Acute morbidity associated with scabies and other ectoparasitoses rapidly improves after treatment with ivermectin

Secondary Bacterial Infections in Patients with Atopic Dermatitis or Other Common Dermatoses

Secondary bacterial infections of common dermatoses such as atopic dermatitis, ectoparasitosis, and varicella zoster virus infections are frequent, with Staphylococcus aureus and Streptococcus pyogenes being the bacteria most involved. There are also Gram-negative infections secondary to common dermatoses such as foot dyshidrotic eczema and tinea pedis. Factors favoring secondary bacterial infections in atopic dermatitis, ectoparasitosis, and varicella zoster virus infections mainly include an epidermal barrier alteration as well as itch. Mite-bacteria interaction is also involved in scabies and some environmental factors can promote Gram-negative bacterial infections of the feet. Furthermore, the bacterial ecology of these superinfections may depend on the geographical origin of the patients, especially in ectoparasitosis. Bacterial superinfections can also have different clinical aspects depending on the underlying dermatoses. Subsequently, the choice of class, course, and duration of antibiotic treatment depends on the severity of the infection and the suspected bacteria, primarily targeting S. aureus. Prevention of these secondary bacterial infections depends first and foremost on the management of the underlying skin disorder. At the same time, educating the patient on maintaining good skin hygiene and reporting changes in the primary lesions is crucial. In the case of recurrent secondary infections, decolonization of S. aureus is deemed necessary, particularly in atopic dermatitis.

Costs of mass drug administration for scabies in Fiji

In 2019, the Murdoch Children’s Research Institute in partnership with the Fiji Ministry of Health and Medical Services carried out an integrated mass drug administration (MDA) for the treatment of scabies and lymphatic filariasis in the Northern Division of Fiji (population estimate 131,914). We conducted a retrospective micro-costing exercise focused on the cost of scabies control in order to inform budgeting and policy decision making in an endemic setting. We collected detailed information on financial and economic costs incurred by both parties during the course of the MDA campaign (April 2018 to July 2019). We also conducted interviews with personnel involved in the financial administration of the MDA campaign. The economic cost of delivering two doses of ivermectin was US$4.88 per person. The cost of donated drugs accounted for 36.3% of total MDA costs. In this first large-scale MDA for the public health control of scabies, the estimated cost of delivering MDA per person for scabies was considerably more expensive than the costs reported for other neglected tropical diseases. The important cost drivers included the remuneration of health care workers who were extensively involved in the campaign, coverage of hard-to-reach, mainly rural populations and the two-dose regimen of ivermectin. These results highlight the importance of these cost determinants and can be used to plan current and future MDA programs.

Scabies poses a significant burden on both health and economic systems. The Global Burden of Disease estimated that this skin disease affects more than 200 million people globally. However, the economic burden of scabies has not been studied widely and there are limited data on the cost of treating scabies in highly endemic areas. We conducted a costing study of a mass drug administration (MDA) program in the Northern Division of Fiji (population of 131,914). We collected financial and economic costs of administering ivermectin and permethrin to the whole of the Northern Division population in order to estimate the per capita cost of delivering MDA. The costs of MDA for scabies in Fiji were higher than those estimated in previous studies of MDA for other neglected tropical diseases. The study highlights significant cost components of implementing a large-scale MDA and provides key insights for the design and implementation of future MDA programs for scabies. It also adds to the general knowledge in understanding cost inputs and estimating the overall cost-effectiveness of this public health intervention.

Nocturnal pruritus and sleep disturbance associated with dermatologic disorders in adult patients

Nocturnal pruritus (NP) is a relatively common reason for dermatologic consultation. Its pathophysiology is partially understood. Skin conditions such as atopic dermatitis, psoriasis, urticaria, and prurigo nodularis are well-described causes of NP. The most distressing sequela of NP is sleep deficit, which can lead to physical and mental disturbances (e.g., daytime somnolence and fatigue) and negative emotional states that profoundly affect quality of life. However, this aspect of NP is often overlooked by dermatologists. It is essential to assess sleep quality in such patients and adopt appropriate measures to arrest the problem at an early stage. We conducted an evidence-based literature review to highlight the pathogenetic mechanisms of NP, identify dermatologic etiologies, and explore methods that have been used to assess the quality of sleep. Furthermore, we performed a systematic review of studies on sleep disturbance relevant to NP in patients with dermatologic conditions. Finally, we discuss the evidence on treatment options for NP and indicate therapies that may target both NP and sleep disturbance.

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.

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.

The scabicide effect of moxidectin in vitro and in experimental animals: Parasitological, histopathological and immunological evaluation

Scabies is considered one of the commonest dermatological diseases that has a global health burden. Current treatment with ivermectin (IVM) is insufficient and potential drug resistance was noticed. Moxidectin (MOX), with a better pharmacological profile may be a promising alternative. The efficacy of moxidectin against Sarcoptes scabiei was assessed both in vitro and in vivo in comparison with ivermectin. For the in vitro assay, both drugs were used in two concentrations (50 μg/ml and 100 μg/ml). For the in vivo assay, twenty rabbits infected with Sarcoptes scabiei were divided into three groups: untreated, moxidectin-treated and ivermectin-treated with the same dose of 0.3 mg/kg once. Another four rabbits were used as a normal control non-infected group. Treatment efficacy was evaluated by clinical assessment, parasitological evaluation and histopathological examination of skin samples using Hematoxylin and eosin and toluidine blue for mast cell staining. Immune response was also assessed by immunohistochemical staining of CD3 T cells in skin samples. Our results showed that moxidectin had a high efficacy (100%) in killing mites when used in both concentrations (50 μg/ml, 100 μg/ml) in the in vitro assay. Concerning the in vivo assay, on day 14 post-treatment, all MOX-treated rabbits were mite-free with full clinical cure by the end of the study (D21) showing (100%) reduction of mites count. Also, marked improvement in the epidermis with absence of mites in skin samples were shown. Poor clinical and parasitological improvements were noted in the ivermectin-treated rabbits, when given as a single dose with a percentage reduction (60.67%) in the 2nd week and progressive increase in lesions and mites count in the 3rd week post-treatment. Regarding the immune response, MOX-treated group showed mild infiltration with both mast cells and CD3 T cells in comparison to severe infiltration with both types of cells in the untreated and IVM-treated group. On conclusion, our results demonstrated that a single dose of MOX was more effective than IVM, supporting MOX as a valuable therapeutic approach for scabies therapy.

Rate and factors for scabies recurrence in children in Saudi Arabia: a retrospective study

Background

Despite the fact that several scabies outbreaks emerged in schools in Saudi Arabia in 2018, no study has investigated the risk of scabies recurrence among children in Saudi Arabia. This study aimed to estimate the rate of scabies recurrence and identify factors that were associated with an increased risk of recurrence among children.

Methods

This is a multi-center retrospective study of children (age < 14 years) who were diagnosed between May 20, 2015 and September 12, 2018 with one or multiple recurrent scabies at the Ministry of National Guard Health Affairs (MNGHA) hospitals and clinics in Saudi Arabia. Data were obtained from an electronic health system, BestCare database.

Results

A sample of 264 children analyzed (mean age of 6.7 years) resulted in a cumulative number of 316 scabies diagnoses in which 86 (27.2%) experienced scabies recurrence (at least once). Independent factors associated with a high risk of scabies recurrence: older children (adjusted hazard ratio [aHR], 1.036; 95% CI, 1.002–1.072; P = 0.039), female gender (aHR, 1.734; 95% CI, 1.329–2.262; P = 0.001), Western region of Saudi Arabia (aHR, 1.548; 95% CI, 1.115–2.151; P = 0.009), and 2nd tertile season [May to August] (aHR, 2.368; 95% CI, 1.706–3.288; P = 0.001).

Conclusions

The study demonstrated that the recurrence rate of scabies among children is high. Older children, the female gender, the Western region of Saudi Arabia, and the seasonality were independently associated with an increased risk of scabies recurrence. High temperature and low humidity should be explored as leading factors for scabies infestations in Saudi Arabia. Findings derived from this study may be useful for clinicians and governments in optimizing clinical management of scabies cases and contacts.

Scabies in Resource-Poor Communities in Nasarawa State, Nigeria: Epidemiology, Clinical Features and Factors Associated with Infestation

Epidemiology and clinical features of scabies remain largely unknown in Nigeria’s rural communities. To fill this gap, we performed a cross-sectional study in three rural communities in north central Nigeria. A total of 500 individuals were included and examined for scabies infestation; a questionnaire was applied to collect socio-demographic and behavioral data. Scabies was diagnosed in 325 (65.0%) participants. Excoriations (68.6%), vesicles (61.8%), and papules (58.8%) were common skin lesions. Itching was the most common symptom (77.5%); 64% complained of sleep disturbances. Lymphadenopathy was identified in 48.3%. Lesions were most commonly encountered on the abdomen (35.5%), inguinal area (19.1%), and interdigital spaces (14.2%). Poverty-related variables, such as illiteracy (OR: 7.15; 95% CI: 3.71–13.95), low household income (7.25; 1.19–88.59), absence of a solid floor inside house (12.17; 2.83–52.34), and overcrowding (1.98; 1.08–2.81) were significantly associated with infestation. Individual behavior, such as sharing of beds/pillows (2.11; 1.42–3.14) and sharing of clothes (2.51; 1.57–3.99), was also highly significantly associated with scabies. Regular bathing habits (0.37; 0.24–0.56) and regular use of bathing soap (0.36; 0.21–0.53) were protective factors. Scabies is extremely common in the communities under study and is associated with considerable morbidity. The disease is intrinsically linked with extreme poverty.

Ivermectin susceptibility, sporontocidal effect, and inhibition of time to re-feed in the Amazonian malaria vector Anopheles darlingi

BACKGROUND

Outdoor malaria transmission hinders malaria elimination efforts in the Amazon region and novel vector control tools are needed. Ivermectin mass drug administration (MDA) to humans kills wild Anopheles, targets outdoor-feeding vectors, and can suppress malaria parasite transmission. Laboratory investigations were performed to determine ivermectin susceptibility, sporontocidal effect and inhibition of time to re-feed for the primary Amazonian malaria vector, Anopheles darlingi.

METHODS

To assess ivermectin susceptibility, various concentrations of ivermectin were mixed in human blood and fed to An. darlingi. Mosquito survival was monitored daily for 7 days and a non-linear mixed effects model with Probit analysis was used to calculate lethal concentrations of ivermectin that killed 50% (LC₅₀), 25% (LC₂₅) and 5% (LC₅) of mosquitoes. To examine ivermectin sporonticidal effect, Plasmodium vivax blood samples were collected from malaria patients and offered to mosquitoes without or with ivermectin at the LC₅₀, LC₂₅ or LC₅. To assess ivermectin inhibition of mosquito time to re-feed, concentrations of ivermectin predicted to occur after a single oral dose of 200 μg/kg ivermectin were fed to An. darlingi. Every day for 12 days thereafter, individual mosquitoes were given the opportunity to re-feed on a volunteer. Any mosquitoes that re-blood fed or died were removed from the study.

RESULTS

Ivermectin significantly reduced An. darlingi survivorship: 7-day-LC₅₀ = 43.2 ng/ml [37.5, 48.6], -LC₂₅ = 27.8 ng/ml [20.4, 32.9] and -LC₅ = 14.8 ng/ml [7.9, 20.2]. Ivermectin compound was sporontocidal to P. vivax in An. darlingi at the LC₅₀ and LC₂₅ concentrations reducing prevalence by 22.6 and 17.1%, respectively, but not at the LC₅. Oocyst intensity was not altered at any concentration. Ivermectin significantly delayed time to re-feed at the 4-h (48.7 ng/ml) and 12-h (26.9 ng/ml) concentrations but not 36-h (10.6 ng/ml) or 60-h (6.3 ng/ml).

CONCLUSIONS

Ivermectin is lethal to An. darlingi, modestly inhibits sporogony of P. vivax, and delays time to re-feed at concentrations found in humans up to 12 h post drug ingestion. The LC₅₀ value suggests that a higher than standard dose (400-μg/kg) is necessary to target An. darlingi. These results suggest that ivermectin MDA has potential in the Amazon region to aid malaria elimination efforts.

High-resolution infrared thermography: a new tool to assess tungiasis-associated inflammation of the skin

BACKGROUND

Tungiasis is highly prevalent in low- and middle-income countries but remains often under diagnosed and untreated eventually leading to chronic sequels. The objective of the study was to assess whether tungiasis-associated inflammation can be detected and quantified by high-resolution infrared thermography (HRIT) and whether after removal of the parasite inflammation resolves rapidly.

METHODS

Patients with tungiasis were identified through active case finding. Clinical examination, staging, and thermal imaging as well as conventional photography were performed. In exemplary cases, the embedded sandfly was extracted and regression of inflammation was assessed by thermal imaging 4 days after extraction.

RESULTS

The median perilesional temperature was significantly higher than the median temperature of the affected foot (rho = 0.480, p = 0.003). Median perilesional temperature measured by high-resolution infrared thermography was positively associated with the degree of pain (rho = 0.395, p < 0.017) and semi-quantitative scores for acute (rho = 0.380, p < 0.022) and chronic (rho = 0.337, p < 0.044) clinical pathology. Four days after surgical extraction, inflammation and hyperthermia of the affected area regressed significantly (rho = 0.457, p = 0.005). In single cases, when clinical examination was difficult, lesions were identified through HRIT.

CONCLUSION

We proved that HRIT is a useful tool to assess tungiasis-associated morbidity as well as regression of clinical pathology after treatment. Additionally, HRIT might help to diagnose hidden and atypical manifestations of tungiasis. Our findings, although still preliminary, suggest that HRIT could be used for a range of infectious skin diseases prevalent in the tropics.

TRIAL REGISTRATION

ISRCTN11415557, Registration date: 13 July 2011.

A Study of Clinical Profile and Quality of Life in Patients with Scabies at a Rural Tertiary Care Centre

INTRODUCTION

Scabies is a contagious disease primarily related to poverty and overcrowding, it rapidly spreads from person to person specially in people with poor hygiene. We come across many patients from rural areas with scabies. In India the incidence ranges from 13% to 59% in rural and urban areas. Many people complain of sleep disturbances and affection of work and leisure activities due to itching. Very few studies are done in India about the affection of quality of life in such patients.

AIM

To study the demographic details, clinical profile and quality of life in patients with scabies.

MATERIALS AND METHODS

A prospective, observational and cross-sectional study conducted at Department of Dermatology and Venereology, rural based tertiary care centre, Gujarat for a period of 6 months from March to August 2015, after ethical approval from the institute. Study included all patients with clinical features suggestive of scabies. The data including age, sex, occupation, education, socioeconomic status, complaints, past history, family history and clinical features along with the questionnaire for affection of quality of life were recorded in predesigned proforma and detailed analysis was done. Total of 102 newly diagnosed scabies patients attending skin OPD were included in the study.

RESULTS

Out of 102 patients, 50.98% were males. The most common age group affected was 21-40 years, in 44.11% patients. Students were commonly affected with 41.17% followed by housewives with 20.58% cases. Most common lesion seen was papules in 84.3% followed by excoriations in 82.3% cases. Maximum 51.6% adults had small effect on quality of life while 62.5% children reported minimal effect on quality of life.

CONCLUSION

Scabies is an important and commonly encountered health problem which is highly contagious and if not attended timely and adequately can affect the quality of life in the form of work affection, sleep disturbances and psychosocial problems in patients as well as its family members. This could be easily prevented if the patients of scabies are recognised and treated early and proper awareness is must to avoid recurrences. The profile of scabies patients helps in early recognition of scabies even at the peripheral centers.

Protocol for the systematic review of the prevention, treatment and public health management of impetigo, scabies and fungal skin infections in resource-limited settings

BACKGROUND

Impetigo, scabies, and fungal skin infections disproportionately affect populations in resource-limited settings. Evidence for standard treatment of skin infections predominantly stem from hospital-based studies in high-income countries. The evidence for treatment in resource-limited settings is less clear, as studies in these populations may lack randomisation and control groups for cultural, ethical or economic reasons. Likewise, a synthesis of the evidence for public health control within endemic populations is also lacking. We propose a systematic review of the evidence for the prevention, treatment and public health management of skin infections in resource-limited settings, to inform the development of guidelines for the standardised and streamlined clinical and public health management of skin infections in endemic populations.

METHODS

The protocol has been designed in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols statement. All trial designs and analytical observational study designs will be eligible for inclusion. A systematic search of the peer-reviewed literature will include PubMed, Excertpa Medica and Global Health. Grey literature databases will also be systematically searched, and clinical trials registries scanned for future relevant studies. The primary outcome of interest will be the clinical cure or decrease in prevalence of impetigo, scabies, crusted scabies, tinea capitis, tinea corporis or tinea unguium. Two independent reviewers will perform eligibility assessment and data extraction using standardised electronic forms. Risk of bias assessment will be undertaken by two independent reviewers according to the Cochrane Risk of Bias tool. Data will be tabulated and narratively synthesised. We expect there will be insufficient data to conduct meta-analysis. The final body of evidence will be reported against the Grades of Recommendation, Assessment, Development and Evaluation grading system.

DISCUSSION

The evidence derived from the systematic review will be used to inform the development of guidelines for the management of skin infections in resource-limited settings. The evidence derived will be intended for use by clinicians, public health practitioners and policy makers in the treatment of skin infections and the development of skin infection control programmes. The review will identify any gaps in the current evidence to provide direction for future research.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42015029453.

Scabies

Scabies is a contagious skin infestation caused by a mite. It causes significant global morbidity, with an estimated 300 million cases annually. Although it can affect individuals at any socioeconomic level, individuals who live in poverty or in overcrowded conditions are at much higher risk for scabies. Lack of local expertise can result in failure to recognize scabies, leading to delayed diagnosis and inadequate treatment of cases and contacts. Scabies disproportionately affects many Indigenous (First Nations, Inuit, Métis) communities where risk factors are present. Scabies risk is also higher in young children, the elderly and immunocompromised individuals. Institutional outbreaks of scabies have also been reported. Apart from a very itchy rash, scabies can lead to secondary bacterial infections and related complications, as well as to stigmatization, depression, insomnia and significant financial costs. Topical antiscabies lotions are still the mainstay of treatment, but oral ivermectin has also proven effective under certain circumstances. Asymptomatic and symptomatic household members should all be treated at the same time. In Canada and globally, the presence of scabies is usually a symptom of poor living conditions and a sign that basic necessities need improvement. Clinicians who work with Indigenous communities can improve their ability to diagnose and treat scabies, and should advocate for better living conditions where scabies is prevalent.

Scabies and Bacterial Superinfection among American Samoan Children, 2011-2012

Background

Scabies, a highly pruritic and contagious mite infestation of the skin, is endemic among tropical regions and causes a substantial proportion of skin disease among lower-income countries. Delayed treatment can lead to bacterial superinfection, and treatment of close contacts is necessary to prevent reinfestation. We describe scabies incidence and superinfection among children in American Samoa (AS) to support scabies control recommendations.

Methodology/Principal Findings

We reviewed 2011–2012 pharmacy records from the only AS pharmacy to identify children aged ≤14 years with filled prescriptions for permethrin, the only scabicide available in AS. Medical records of identified children were reviewed for physician-diagnosed scabies during January 1, 2011–December 31, 2012. We calculated scabies incidence, bacterial superinfection prevalence, and reinfestation prevalence during 14–365 days after first diagnosis. We used log binomial regression to calculate incidence ratios for scabies by age, sex, and county. Medical record review identified 1,139 children with scabies (incidence 29.3/1,000 children aged ≤14 years); 604 (53%) had a bacterial superinfection. Of 613 children who received a scabies diagnosis during 2011, 94 (15.3%) had one or more reinfestation. Scabies incidence varied significantly among the nine counties (range 14.8–48.9/1,000 children). Children aged <1 year had the highest incidence (99.9/1,000 children). Children aged 0–4 years were 4.9 times more likely and those aged 5–9 years were 2.2 times more likely to have received a scabies diagnosis than children aged 10–14 years.

Conclusions/Significance

Scabies and its sequelae cause substantial morbidity among AS children. Bacterial superinfection prevalence and frequent reinfestations highlight the importance of diagnosing scabies and early treatment of patients and close contacts. Investigating why certain AS counties have a lower scabies incidence might help guide recommendations for improving scabies control among counties with a higher incidence. We recommend interventions targeting infants and young children who have frequent close family contact.

Topical ivermectin versus crotamiton cream 10% for the treatment of scabies

Scabies, known colloquially as the 7-year itch, is a contagious skin infection that occurs among humans and other animals. The treatment of choice is still controversial. The aim of this study was to compare the efficacy and safety of topical ivermectin vs. crotamiton cream 10% for the treatment of scabies. In total, 340 patients with scabies were enrolled, and randomized into two groups. The first group received 1% ivermectin applied topically to the affected skin. The dose employed was 400 μg/kg, repeated once the following week, and the second group received crotamiton 10% cream and were told to apply this twice daily for five consecutive days. Treatment was evaluated at intervals of two and four weeks, and if there was treatment failure at the 2-week follow-up, treatment was repeated. Two applications of topical ivermectin provided a cure rate of 64.7% at the 2-week follow-up, which increased to 82.3% at the 4-week follow-up after repeating the treatment. Treatment with single applications of crotamiton cream 10% was effective in 41.2% of patients at the 2-week follow-up, which increased to 64.7% at the 4-week follow-up after this treatment was repeated. Ivermectin was quite safe in our cases. Two applications of ivermectin were as effective as single applications of crotamiton 10% cream at the 2-week follow-up. After repeating the treatment, ivermectin was superior to crotamiton cream 10% at the 4-week follow-up.

Scabies mites alter the skin microbiome and promote growth of opportunistic pathogens in a porcine model

Background

The resident skin microbiota plays an important role in restricting pathogenic bacteria, thereby protecting the host. Scabies mites (Sarcoptes scabiei) are thought to promote bacterial infections by breaching the skin barrier and excreting molecules that inhibit host innate immune responses. Epidemiological studies in humans confirm increased incidence of impetigo, generally caused by Staphylococcus aureus and Streptococcus pyogenes, secondary to the epidermal infestation with the parasitic mite. It is therefore possible that mite infestation could alter the healthy skin microbiota making way for the opportunistic pathogens. A longitudinal study to test this hypothesis in humans is near impossible due to ethical reasons. In a porcine model we generated scabies infestations closely resembling the disease manifestation in humans and investigated the scabies associated changes in the skin microbiota over the course of a mite infestation.

Methodology/Principal Findings

In a 21 week trial, skin scrapings were collected from pigs infected with S. scabies var. suis and scabies-free control animals. A total of 96 skin scrapings were collected before, during infection and after acaricide treatment, and analyzed by bacterial 16S rDNA tag-encoded FLX-titanium amplicon pyrosequencing. We found significant changes in the epidermal microbiota, in particular a dramatic increase in Staphylococcus correlating with the onset of mite infestation in animals challenged with scabies mites. This increase persisted beyond treatment from mite infection and healing of skin. Furthermore, the staphylococci population shifted from the commensal S. hominis on the healthy skin prior to scabies mite challenge to S. chromogenes, which is increasingly recognized as being pathogenic, coinciding with scabies infection in pigs. In contrast, all animals in the scabies-free cohort remained relatively free of Staphylococcus throughout the trial.

Conclusions/Significance

This is the first experimental in vivo evidence supporting previous assumptions that establishment of pathogens follow scabies infection. Our findings provide an explanation for a biologically important aspect of the disease pathogenesis. The methods developed from this pig trial will serve as a guide to analyze human clinical samples. Studies building on this will offer implications for development of novel intervention strategies against the mites and the secondary infections.

Scabies is a neglected, contagious skin disease caused by a parasitic mite Sarcoptes scabiei. It is highly prevalent world-wide, and now recognized as a possible underlying factor for secondary bacterial infections with potential serious downstream complications. There is currently few experimental data demonstrating directly that mite infestation promotes bacterial infections. Due to remarkable similarities in terms of immunology, physiology and skin anatomy between pigs and humans, we developed a sustainable porcine model enabling in vivo studies of scabies mite infestations. Here, we investigated the impact of the scabies mite infection on the normal pig skin microbiota in the inner ear pinnae in young piglets. Samples obtained prior to, during infection and after acaricide treatment were analyzed by sequencing of bacterial 16S rDNA. We report that scabies infestation has an impact on the host's skin microbiota. Staphylococcus abundance increased with the onset of infection and remained beyond treatment and healing. A shift from commensal to pathogenic Staphylococci was observed. This study supports the link between scabies and Staphylococcus infections, as seen in humans. It is the first in vivo demonstration of a mite induced shift in the skin microbiota, providing a basis for a similar study in humans.

Impact of scabies in resource-poor communities

PURPOSE OF REVIEW

Features of endemic scabies are specific in resource-poor and underprivileged communities, with implications for control measures on the community level. In this review, these special aspects are addressed.

RECENT FINDINGS

Scabies is endemic in many resource-poor communities, with a prevalence of 20% and higher. Transmission is influenced by social attitudes, migration, access to healthcare services, housing conditions, hygiene conditions, and crowding. Endemic scabies occurs with severe infestations, complications, and sequels, mainly in children. Sleep loss as a result of scabies-related itching is common. Complications include secondary infections by group A streptococci and acute poststreptococcal glomerulonephritis. Shame, restriction of leisure activities, and stigmatization are common. Treatment of scabies includes a variety of topical compounds, but control on the community level is not an easy task. As ivermectin kills a variety of other parasites, this oral drug is increasingly used for mass treatment. Intervention should address socioemotional aspects using an integrated approach with professionals from different areas, and the community.

SUMMARY

Scabies is a neglected disease and needs to be perceived as an important public health problem causing morbidity in many resource-poor communities. Future work on epidemiology, clinical aspects, transmission dynamics, socioeconomic aspects, and sustainable control in resource-poor communities is needed.

Comparison of oral ivermectin vs. lindane lotion 1% for the treatment of scabies

BACKGROUND

Scabies is a common parasitic infestation that is an important public-health problem in many resource-poor regions. It is commonly treated with the insecticides ivermectin and permethrin.

AIM

To compare the efficacy and safety of oral ivermectin vs. lindane lotion 1% for the treatment of scabies.

METHODS

In total, 148 patients with scabies were enrolled, and were randomized into two groups: the first group received a single dose of oral ivermectin 200 μg/kg body weight, and the second group were treated with two applications of topical lindane lotion 1%, with a 1-week interval between applications. Treatment was evaluated at intervals of 2 and 4 weeks, and if there was treatment failure at the 2-week follow-up, treatment was repeated.

RESULTS

A single dose of ivermectin provided a cure rate of 60.8% at the 2-week follow-up, which increased to 89.1% at the 4-week follow-up. after crossing over to the lindane lotion 1% group. Treatment with two applications of lindane lotion 1%, with a 1-week interval between them, was effective in 47.2% of patients at the 2-week follow-up, which increased to 72.9% at the 4-week follow-up after this treatment was repeated.

CONCLUSIONS

A single dose of ivermectin was as effective as two applications of lindane lotion 1% at the 2-week follow-up. After repeat treatment, ivermectin was superior to lindane lotion 1% at the 4-week follow up. The delay in clinical response with ivermectin suggests that it may not be effective against all the stages in the life cycle of the parasite.

The efficacy of topical ivermectin versus malation 0.5% lotion for the treatment of scabies

Objective: There are different medications for the treatment of scabies but the treatment of choice is still controversial. This study aimed at comparing the efficacy of topical ivermectin versus malation 0.5% lotion for the treatment of scabies. Methods: In total, 340 patients with scabies were enrolled, and randomized into two groups: the first group received 1% ivermectin applied topically to the affected skin and the second group received topical malation 0.5% lotion and were told to apply this twice with 1 week interval. Treatment was evaluated at intervals of 2 and 4 weeks, and if there was treatment failure at the 2-week follow-up, treatment was repeated. Results: Two application of topical ivermectin provided a cure rate of 67.6% at the 2-week follow-up, which increased to 85.2% at the 4-week follow-up after repeating the treatment. Treatment with two applications of malation 0.5% lotion was effective in 44.1% of patients at the 2-week follow-up, which increased to 67.6% at the 4-week follow-up after this treatment was repeated. Conclusion:Two application of ivermectin was as effective as single applications of malation 0.5% lotion at the 2-week follow-up. After repeating the treatment, ivermectin was superior to malation 0.5% lotion at the 4-week follow up.

Comparison of oral ivermectin versus crotamiton 10% cream in the treatment of scabies

OBJECTIVE

Scabies is a relatively contagious infection caused by a tiny mite (Sarcoptes scabiei). Products used to treat scabies are called scabicides because they kill scabies mites; some also kill mite eggs. The aim of this study was to compare the efficacy and safety of oral ivermectin versus crotamiton 10% cream for the treatment of scabies.

METHODS

In total, 320 patients with scabies were enrolled, and were randomized into two groups: the first group received a single dose of oral ivermectin 200 µg/kg body weight, and the second group were treated with crotamiton 10% cream and were told to apply this twice daily for five consecutive days. Treatment was evaluated at intervals of two and four weeks, and if there was treatment failure at the two-week follow-up, the treatment was repeated.

RESULTS

A single dose of ivermectin provided a cure rate of 62.5% at the two-week follow-up, which increased to 87.5% at the four-week follow-up after repeating the treatment. Treatment with crotamiton 10% cream was effective in 46.8% of patients at the two-week follow-up, which increased to 62.5% at the four-week follow-up after this treatment was repeated.

CONCLUSION

A single dose of ivermectin was as effective as one application of crotamiton 10% cream at the two-week follow-up. After repeat treatment, ivermectin was superior to crotamiton 10% cream at the four-week follow up. The delay in clinical response with ivermectin suggests that it may not be effective against all the stages in the life cycle of the parasite.