A community-based validation of the International Alliance for the Control of Scabies Consensus Criteria by expert and non-expert examiners in Liberia

Walker, Stephen L.; Collinson, Shelui; Timothy, Joseph; Zayzay, Samuel; Kollie, Karsor; Candy, Neima; Lebas, Eve; Halliday, Katherine E.; Pullan, Rachel L.; Fallah, Mosoka; Marks, Michael

doi:10.1371/journal.pntd.0008717

Cited by 23 publications

(32 citation statements)

References 14 publications

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“…Over half of all scabies cases diagnosed during the survey (52%) were categorised as extensive, with individuals each having 50 or more lesions. As previously reported, the sensitivity of MLHWs in diagnosing scabies is greater in more extensive disease [ 18 , 32 ] and it is possible that some cases of less extensive disease were not captured, however the number of cases of extensive disease indicates a substantial unmet need in scabies management. Our study further indicates that scabies has a large effect on quality of life.…”

Section: Discussionmentioning

confidence: 95%

“…Our study further indicates that scabies has a large effect on quality of life. From our validation study, extent of disease, as measured by lesion counts, correlated with the degree of itchiness experienced by the patient [ 18 ]. Pruritic skin diseases are known to have a negative impact on quality of life and our data suggests that pruritus associated with scabies is one of the major drivers of the impact of infestation on HRQoL scores.…”

Section: Discussionmentioning

confidence: 99%

“…The survey team consisted of three Liberian mid-level health workers (MLHWs) who had been trained to perform skin examinations and diagnose scabies and impetigo and a local guide to accompany them in each community. We have reported on the training methodology and accuracy of the MLHWs compared to a reference standard examination [ 18 ].…”

Section: Methodsmentioning

confidence: 99%

“…Scabies was diagnosed if examiners identified burrows (category B1) or found an individual with typical scabies lesions in a typical distribution and one (category C1) or two (category B3) history features [ 11 ]. On the basis of our findings from a validation study, conducted in Monrovia, of the IACS criteria and those of a previous study we limited examination to the face, upper limb and axilla and exposed areas of the lower limb for individuals aged five and over, as this has been shown to have a sensitivity of more than 90% compared to a full-body examination for detecting the presence of scabies lesions [ 18 , 19 ], however if an individual reported a lesion elsewhere that they wished to have examined, this was also assessed. A wider distribution of lesions is typically found in infants and therefore children aged less than five years old had a full skin examination performed [ 11 ].…”

Section: Methodsmentioning

confidence: 99%

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The prevalence of scabies in Monrovia, Liberia: A population-based survey

et al. 2020

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Scabies is known to be a public health problem in many settings but the majority of recent data is from rural settings in the Pacific. There is a need for high quality data from sub-Saharan Africa and peri-urban settings to inform scale up of scabies control efforts. There have been anecdotal reports of scabies being a public health problem in Liberia but robust data are lacking. We conducted a cross-sectional cluster-randomised prevalence survey for scabies in a peri-urban community in Monrovia, Liberia in February-March 2020. Participants underwent a standardised examination conducted by trained local health care workers. Health related quality of life (HRQoL) was assessed using age-appropriate versions of the dermatology life quality index (DLQI). Prevalence estimates were calculated accounting for clustering at community and household levels and associations with key demographic variables assessed through multivariable random-effects logistic regression. 1,318 participants from 477 households were surveyed. The prevalence of scabies was 9.3% (95% CI: 6.5–13.2%), across 75 (19.7%) households; impetigo or infected scabies prevalence was 0.8% (95% CI: 0.4–1.9%). The majority (52%) of scabies cases were classified as severe. Scabies prevalence was lower in females and higher in the youngest age group; no associations were found with other collected demographic or socio-economic variables. DLQI scores indicated a very or extremely large effect on HRQoL in 29% of adults and 18% of children diagnosed with scabies. Our study indicates a substantial burden of scabies in this peri-urban population in Liberia. This was associated with significant impact on quality of life, highlighting the need for action to control scabies in this population. Further work is needed to assess the impact of interventions in this context on both the prevalence of scabies and quality of life.

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Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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The prevalence of scabies in Monrovia, Liberia: A population-based survey

et al. 2020

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“…Elsewhere, non-expert examiners who underwent brief training similar to our study diagnosed less scabies but with high speci city compared to consensus expert opinion. 15,23 The approach is a valid tool for scabies diagnosis in population-level research.…”

Section: Discussionmentioning

confidence: 99%

Prevalence of Scabies and Impetigo in School-Age Children in Timor-Leste

Matthews

Le²,

Amaral

et al. 2020

Preprint

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Background Scabies and impetigo are endemic in many tropical, low- and middle-income countries. With control strategies emerging based on mass drug administration (MDA) with ivermectin, there is a need for comprehensive data on the occurrence and risk factors of these conditions to guide interventions and enable their impact to be assessed. In 2019, Timor-Leste Ministry of Health planned to implement MDA including ivermectin for the control of lymphatic filariasis, so we undertook a baseline assessment of scabies and impetigo. Methods A cross-sectional school survey was conducted in April-May 2019 at six primary schools in a semi-urban (Dili) and two rural (Ermera and Manufahi) settings. Children under 19 years of age present at school on survey days were eligible to participate, of whom we enrolled 1183. Trained health workers interviewed and examined 1043 participants to clinically diagnose scabies using the 2020 International Alliance for the Control of Scabies (IACS) diagnostic criteria, as well as impetigo. Prevalence was adjusted for age and sex. Mixed-effects logistic regression models were used to analyse odds of scabies and impetigo infection accounting for clustering at school level. Population attributable risk of scabies as a cause of impetigo was also estimated. Results The overall weighted prevalence of scabies was 30.6%. Children in rural Manufahi were more likely to have scabies than those in semi-urban Dili (53.6% vs 28.2%, adjusted odds ratio (AOR) 3.5). Most cases of scabies were mild (3 to 10 lesions), and distributed on more than one body region. Scabies prevalence was lower among 10 to 14 year olds compared to 5 to 9 year olds. Overall weighted prevalence of impetigo was 11.3%. Relative to Dili, children in rural Ermera and Manufahi were twice as likely to have impetigo. Impetigo was twice as common in children with scabies than in those without, corresponding to an attributable risk of scabies as a cause of impetigo of 22.7%. Conclusions Scabies and impetigo prevalence in Timor-Leste are among the highest reported globally, particularly in rural areas. Scabies infestation was strongly associated with impetigo. Comprehensive control strategies are urgently needed in Timor-Leste.

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The body distribution of scabies skin lesions

Osti

Sokana²,

Lake

et al. 2022

JEADV Clinical Practice

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Background: The clinical diagnosis of scabies relies on the assessment of signs and symptoms and an improved understanding of the distribution of skin lesions may lead to improved diagnostic performance.Objectives: To investigate the detailed body distribution of scabies lesions and to explore the accuracy of simplified, focused examination approaches.Methods: We did a prospective, cross-sectional study in the Western Province of Solomon Islands (2019). Consenting individuals of all ages were eligible. The entire skin surface was examined, and the presence and number of typical scabies lesions were recorded at 98 topographic body sites, corresponding to 5 regions and 16 subregions. We compared the distribution at sites, regions and subregions overall, and by age and sex. We also calculated the expected sensitivity of examination of limited body areas. Choropleth maps were generated to provide detailed descriptions of the distribution of lesions.Results: A total of 467 individuals were enrolled (median age: 9 years [range: 0-86]; female: 54.6%) of whom 269 (57.6%) participants had typical scabies lesions.The most common sites for scabies lesions were the dorsal fingers (65.7% of participants with scabies lesions), dorsal finger web spaces (62.1%) and dorsal hands (61.7%). Of those less than 2 years old with scabies, eight (30.8%) had lesions at the head and neck region compared to 10.8% of those aged 2-5. Genital lesions were more common in males than females (27.3% vs. 7%, relative risk 3.9, 95% confidence interval: 1.2-2.1). Simplified, focused examinations were estimated have very high sensitivity (hands and wrists only: 93.3%; exposed arms and legs: 99.3%) compared to whole-body examinations. Conclusion:We report highly detailed descriptions of the body distribution of scabies lesions, including differences by age and sex. These data are valuable for training and diagnosis and support the use of simplified, focused examinations for scabies mapping.

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A community-based validation of the International Alliance for the Control of Scabies Consensus Criteria by expert and non-expert examiners in Liberia

Cited by 23 publications

References 14 publications

The prevalence of scabies in Monrovia, Liberia: A population-based survey

The prevalence of scabies in Monrovia, Liberia: A population-based survey

Prevalence of Scabies and Impetigo in School-Age Children in Timor-Leste

The body distribution of scabies skin lesions

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