative diagnostics for infection

Sarcoptes scabiei is a widespread, highly contagious skin disease that affects many mammals including humans. The biological characteristics of S. scabiei remain unclear. Therefore, the ability to collect adequate amount of mites for studies is required to advance our understanding of the parasite. The present study aimed to find a method to collect an adequate amount of live S. scabiei mites within a short time frame. The cornified layer and fur from an infected raccoon dog were inserted into a 50-ml catheter tip-type syringe. A 1.5-ml microtube was attached at the tip of the syringe to collect the mites, which crawled out from the cornified layer and fur. Four conditions were examined, and the following condition was determined to be the best: the syringe and microtube were shaded by aluminum foil, and the microtube was heated using a pet heater (36 °C). In addition, the effectiveness of this method as an alternative method to diagnose S. scabiei infections in animal was evaluated. S. scabiei live mites were not detected in the raccoon dog samples 24 h after the administration of medication (ivermectin or selamectin). The present study revealed that this technique was useful to collect adequate amounts of live mites, and the mites prefer a heated environment and actively move when using the shaded conditions. In addition, this technique was effective as an alternative diagnostic technique to detect live mites on an animal body.

In vitro activity of ten essential oils against Sarcoptes scabiei

Background

The development of alternative approaches in ectoparasite management is currently required. Essential oils have been demonstrated to exhibit fumigant and topical toxicity to a number of arthropods. The aim of the present study was to assess the potential efficacy of ten essential oils against Sarcoptes scabiei.

Methods

The major chemical components of the oils were identified by GC-MS analysis. Contact and fumigation bioassays were performed on Sarcoptes mites collected from experimentally infected pigs. For contact bioassays, essential oils were diluted with paraffin to get concentrations at 10, 5, and even 1% for the most efficient ones. The mites were inspected under a stereomicroscope 10, 20, 30, 40, 50, 60, 90, 120, 150, and 180min after contact. For fumigation bioassay, a filter paper was treated with 100 μL of the pure essential oil. The mites were inspected under a stereomicroscope for the first 5min, and then every 5min until 1h.

Results

Using contact bioassays, 1% clove and palmarosa oil killed all the mites within 20 and 50min, respectively. The oils efficacy order was: clove > palmarosa > geranium > tea tree > lavender > manuka > bitter orange > eucalyptus > Japanese cedar. In fumigation bioassays, the efficacy order was: tea tree > clove > eucalyptus > lavender > palmarosa > geranium > Japanese cedar > bitter orange > manuka. In both bioassays, cade oil showed no activity.

Conclusion

Essential oils, especially tea tree, clove, palmarosa, and eucalyptus oils, are potential complementary or alternative products to treat S. scabiei infections in humans or animals, as well as to control the mites in the environment.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-016-1889-3) contains supplementary material, which is available to authorized users.

On the benefits of systematic reviews for wildlife parasitology

Systematic reviews and meta-analyses are widely accepted as the best means to synthesise quantitative or qualitative scientific evidence. Many scientific fields have embraced these more rigorous review techniques as a means to bring together large and complex bodies of literature and their data. Unfortunately, due to perceived difficulties and unfamiliarity with processes, other fields are not using these options to review their literature. One way to provide guidance for a specific field is to examine critically recent reviews and meta-analyses and to explain the advantages and disadvantages of the various review techniques. In this paper, we examine review papers in the emerging field of wildlife parasitology and compare five different literature review types-configurative narrative review, aggregative scoping review, aggregative literature review, aggregative meta-analysis, and aggregative systematic review. We found that most literature reviews did not adequately explain the methodology used to find the literature under review. We also found that most literature reviews were not comprehensive nor did they critically appraise the literature under review. Such a lack severely reduces the reliability of the reviews. We encourage all authors to consider using systematic reviews in the future, and for authors and peer-reviewers to be aware of the limitations of non-systematic reviews.

The emergence of sarcoptic mange in Australian wildlife: an unresolved debate

Due to its suspected increase in host range and subsequent global diversification, Sarcoptes scabiei has important implications at a global scale for wildlife conservation and animal and human health. The introduction of this pathogen into new locations and hosts has been shown to produce high morbidity and mortality, a situation observed recently in Australian and North American wildlife.

Of the seven native animal species in Australia known to be infested by S. scabiei, the bare-nosed wombat (Vombatus ursinus) suffers the greatest with significant population declines having been observed in New South Wales and Tasmania. The origins of sarcoptic mange in Australian native animals are poorly understood, with the most consistent conclusion being that mange was introduced by settlers and their dogs and subsequently becoming a major burden to native wildlife. Four studies exist addressing the origins of mange in Australia, but all Australian S. scabiei samples derive from only two of these studies. This review highlights this paucity of phylogenetic knowledge of S. scabiei within Australia, and suggests further research is needed to confidently determine the origin, or multiple origins, of this parasite.

At the global scale, numerous genetic studies have attempted to reveal how the host species and host geographic location influence S. scabiei phylogenetics. This review includes an analysis of the global literature, revealing that inconsistent use of gene loci across studies significantly influences phylogenetic inference. Furthermore, by performing a contemporary analytical approach on existing data, it is apparent that (i) new S. scabiei samples, (ii) appropriate gene loci targets, and (iii) advanced phylogenetic approaches are necessary to more confidently comprehend the origins of mange in Australia. Advancing this field of research will aid in understanding the mechanisms of spillover for mange and other parasites globally.

Assessment of the cytokine profile in peripheral blood mononuclear cells of naturally Sarcoptes scabiei var. canis infested dogs

The mechanism of cytokine secretion from T lymphocytes plays an important role in the immune response of dogs and parasitic skin infestations. Assessment of the cytokine profile of naturally S. scabiei var. canis infested dogs could augment understanding of the pathobiology of canine sarcoptic mange. Therefore, the present study examined the cytokines in peripheral blood mononuclear cells of dogs suffering from sarcoptic mange. Thirteen dogs naturally infected with sarcoptic mange participated in the study. The dogs were found positive for S. scabiei var. canis mites in skin scraping examinations and revealed at least three clinical inclusion criteria. Another five clinically healthy dogs were kept as healthy controls. Peripheral blood mononuclear cells were isolated from heparinized blood samples and used for extraction of mRNA. Further, cDNA was synthesized by using 1 mg of mRNA by reverse transcription using oligonucleotide primers. Relative levels of cytokine expression were compared with normalized glyceraldehyde-3-phosphate dehydrogenase (GAPDH) transcripts. The levels of interleukin-4, interleukin-5 and transforming growth factor beta (TGF-β) mRNA expression in dogs with sarcoptic mange were significantly higher (P ≤ 0.01), whereas the level of tumor necrosis factor alpha (TNF-α) was significantly lower (P ≤ 0.01) in comparison with the healthy dogs. No remarkable difference was seen for interleukin-2 mRNA expression between these animals. An overproduction IL-4 and IL-5 might be involved in immuno-pathogenesis of canine sarcoptic mange. S. scabiei var. canis mites possibly induce an overproduction of TGF-β and reduced expression of TNF-α and thus could be conferring the immune suppression of infested dogs.

Sarcoptic mange and other ectoparasitic infections in a red fox (Vulpes vulpes) population from central Italy

Fifty red foxes (Vulpes vulpes) from the district of Pisa (central Italy) were examined for ectoparasites. Sarcoptic mange was diagnosed on the presence of clearly visible skin lesions with confirmatory demonstration of Sarcoptes scabiei at parasitological and histopathological analysis. Ticks and fleas were collected directly from the carcases during post mortem examination, fixed and identified by morphological examination. For the detection of ear Malassezia and mite infections, cytological and parasitological examinations of ear wax samples were performed. All data were statistically analysed using a χ2 test with the Yates correction. An overall prevalence of 84% for ectoparasitic infections was found in examined subjects. In regard to isolated ectoparasites, 38%, 8%, 82%, 6% and 8% of foxes resulted positive for S. scabiei, Otodectes cynotis, Malassezia spp., fleas (Archaeopsylla erinacei, Pulex irritans, Ctenocephalides canis) and ticks (Ixodes ricinus and Rhipicephalus sanguineus), respectively. Malassezia ear infection was significantly more prevalent in animals older than 1 year (P < 0.01). Prevalence (38%), severity of lesions and poor body conditions observed in most Sarcoptes-infected animals indicate that sarcoptic mange should be considered the most important ectoparasitic infection of red foxes in the examined area.

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An overall prevalence of 84% for ectoparasitic infections was found in 50 Italian red foxes.

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Red foxes were infected by ticks, mites, fleas and Malassezia yeasts.

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Auricular infection with Malassezia was significantly more prevalent in animals older than 1 year.

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Malassezia was almost constantly associated with the presence of Sarcoptes mites and skin lesions.

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Based on prevalence, lesions and body condition, sarcoptic mange was the most relevant disease.

Are humans the initial source of canine mange?

Background

Scabies, or mange as it is called in animals, is an ectoparasitic contagious infestation caused by the mite Sarcoptes scabiei. Sarcoptic mange is an important veterinary disease leading to significant morbidity and mortality in wild and domestic animals. A widely accepted hypothesis, though never substantiated by factual data, suggests that humans were the initial source of the animal contamination. In this study we performed phylogenetic analyses of populations of S. scabiei from humans and from canids to validate or not the hypothesis of a human origin of the mites infecting domestic dogs.

Methods

Mites from dogs and foxes were obtained from three French sites and from other countries. A part of cytochrome c oxidase subunit 1 (cox1) gene was amplified and directly sequenced. Other sequences corresponding to mites from humans, raccoon dogs, foxes, jackal and dogs from various geographical areas were retrieved from GenBank. Phylogenetic analyses were performed using the Otodectes cynotis cox1 sequence as outgroup. Maximum Likelihood and Bayesian Inference analysis approaches were used. To visualize the relationship between the haplotypes, a median joining haplotype network was constructed using Network v4.6 according to host.

Results

Twenty-one haplotypes were observed among mites collected from five different host species, including humans and canids from nine geographical areas. The phylogenetic trees based on Maximum Likelihood and Bayesian Inference analyses showed similar topologies with few differences in node support values. The results were not consistent with a human origin of S. scabiei mites in dogs and, on the contrary, did not exclude the opposite hypothesis of a host switch from dogs to humans.

Conclusions

Phylogenetic relatedness may have an impact in terms of epidemiological control strategy. Our results and other recent studies suggest to re-evaluate the level of transmission between domestic dogs and humans.

Universal conventional and real-time PCR diagnosis tools for Sarcoptes scabiei

BACKGROUND

The mite Sarcoptes scabiei has a known host-range of over 100 mammal species including humans. One of the prime objectives of the Sarcoptes-World Molecular Network (WMN) is to design and develop universal Sarcoptes PCR-based diagnosis methods.

METHODS

We describe here for the first time two universal mitochondrial-based diagnosis methods: (i) conventional end-point PCR and (ii) TaqMan real-time PCR. The design of both of these universal diagnosis methods was based on Sarcoptes samples collected from 23 host species in 14 countries.

RESULTS

These methods, based on skin scrapings, were successfully used to etiologically confirm the diagnosis of different clinical degrees of sarcoptic mange in 48 animals belonging to six species. These universal PCR-based diagnosis methods are highly specific, technically sensitive and simple, and are based on the amplification of 135 bp from the Mitochondrial 16S rDNA. The method based on TaqMan real-time qPCR was more sensitive than the conventional end-point PCR.

CONCLUSIONS

Two universal PCR-based diagnosis methods for S. scabiei were successfully designed and applied; one based on conventional end-point PCR and the other on TaqMan real-time PCR. We recommend further testing and the application of these new universal methods worldwide.

Sarcoptes scabiei mites in humans are distributed into three genetically distinct clades

Scabies is an ectoparasitic infestation caused by the mite Sarcoptes scabiei. Currently, S. scabiei is taxonomically divided into different varieties on the basis of host origin. Genetics-based research on scabies has been conducted, but the data on genetic diversity of populations of this mite in humans in Europe are lacking. We evaluated the genetic diversity of populations of S. scabiei. A large series of mites obtained from humans in France and the data of mites from various hosts and geographical areas retrieved from GenBank were included to investigate whether mites are divided into distinct populations. The study of cytochrome c oxidase subunit 1 gene polymorphisms were found to be best suited for phylogenetic analysis. S. scabiei mites were distributed into three genetically distinct clades, with most mites clustering in clades B and C. The Fst value and the Nm value calculated for mites included in clades B and C indicated a strong population structure and a very low gene flow between mites of those clades. The results of the present study not only support the rejection of the hypothesis of panmixia for S. scabiei in humans but also suggest that mites belonging to different clades are genetically isolated. Moreover, the results suggest that the subdivision of S. scabies in varieties according to animal or human hosts is not warranted. In conclusion, S. scabiei mites in humans do not constitute a homogeneous population. Further investigations are now required to assess whether different clinical forms of scabies are associated with particular haplotypes or clades.

Coexistence of two different genotypes of Sarcoptes scabiei derived from companion dogs and wild raccoon dogs in Gifu, Japan: The genetic evidence for transmission between domestic and wild canids

Sarcoptes scabiei is the causal agent of sarcoptic mange in domestic/companion dogs (Canis lupus familiaris) and raccoon dogs (Nyctereutes procyonoides). Although there have been successful cases of experimental transmission of S. scabiei from mangy wild Canidae hosts to healthy dogs, and suspected cases of transmission between raccoon dogs and companion dogs, no clear-cut evidence has been obtained. In the present study, the genetic relationships between Sarcoptes mites from raccoon dogs and companion dogs living in the same region were elucidated.One hundred and thirty Sarcoptes mites from 22 raccoon dogs and 5 companion dogs were collected from the Gifu area in Japan. Using 9 microsatellite markers, the genotypes were compared, and the genetic structure of these mites was analyzed. In 6 pairs of companion dog- and raccoon dog-derived mites, 17 out of the 18 alleles analyzed were identical. Using a Bayesian approach, these 130 mites were separated into at least two groups, and companion dog- and raccoon dog-derived mites were segregated into both groups. In addition, comparatively large numbers of alleles at these loci were revealed by comparison with data from past studies. These results demonstrated that the host specificity at the 9 microsatellite-level could not be confirmed, strongly suggesting the transmission of Sarcoptes mites between raccoon dogs and companion dogs. This is the first report to provide a genetic evidence of Sarcoptes transmission between domestic and wild mammals in the natural environment. The possibility of a prior introduction of mites with novel genotypes (e.g., spillover of sarcoptic mange from domestic/companion dogs to raccoon dogs) could not be eliminated when considering the cause of the large number of alleles, and the coexistence of 2 mite groups in sympatric raccoon dogs and companion dogs in this local area.

Wombats acquired scabies from humans and/or dogs from outside Australia

According to previous studies, Sarcoptes mites of wombats were relatively recently introduced into Australia by colonizers and/or their dogs. However, that affirmation has been called into question due to apparent flaws in the design of the phylogenetic studies. With the aim of providing a definitive answer to this question, a part of the mitochondrial gene coding for 12S rRNA of S. scabiei mites from 23 humans and one dog collected in France was sequenced and a phylogenetic analysis including the sequences previously deposited in Genbank was performed. Phylogenetic analysis did not show host segregation or geographical isolation of the mites. Conversely, the present work suggested that mange in wombats is indeed due to the introduction of S. scabiei into Australia by immigrating individuals and/or their companion animals.

Parasitic mites of medical and veterinary importance--is there a common research agenda?

There are an estimated 0.5-1 million mite species on earth. Among the many mites that are known to affect humans and animals, only a subset are parasitic but these can cause significant disease. We aim here to provide an overview of the most recent work in this field in order to identify common biological features of these parasites and to inform common strategies for future research. There is a critical need for diagnostic tools to allow for better surveillance and for drugs tailored specifically to the respective parasites. Multi-'omics' approaches represent a logical and timely strategy to identify the appropriate mite molecules. Recent advances in sequencing technology enable us to generate de novo genome sequence data, even from limited DNA resources. Consequently, the field of mite genomics has recently emerged and will now rapidly expand, which is a particular advantage for parasitic mites that cannot be cultured in vitro. Investigations of the microbiota associated with mites will elucidate the link between parasites and pathogens, and define the role of the mite in transmission and pathogenesis. The databases generated will provide the crucial knowledge essential to design novel diagnostic tools, control measures, prophylaxes, drugs and immunotherapies against the mites and associated secondary infections.

Genetic epidemiology and pathology of raccoon-derived Sarcoptes mites from urban areas of Germany

The raccoon, Procyon lotor (Carnivora: Procyonidae), is an invasive species that is spreading throughout Europe, in which Germany represents its core area. Here, raccoons mostly live in rural regions, but some urban populations are already established, such as in the city of Kassel, or are starting to build up, such as in Berlin. The objective of this study was to investigate Sarcoptes (Sarcoptiformes: Sarcoptidae) infections in racoons in these two urban areas and to identify the putative origin of the parasite. Parasite morphology, and gross and histopathological examinations of diseased skin tissue were consistent with Sarcoptes scabiei infection. Using nine microsatellite markers, we genotyped individual mites from five raccoons and compared them with Sarcoptes mites derived from fox, wild boar and Northern chamois, originating from Italy and Switzerland. The raccoon-derived mites clustered together with the fox samples and were clearly differentiated from those of the wild boar and chamois samples, which suggests a fox origin for the raccoon mange infection. These results are evidence of the cross-transmission of S. scabiei among wild carnivores. Although our results cannot elucidate whether raccoons became infected by frequent interaction with endemically or epidemically infected foxes or whether these cases resulted from occasional contacts among these animal species, they do nevertheless show that pathogens can be shared among urban populations of native and invasive carnivores.

Prevalence of Sarcoptes scabiei infection in pet dogs in southern China

Little is known about the prevalence of Sarcoptes scabiei infection in pet dogs in China. In the present study, the prevalence of S. scabiei infection in pet dogs in Guangzhou, southern China, was investigated between January and December, 2009. A total of 3,977 pet dogs admitted to animal hospitals were examined for the presence of S. scabiei using a parasitological approach. The average prevalence of S. scabiei infection in pet dogs is 1.18% (95% confidence interval (CI): 0.85–1.52%). The prevalence of S. scabiei was higher in winter (1.42%; 95% CI: 0.29–2.55%), summer (1.39%; 95% CI: 0.83–1.96%), and autumn (1.1%; 95% CI: 0.53–1.68%) than in spring (0.63%; 95% CI: 0.02–1.25%). Furthermore, the prevalence of S. scabiei was the highest in Pekingese (21.88%; 95% CI: 7.55–36.2%), followed by Papillon (5.26%; 95% CI: 0–11.06%) and Bichon Frise (3.19%; 95% CI: 0–6.75%). The results of the present investigation indicate that S. scabiei infection is prevalent in pet dogs in Guangzhou, China, which provides relevant “baseline” data for conducting control strategies and measures against scabies in this region and elsewhere in China. To our knowledge, this is the first comprehensive report of S. scabiei prevalence in pet dogs in China.

Preliminary molecular characterizations of Sarcoptes scaibiei (Acari: Sarcoptidae) from farm animals in Egypt

Little is known about the genetic diversity of Sarcoptes scabiei mites in farm animals in Egypt. In this study, we characterized S. scabiei in 25 skin scrapes from water buffalo, cattle, sheep, and rabbits at the nuclear marker ITS2 and mitochondrial markers COX1 and 16S rRNA. Sequences of the ITS2 showed no host segregation or geographical isolation, whereas those of the mitochondrial COX1 and 16S rRNA genes indicated the presence of both host-adapted and geographically segregated populations of S. scabiei. Host adaptation may limit inter-species transmission of. S. scabiei, thus restrict gene flow among S. scabiei from different hosts. This is the first report on the molecular characterization of sarcoptic mites in Egypt. Further genetic studies involving larger numbers of specimens, especially those from humans and companion animals, are needed to understand the molecular epidemiology of sarcoptic mange in Egypt.

Advances in studies of disease-navigating webs: Sarcoptes scabiei as a case study

The discipline of epidemiology is the study of the patterns, causes and effects of health and disease conditions in defined anima populations. It is the key to evidence-based medicine, which is one of the cornerstones of public health. One of the important facets of epidemiology is disease-navigating webs (disease-NW) through which zoonotic and multi-host parasites in general move from one host to another. Epidemiology in this context includes (i) classical epidemiological approaches based on the statistical analysis of disease prevalence and distribution and, more recently, (ii) genetic approaches with approximations of disease-agent population genetics. Both approaches, classical epidemiology and population genetics, are useful for studying disease-NW. However, both have strengths and weaknesses when applied separately, which, unfortunately, is too often current practice. In this paper, we use Sarcoptes scabiei mite epidemiology as a case study to show how important an integrated approach can be in understanding disease-NW and subsequent disease control.

The use of radio-collars for monitoring wildlife diseases: a case study from Iberian ibex affected by Sarcoptes scabiei in Sierra Nevada, Spain

BACKGROUND

Wildlife radio tracking has gained popularity during the recent past. Ecologists and conservationists use radio-collars for different purposes: animal movement monitoring, home range, productivity, population estimation, behaviour, habitat use, survival, and predator-prey interaction, among others. The aim of our present study is to highlight the application of radio-collars for wildlife diseases monitoring. The spread of wildlife diseases and the efficacy of management actions for controlling them propose serious challenges for ecologists and conservationists, since it is difficult to re-capture (or simply observe) the same animal in pre-determined temporal interval, but such difficulty is overcome by the use of gps-gsm radio collars.

METHODS

In the present study we report, for the first time to our knowledge, the use of radio-collars in the monitoring of Iberian ibex affected by Sarcoptes scabiei in Sierra Nevada mountain range, Spain. Twenty-five moderate or slightly mangy animals were radio-collared between 2006 and 2013.

RESULTS

The radio-collars allowed us to confirm the presence of resistance to S. scabiei within Iberian ibex population. Twenty (80%) of the collared animals recovered totally from mange, while the disease progressed in the other five Iberian ibex (20% of the collared animals) and the animals died. The average estimated recovery time of the resistant animals was 245 ± 277 days, and the estimated average survival time of the non-resistant Iberian ibex was 121 ± 71 days. Non-resistant animals survived at least 100 days, while all of them died with less than 200 days. Sixty per cent of the resistant animals were recovered with less than 200 days.

CONCLUSIONS

We report, for the first time, the successful use of radio collars for wildlife diseases monitoring using Iberian ibex/S. scabiei as a model. By using radio collars we documented that most of the Sarcoptes-infected Iberian ibex are resistant to this disease, and we estimated the average time for Iberian ibex recovering from mange infection and the average survival time of the non-resistant ones. We expect wider use of radio-collars for wild animals diseases monitoring, affected/not-affected animals interaction, and treatment efficacy, among others.