Prevalence of scabies and impetigo in school-age children in Timor-Leste

Prevalence and associated risk factors of scabies and impetigo: A cross-sectional study in Tutume district, Botswana

BACKGROUND

The epidemiology of scabies is poorly understood, particularly in regions with high disease burden. This lack of epidemiological data, especially in sub-Saharan Africa, hampers the control and preventative measures. This study is aimed at estimating the prevalence and associated risk factors of scabies and impetigo in the Nata and Sowa catchment areas of Tutume district.

METHODOLOGY

A cross-sectional study was conducted in the Tutume District, targeting the settlements of Manxhotae, Malelejwe, Ndutshaa, and Tshwaane. Participants were randomly selected from households in the settlements. Data were collected using questionnaires, and participants were classified as having scabies typical lesions if they met criteria B and or C of International Alliance for the Control of Scabies (IACS) consensus criteria. Statistical significance was set at p<0.05, with a 95% confidence interval for precision.

RESULTS

A total of 429 participants were enrolled across the four settlements. The overall prevalence of scabies was found to be 18.18% (95%CI 14.8-22.1). The highest prevalence of scabies was in Manxhotae at 27.1% (95%CI 21.2-34.0) and Ndutshaa at 23.4% (95%CI 13.4-37.3). Malelejwe and Tshwaane had lower prevalence of 10.4% (95%CI 6.2-16.8) and 3.4% (95%CI 0.8-12.7), respectively. Only five (5) cases of impetigo were identified. Multivariable logistic regression analysis revealed that younger age of 0-4 years, 5-18 years and a household member with an itch were strongly associated with scabies, with adjusted odds ratios (aOR) of 7.9 (95%CI 2.4-25.6) p-value 0.001, 5.7(95%CI 2.7-11.7), p-value 0.001 and 14.3(95%CI 5.3-38.5) p-value 0.001 respectively.

CONCLUSION

The prevalence of scabies in the Nata catchment area was noted to be high. The risk factors included younger age, a household member with an itch, and less frequent bathing. Prospective studies are needed to explore household disease transmission dynamics and risk factors specific to the youth.

Case report of crusted scabies, brief review of its pathophysiology and latest data

Background

Crusted scabies is a rare form of parasitic infection provoked by a massive infestation of the ectoparasite Sarcoptes scabiei varietas hominis on human skin. It is an extremely contagious type of disease and can even lead to a social stigma. In European countries like Greece, many cases remain undiagnosed for long periods, causing extreme distress in the patient's everyday life and social environment.

Case Description

Herein, we present a case of an 86-year-old woman with crusted scabies in Greece, who remained undiagnosed for 5 months. Massive hyperkeratotic plaques on the extremities, and face, palmoplantar keratoderma, and numerous small erythematous papules on the torso with extreme itch were the main clinical manifestations of the patient. Dermoscopy revealed the parasite. All necessary decontamination measures were taken by personnel. Treatment was administered and a complete cure of the disease was observed.

Conclusions

In this case, the use of dermoscopy has attributed to precise crusted scabies diagnosis and acute pharmacological management of the patient. Early diagnosis of such diseases not only saves patients from lethal secondary infections, but also reduces the risk of a massive scabies outbreak. We also conducted a mini-review, analyzing all recent data concerning crusted scabies macroscopic, dermatoscopic, and histological images. All new information concerning the pathophysiological mechanism of crusted scabies manifestation, updated treatment options, and potential resistance to widely-used treatments are provided.

Prevalence of scabies worldwide-An updated systematic literature review in 2022

Scabies is a World Health Organization-defined neglected tropical disease, with continuously rising incidence worldwide in recent years. The aim of this study was to provide an update of the worldwide prevalence and new treatment approaches of scabies in population-based settings. MEDLINE (PubMed), Embase and LILACS databases were reviewed for English and German language population-based studies from October 2014 to March 2022. Two authors independently screened the records for eligibility, extracted all data and one critically appraised the quality of the studies and risk of bias. Systematic review registration: PROSPERO CRD42021247140. Overall, 1273 records were identified through database searching, of which 43 studies were included for the systematic review. Most of the studies (n = 31) examined the scabies prevalence in medium or low human development index countries. The highest prevalence of scabies reported in the general population (children and adults) was recorded in five randomly selected communities in Ghana (71.0%), whereas the highest scabies prevalence in studies, which only examined children (76.9%), was recorded in an Indonesian boarding school. The lowest prevalence was recorded in Uganda (0.18%). The systematic review highlights the prevalence of scabies worldwide, showing that scabies is still a serious, increasing disease that occurs globally and is clustered in developing countries. More transparent data on scabies prevalence are needed to identify risk factors to find new prevention measures.

The impact of ivermectin, diethylcarbamazine citrate, and albendazole mass drug administration on the prevalence of scabies and soil-transmitted helminths in school-aged children in three municipalities in Timor-Leste: a before-after assessment

BACKGROUND

Integrated programmes that use combination mass drug administration (MDA) might improve control of multiple neglected tropical diseases simultaneously. We investigated the impact of Timor-Leste's national ivermectin, diethylcarbamazine citrate, and albendazole MDA, for lymphatic filariasis elimination and soil-transmitted helminth (STH) control, on scabies, impetigo, and STH infections.

METHODS

We did a before-after study in six primary schools across three municipalities in Timor-Leste (urban [Dili], semi-urban [Ermera], and rural [Manufahi]) before (April 23 to May 11, 2019) and 18 months after (Nov 9 to Nov 27, 2020) MDA delivery between May 17 and June 1, 2019. Study participants included schoolchildren, as well as infants, children, and adolescents who were incidentally present at school on study days. All schoolchildren whose parents provided consent were eligible to participate in the study. Infants, children, and adolescents younger than 19 years who were not enrolled in the school but were incidentally present at schools on study days were also eligible to participate if their parents consented. Ivermectin, diethylcarbamazine citrate, and albendazole MDA was implemented nationally, with single doses of oral ivermectin (200 μg/kg), diethylcarbamazine citrate (6 mg/kg), and albendazole (400 mg) administered by the Ministry of Health. Scabies and impetigo were assessed by clinical skin examinations, and STHs using quantitative PCR. The primary (cluster-level) analysis adjusted for clustering while the secondary (individual-level) analysis adjusted for sex, age, and clustering. The primary outcomes of the study were prevalence ratios for scabies, impetigo, and STHs (Trichuris trichiura, Ascaris lumbricoides, Necator americanus, and moderate-to-heavy A lumbricoides infections) between baseline and 18 months from the cluster-level analysis.

FINDINGS

At baseline, 1043 (87·7%) of 1190 children registered for the study underwent clinical assessment for scabies and impetigo. The mean age of those who completed skin examinations was 9·4 years (SD 2·4) and 514 (53·8%) of 956 were female (87 participants with missing sex data were excluded from this percentage calculation). Stool samples were received for 541 (45·5%) of 1190 children. The mean age of those for whom stool samples were received was 9·8 years (SD 2·2) and 300 (55·5%) were female. At baseline, 348 (33·4%) of 1043 participants had scabies, and 18 months after MDA, 133 (11·1%) of 1196 participants had scabies (prevalence ratio 0·38, 95% CI 0·18-0·88; p=0·020) in the cluster-level analysis. At baseline, 130 (12·5%) of 1043 participants had impetigo, compared with 27 (2·3%) of 1196 participants at follow-up (prevalence ratio 0·14, 95% CI 0·07-0·27; p<0·0001). There was a significant reduction in T trichiura prevalence from baseline (26 [4·8%] of 541 participants) to 18-month follow-up (four [0·6%] of 623 participants; prevalence ratio 0·16, 95% CI 0·04-0·66; p<0·0001). In the individual-level analysis, moderate-to-heavy A lumbricoides infections reduced from 54 (10·0%; 95% CI 0·7-19·6) of 541 participants to 28 (4·5%, 1·2-8·4) of 623 participants (relative reduction 53·6%; 95% CI 9·1-98·1; p=0·018).

INTERPRETATION

Ivermectin, diethylcarbamazine citrate, and albendazole MDA was associated with substantial reductions in prevalence of scabies, impetigo, and T trichiura, and of moderate-to-heavy intensity A lumbricoides infections. Combination MDA could be used to support integrated control programmes to target multiple NTDs.

FUNDING

National Health and Medical Research Council of Australia and the Department of Foreign Affairs and Trade Indo-Pacific Centre for Health Security.

TRANSLATION

For the Tetum translation of the abstract see Supplementary Materials section.

Gastrointestinal Carriage of Antimicrobial Resistance in School-Aged Children in Three Municipalities of Timor-Leste

Invasive bacterial infections are a leading cause of death in children, primarily in low- and middle-income countries (LMIC). Links between carriage of antimicrobial-resistant organisms and more resistant infections have been established; however, little has been reported regarding community carriage of antibiotic-resistant organisms such as extended-spectrum β-lactamase (ESBL)-producing Enterobacterales in LMIC. The aim of this study was to determine colonic carriage of ESBL-producing fluoroquinolone- and aminoglycoside-resistant Enterobacterales in healthy children in three municipalities of Timor-Leste. In November 2020, 621 stool samples were collected from school-aged children and underwent screening for the presence of Enterobacterales species and antimicrobial resistance (AMR). Ciprofloxacin-resistant Gram-negative organisms were cultured from 16.5% (95% CI 6.2−26.9), and gentamicin resistance was identified in 6.8% (95% CI 2.8−10.7). Compared to the prevalence of ciprofloxacin resistance in Dili (36.1%), there was significantly lower prevalence in the rural municipalities of Ermera (12.9%; AOR 0.38, 95% CI 0.24−0.60, p < 0.001) and Manufahi (4.5%; AOR 0.07, 95% CI 0.01−0.51, p = 0.009). The overall cluster-adjusted prevalence of ESBL-producing bacteria was 8.3%, with no significant differences between municipalities. This study demonstrates high rates of carriage of AMR among school-aged children in Timor-Leste, with higher rates observed in Dili compared to rural municipalities. Empiric antibiotic guidelines should include recommendations for treating community-acquired infections that account for the possibility of antimicrobial resistance.

The efficacy of sampling strategies for estimating scabies prevalence

Background

Estimating community level scabies prevalence is crucial for targeting interventions to areas of greatest need. The World Health Organisation recommends sampling at the unit of households or schools, but there is presently no standardised approach to scabies prevalence assessment. Consequently, a wide range of sampling sizes and methods have been used. As both prevalence and drivers of transmission vary across populations, there is a need to understand how sampling strategies for estimating scabies prevalence interact with local epidemiology to affect the accuracy of prevalence estimates.

Methods

We used a simulation-based approach to compare the efficacy of different scabies sampling strategies. First, we generated synthetic populations broadly representative of remote Australian Indigenous communities and assigned a scabies status to individuals to achieve a specified prevalence using different assumptions about scabies epidemiology. Second, we calculated an observed prevalence for different sampling methods and sizes.

Results

The distribution of prevalence in subpopulation groups can vary substantially when the underlying scabies assignment method changes. Across all of the scabies assignment methods combined, the simple random sampling method produces the narrowest 95% confidence interval for all sample sizes. The household sampling method introduces higher variance compared to simple random sampling when the assignment of scabies includes a household-specific component. The school sampling method overestimates community prevalence when the assignment of scabies includes an age-specific component.

Discussion

Our results indicate that there are interactions between transmission assumptions and surveillance strategies, emphasizing the need for understanding scabies transmission dynamics. We suggest using the simple random sampling method for estimating scabies prevalence. Our approach can be adapted to various populations and diseases.

Scabies is a parasitic infestation that is commonly observed in disadvantaged populations. A wide range of sampling sizes and methods have been used to estimate scabies prevalence. With differing key drivers of transmission and varying prevalence across populations, it can be challenging to determine an effective sampling strategy. In this study, we propose a simulation approach to compare the efficacy of different sampling methods and sizes. First, we generate synthetic populations and then assign a scabies status to individuals to achieve a specified prevalence using different assumptions about scabies epidemiology. Second, we calculate an observed prevalence for different sampling methods and sizes. Our results indicate that there are interactions between transmission assumptions and surveillance strategies. We suggest using the simple random sampling method for estimating prevalence as it produces the narrowest 95% confidence interval for all sampling sizes. We propose guidelines for determining a sample size to achieve a desired level of precision in 95 out 100 samples, given estimates of the population size and a priori estimates of true prevalence. Our approach can be adapted to various populations, informing an appropriate sampling strategy for estimating scabies prevalence with confidence.

Estimation of scabies prevalence using simplified criteria and mapping procedures in three Pacific and southeast Asian countries

Background

Scabies causes considerable morbidity in disadvantaged populations. The International Alliance for the Control of Scabies (IACS) published consensus criteria in 2020 to standardize scabies diagnosis. However, these criteria are complex, and a WHO informal consultation proposed simplified criteria for mapping, to identify regions of high prevalence as targets for mass drug administration. We aimed to investigate the accuracy of simplified criteria in determining scabies prevalence, compared to the 2020 IACS criteria.

Methods

We obtained data relating to demographics, relevant history and skin lesions from all-age prevalence surveys from Fiji (n = 3365) and Solomon Islands (n = 5239), as well as school-aged children in Timor-Leste (n = 1043). We calculated prevalence using the 2020 IACS criteria and simplified criteria and compared these disease estimates.

Results

There was no significant difference in the pooled prevalence using the two methods (2020 IACS criteria: 16.6%; simplified criteria: 15.6%; difference = 0.9, [95% CI -0.1, 2.0]). In Timor-Leste, the prevalence using simplified criteria was lower (26.5% vs 33.8%). Simplified criteria had a sensitivity of 82.3% (95% CI 80.2, 84.2) and specificity of 97.6% (95% CI 97.2, 97.9) compared to the 2020 IACS criteria.

Conclusions

The scabies prevalence estimation using simplified criteria was similar to using the 2020 IACS criteria in high prevalence, tropical countries. The prevalence estimation was lower in the school-based survey in Timor-Leste. Mapping using simplified criteria may be a feasible and effective public health tool to identify priority regions for scabies control. Further work assessing use of simplified criteria for mapping in a field setting should be conducted.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-12039-2.

Community control strategies for scabies: A cluster randomised noninferiority trial

BACKGROUND

Scabies is a neglected tropical disease hyperendemic to many low- and middle-income countries. Scabies can be successfully controlled using mass drug administration (MDA) using 2 doses of ivermectin-based treatment. If effective, a strategy of 1-dose ivermectin-based MDA would have substantial advantages for implementing MDA for scabies at large scale.

METHODS AND FINDINGS

We did a cluster randomised, noninferiority, open-label, 3-group unblinded study comparing the effectiveness of control strategies on community prevalence of scabies at 12 months. All residents from 35 villages on 2 Fijian islands were eligible to participate. Villages were randomised 1:1:1 to 2-dose ivermectin-based MDA (IVM-2), 1-dose ivermectin-based MDA (IVM-1), or screen and treat with topical permethrin 5% for individuals with scabies and their household contacts (SAT). All groups also received diethylcarbamazine and albendazole for lymphatic filariasis control. For IVM-2 and IVM-1, oral ivermectin was dosed at 200 μg/kg and when contraindicated substituted with permethrin. We designated a noninferiority margin of 5%. We enrolled 3,812 participants at baseline (July to November 2017) from the 35 villages with median village size of 108 (range 18 to 298). Age and sex of participants were representative of the population with 51.6% male and median age of 25 years (interquartile range 10 to 47). We enrolled 3,898 at 12 months (July to November 2018). At baseline, scabies prevalence was similar in all groups: IVM-2: 11.7% (95% confidence interval (CI) 8.5 to 16.0); IVM-1: 15.2% (95% CI 9.4 to 23.8); SAT: 13.6% (95% CI 7.9 to 22.4). At 12 months, scabies decreased substantially in all groups: IVM-2: 1.3% (95% CI 0.6 to 2.5); IVM-1: 2.7% (95% CI 1.1 to 6.5); SAT: 1.1% (95% CI 0.6 to 2.0). The risk difference in scabies prevalence at 12 months between the IVM-1 and IVM-2 groups was 1.2% (95% CI -0.2 to 2.7, p = 0.10). Limitations of the study included the method of scabies diagnosis by nonexperts, a lower baseline prevalence than anticipated, and the addition of diethylcarbamazine and albendazole to scabies treatment.

CONCLUSIONS

All 3 strategies substantially reduced prevalence. One-dose was noninferior to 2-dose ivermectin-based MDA, as was a screen and treat approach, for community control of scabies. Further trials comparing these approaches in varied settings are warranted to inform global scabies control strategies.

TRIAL REGISTRATION

Clinitrials.gov NCT03177993 and ANZCTR N12617000738325.