Failure of scabies treatment: a systematic review and meta-analysis.

BACKGROUND: Treatment failure is considered to be an important factor in relation to the increase in scabies incidence over the last decade. However, the regional and temporal differences, in addition to the predictors of therapy failure, are unclear. OBJECTIVES: We aimed to conduct a systematic review of the prevalence of treatment failure in patients with scabies and investigation of associated factors. METHODS: We searched MEDLINE, EMBASE, CINAHL, Web of Science, Scopus, Global Health and the Cochrane Central Register of Controlled Trials from inception to August 2021 for randomized and quasi-randomized trials, in addition to observational studies that enrolled children or adults diagnosed with confirmed or clinical scabies treated with permethrin, ivermectin, crotamiton, benzyl benzoate, malathion, sulfur or lindane, and measured treatment failure or factors associated with treatment failure. We performed a random effects meta-analysis for all outcomes reported by at least two studies. RESULTS: A total of 147 studies were eligible for inclusion in the systematic review. The overall prevalence of treatment failure was 15.2% [95% confidence interval (CI) 12.9-17.6; I2 = 95.3%, moderate-certainty evidence] with regional differences between World Health Organization regions (P = 0.003) being highest in the Western Pacific region (26.9%, 95% CI 14.5-41.2). Oral ivermectin (11.8%, 95% CI 8.4-15.4), topical ivermectin (9.3%, 95% CI 5.1-14.3) and permethrin (10.8%, 95% CI 7.5-14.5) had relatively lower failure prevalence compared with the overall prevalence. Failure prevalence was lower in patients treated with two doses of oral ivermectin (7.1%, 95% CI 3.1-12.3) compared with those treated with one dose (15.2%, 95% CI 10.8-20.2; P = 0.021). Overall and permethrin treatment failure prevalence in the included studies (1983-2021) increased by 0.27% and 0.58% per year, respectively. Only three studies conducted a multivariable risk factor analysis; no studies assessed resistance. CONCLUSIONS: A second dose of ivermectin showed lower failure prevalence than single-dose ivermectin, which should be considered in all guidelines. The increase in treatment failure over time hints at decreasing mite susceptibility for several drugs, but reasons for failure are rarely assessed. Ideally, scabicide susceptibility testing should be implemented in future studies.

Comparison of topical permethrin 5% vs. benzyl benzoate 25% treatment in scabies: a double-blinded randomized controlled trial.

BACKGROUND: Scabies is a pruritic parasitic infestation of the skin. High-income countries have reported an increasing incidence over the last few years. Studies have indicated a reduction in the sensitivity of scabies mites to the standard treatment of choice, topical permethrin 5%. OBJECTIVES: To evaluate in a head-to-head manner the efficacy of two topical scabicides [permethrin 5% and benzyl benzoate 25% (BB)] in the treatment of scabies using the same administration modality; and to address potential confounding factors such as incorrectly performed treatment and hygiene measures. METHODS: In total, 110 patients with dermoscopy-verified scabies infestation were enrolled and randomized into two equally sized groups in a double-blinded manner. Fifty-five received topical permethrin 5% and 55 received topical BB 25%, both for daily use over a period of three consecutive days. Treatment outcome was evaluated by dermoscopy at a 3-week follow-up visit. RESULTS: Treatment resulted in a dermoscopy-verified cure rate of 27% in the permethrin group and 87% in the BB group. The tolerability and safety profile of permethrin 5% cream was excellent, while the BB emulsion produced a burning sensation in 43% of patients. CONCLUSIONS: Topical permethrin demonstrated a lack of efficacy in the majority of scabies cases, whereas BB demonstrated an excellent cure rate and reasonable tolerability. Considering the reduced sensitivity of scabies mites to permethrin 5%, our results suggest that BB is an appropriate first-line therapy in the treatment of scabies.

Traditional healers' perception on scabies causation and management in Ghana.

INTRODUCTION: Scabies is an underdiagnosed skin infestation caused by the Sarcoptes scabiei mite. The infection causes severe itching and a skin rash but can be effectively treated using topical or systemic drugs. Scabies outbreaks are commonly reported in resource-poor countries, including Ghana. Traditional healers play an important role in primary care in rural areas. The role of these traditional healers in the management of scabies has so far not been explored. The aim of this study was therefore to investigate the perceptions of traditional healers regarding the causation and management of scabies. METHODS: A phenomenological qualitative approach was employed. Traditional healers in the Asante Akim North and Central districts in Ghana were approached with an interview request. Using a semi-structured interview protocol, 15 traditional healers were interviewed. The results were coded and analysed, after which seven themes were extrapolated. RESULTS: Scabies infections were frequently reported by traditional healers. Itching and skin rash were unanimously regarded as the major symptoms of scabies. The majority acknowledged the infectious nature of scabies, but no participant reported the causative organism. A dichotomous disease classification was noted, consisting of 'natural' and 'spiritual' variants each with a unique disease profile and management requirements, as reported by the traditional healers. All but two traditional healers reported to treat scabies using almost exclusively herbs and spiritual rituals. CONCLUSION: The majority of traditional healers were open to collaboration with allopathic healthcare providers. Collaboration could broaden the primary care network in rural areas, but mistrust and lack of transparency form potential barriers to collaboration. We, therefore, emphasise the need for additional efforts to investigate strategies for future collaboration.

Non-specific effects of inactivated Mycobacterium bovis oral and parenteral treatment in a rabbit scabies model.

Tuberculosis BCG vaccination induced non-specific protective effects in humans led to postulate the concept of trained immunity (TRAIM) as an innate type of immune mechanism that triggered by a pathogen, protects against others. Killed vaccines have been considered not to be effective. However, field efficacy of a commercial vaccine against paratuberculosis, as well as of a recently developed M. bovis heat-inactivated vaccine (HIMB) prompted to test whether it could also induce TRAIM. To this, we used a sarcoptic mange rabbit model. Twenty-four weaned rabbits were treated orally or subcutaneously with a suspension of either HIMB (107 UFC) or placebo. Eighty-four days later the animals were challenged with approximately 5000 S. scabiei mites on the left hind limb. Skin lesion extension was measured every 2 weeks until 92 days post-infection (dpi). Two animals were killed at 77 dpi because of extensive skin damage. The rest were euthanized and necropsied and the lesion area and the mite burden per squared cm were estimated. Specific humoral immune responses to S. scabiei and to M. bovis were investigated with the corresponding specific ELISA tests. Subcutaneously and orally HIMB vaccinated animals compared with placebo showed reduced lesion scores (up to 74% and 62%, respectively) and mite counts (-170% and 39%, respectively). This, together with a significant positive correlation (r = 0.6276, p = 0.0031) between tuberculosis-specific antibodies and mite count at 92 dpi supported the hypothesis of non-specific effects of killed mycobacterial vaccination. Further research is needed to better understand this mechanism to maximize cross protection.

Adaptive interventions for advancing in situ wildlife disease management.

There is a critical need for advancements in disease management strategies for wildlife, but free-living animals pose numerous challenges that can hinder progress. Most disease management attempts involve fixed interventions accompanied by post hoc outcome assessments focused on success or failure. Though these approaches have led to valuable management advances, there are limitations to both the rate of advancement and amount of information that can be gained. As such, strategies that support more rapid progress are required. Sarcoptic mange, caused by epidermal infection with Sarcoptes scabiei mites, is a globally emerging and re-emerging panzootic that exemplifies this problem. The bare-nosed wombat (Vombatus ursinus), a marsupial endemic to southeastern Australia, is impacted by sarcoptic mange throughout its geographic range and enhanced disease management capabilities are needed to improve upon existing in situ methods. We sought to advance in situ wildlife disease management for sarcoptic mange in free-living bare-nosed wombats, implementing an adaptive approach using fluralaner (Bravecto, MSD Animal Health) and a structured process of learning and method-optimisation. By using surveillance of treated wombats to inform real-time management changes, we have demonstrated the efficacy of topically administered fluralaner at 45 and 85 mg/kg against sarcoptic mange. Importantly, we observed variation in the effects of 45 mg/kg doses, but through our adaptive approach found that 85 mg/kg doses consistently reduced mange severity. Through modifying our surveillance program, we also identified individual-level variation in wombat observability and used this to quantify the level of surveillance needed to assess long-term management success. Our adaptive intervention represents the first report of sarcoptic mange management with fluralaner in free-living wildlife and evaluation of its efficacy in situ. This study illustrates how adapting interventions in real time can advance wildlife disease management and may be applicable to accelerating in situ improvements for other host-pathogen systems.

Gianotti-Crosti syndrome mimicking scabies.

This case report highlights a case of a 65-year-old woman who presented to our clinic with suspicion of refractory scabies. She had undergone multiple treatments without improvement. However, the clinical condition was not scabies but rather Gianotti-Crosti Syndrome (GCS), leading to rapid clinical improvement and avoiding the need for further unnecessary tests and treatments. GCS is a postviral exanthem characterized by symmetrical, red papules on the extremities and buttocks, typically occurring in children but can also affect adults. It is crucial for every physician to distinguish it from other causes of rash, including scabies, to ensure an accurate diagnosis and appropriate management.

Risk factors for scabies in hospital: a systematic review.

BACKGROUND: Annually, 175.4 million people are infected with scabies worldwide. Although parasitic infections are important nosocomial infections, they are unrecognized compared to bacterial, fungal, and viral infections. In particular, nonspecific cutaneous manifestations of scabies lead to delayed diagnosis and frequent nosocomial transmission. Hospital-based studies on the risk factors for scabies have yet to be systematically reviewed. METHODS: The study followed the PRISMA guidelines and was prospectively registered in PROSPERO (CRD42023363278). Literature searches were conducted in three international (PubMed, Embase, and CINAHL) and four Korean (DBpia, KISS, RISS, and Science ON) databases. We included hospital-based studies with risk estimates calculated with 95% confidence intervals for risk factors for scabies infection. The quality of the studies was assessed using the Joanna Briggs Institute critical appraisal tools. Two authors independently performed the screening and assessed the quality of the studies. RESULTS: A total of 12 studies were included. Personal characteristics were categorized into demographic, economic, residential, and behavioral factors. The identified risk factors were low economic status and unhygienic behavioral practices. Being a patient in a long-term care facility or institution was an important factor. Frequent patient contact and lack of personal protective equipment were identified as risk factors. For clinical characteristics, factors were categorized as personal health and hospital environment. People who had contact with itchy others were at higher risk of developing scabies. Patients with higher severity and those with a large number of catheters are also at increased risk for scabies infection. CONCLUSIONS: Factors contributing to scabies in hospitals range from personal to clinical. We emphasize the importance of performing a full skin examination when patients present with scabies symptoms and are transferred from settings such as nursing homes and assisted-living facilities, to reduce the transmission of scabies. In addition, patient education to prevent scabies and infection control systems for healthcare workers, such as wearing personal protective equipment, are needed.

Prevalence and determinants of impetigo in Ghana: a cross-sectional study.

INTRODUCTION: Skin diseases such as impetigo pose a significant public health challenge in low resource settings. Despite this, there is a dearth of epidemiological data on the prevalence of this condition in Ghana. METHODS: We conducted a cross sectional study in three settings in Ghana: community members in East Mamprusi district in the North East region, a secondary school in Sekyere East district, and inmates of the Kumasi central prisons both in the Ashanti region. Following a period of training, we performed a standardised skin examination on each participant to assess for scabies and impetigo. We calculated the prevalence of each skin condition and investigated determinants of impetigo. RESULTS/ FINDINGS: Of the 1327 participants [males 64.1% and median age 22 (16-29) years], 746 (56.2%) had scabies and 186 (14%) had impetigo which was usually very mild or mild in severity. Most participants with impetigo also had scabies (161/186, 86.6%). Having an itch [RR 6.05 (95% CI 2.53-14.47)], presence of scabies burrows [RR 1.99 (95% CI 1.54-2.59)], clinical scabies [RR 3.15 (2.11-4.72)] or being in preschool [RR 4.56 (1.78-11.67)] increased the risk for impetigo. A combination of the presence of clinical scabies, age, sex and itch most accurately predicted the odds of having impetigo. CONCLUSIONS: There is substantial burden of impetigo and scabies in Ghana. There is a need to institute measures to improve detection and control of these common dermatoses as part of Universal Health Coverage package to reduce the scourge of the diseases in this setting.

Detecting spatial clusters of human scabies in Tigray, Ethiopia from 2018 to 2023.

BACKGROUND: Scabies is one of public health concerns among communicable disease in Ethiopia, especially among disadvantaged and the poor. This current study aims to detect the spatiotemporal patterns of scabies in Tigray from 2018 to 2023 using scabies data aggregated at the zonal level. The study also examined the persistent patterns in the spatial variation of scabies incidence across the administrative regions during the study period. METHOD: We collected scabies data using a weekly disease surveillance reporting format of the country from 2018 to 2023 across all accessible district health facilities in Tigray region, Ethiopia. We conducted retrospective analyses using both purely spatial and spatiotemporal scan statistic approaches, employing a discrete Poisson probability model to identify statistically significant clusters of high scabies rates throughout the Tigray regional zones in Ethiopia. Our methodology involved the use of Kulldorff's spatial scan statistic software (SaTScan v10.1.3), R programming software version 4.3.1, and ArcGIS Pro for all analyses. RESULTS: A total of 101,116 cases of scabies were reported from 2018 to 2023. Our study indicated a spatial heterogeneity in the pattern of scabies across Tigray region as well as its localization among geographically contiguous zones across space, except for the Western zone of Tigray where no data was collected. The detected statistically significant spatial clusters [Formula: see text] persisted mainly in the Central, Eastern and Northwestern zones of Tigray over the six years of the study period. The highest relative risk (RR) was recorded in year 2021 ([Formula: see text]. The central zone had the major clusters of scabies at district level from 2018 to 2023. The heterogeneous distribution of scabies across Tigray could be due to the spatial variations in the determinants of scabies (such as socioeconomic status, demographics, and material deprivation) across the region. CONCLUSION: An enormous burden of scabies was reported over a period of six years. The present study found localized clusters of high scabies rates at district and zonal levels in Tigray, Ethiopia, possibly due to differences in various determinants of scabies such as access to WASH services. The findings could help the government and health authorities to develop and implement scabies control strategies in Tigray, with a focus on high-risk districts and zones to ensure optimal resource allocation.

A cross-sectional survey of knowledge and attitudes towards scabies control in Australian aged care facilities.

Scabies outbreaks cause significant morbidity and disruption in aged care facilities and other institutional settings. Failure to manage scabies outbreaks may be attributable to low awareness amongst healthcare workers. A survey was distributed to healthcare workers across aged care facilities in South-East Queensland, Australia. The survey captured demographics, prior scabies experience, knowledge-based questions, and attitudes. Scabies was common in aged care facilities, with 41% of 128 respondents encountering the disease while working in aged care. Participants demonstrated sound theoretical knowledge regarding scabies (median knowledge score 82%). Scabies knowledge was not associated with years of experience in the sector or educational level but was associated with respondent age (p = 0.017). Knowledge gaps were evident regarding diagnosis, incubation periods, and treatment. Respondents demonstrated an inconsistent ability to identify atypical clinical presentations of scabies, showing discordance between theoretical knowledge and its practical application. The ability to identify crusted scabies was low, reflecting the high frequency of misdiagnosis of index cases in scabies outbreaks. Respondents considered scabies to be a problem and were supportive of improved management guidelines. These study outcomes will inform the design of accessible, targeted educational resources for scabies to help prevent and reduce the impact of outbreaks.

Parasitological prevalence of scabies and secondary bacterial infections among scabies suspected patients at Borumeda General Hospital, Northeast Ethiopia.

BACKGROUND: Scabies disproportionately affects people in resource-poor areas. Clinical diagnosis risks misdiagnosis due to resemblance to other skin diseases, but laboratory confirmation improves accuracy. Scabies allow for secondary bacterial infections. Associated bacteria exacerbate scabies and antibiotic resistance. Ethiopian scabies diagnosis relies solely on clinical exams without confirming parasites or investigating secondary bacterial infections. This study aims to identify parasites via scraping, isolate secondary bacteria, and evaluate their antibiotic susceptibility profiles. METHODS: A hospital based cross-sectional study was conducted from September 2022 to July 2023 among scabies suspected patients who visited the dermatology clinic at Borumeda General Hospital in Northeast Ethiopia. A systematic random sampling technique was used to select 422 study participants. Socio-demographic, hygiene, and clinical characteristics data were collected via face-to-face interviews and observation. Skin scrapings for parasitological investigations and swab samples for microbiological investigations were collected and transported for analysis and drug susceptibility testing. Descriptive statistics and logistic regression analysis were employed to assess risk factors. RESULT: Among 422 skin scraping samples, 156 (37.0%) cases of scabies were microscopically confirmed. Bed-sharing and having contact history were independent predictors of microscopically confirmed scabies. The prevalence of secondary bacterial infections among scabies-confirmed patients was 35.9% (56/156). The most prevalent bacterial species were Staphylococcus aureus, coagulase-negative staphylococci, and Streptococcus pyogenes. Tetracycline for Gram-positive bacteria and ampicillin for Gram-negative bacteria showed the highest rate of resistance. In both Gram-positive and Gram-negative strains, multidrug resistance was also observed. CONCLUSION: This study found that over one-third of skin scrapings tested positive for scabies. Additionally, more than one-third of scabies cases were complicated by secondary bacterial infections. Improved scabies diagnosis and consideration of secondary bacterial infections are important for better controlling this neglected tropical disease.

Seasonal distribution and correlation between IL-10 and IL-13 gene polymorphism and their expression in scabies-infected patients.

Scabies is a significant concern in global health. It is more prevalent in individuals who have poor hygiene and live in crowded conditions, hence, it is seasonal distribution and immunological response in Erbil population is the aim of the present study. In the Erbil Dermatology Education Centre in Erbil, Iraq, 154 patients were recruited for the research between April 2022 and March 2023. If a patient has a suspicious skin lesion and itching for a minimum of one week, scabies may be considered. Blood samples were collected from each participant in the study to evaluate serum levels of IL-10 and IL-13, then the DNA was isolated to study the gene polymorphism for the mentioned cytokines. Results showed that female 60.3% were more infected than male 39.6%. The median age of participants was (10 - >51) years, among infested, adolescents aged 10-20 years displayed the highest rate (31.8%). The carriers of GA genotype of IL-10 were protective against the infection, OR:0.61. while the TT carriers of IL-13 were susceptible to scabies infection with OR:2.14. IL-10 GA genotype was more prevalent in male patients OR:2.14 whereas the AA genotype was most protective in females OR:0.32. the IL-13 CT genotype was protective for males with OR:0.52. Both of IL-10 and IL-13 serum levels were increased significantly with infection and highest levels were found in wild homozygous genotypes (GG and CC) and lowest ratio was found in mutant homozygous genotypes of IL-10 and IL-13 respectively. Point mutation in IL-10 GA was protective and wild TT genotype of IL-13 was susceptible to the scabies infection. Double mutation in IL-10 AA was protective to females and single mutation of IL-13 CT was protective to males.

Scabies in infants and children - a narrative review.

Scabies is a human ectoparasitosis caused by Sarcoptes scabei var. hominis. World-wide around 300 million patients are affected. Infants and children have the highest incidence rates. Poverty and overcrowding are social factors contributing to a higher risk of transmission and treatment failure. The leading symptom of the infestation is itch. Complications are bacterial infections that are responsible for mortality. Diagnosis is clinical. Non-invasive imaging technologies like dermoscopy can be used. Polymerase chain reaction (PCR) is less sensitive and specific than microscopy of skin scrapings. Treatment of choice is topical permethrin 5%. Ivermectin is the only oral drug FDA-approved for scabies. It should be used in cases non-responsive to topical therapy and in case of high number of infested patients in addition to topical therapy. Pseudo-resistance to treatment is not uncommon. New drugs are on the horizon. What is Known: • Pruritus is the leading symptom causing sleep disturbances and scratching with the risk of secondary bacterial infections. • Treatment failure is related to inappropriate application of topical drugs and asymptomatic family members. What is New: • COVID-19 pandemic and migration are contributing to an increased incidence of scabies. • New compounds to treat scabies are on the horizon.

The effects of spatially-constrained treatment regions upon a model of wombat mange.

The use of therapeutic agents is a critical option to manage wildlife disease, but their implementation is usually spatially constrained. We seek to expand knowledge around the effectiveness of management of environmentally-transmitted Sarcoptes scabiei on a host population, by studying the effect of a spatially constrained treatment regime on disease dynamics in the bare-nosed wombat Vombatus ursinus. A host population of wombats is modelled using a system of non-linear partial differential equations, a spatially-varying treatment regime is applied to this population and the dynamics are studied over a period of several years. Treatment could result in mite decrease within the treatment region, extending to a lesser degree outside, with significant increases in wombat population. However, the benefits of targeted treatment regions within an environment are shown to be dependent on conditions at the start (endemic vs. disease free), as well as on the locations of these special regions (centre of the wombat population or against a geographical boundary). This research demonstrates the importance of understanding the state of the environment and populations before treatment commences, the effects of re-treatment schedules within the treatment region, and the transient large-scale changes in mite numbers that can be brought about by sudden changes to the environment. It also demonstrates that, with good knowledge of the host-pathogen dynamics and the spatial terrain, it is possible to achieve substantial reduction in mite numbers within the target region, with increases in wombat numbers throughout the environment.

Global prevalence and predictors of scabies among prisoners: systematic review and meta-analysis.

INTRODUCTION: Scabies is a widespread issue in prisons due to overcrowded living conditions and limited healthcare resources. A recent study published in the Journal of Infection and Public Health discovered that the prevalence of scabies varies greatly among prisoners in different regions and facilities. This review aimed to determine the global prevalence and predictors of scabies among prisoners by conducting a systematic review and meta-analysis. METHODS: We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis checklist to report the findings of our systematic review and meta-analysis. Relevant databases including PubMed, Cochrane Library, ScienceDirect, and other grey literature databases were used to search and retrieve articles. The study included both published and unpublished research written in English languages for studies reporting the prevalence of human scabies among prisoners. This review has been registered on PROSPERO. The heterogeneity of the data was evaluated using the I2 statistic. A meta-analysis was conducted using STATA 17 software, with a 95% confidence interval. The researchers also conducted publication bias and sensitivity analysis. RESULTS: The review included 7 studies involving 1, 309,323 prisoners. All included studies involved cross-sectional study design. The prevalence of scabies among prisoners ranges from 0.72% in Italy to 41.01% in Cameroon. The global pooled prevalence of human scabies among prisoners was found to be 6.57% (95% CI; 2.16-19.94). According to subgroup analysis, the overall prevalence of scabies among African prisoners was 19.55% (95% CI; 9.44-40.45), while the prevalence among prisoners outside of Africa was 1.57% (95% CI; 0.77-3.19). The length of time spent in prison, sharing of clothing or beds, and hygiene practices were found to be factors that were significantly associated with the likelihood of prisoners developing human scabies. CONCLUSION: The overall prevalence of human scabies is high among prisoners worldwide. Prisoners who spent more time in prison shared clothing or beds, and had poor hygiene practices were more likely to develop human scabies. Thus, efforts should be made by policymakers and program administrators to decrease the prevalence of scabies in prisons. The protocol for this systematic review and meta-analysis was registered in the International Prospective Register of Systematic Reviews with registration number CRD42024516064.

Effects of weather and air pollution on outpatient visits for insect-and-mite-caused dermatitis: an empirical and predictive analysis.

BACKGROUND: Dermatitis caused by insects and mites, diagnosed as papular urticaria or scabies, is a common skin disease. However, there is still a lack of studies about the effects of weather and air pollution on outpatient visits for this disease. This study aims to explore the impacts of meteorological and environmental factors on daily visits of dermatitis outpatients. METHODS: Analyses are conducted on a total of 43,101 outpatient visiting records during the years 2015-2020 from the largest dermatology specialist hospital in Guangzhou, China. Hierarchical cluster models based on Pearson correlation between risk factors are utilized to select regression variables. Linear regression models are fitted to identify the statistically significant associations between the risk factors and daily visits, taking into account the short-term effects of temperatures. Permutation importance is adopted to evaluate the predictive ability of these factors. RESULTS: Short-term temperatures have positive associations with daily visits and exhibit strong predictive abilities. In terms of total outpatients, the one-day lagged temperature not only has a significant impact on daily visits, but also has the highest median value of permutation importance. This conclusion is robust across most subgroups except for subgroups of summer and scabies, wherein the three-day lagged temperature has a negative effect. By contrast, air pollution has insignificant associations with daily visits and exhibits weak predictive abilities. Moreover, weekdays, holidays and trends have significant impacts on daily visits, but with weak predictive abilities. CONCLUSIONS: Our study suggests that short-term temperatures have positive associations with daily visits and exhibit strong predictive abilities. Nevertheless, air pollution has insignificant associations with daily visits and exhibits weak predictive abilities. The results of this study provide a reference for local authorities to formulate intervention measures and establish an environment-based disease early warning system.

Scabies in French Guiana: Quantitative and qualitative factors associated with therapeutic failure.

BACKGROUND: Strategies for the control of scabies should be adapted to local settings. Traditional communities in French Guiana have non-Western conceptions of disease and health. OBJECTIVES: The objectives for this study were to explore knowledge, attitudes and practices to identify potential factors associated with the failure of scabies treatment in these communities. METHODS: Patients with a clinical diagnosis of scabies, seen at either the Cayenne Hospital or one of 13 health centres between 01 April 2021 and 31 August 2021, were included as participants, and were seen again after 6 weeks to check for persistence of lesions. Factors associated with treatment failure were looked for both at inclusion and at 6 weeks. Semi-structured interviews were conducted with a diversified subsample of participants. RESULTS: In total, 164 participants were included in the quantitative component, and 21 were interviewed for the qualitative component. Declaring that the second treatment dose had been taken was associated with therapeutic success. Western treatments were not always affordable. Better adherence was observed with topical treatments than with oral ivermectin, whereas permethrin monotherapy was associated with failure. Scabies-associated stigma was high among Amerindians and Haitians but absent in Ndjuka Maroons. Participants reported environmental disinfection as being very complex. CONCLUSIONS: The treatment of scabies in traditional Guianan communities may vary depending on local perceptions of galenic formulations, disease-associated stigma and differences in access to health care. These factors should be taken into account when devising strategies for the control of scabies aimed at traditional communities living in remote areas, and migrant populations.

Plantar keratoderma-like crusted scabies in an immunocompetent infant after topical steroids.

A healthy 6-month-old girl presented with plantar keratoderma-like lesions unresponsive to topical corticosteroids. Nocturnal pruritus in 13 relatives, presence of burrows on clinical exam, and the positive scabies preparation led to the diagnosis of crusted scabies. She was successfully treated with topical and oral scabicides. Crusted scabies is a severe form of Sarcoptes scabiei infection uncommon in immunocompetent subjects, in whom previous corticosteroid use may favor its occurrence.

A metapopulation model of social group dynamics and disease applied to Yellowstone wolves.

The population structure of social species has important consequences for both their demography and transmission of their pathogens. We develop a metapopulation model that tracks two key components of a species' social system: average group size and number of groups within a population. While the model is general, we parameterize it to mimic the dynamics of the Yellowstone wolf population and two associated pathogens: sarcoptic mange and canine distemper. In the initial absence of disease, we show that group size is mainly determined by the birth and death rates and the rates at which groups fission to form new groups. The total number of groups is determined by rates of fission and fusion, as well as environmental resources and rates of intergroup aggression. Incorporating pathogens into the models reduces the size of the host population, predominantly by reducing the number of social groups. Average group size responds in more subtle ways: infected groups decrease in size, but uninfected groups may increase when disease reduces the number of groups and thereby reduces intraspecific aggression. Our modeling approach allows for easy calculation of prevalence at multiple scales (within group, across groups, and population level), illustrating that aggregate population-level prevalence can be misleading for group-living species. The model structure is general, can be applied to other social species, and allows for a dynamic assessment of how pathogens can affect social structure and vice versa.

Scabies: Immunopathogenesis and pathological changes.

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