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

Abstract

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.

Prevalence and determinants of scabies: a global systematic review and meta-analysis

“…The sample size of each of the constituent studies ranged from 50 to 9,057,427 participants. Of the 54 eligible studies, nine were conducted in Ethiopia [30][31][32][33][34][35][36][37][38], eight in Fiji [14] [39][40][41][42][43], six in the Solomon Islands [13][ [16][17][ [43][44][45][46], four in Timor-Leste [43] [47][48][49], four in India [11][50-52], three in Ghana [53][54][55], two in Australia [15][56], two in Nigeria [57][58], two in Malaysia [59][60] and one each in Cameroon [61], Egypt [62], Gambia [63], Iran [64], Lao [65], Liberia [66], Malawi [12], New Zealand [67], Samoa [68], Sri Lanka [69], Tanzania [18], Turkey [70], United Kingdom…”

Minimal training of fieldworkers in resource-poor settings for rapid assessment of scabies prevalence: a diagnostic accuracy study in Mopeia, Mozambique

“…In another study, two dermatologists trained five nurses, and screened 135 people for scabies, and found 55% sensitivity and 90% specificity, with again higher levels of sensitivity for moderate and severe cases (14). Finally, a study evaluated the use of a modified, simplified version of the IACS 2020 criteria for mapping and rapidly assessing scabies prevalence (15) in very-high prevalence settings. This modified version had a sensitivity of 82% and specificity of 98% compared to diagnosis using of the full 2020 IACS criteria, with no difference in the pooled prevalence estimates using the two methods.…”

Personal Hygiene as Scabies Factors Incidence in the Institute Rehabilitation Center of the Vagrants, Scrounger and Mental Disabilities in South Sumatra Region

“…The International Alliance for the Control of Scabies (IACS) stated that the prevalence of scabies in Southeast Asia, especially in Timor Leste, was 19.2% (12). According to the Government of Health of the Republic of Indonesia in 2018, the prevalence of scabies ranged from 5.6% to 12.95%, making scabies the most common skin disease in Indonesia (13).…”