A review of Sarcoptes scabiei: past, present and future

Infestation, histology, and molecular confirmation of Sarcoptes scabiei in an Andean porcupine (Coendou quichua) from the Central Andes of Colombia

Sarcoptic mange is a highly contagious, worldwide disease that affects the skin of mammals, including humans. It is caused by the mite Sarcoptes scabiei, however, the information available in wild mammal populations in the world, and particularly in Colombia is limited. Here, we document a new case of sarcoptic mange in an Andean porcupine (Coendou quichua) from the Andean region of Colombia. We morphologically and molecularly confirmed the mite as S. scabiei and documented the histopathology associated with scabies, and show the different stages of the life cycle of S. scabiei from the Andean porcupine skin samples. Our review of reports of additional cases of scabies in wild mammal species in South America showed 15 species, mostly carnivores, artiodactyls, and rodents. Considering the limited information in Colombia, it is urgent to evaluate the risk of this condition on mammals which would contribute to the epidemiological knowledge and the potential implications of sarcoptic mange in the ecology and conservation of wild mammals in the country.

Evidence underscoring immunological and clinical pathological changes associated with Sarcoptes scabiei infection: synthesis and meta-analysis

Background

Sarcoptes scabiei is one of the most impactful mammalian parasites. There has been much research on immunological and clinical pathological changes associated with S. scabiei parasitism across a range of host species. This rich body of literature is complex, and we seek to bring that complexity together in this study. We first (1) synthesise narrative reviews of immunopathological relationships to S. scabiei infection to construct overarching hypotheses; then (2) undertake a systematic meta-analysis of primary literature on immunological and clinical pathological changes; and lastly (3) contrast our findings from the meta-analysis to our synthesis from narrative reviews.

Methods

We synthesised 55 narrative reviews into two overarching hypotheses representing type I and type IV immune responses to S. scabiei infection. We then systematically extracted all literature reporting immunological variables, acute phase proteins, oxidant/antioxidant status, and erythrocytic, hepatological and nephrological changes, calculating 565 effect sizes between controls and sarcoptic mange affected groupings, refining (simplifying) hypotheses from narrative reviews.

Results

Immunological and clinical pathological parameters were most often studied in dogs (n = 12) and humans (n = 14). Combining immunological and clinical pathological information across mammalian species (n = 19) helped yield general insights into observed disease responses. This is evidenced by interspecific consensus in 27 immunological and clinical pathology variables (6/26 type I hypersensitivity, 3/20 type IV hypersensitivity, 6/10 oxidant/antioxidant status, 3/6 acute phase protein, 4/7 erythrocytic, and 5/10 hepatological/nephrological).

Conclusions

Elevated IgE, eosinophils and mast cells in type I hypersensitivity response corresponded to what was described in narrative reviews. Results from type IV hypersensitivity response suggested typical antibody response, however cell-mediated response was less evident. Some consensus of acute phase protein response and shifted oxidant/antioxidant balance and slight evidence of anemia. We highlight the need for mange/scabies studies to more routinely compare immunological and clinical pathological changes against controls, and include collection of a more standardised suite of variables among studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07635-5.

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.

Pathophysiological and Pharmaceutical Considerations for Enhancing the Control of Sarcoptes scabiei in Wombats Through Improved Transdermal Drug Delivery

Sarcoptic scabiei is an invasive parasitic mite that negatively impacts wombats, causing sarcoptic mange disease, characterized by alopecia, intense pruritus, hyperkeratosis, and eventual mortality. Evidence suggests that wombats may be unable to recovery from infection without the assistance of treatments. Transdermal drug delivery is considered the most ideal route of administration for in situ treatment in free-ranging wombats, as it is non-invasive and avoids the need to capture affected individuals. Although there are effective antiparasitic drugs available, an essential challenge is adequate administration of drugs and sufficient drug retention and absorption when delivered. This review will describe the implications of sarcoptic mange on the physiology of wombats as well as discuss the most widely used antiparasitic drugs to treat S. scabiei (ivermectin, moxidectin, and fluralaner). The prospects for improved absorption of these drugs will be addressed in the context of pathophysiological and pharmaceutical considerations influencing transdermal drug delivery in wombats with sarcoptic mange.

Crusted Scabies, a Neglected Tropical Disease: Case Series and Literature Review

Crusted scabies is a rare form of scabies that presents with more severe symptoms than those of classic scabies. It is characterized by large crusted lesions, extensive scales, thick hyperkeratosis, and contains a large number of highly contagious itch mites. Crusted scabies is more prevalent in immunocompromised, malnourished, and disabled individuals. This disease has been linked to a variety of health problems, including delayed diagnosis, infection risk, and high mortality, mainly from sepsis, and it has the potential to cause an outbreak due to its hyper-infestation, which makes it highly infectious. This article reports three cases of crusted scabies in North Sulawesi, Indonesia. Recent updates and a comprehensive review of the literature on the disease are also included, emphasizing the critical importance of early diagnosis and effective medical management of patients, which are necessary to prevent the complications and spread in communities.

Effects of the clinical severity of disease and concomitant pyoderma on serum acute-phase proteins concentrations in dogs with sarcoptic mange

BACKGROUND

Information on acute-phase protein (APP) concentrations in dogs with sarcoptic mange (SM) is scarce.

OBJECTIVE

To determine the effects of the clinical severity of disease and concomitant pyoderma on serum C-reactive protein (CRP), serum amyloid-A (SAA), haptoglobin (Hp) and ceruloplasmin (Cp) concentrations in dogs with SM.

ANIMALS

Forty client-owned dogs with SM (INF group) and 10 healthy control dogs (CON group).

MATERIALS AND METHODS

The INF group was divided into three subgroups; Group 1 (mild/moderate), Group 2 (severe) and Group 3 (severe+pyoderma) according to the extent of skin lesions and the presence of concomitant pyoderma. Serum CRP, SAA, Hp and Cp concentrations of all study groups were measured.

RESULTS

Serum CRP (P < 0.001), SAA (P < 0.001) and Hp (P = 0.016) concentrations of the INF group were higher than the CON group, with no difference in terms of Cp. A statistical difference was measured between groups 2 and 1 in SAA only. C-reactive protein was found to be significantly higher in dogs with severe SM accompanied by pyoderma (Group 3) when compared with dogs with severe SM (Group 2). The area under the receiver-operating characteristic curves differentiating pyoderma among dogs with severe SM was 0.850 for CRP (P = 0.0001, cut-off value >61.3 mg/L with sensitivity 69.29% and specificity 90.91%).

CONCLUSIONS

The unique findings in this were that the SAA serum concentrations are related to the severity of SM and that serum CRP concentrations are effective in detecting the presence of pyoderma in dogs with severe SM.

Adolescent Scalp Dermatitis Associated with Dermatophagoides spp. (Acariformes; Pyroglyphidae) Mite

PURPOSE

Dermatophagoides spp. (Acariformes; Pyroglyphidae), house dust-mite well known as the causative agent of atopic hypersensitivity and allergy could potentially cause severe dermatitis. Herein we report an uncommon case of scalp dermatitis associated with the presence of Dermatophagoides spp.

METHODS

A 17-year old male presented with patchy alopecia on the scalp without intense peeling or itching, surround by unchanged skin and hair. Initially, superficial fungal infection was suspected; however, parasitological examination revealed the presence of live mites.

RESULTS

All the anatomical measurements and parameters from the specimens were compatible with Dermatophagoides spp.

CONCLUSIONS

Dermatophagoides spp. are not yet confirmed as causative agents of parasitic infestation, but the presence of these mites could have caused an allergic reaction followed by dermatitis with mild-to-moderate clinical manifestations. However, true parasitism as well as phoresy could also be considered. The clinical manifestations caused by house-dust mite cannot be easily recognized and the lack of diagnostic tools is a hindrance that often leads to misdiagnosis and inadequate therapy.

Comparative Genomics Reveals Insights into the Divergent Evolution of Astigmatic Mites and Household Pest Adaptations

Highly diversified astigmatic mites comprise many medically important human household pests such as house dust mites causing ∼1–2% of all allergic diseases globally; however, their evolutionary origin and diverse lifestyles including reversible parasitism have not been illustrated at the genomic level, which hampers allergy prevention and our exploration of these household pests. Using six high-quality assembled and annotated genomes, this study not only refuted the monophyly of mites and ticks, but also thoroughly explored the divergence of Acariformes and the diversification of astigmatic mites. In monophyletic Acariformes, Prostigmata known as notorious plant pests first evolved, and then rapidly evolving Astigmata diverged from soil oribatid mites. Within astigmatic mites, a wide range of gene families rapidly expanded via tandem gene duplications, including ionotropic glutamate receptors, triacylglycerol lipases, serine proteases and UDP glucuronosyltransferases. Gene diversification after tandem duplications provides many genetic resources for adaptation to sensing environmental signals, digestion, and detoxification in rapidly changing household environments. Many gene decay events only occurred in the skin-burrowing parasitic mite Sarcoptes scabiei. Throughout the evolution of Acariformes, massive horizontal gene transfer events occurred in gene families such as UDP glucuronosyltransferases and several important fungal cell wall lytic enzymes, which enable detoxification and digestive functions and provide perfect drug targets for pest control. This comparative study sheds light on the divergent evolution and quick adaptation to human household environments of astigmatic mites and provides insights into the genetic adaptations and even control of human household pests.

Occurrence of sarcoptic mange in free-ranging vicuñas (Vicugna vicugna) of the Andean high plateau region of Argentina

Free-ranging vicuñas (Vicugna vicugna) are handled in some areas of the Andean high plateau region following an ancestral practice known as chaku, which consists in their transient capture and shearing of their fiber for commercialization. In this study, 807 vicuñas captured during 12 chaku events that took place in 2019 in the province of Jujuy, Argentina, were examined for typical mange skin lesions. Twenty-eight of the examined vicuñas presented alopecia with erythema, exudation, hyperkeratosis, and/or bleeding scarred lesions, mostly in the chest, rear and front legs, and inguinal zone. Most of the cases (82%) appeared in Laguna Cucho at 4900 masl, where 23% of the animals presented these skin reactions. Microscopic evaluation of skin scrapings revealed the presence of a great number of 0.1- to 0.4-mm-long mites of different life cycle stages, morphologically compatible with the species Sarcoptes scabiei. This etiological agent was confirmed by PCR amplification and sequencing of a cox-1 species-specific segment. Histopathological examination of skin biopsies showed extensive infiltration of the dermis with lymphocytes, neutrophils and eosinophils, hyperplasia at different stages, epidermis degeneration, and hyperkeratosis. This is the first characterization of sarcoptic mange in free-ranging vicuñas by clinical examination, mite morphology, histopathological studies, and molecular confirmation in the region. Mange hampers the welfare of vicuñas and the economy of the local communities that organize chaku events since infested vicuñas cannot be sheared. Its long-term effects are unknown but it might affect the fitness and survival of this iconic South American camelid.

Current and future strategies against cutaneous parasites

Cutaneous parasites are identified by their specific cutaneous symptoms which are elicited based on the parasite's interactions with the host. Standard anti-parasitic treatments primarily focus on the use of specific drugs to disrupt the regular function of the target parasite. In cases where secondary infections are induced by the parasite itself, antibiotics may also be used in tandem with the primary treatment to deal with the infection. Whilst drug-based treatments are highly effective, the development of resistance by bacteria and parasites, is increasingly prevalent in the modern day, thus requiring the development of non-drug based anti-parasitic strategies. Cutaneous parasites vary significantly in terms of the non-systemic methods that are required to deal with them. The main factors that need to be considered are the specifically elicited cutaneous symptoms and the relative cutaneous depth in which the parasites typically reside in. Due to the various differences in their migratory nature, certain cutaneous strategies are only viable for specific parasites, which then leads to the idea of developing an all-encompassing anti-parasitic strategy that works specifically against cutaneous parasites. The main benefit of this would be the overall time saved in regards to the period that is needed for accurate diagnosis of parasite, coupled with the prescription and application of the appropriate treatment based on the diagnosis. This review will assess the currently identified cutaneous parasites, detailing their life cycles which will allow for the identification of certain areas that could be exploited for the facilitation of cutaneous anti-parasitic treatment.

The national burden of scabies in Germany: a population-based approach using Internet search engine data

PURPOSE

Scabies is a World Health Organization-defined neglected tropical disease and a growing public health issue worldwide. It is difficult to obtain reliable data on prevalence due to the lack of standardized tests. The aim of this study was to assess scabies online search behavior in Germany to identify local differences using Google search volume.

METHODS

Google Ads Keyword Planner was used to investigate the scabies-related search volume for Germany as a whole, its 16 federal states, and 15 large cities for the period from January 2016 to December 2019. The identified search terms were qualitatively categorized and critically analyzed.

RESULTS

A total of 572 keywords with an overall search volume of 11,414,180 searches regarding scabies were identified in Germany. The number of searches was higher in winter than in summer, with a national peak in March 2018. Around 30.6% of the searches regarding scabies therapy (n = 978,420) were related to home remedies. Regarding body localization, most searches focused on the whole body (n = 109,050), followed by head (n = 89,360) and the genital area (n = 28,640).

CONCLUSIONS

The analysis of Google search data provides an overview of the populations' interest regarding scabies. The analysis can detect local peaks and assess the relevance of scabies at individual localizations of the body. The study highlighted current possible shortcomings in the therapy of scabies. It also underlined the importance of improving awareness regarding scabies so that affected individuals can consult a doctor earlier for treatment.

Sarcoptic mange outbreak decimates South American wild camelid populations in San Guillermo National Park, Argentina

Sarcoptic mange epidemics can devastate wildlife populations. In 2014, mange was first detected in vicuñas (Vicugna vicugna) and guanacos (Lama guanicoe) in San Guillermo National Park (SGNP), Argentina. This study describes the temporal dynamics of the outbreak, its effects on the park's wild camelid populations between 2017-2019, and investigates the potential source of the epidemic. From May 2017 to June 2018, transect surveys indicated a sharp decrease in the density of living vicuñas and guanacos by 68% and 77%, respectively. By April 2019 no vicuñas or guanacos were recorded on transect surveys, suggesting their near-extinction in the park. Clinical signs consistent with mange (e.g., intense scratching, hyperkeratosis, alopecia) were observed in 24% of living vicuñas (n = 478) and 33% of living guanacos (n = 12) during surveys, as well as in 94% of vicuña carcasses (n = 124) and 85% of guanaco carcasses (n = 20) examined. Sarcoptes scabiei was identified as the causal agent by skin scrapings, and the cutaneous lesions were characterized by histopathology (n = 15). Genetic characterization revealed that mites recovered from seven vicuñas (n = 13) and three guanacos (n = 11) shared the same genotype, which is consistent with a single source and recent origin of the epidemic. Tracing the potential source, we identified a governmental livestock incentive program which introduced llamas (Lama glama) in areas adjacent to SGNP in 2009, some of which had alopecic scaling consistent with sarcoptic mange. Though at the time of our study no llamas with mange were available for confirmatory sampling, we hypothesize that the introduction of mange-infected llamas may have triggered the outbreak in wild camelids. This unprecedented event in SGNP had devastating effects on dominating herbivores with potentially profound cascading effects at the community and ecosystem levels.

MRSA Femoral Osteomyelitis from Superinfected Scabies Lesions: A Pediatric Case Report

Scabies is a skin infestation from the Sarcoptes scabiei. It is considered a public health issue causing concern in developing countries and is considered a “neglected tropical disease” by the World Health Organization (WHO). Scabies skin lesions may cause severe itching and can be the portal of entry for opportunistic and pathogenic bacteria, which can cause serious systemic infections. We report the case of a 3-year-old boy with recurrent scabies infections who presented to the emergency department because of a fever and refusal to walk. Blood tests showed neutrophilic leukocytosis and significantly increased C reactive protein (CRP) and procalcitonin. Upon medical examination, his right thigh was extremely painful upon palpation, knee flexion was lost and he was unable to stand, so magnetic resonance imaging (MRI) was performed. MRI showed osteomyelitis of metaphysis and distal diaphysis of the right femur with associated subperiosteal purulent collection and concomitant pyomyositis and fasciitis of the distal right thigh. Blood cultures were positive for methicillin-resistant Staphylococcus aureus (MRSA). The patient received a long course of intravenous antibiotic therapy and his condition slowly improved. Follow-up femur X-ray showed a mixed pattern of erosion and sclerosis at the meta-diaphyseal region and periosteal reaction at the diaphyseal region. This case highlights the importance of early scabies diagnosis even in Western countries where poverty and household overcrowding are uncommon. Early diagnosis, timely initiation of proper treatment and evidence of clinical resolution are important elements to prevent recurrence of infection and serious systemic superinfections even from multi-drug resistant bacteria. Clinical consequences from unrecognized disease or inadequate eradication are preventable.

Survey of mange mite infesting sheep in Riyadh region, Saudi Arabia

The study was performed to survey the Sarcoptic mange in sheep and the effect of infection on the local strains during a specific period in different regions of Riyadh, Saudi Arabia. A total of 1745 sheep were examined clinically and were selected from the suspected cases for laboratory investigation of skin scrapings for disease diagnosis. The examined animals included (509) Naimi, (396) Najdi, (518) Hurri, and (322) Rufidi native sheep.

The results showed that the infestation rate was (12.77%) in all sheep. The highest strain was recorded (17.2%, 14.3%, 9.6%, and 8.6%), respectively. The infestation was highest in sheep over two years of age (15.2%) while it was lowest in sheep under two years of age (11.2 %). In addition, the infection rate in females was higher than in males. The prevalence of mange mites in females was (14%) compared to (11.2%) in males. The highest percentage of infestation was recorded in the head region at 67.2%, followed by that in the neck (4.4%), back (16.5%), tail (11.6%), and legs (0%).

The presence of mange mites was discovered by microscopic examination of deep skin scrapings of infected animals that were identified morphologically. The infection was assured by histological investigations. This study revealed that mange mite is one of the most significant sheep health constraints in Riyadh. Therefore, proper prevention measures must be implemented to take into consideration other non-host-related risk factors.

Previous Long-term Care Facility Admission as a Risk Factor for Scabies in a Medical Facility

The study aimed to elucidate simple and effective risk factors for scabies infection in the medical environment for early detection and prevention of exposure to other patients and medical staff. We conducted a case-control study of patients who were diagnosed with scabies among hospitalized patients between 2008 and 2019 in an acute-care teaching hospital. Each case was matched according to sex and age with two randomly selected controls without scabies during hospitalization. Clinical characteristics of cases at the time of hospital admission were compared to those of the control group. The scabies group included 34 patients and 68 patients who were included in the control group. After adjusting for confounding factors, previous long-term care facility admission was only associated with scabies (adjusted odds ratio, 5.44; 95% confidence interval, 1.46-20.27; P = 0.012). Careful examination, particularly for patients with previous long-term care facility admission, might be useful for the early detection of scabies.

Canine and Feline Parasitology: Analogies, Differences, and Relevance for Human Health

Cats and dogs are treated as family members by most pet owners. Therefore, a high quality of veterinary care and preventive medicine is imperative for animal health and welfare and for the protection of humans from zoonotic pathogens. There is a general perception of cats being treated as "small dogs," especially in the field of clinical parasitology. As a result, several important differences between the two animal species are not taken into proper consideration and are often overlooked. Dogs and cats are profoundly different under evolutionary, biological, ethological, behavioral, and immunological standpoints. These differences impact clinical features, diagnosis, and control of canine and feline parasites and transmission risk for humans. This review outlines the most common parasitoses and vector-borne diseases of dogs and cats, with a focus on major convergences and divergences, and discusses parasites that have (i) evolved based on different preys for dogs and cats, (ii) adapted due to different immunological or behavioral animal profiles, and (iii) developed more similarities than differences in canine and feline infections and associated diseases. Differences, similarities, and peculiarities of canine and feline parasitology are herein reviewed in three macrosections: (i) carnivorism, vegetarianism, anatomy, genetics, and parasites, (ii) evolutionary adaptation of nematodes, including veterinary reconsideration and zoonotic importance, and (iii) behavior and immune system driving ectoparasites and transmitted diseases. Emphasis is given to provide further steps toward a more accurate evaluation of canine and feline parasitology in a changing world in terms of public health relevance and One Health approach.

Membrane Technology for Rapid Point-of-Care Diagnostics for Parasitic Neglected Tropical Diseases

Parasitic neglected tropical diseases (NTDs) affect over one billion people worldwide, with individuals from communities in low-socioeconomic areas being most at risk and suffering the most. Disease management programs are hindered by the lack of infrastructure and resources for clinical sample collection, storage, and transport and a dearth of sensitive diagnostic methods that are inexpensive as well as accurate. Many diagnostic tests and tools have been developed for the parasitic NTDs, but the collection and storage of clinical samples for molecular and immunological diagnosis can be expensive due to storage, transport, and reagent costs, making these procedures untenable in most areas of endemicity. The application of membrane technology, which involves the use of specific membranes for either sample collection and storage or diagnostic procedures, can streamline this process, allowing for long-term sample storage at room temperature. Membrane technology can be used in serology-based diagnostic assays and for nucleic acid purification prior to molecular analysis. This facilitates the development of relatively simple and rapid procedures, although some of these methods, mainly due to costs, lack accessibility in low-socioeconomic regions of endemicity. New immunological procedures and nucleic acid storage, purification, and diagnostics protocols that are simple, rapid, accurate, and cost-effective must be developed as countries progress control efforts toward the elimination of the parasitic NTDs.

An annotated checklist of the eukaryotic parasites of humans, exclusive of fungi and algae

The classification of "parasites" in the medical field is a challenging notion, a group which historically has included all eukaryotes exclusive of fungi that invade and derive resources from the human host. Since antiquity, humans have been identifying and documenting parasitic infections, and this collective catalog of parasitic agents has expanded considerably with technology. As our understanding of species boundaries and the use of molecular tools has evolved, so has our concept of the taxonomy of human parasites. Consequently, new species have been recognized while others have been relegated to synonyms. On the other hand, the decline of expertise in classical parasitology and limited curricula have led to a loss of awareness of many rarely encountered species. Here, we provide a comprehensive checklist of all reported eukaryotic organisms (excluding fungi and allied taxa) parasitizing humans resulting in 274 genus-group taxa and 848 species-group taxa. For each species, or genus where indicated, a concise summary of geographic distribution, natural hosts, route of transmission and site within human host, and vectored pathogens are presented. Ubiquitous, human-adapted species as well as very rare, incidental zoonotic organisms are discussed in this annotated checklist. We also provide a list of 79 excluded genera and species that have been previously reported as human parasites but are not believed to be true human parasites or represent misidentifications or taxonomic changes.

Prevalence and molecular characterization of Sarcoptes scabiei from vicuñas (Vicugna vicugna) from Southern Peruvian Andes

Sarcoptic mange is a disease caused by an infectious parasite in the vicuñas (Vicugna vicugna) from South America. Although molecular studies have provided much information about the epidemiology of this disease, this information is still unknown in vicuñas. This study determined the prevalence and molecular characterization of Sarcoptes scabiei from vicuñas from Southern Peruvian Andes. During the 2018 shearing season, 181 vicuñas were clinically evaluated for lesions compatible with mange. Sarcoptes scabiei was detected in 35 (19.3%) vicuñas, and 50 mites from 25 vicuñas were selected for molecular analyses of the mitochondrial (cox1) and nuclear (ITS2) genetic markers. Molecular analyses of the cox1 and ITS2 sequences showed an identity of 94–99% and 99.8–100% with previous S. scabiei sequences registered in the GenBank, respectively. Sequence polymorphisms were more evident in the ITS2 than in the cox1, but only the cox1 had an association with the host. Phylogenetic analysis of S. scabiei cox1 sequences from vicuñas showed a cluster with S. scabiei cox1 sequences from canids, suggesting that the origin of S. scabiei from vicuña is associated with canid mites. This research is the first molecular analysis of S. scabiei from vicuñas. Future molecular studies will be necessary to determine the species variety, geographic segregation and host–parasite adaptation for this vicuña's mite.

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.

Amelioration of Sarcoptic Mange-Induced Oxidative Stress and Growth Performance in Ivermectin-Treated Growing Rabbits Using Turmeric Extract Supplementation

Simple Summary

Sarcoptic mange is a common rabbit disease that can be spread directly from sick to healthy rabbits. Infection in rabbits causes intense pruritus, head shaking, and scabby lesions on the inner side of the pinnae and on the external ear canal, as well as diminished growth performance and an increased rate of oxidative stress. Ivermectin has been shown to be an effective treatment for sarcoptic mange in rabbits; however, it has side effects on their performance. Botanicals such as turmeric extract have a remarkable antioxidant potential contributing to the deterrence of Sarcoptes-induced oxidative discrepancy in rabbits. The goal of this study was to investigate if turmeric extract can alleviate side effects in Ivermectin-treated rabbits while simultaneously improving their performance and antioxidant status. The results indicated that turmeric extract was utilized with varied efficacy against mites, and also helped rabbits recover faster and improved Ivermectin’s miticidal efficacy by improving performance and compromised immunity. Turmeric extract has strong antioxidant properties, suggesting that it could be used as an adjunctive remedy to reduce the side effects of Ivermectin while treating clinical rabbit sarcoptic mange. Furthermore, no adverse effects were observed in turmeric extract adjunctively supplemented rabbits, and the provided dose regimen of these supplements was found to be safe.

Abstract

In this experiment, the protective effect of turmeric extract (TE) on side effects of Ivermectin-treated rabbits, while improving their performance, blood characteristics, and antioxidant status, was investigated. Sixty-three clinically Sarcoptes-infested rabbits aged 60 days were randomly allocated into three groups, with 21 rabbits in each group, to receive either no TE or TE supplementation (1 or 2 mg/kg diet) for 30 days after being subcutaneously injected with Ivermectin (IVM) 1% w/v at a dose of 0.2 mg/kg body weight twice a week. Another 21 healthy rabbits were used as the control. Treatment with IVM + 1 and 2 mg TE improved body weight (BW), body weight gain (BWG), feed intake (FI), and feed conversion ratio (FCR) in infested rabbits (p < 0.05). The IVM alone treatment had the highest mortality rate compared with the other treatments. Rabbits treated with IVM + 1 and 2 mg TE demonstrated progressive recovery manifested by improved nutrient digestibility and nitrogen balance. On day 7, the serum total protein, albumin, and albumin/globulin (A/G) ratio were significantly lower in the treated groups compared with the control group; also, the lowest values were observed in rabbits treated only with Ivermectin, followed by IVM + 1 and 2 mg TE. Treated rabbits had higher thiobarbituric acid reactive substance (TBAR) levels, but lower total antioxidant capacity (TAC), superoxidase dismutase (SOD), and glutathion peroxidase (GSH-Px) levels compared with the control group. On day 30 post-treatment, the rabbits in the IVM + 1 and 2 mg TE treatment groups showed progressive recovery manifested by improved biochemichal parameters, as well as a remarkable improvements in the oxidant/antioxidant balance towards normalcy (p < 0.05), and became comparable to that of the control compared with IVM alone treatment. In conclusion, turmeric extract improved rabbits’ performance toward normalcy, and has remarkable antioxidant properties and can be used in conjunction with a miticide to treat sarcoptic mange in rabbits.

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.

Laboratory diagnosis of mange-causing mites in dogs using a modified centrifugation-flotation technique in sucrose solution

Among the skin disorders of dogs, scabies is notable for its high occurrence rate and the need for veterinary interventions. There are two obstacles to making this diagnosis through direct investigation under a microscope (DIM): the continual need to make new slides when the results are negative and the long time needed for reading these slides. Thus, the objective of the present study was to compare efficacy between DIM and the technique of centrifugation-flotation in sucrose solution (CFSS) in samples from dogs in the semiarid region of the state of Paraíba, Brazil. Samples from 136 dogs were used, and three slides were made for each examination (DIM and CFSS). The readings were halted in cases of positivity. Positive samples were obtained from 56.6% of the dogs (77/136), of which 76.6% (59/77) were positive through both techniques, 13% (10/77) only through DIM and 10.4% (8/77) only through CFSS. The positivity rate did not differ statistically between the techniques. CFSS showed higher quality of readings, due to the considerably fewer artifacts on the slides, thereby optimizing the reading time. Sensitivity (85.6%), specificity (88.1%), accuracy (86.8%), positive predictive value (88.1%) and negative predictive value (85.1%) were obtained and the kappa coefficient (0.73) was considered substantial. It was concluded that CFSS showed high diagnostic capacity for scabies, similar to that of DIM, with optimized reading time, fewer artifacts and better display of mites.

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.

Scabies as a part of the World Health Organization roadmap for neglected tropical diseases 2021-2030: what we know and what we need to do for global control

Background

Scabies is an under-recognized global health problem with an unacceptably high prevalence in many settings worldwide. Fortunately, the World Health Organization (WHO) has formally designated scabies as a neglected tropical disease in 2017, in the hope of increasing awareness and encouraging efforts to eradicate it. Also, scabies has recently been included as part of the WHO roadmap for neglected tropical diseases 2021–2030, aimed at ending the neglect to attain the Sustainable Development Goals.

Main abstract body

This review article places scabies in focus. The literature was reviewed to explore discussions on controversial issues in scabies control, with the aim of clarifying whether global control of scabies is a feasible and worthwhile objective. The existing status of scabies and its burden are discussed along with future prospects for its global control. The article investigates the feasibility of scabies control and provides updates on the various impediments to this goal, such as challenges related to transmission, diagnosis, treatment, and vaccine development. Also examined are relevant research needs, success factors, and reasons for failure. This article aims to increase the global awareness of scabies and promote discussion, enhance coordinated international efforts, and ultimately, enact change at the national and worldwide levels toward the control of this preventable disease of the poor.

Conclusion

Despite the current challenges, scabies control is now within reach. With sustained interventions, continuous resources, and sincere commitment and support, scabies global control appears to be a worthwhile, realistic goal that is potentially achievable in the not so distant future.

Genome-Resolved Metagenomic Analyses Reveal the Presence of a Putative Bacterial Endosymbiont in an Avian Nasal Mite (Rhinonyssidae; Mesostigmata)

Rhinonyssidae (Mesostigmata) is a family of nasal mites only found in birds. All species are hematophagous endoparasites, which may damage the nasal cavities of birds, and also could be potential reservoirs or vectors of other infections. However, the role of members of Rhinonyssidae as disease vectors in wild bird populations remains uninvestigated, with studies of the microbiomes of Rhinonyssidae being almost non-existent. In the nasal mite (Tinaminyssus melloi) from rock doves (Columba livia), a previous study found evidence of a highly abundant putatively endosymbiotic bacteria from Class Alphaproteobacteria. Here, we expanded the sample size of this species (two different hosts- ten nasal mites from two independent samples per host), incorporated contamination controls, and increased sequencing depth in shotgun sequencing and genome-resolved metagenomic analyses. Our goal was to increase the information regarding this mite species and its putative endosymbiont. We obtained a metagenome assembled genome (MAG) that was estimated to be 98.1% complete and containing only 0.9% possible contamination. Moreover, the MAG has characteristics typical of endosymbionts (namely, small genome size an AT bias). Overall, our results support the presence of a potential endosymbiont, which is the first described for avian nasal mites to date, and improve the overall understanding of the microbiota inhabiting these mites.

First evidence of the activity of an entomopathogenic fungus against the eggs of Sarcoptes scabiei

The entomopathogenic fungus Beauveria bassiana has been successfully used for the control of phytopathogenic arthropods and there are a growing number of studies suggesting that this kind of fungus could also be used for the control of ectoparasites in mammals. This study evaluated for the first time the efficacy of different Beauveria strains against the eggs of Sarcoptes scabiei collected from experimentally infected pigs. Eggs were exposed to fungal conidia and monitored for hatching over 10 days. The strongest effect (28.75 % of hatching inhibition) was obtained with a commercial B. bassiana strain. Furthermore, the detection of fungal genomic within the surface-cleaned eggs demonstrated the ability of B. bassiana to penetrate and proliferate in the egg-shell of S. scabiei. This study provides the first evidence, using molecular techniques, that the development of mycoacaricides may be of interest for the control of S. scabiei infection.

Sarcoptes Infestation. What Is Already Known, and What Is New about Scabies at the Beginning of the Third Decade of the 21st Century?

Currently, there are three known subtypes of scabies: ordinary, crusted, and bullous. The worldwide prevalence of scabies remains high in the 21st century. To decrease the social, economic, and psychological impact on the enormous population infected, a lot of important work has been completed over the last 20 years concerning the management of scabies. For example, a standardization of guidelines for the treatment of scabies has been completed and programs have been designed for the prevention and treatment in endemic populations, called mass drug administrations. Unfortunately, these only apply to the ordinary form of scabies. Moreover, resistance to the drugs currently used in treatment is growing, which imposes the need to search for new treatments. For this purpose, new acaricides are being developed to enhance the therapeutic options for the patients' benefit and effectively treat this disease. There is also the necessity for prevention before the development of scabies. An effective vaccine has the potential to protect people before this disease, especially in endemic areas. Unfortunately, there are no such vaccines against Sarcoptes yet.

Mass drug administration for endemic scabies: a systematic review

Background

Scabies is an extremely fastidious infestation caused by the Sarcoptes scabiei mite. It causes a persistent itch that can disrupt a person’s mental health, sleep, and overall quality of life. In endemic areas, treatment by targeting symptomatic individuals and their contacts is often unsuccessful due to an asymptomatic period and high rates of re-infection. To overcome this, Mass Drug Administration (MDA) is often used to treat the whole community, irrespective of whether individuals presently have scabies. This review summarises the evidence for the effectiveness of MDA in treating scabies.

Methods

An exhaustive literature review was conducted on MEDLINE, EMBASE, Web of Science and Scopus. All peer-reviewed articles published in English January 1990 to March 2020 were eligible and only if the studies were primary and interventional. Furthermore, the intervention had to be a pharmacological MDA method involving human subjects.

Results

TWELVE articles that qualified for inclusion were identified. MDA for scabies significantly reduced its prevalence in communities at follow up. Some of the drivers of success were communities with low levels of migration, an uptake of MDA of > 85%, the use of oral Ivermectin therapy, the treatment of children and pregnant women within the treated population, and repeated treatment for participants diagnosed with scabies at baseline.

Conclusions

The average absolute reduction in prevalence of scabies was 22.0% and the relative reduction average was 73.4%. These results suggest MDA is effective in treating scabies in the endemic community. Further evidence is needed surrounding MDA use in urban areas with increased levels of migration. Importantly, MDA should not substitute the tackling of socioeconomic factors which contribute to endemic disease such as good sanitation and hygiene.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40794-021-00143-5.

Second internal transcribed spacer (ITS-2) as genetic marker for molecular characterization of Sarcoptes scabiei in rabbits from several areas of East Java, Indonesia

OBJECTIVES

The purpose of this study is to use the second internal transcribed spacer (ITS-2) to determine the molecular characteristics of Sarcoptes scabiei in rabbits from several areas of East Java.

METHODS

Collecting S. scabiei mites from rabbits with clinical signs of scabies; DNA extraction with minikit QIAamp DNA; polymerase chain reaction amplification; nucleotide sequence analysis; homology and phylogenetic tree using the Neighbor-Joining method in the program molecular evolutionary genetics analysis-7 (MEGA-7).

RESULTS

Sequence analysis of ITS-2 S. scabiei from five regions in East Java showed an identity >91.23% with isolates from China (KX695125.1). The phylogenetic analysis of ITS-2 S. scabiei from Mojokerto rabbits has a close relationship with AB82977.1; Surabaya and Nganjuk rabbits are closely related to KX695125.1; while Sidoarjo and Pasuruan rabbits are closely related to EF514469.2. and AB369384.1.

CONCLUSIONS

The homology analysis of all samples showed identity of more than 91.23% with isolate China (KX695125.1). The sequences of ITS-2 gen of S. scabiei from rabbits in several areas were relatively close to S. scabiei obtain various hosts from National Centre for Biotechnology Information (NCBI) data.

The Patterns and Causes of Dermatitis in Terrestrial and Semi-Aquatic Mammalian Wildlife

Causative disease and stress agents which manifest as dermatitis in mammals have varying effects on individual animals, from benign irritation and inflammation, to causing morbidity and even mortality. Bacteria, viruses and ectoparasites are all potential causes of dermatitis, and it can be exacerbated by various environmental, genetic and social factors. Furthermore, it is uncertain whether dermatitis is more likely to manifest in already-vulnerable wildlife species. Here, we systematically review the literature for reports of dermatitis in terrestrial and semi-aquatic wild mammalian species, with the goal of determining the biogeographical scale of dermatitis reports, the causes of dermatitis, and whether manifestation of dermatitis is reported more commonly in certain wildlife species or their captivity status (i.e., free-living, in captivity or in a laboratory). We reveal biases in the reporting of dermatitis by a biogeographic realm, with 55% of cases reported in the Nearctic, and towards particular orders of mammals, namely Artiodactyla and Carnivora. Overall, free-living wildlife is almost twice as likely to be reported as having dermatitis than individuals in captivity and six times more likely than individuals in laboratories, which we interpret as owing to exposure to a broader spectrum of parasites in free-ranging individuals, and potential reporting bias in captive individuals. Notably, dermatitis was reported in 23 threatened species, with some species more likely than others to be reported exhibiting clinical signs of dermatitis resulting from underlying health problems. We also find that threatened species are more likely to be reported as having dermatitis in captivity, particularly outside of their endemic home range. This review highlights diverse patterns of dermatological disease causes in captive and free-ranging wildlife, conditions under which they are more likely to be documented, and the need for cross-disciplinary research to ascertain (and so better manage) the varied causes.

Infection-provoked psoriasis: Induced or aggravated (Review)

Psoriasis is a common chronic, immune-mediated, inflammatory skin disorder, with a reported prevalence of 0.0-2.1% among children and 0.91-8.50% among adults, worldwide. Psoriasis is induced by several environmental factors, including infection, alcohol consumption, drugs, trauma, acute withdrawal of systemic or potent topical corticosteroids, body mass index and endocrine disorders. Increasing evidence suggest that a variety of microorganisms play key roles in the induction and exacerbation of psoriasis. Pathogens, such as streptococci and staphylococci are considered causal factors, presumably via superantigen activation of skin-seeking T cells. In addition, fungal pathogens, such as Candida and Malassezia, and viral agents, such as human immunodeficiency virus, hepatitis C virus infection and human papillomavirus, are also closely associated with psoriasis. Recently, several types of pathogens, such as Helicobacter pylori infection, Zika virus and scabies, have been reported to potentially trigger psoriasis. The present review discusses the underlying molecular mechanisms by which these infections influence psoriasis to provide a better understanding of the pathogenesis of psoriasis.

Risk factors associated with scabies infestation among primary schoolchildren in a low socio-economic area in southeast of Iran

Background

Scabies is a neglected tropical disease caused by the mite Sarcoptes scabiei that burrows under the skin. It is a major health problem in tropical areas, largely affecting children. Scabies is common and highly contagious and in schoolchildren spreads quite rapidly, due to overcrowding and close contact within the schools. This study aimed to determine the risk factors associated with scabies infestation among primary schoolchildren in Bashagard County, one of the low socio-economic areas in southeast of Iran.

Methods

To conduct this community-based, descriptive, and cross-sectional study, four primary schools were randomly selected in the Bashagard County. All students in these schools were selected and examined for scabies. Clinical examination and sociodemographic profile of students were assessed using a pre-tested structured questionnaire. Chi-square test, and binary logistic regression were used to analyse the factors associated with scabies infestation by SPSS version 21 software.

Results

Out of 480 studied schoolchildren, 15 cases of scabies with a prevalence of 3.1 % were observed. The frequency of infestation in males was 1.6 % and it was 4.7 % in females. Independent factors associated with a high risk of scabies infestation in unadjusted analysis were being student of grade 5–6 (cOR = 13.12, 95 % CI 2.92–58.89, p = 0.0001), low educational level of father (cOR = 4.37, 95 % CI 0.97–19.59, p = 0.036), low educational level of mother (cOR = 4.14, 95 % CI 1.92–18.57, p = 0.045), joblessness of father (cOR = 14.77, 95 % CI 4.97–43.89, p = 0.0001), employment of mother (cOR = 5.28, 95 % CI 1.38–20.16, p = 0.007), large family size (cOR = 3.34, 95 % CI 1.05–10.64, p = 0.031), use of shared articles (cOR = 33.37, 95 % CI 10.82–102.90, p = 0.0001), and absence of bathroom in the house (cOR = 11.77, 95 % CI 2.16–63.94, p = 0.0001).

Conclusions

Results of this study confirmed that scabies is still one of the most important health problems in the primary schools of the Bashagard County. Low socioeconomic status and personal hygiene of the schoolchildren were the most important factors influencing the prevalence of scabies. Improvement of socioeconomic conditions and implementation of appropriate educational programs and active surveillance system to quickly detect and treat scabies cases are necessary in order to reduce the prevalence of scabies in schoolchildren in this area.

Paediatrics: how to manage scabies

This narrative review addresses scabies, a highly contagious, pruritic infestation of the skin caused by the mite Sarcoptes scabiei var hominis. Scabies is a common disorder that has a prevalence worldwide estimated to be between 200 and 300 million cases per year. Infestation is of greatest concern in children, the elderly, immunocompromised people and resource-poor endemic populations at risk of chronic complications. A diagnosis of scabies involves a clinical suspicion, a detailed targeted history, clinical examination and contact tracing. Dermoscopy and microscopy, where available, is confirmatory. Due to its infectivity and transmissibility, the management for scabies requires a multimodal approach: topical antiscabetic agents are the first line for most cases of childhood classic scabies and their contacts, which must also be identified and treated to prevent treatment failure and reacquisition. Environmental strategies to control fomite-related reinfestation are also recommended. Oral ivermectin, where available, is reserved for use in high-risk cases in children or in mass drug administration programmes in endemic communities. The prevention of downstream complications of scabies includes surveillance, early identification and prompt treatment for secondary bacterial infections, often superficial but can be serious and invasive with associated chronic morbidity and mortality. Post-scabetic itch and psychosocial stigma are typical sequelae of the scabies mite infestation. The early identification of patients with scabies and treatment of their contacts reduces community transmission. Although time consuming and labour intensive for caregivers, the implementation of appropriate treatment strategies usually results in prompt cure for the child and their contacts. Here, we provide a summary of treatments and recommendations for the management of paediatric scabies.

Sarcoptic mange: An emerging panzootic in wildlife

Sarcoptic mange, a skin infestation caused by the mite Sarcoptes scabiei, is an emerging disease for some species of wildlife, potentially jeopardizing their welfare and conservation. Sarcoptes scabiei has a near-global distribution facilitated by its forms of transmission and use of a large diversity of host species (many of those with broad geographic distribution). In this review, we synthesize the current knowledge concerning the geographic and host taxonomic distribution of mange in wildlife, the epidemiological connections between species, and the potential threat of sarcoptic mange for wildlife conservation. Recent sarcoptic mange outbreaks in wildlife appear to demonstrate ongoing geographic spread, increase in the number of hosts and increased virulence. Sarcoptic mange has been reported in at least 12 orders, 39 families and 148 species of domestic and wild mammals, making it one of the most generalist ectoparasites of mammals. Taxonomically, the orders with most species found infested so far include Perissodactyla (67% species from the entire order), Artiodactyla (47%), and Diprotodontia (67% from this order). This suggests that new species from these mammal orders are likely to suffer cross-species transmission and be reported positive to sarcoptic mange as surveillance improves. We propose a new agenda for the study of sarcoptic mange in wildlife, including the study of the global phylogeography of S. scabiei, linkages between ecological host traits and sarcoptic mange susceptibility, immunology of individuals and species, development of control strategies in wildlife outbreaks and the effects of global environmental change in the sarcoptic mange system. The ongoing transmission globally and sustained spread among areas and wildlife species make sarcoptic mange an emerging panzootic in wildlife. A better understanding of sarcoptic mange could illuminate the aspects of ecological and evolutionary drivers in cross-species transmission for many emerging diseases.

Sarcoptic mange in wild ruminants in Spain: solving the epidemiological enigma using microsatellite markers

BACKGROUND

In Spain, sarcoptic mange was first described in native wildlife in 1987 in Cazorla Natural Park, causing the death of nearly 95% of the local native population of Iberian ibex (Capra pyrenaica). Since then, additional outbreaks have been identified in several populations of ibex and other wild ungulate species throughout the country. Although the first epizootic outbreak in wildlife was attributed to the introduction of an infected herd of domestic goats, the origin and the cause of its persistence remain unclear. The main aims of this study are to understand (i) the number of Sarcoptes scabiei "strains" circulating in wild ruminant populations in Spain, and (ii) the molecular epidemiological relationships between S. scabiei and its hosts.

METHODS

Ten Sarcoptes microsatellite markers were used to characterize the genetic structure of 266 mites obtained from skin scrapings of 121 mangy wild ruminants between 2011 and 2019 from 11 areas in Spain.

RESULTS

Seventy-three different alleles and 37 private alleles were detected. The results of this study show the existence of three genetic strains of S. scabiei in the wild ruminant populations investigated. While two genetic clusters of S. scabiei were host- and geography-related, one cluster included multi-host mites deriving from geographically distant populations.

CONCLUSIONS

The molecular epidemiological study of S. scabiei in wild ruminants in Spain indicates that the spreading and persistence of the parasite may be conditioned by host species community composition and the permissiveness of each host population/community to the circulation of individual "strains," among other factors. Wildlife-livestock interactions and the role of human-driven introduction or trade of wild and domestic animals should be better investigated to prevent further spread of sarcoptic mange in as yet unaffected natural areas of the Iberian Peninsula.

Development of a rapid scabies immunodiagnostic assay based on transcriptomic analysis of Sarcoptes scabiei var. nyctereutis

Scabies is a highly contagious skin disease caused by the mite Sarcoptes scabiei that affects many mammals. However, the sensitivity of traditional tests for scabies diagnosis in humans is less than 50%. To simplify the diagnosis of scabies, methods that are simple, sensitive, specific, and cost-effective are required. We developed an immunodiagnostic test based on S. scabiei var. nyctereutis RNA-seq data collected from Japanese raccoon dogs with sarcoptic mange. Three candidate antigens-a highly expressed hypothetical protein "QR98_0091190," another mite allergen known as "SMIPP-Cc," and an abundant "vitellogenin-like protein"-were evaluated by western-blot analysis. A lateral flow immunoassay, using specific antibodies against the vitellogenin-like protein, successfully detected scabies in the skin flakes of S. scabiei-infected raccoon dogs. This assay can potentially diagnose scabies more accurately in wildlife, as well as in humans.

Recent advances in understanding and treating scabies

Scabies is an infestation of the skin caused by the mite Sarcoptes scabiei. In 2017, scabies was recognised by the World Health Organisation as a disease of public importance and was consequently added to the list of neglected tropical diseases. An estimated 200 million people currently have scabies worldwide. Scabies is endemic in many developing countries, with the highest prevalence being in hot, humid climates such as the Pacific and Latin American regions. Scabies causes a host immune response which is intensely itchy. Scratching of the lesions can lead to secondary bacterial infections of the skin, such as impetigo, most commonly caused by Streptococcus pyogenes or Staphylococcus aureus. This can have fatal consequences, such as septicaemia, glomerulonephritis, and rheumatic heart disease. Advances over the past 5 years indicate that mass drug administration is an effective strategy to treat scabies. This review will outline advances in the mite biology, epidemiological understanding, diagnosis, and treatment of scabies.

Comparative analysis of the allergenic characteristics and serodiagnostic potential of recombinant chitinase-like protein-5 and -12 from Sarcoptes scabiei

Background

Scabies is caused by burrowing of the mite Sarcoptes scabiei into the stratum corneum. Currently, diagnosis via routine skin scraping is very difficult, and information on the allergenic identification of S. scabiei remains limited.

Methods

We performed comparative analysis of the serological diagnostic potential of recombinant S. scabiei chitinase-like protein-5 (rSsCLP5) and recombinant S. scabiei chitinase-like protein-12 (rSsCLP12) by measuring the levels of serum-specific IgG and IgE antibodies (Abs) as diagnostic markers. In addition, the allergenic characteristics of rSsCLP5 and rSsCLP12 were evaluated using IgE-binding experiments and skin tests.

Results

The IgE Abs-based indirect enzyme-linked immunosorbent assay (ELISA) methods showed high sensitivity and specificity: the rSsCLP5-based assay had 93.5% sensitivity and 94.4% specificity; the rSsCLP12-based assay had 100% sensitivity and 98.1% specificity. The specific IgE Abs in infested mouse sera could bind rSsCLP5 and rSsCLP12. In skin tests, rabbits in the rSsCLP5 and rSsCLP12 groups and positive control (histamine) groups exhibited allergic reactions. Most test sites in the rSsCLP12 group had edema, bleeding spots, and even ulcers or scabs, but such allergy symptoms were rare in the rSsCLP5 group. Moreover, the allergic history rabbit group had more severe allergic reactions and lower levels of IgE Abs compared to the healthy rabbit group in the same protein group.

Conclusions

These findings validate the use of IgE Abs to rSsCLP5 and rSsCLP12 as potentially useful markers for diagnosing scabies. Moreover, both rSsCLP5 and rSsCLP12 have allergenic properties, and the potential allergen rSsCLP12 is a stronger allergen than rSsCLP5.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-04654-0.

Non-Invasive Molecular Survey of Sarcoptic Mange in Wildlife: Diagnostic Performance in Wolf Faecal Samples Evaluated by Multi-Event Capture-Recapture Models

Sarcoptic mange is globally enzootic, and non-invasive methods with high diagnostic specificity for its surveillance in wildlife are lacking. We describe the molecular detection of Sarcoptes scabiei in non-invasively collected faecal samples, targeting the 16S rDNA gene. We applied this method to 843 Iberian wolf Canis lupus signatus faecal samples collected in north-western Portugal (2006-2018). We further integrated this with serological data (61 samples from wolf and 20 from red fox Vulpes vulpes, 1997-2019) in multi-event capture-recapture models. The mean predicted prevalence by the molecular analysis of wolf faecal samples from 2006-2018 was 7.2% (CI₉₅ 5.0-9.4%; range: 2.6-11.7%), highest in 2009. The mean predicted seroprevalence in wolves was 24.5% (CI₉₅ 18.5-30.6%; range: 13.0-55.0%), peaking in 2006-2009. Multi-event capture-recapture models estimated 100% diagnostic specificity and moderate diagnostic sensitivity (30.0%, CI₉₅ 14.0-53.0%) for the molecular method. Mange-infected individually identified wolves showed a tendency for higher mortality versus uninfected wolves (ΔMortality 0.150, CI₉₅ -0.165-0.458). Long-term serology data highlights the endemicity of sarcoptic mange in wild canids but uncovers multi-year epidemics. This study developed and evaluated a novel method for surveying sarcoptic mange in wildlife populations by the molecular detection of S. scabiei in faecal samples, which stands out for its high specificity and non-invasive character.

Itch in Scabies-What Do We Know?

Scabies is a common parasitic skin infestation characterized by severe itch and a heterogenous clinical presentation. Itch, as the cardinal symptom of scabies, is imposing a high burden on affected patients and is often difficult to manage. Decreased life quality and secondary complications, caused by an itch-related disruption of the epidermal barrier and subsequent superinfections, illustrate the need to treat scabies and to understand the underlying mechanisms of itch in respective patients. This review summarizes available data on itch in scabies with a special focus on the clinical aspects and its underlying pathomechanisms.

Clinical, Parasitological, and Serological Follow-Up of Dogs with Sarcoptic Mange Treated Orally with Lotilaner

Canine sarcoptic mange is a highly pruritic and contagious skin disease caused by the mite Sarcoptes scabiei var. canis. This case series describes the clinical, parasitological, and serological follow-up of a cohort of eight adult Saint Bernard dogs with confirmed sarcoptic mange, treated orally with lotilaner. Dogs were evaluated initially and after 14 days and 1, 2, 3, 4, 6, and 12 months for skin lesions, pruritus severity, presence of parasites, and Sarcoptes-IgG levels. A serological indoor allergy panel (IgE) was obtained for seven dogs at day 0 and repeated 12 months later in five dogs to assess potential cross-reactivity between S. scabiei and environmental allergens. Lotilaner was administered to each dog according to the manufacturer's instructions and was repeated after one and two months without any concurrent therapeutic measure or modification of the husbandry conditions. Pruritus ceased after two weeks. The cutaneous score was reduced by 47%, and skin scrapings were negative for all but three animals. All skin scrapings were negative after one month. Lesions were absent after two months. Serological levels decreased gradually, but more slowly than the skin lesions, and two dogs out of six remained positive in the absence of skin lesions or symptoms. All dogs initially tested positive for dust mites and/or storage mites. The IgE titres remained unchanged 12 months later in the five tested dogs. This case report demonstrates the efficacy of lotilaner on scabies in a cohort of infested dogs under natural conditions and the potential antigenic cross-reaction of S. scabiei with house dust and storage mites.

Efficacy of neem (Azadirachta indica) aqueous fruit extracts against Sarcoptes scabiei var. suis in grower pigs

The acaricidal activity of Azadirachta indica (neem) aqueous fruit extracts was evaluated against Sarcoptes scabiei var. suis (mange mites) in an on-farm trial using grower pigs. Aqueous neem fruit extracts of three concentrations 5%, 10%, and 25% w/v and a commercial acaricide, 12.5% amitraz-based Triatix spray (positive control), were compared with pigs that received no treatment (negative control). Thirty grower pigs of the Dalland breed were allocated to the five treatments in a completely randomized experiment. Each experimental animal was sprayed on day 0 and again on day 7. Counts of mange mites, scoring of lesion index, and calculation of rubbing index were done weekly. Topical application of 25% aqueous neem fruit extract had a higher efficacy ratio (p < 0.05) than the other fruit extract concentrations, and performed similarly to an amitraz-based acaricide, suggesting a dose-dependent response. Amitraz (positive control) cured clinical mange on grower pigs after 5 weeks and 25% aqueous neem fruit extract 6 weeks post-treatment. The results indicated that aqueous neem fruit extracts have acaricidal effects against mange mites and can provide a cheaper, safer, and more eco-friendly alternative for the control of Sarcoptes mange in pigs.

Fluralaner as a novel treatment for sarcoptic mange in the bare-nosed wombat (Vombatus ursinus): safety, pharmacokinetics, efficacy and practicable use

Background

Sarcoptic mange causes significant animal welfare and occasional conservation concerns for bare-nosed wombats (Vombatus ursinus) throughout their range. To date, in situ chemotherapeutic interventions have involved macrocytic lactones, but their short duration of action and need for frequent re-administration has limited treatment success. Fluralaner (Bravecto®; MSD Animal Health), a novel isoxazoline class ectoparasiticide, has several advantageous properties that may overcome such limitations.

Methods

Fluralaner was administered topically at 25 mg/kg (n = 5) and 85 mg/kg (n = 2) to healthy captive bare-nosed wombats. Safety was assessed over 12 weeks by clinical observation and monitoring of haematological and biochemical parameters. Fluralaner plasma pharmacokinetics were quantified using ultra-performance liquid chromatography and tandem mass spectrometry. Efficacy was evaluated through clinical assessment of response to treatment, including mange and body condition scoring, for 15 weeks after topical administration of 25 mg/kg fluralaner to sarcoptic mange-affected wild bare-nosed wombats (n = 3). Duration of action was determined through analysis of pharmacokinetic parameters and visual inspection of study subjects for ticks during the monitoring period. Methods for diluting fluralaner to enable ‘pour-on’ application were compared, and an economic and treatment effort analysis of fluralaner relative to moxidectin was undertaken.

Results

No deleterious health impacts were detected following fluralaner administration. Fluralaner was absorbed and remained quantifiable in plasma throughout the monitoring period. For the 25 mg/kg and 85 mg/kg treatment groups, the respective means for maximum recorded plasma concentrations (C_max) were 6.2 and 16.4 ng/ml; for maximum recorded times to C_max, 3.0 and 37.5 days; and for plasma elimination half-lives, 40.1 and 166.5 days. Clinical resolution of sarcoptic mange was observed in all study animals within 3–4 weeks of treatment, and all wombats remained tick-free for 15 weeks. A suitable product for diluting fluralaner into a ‘pour-on’ was found. Treatment costs were competitive, and predicted treatment effort was substantially lower relative to moxidectin.

Conclusions

Fluralaner appears to be a safe and efficacious treatment for sarcoptic mange in the bare-nosed wombat, with a single dose lasting over 1–3 months. It has economic and treatment-effort-related advantages over moxidectin, the most commonly used alternative. We recommend a dose of 25 mg/kg fluralaner and, based on the conservative assumption that at least 50% of a dose makes dermal contact, Bravecto Spot-On for Large Dogs as the most appropriate formulation for adult bare-nosed wombats.

Graphical abstract

Dermal immune responses against Psoroptes ovis in two cattle breeds and effects of anti-inflammatory dexamethasone treatment on the development of psoroptic mange

Psoroptic mange is a common disease of livestock, caused by Psoroptes ovis. Compared to Holstein–Friesian (HF) cattle, the Belgian Blue (BB) cattle breed is highly susceptible to the infestation. However, the mechanism for this difference is still unclear. To determine the factors responsible for this breed susceptibility, the immune response to P. ovis was studied in experimentally infested BB and HF cattle, using clinical signs, histology, immunohistochemical profiling and gene expression analysis of skin biopsies. The mite numbers and lesion area of BB cattle were greater than in HF during the whole study period. Significant influxes of eosinophils in the epidermis and dermis were detected in comparison with the pre-infestation samples in both breeds, with significantly higher eosinophils in BB at 6 weeks post infestation (wpi). Mast cell numbers were unaffected at all stages of infestation in HF, but were significantly elevated relative to pre-infestation in BB cattle at 2 and 6 wpi. The more pronounced cutaneous eosinophilia and higher IL-4 levels at 6 wpi in BB cattle suggest that a Th2-type immune response is underlying the higher susceptibility of the BB breed. In naturally infested BB cattle, development of the psoroptic mange lesions and eosinophils and CD3+ T cell areas were severely depressed after anti-inflammatory treatment with dexamethasone. Together, these results suggest that a stronger Th2-type immune response to P. ovis causes the skin lesions in psoroptic mange in BB cattle and that local anti-inflammatory treatment could potentially be an alternative to control the pathology caused by this parasite.