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

Abstract

Background Scabies and impetigo are endemic in many tropical, low- and middle-income countries. Mass drug administration (MDA) with ivermectin has emerged as a control strategy for these conditions. 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 to better understand local epidemiology and contribute to future surveys assessing the impact of MDA. 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. All models accounted for clustering at the school level through the use of random effect terms. 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 lesions were usually 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 is 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.

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

“…The prevalence of ‘Suspected Scabies subcategory C2’ in Timor-Leste was 8.9% (26.5% of cases), 2.7% in Solomon Islands (18.2% of cases) and 1.5% in Fiji (10.9% of cases, Table 5 ). Itch was present in 1470 cases (93.2% of cases), and contact history in 1266 (80.3% of cases, Table 5 ) [ 23 ].…”

“…In this study of diagnostic accuracy [ 22 ], we utilised data collected during three prevalence surveys for scabies from Fiji, Solomon Islands and Timor-Leste [ 23 – 25 ]. De-identified data were collated from the three countries into a single dataset, including details on age, sex, country and findings of skin examination and history.…”

“…The three surveys were designed and conducted using identical methods for data collection and diagnosis. Survey procedures and sample size calculations are reported in detail elsewhere [ 23 – 26 ]. In brief, the studies in Solomon Islands and Fiji were community prevalence surveys involving participants of all ages.…”

“…In Fiji, 3365 participants from 16 communities in the Northern Division were recruited in May 2019 [ 24 ]. In Timor-Leste, a school-based survey was conducted between April and May 2019, and enrolled a total of 1043 school children and their siblings aged less than 19 years of age from schools across three different municipalities [ 23 ].…”

“…In brief, local healthcare workers completed a one-week training program incorporating interactive tutorials on the features of scabies, based on the clinical categories of the 2020 IACS criteria which are the recommended standards for prevalence surveys [ 12 ]. This was followed by a written assessment of clinical photographs, requiring a minimum pass rate of 80%, and supervised practical sessions [ 23 ]. Demographic data relating to sex, age, locality and ethnicity were recorded.…”